Exhibit 10.1

[***] Certain information in this document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.

SHARE PURCHASE AGREEMENT

This Share Purchase Agreement (this “ Agreement ”) is dated as of June 29, 2015, by and among Juno Therapeutics, Inc., a Delaware corporation (the “ Company ”), Celgene Corporation (“ Celgene Corp. ”) and Celgene RIVOT Ltd (“ Celgene RIVOT ” and together with Celgene Corp., the “ Celgene Parties ”).

RECITALS

A. The Company and the Celgene Parties are executing and delivering this Agreement in reliance upon the exemption from securities registration afforded by Section 4(2) of the Securities Act of 1933, as amended (the “ Securities Act ”), and Rule 506 of Regulation D (“ Regulation D ”) as promulgated by the United States Securities and Exchange Commission (the “ Commission ”) under the Securities Act.

B. Celgene RIVOT wishes to purchase, and the Company wishes to sell, upon the terms and conditions stated in this Agreement, 9,137,672 shares of common stock, par value $0.0001 per share (the “ Common Stock ”), of the Company (the “ Closing Shares ”).

C. The Company wishes to grant (i) the Celgene Parties the right to purchase the First Acquisition Right Shares (as defined herein) pursuant to a First Acquisition Right (as defined herein) and (ii) Celgene Corp. the right to purchase the Second Acquisition Right Shares (as defined herein) pursuant to a Second Acquisition Right (as defined herein). The Closing Shares and the Acquisition Right Shares (as defined herein), together with the Top-Up Shares (as defined herein) are sometimes referred to herein as the “ Shares .”

D. Contemporaneously with the execution and delivery of this Agreement, the parties hereto are executing and delivering a Voting and Standstill Agreement, substantially in the form attached hereto as Exhibit A (the “ Voting and Standstill Agreement ”), pursuant to which, among other things, the Company will agree to grant Celgene Corp. a right to nominate a Company director, and the Celgene Parties will agree to vote their shares in favor of certain corporate actions and to observe certain limitations on their acquisitions and dispositions of shares.

E. Contemporaneously with the execution and delivery of this Agreement, the parties hereto are executing and delivering a Registration Rights Agreement, substantially in the form attached hereto as Exhibit B (the “ Registration Rights Agreement ”), pursuant to which, among other things, the Company will agree to provide certain registration rights with respect to the Shares under the Securities Act and the rules and regulations promulgated thereunder and applicable state securities laws.

NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the Company and the Celgene Parties hereby agree as follows:

ARTICLE I.

DEFINITIONS

1.1 Definitions . In addition to the terms defined elsewhere in this Agreement, for all purposes of this Agreement, the following terms shall have the meanings indicated in this Section 1.1 :

“ Acquiring Person ” has the meaning set forth in Section 4.3 .

“ Acquisition Right Shares ” means the First Acquisition Right Shares and the Second Acquisition Right Shares.

“ Action ” means any action, suit, inquiry, notice of violation, proceeding (including any partial proceeding such as a deposition) or investigation pending or, to the Company’s Knowledge, threatened in writing against the Company or any of its properties or any officer, director or employee of the Company acting in his or her capacity as an officer, director or employee before or by any federal, state, county, local or foreign court, arbitrator, governmental or administrative agency, regulatory authority, stock market, stock exchange or trading facility.

“ Additional Co-Promote Option ” has the meaning set forth in Section 2.4(e) .

“ Affiliate ” means, with respect to any Person, any other Person that, directly or indirectly through one or more intermediaries, Controls, is controlled by or is under common control with such Person, as such terms are used in and construed under Rule 405 under the Securities Act.

“ Agreement ” has the meaning set forth in the Preamble.

“ Antitrust Authorities ” means the Antitrust Division of the United States Department of Justice, the United States Federal Trade Commission or the antitrust or competition law authorities of any other jurisdiction (whether United States, foreign or multinational).

“ Antitrust Information or Document Request ” means any request or demand for the production, delivery or disclosure of documents or other evidence, or any request or demand for the production of witnesses for interviews or depositions or other oral or written testimony, by any Antitrust Authorities relating to the transactions contemplated hereby or by any third party challenging the transactions contemplated hereby, including any so called “second request” for additional information or documentary material or any civil investigative demand made or issued by the Antitrust Division of the United States Department of Justice or the United States Federal Trade Commission or any subpoena, interrogatory or deposition.

“ Applicable FTU Percentage ” means 10%, as adjusted from time to time pursuant to Section 2.3(a) .

“ Applicable STU Percentage ” means the FAR Acquisition Percentage, as adjusted from time to time pursuant to Section 2.3(b) .

“ Applicable TTU Percentage ” means the SAR Acquisition Percentage less 250 basis points, as adjusted from time to time pursuant to Section 2.3(c) .

“ BD Acquiring Party ” shall have the meaning given in the Collaboration Agreement.

“ BD Option Exercise Notice ” shall have the meaning given in the Collaboration Agreement.

“ Board of Directors ” means the board of directors of the Company.

“ Business Day ” means any day except Saturday, Sunday, any day which is a federal legal holiday in the United States or any day on which banking institutions in the State of New York are authorized or required by law or other governmental action to close.

“ Cancer Target” shall have the meaning given in the Collaboration Agreement.

“ CAR/TCR Deferred Program ” shall have the meaning given in the Collaboration Agreement.

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“ CD19 Program ” shall have the meaning given in the Collaboration Agreement.

“ CD22 Program ” shall have the meaning given in the Collaboration Agreement.

“ Celgene Corp. ” has the meaning set forth in the Preamble.

“ Celgene Lead Co-Co Agreement ” shall have the meaning given in the Collaboration Agreement.

“ Celgene RIVOT ” has the meaning set forth in the Preamble.

“ Celgene Co-Promote Right ” shall have the meaning given in the Collaboration Agreement.

“ Celgene Cure Period ” has the meaning set forth in Section 6.1(c)(i) .

“ Celgene Deliverables ” has the meaning set forth in Section 2.2(b) .

“ Celgene Group ” shall mean (i) the Celgene Parties, (ii) any Person that directly or indirectly beneficially owns a majority of the voting securities of or voting interests in a Celgene Party, and (iii) any direct or indirect majority owned subsidiaries of a Celgene Party or of such a Person.

“ Celgene Option ” shall have the meaning given in the Collaboration Agreement.

“ Celgene Parties ” has the meaning set forth in the Recitals.

“ Celgene Program ” shall have the meaning given in the Collaboration Agreement.

“ Change of Control ” shall mean, with respect to Celgene Corp., any of the following events: (i) any Person is or becomes the beneficial owner (except that a Person shall be deemed to have beneficial ownership of all shares that any such Person has the right to acquire, whether such right which may be exercised immediately or only after the passage of time), directly or indirectly, of a majority of the total voting power of Celgene Corp; (ii) Celgene Corp. consolidates with or merges into another corporation or entity, or any corporation or entity consolidates with or merges into a Celgene Party, other than (A) a merger or consolidation which would result in the voting securities of Celgene Corp. outstanding immediately prior to such merger or consolidation continuing to represent (either by remaining outstanding or by being converted into voting securities of the surviving entity or any parent thereof) a majority of the combined voting power of the voting securities of Celgene Corp. or such surviving entity or any parent thereof outstanding immediately after such merger or consolidation, or (B) a merger or consolidation effected to implement a recapitalization of Celgene Corp. (or similar transaction) in which no Person becomes the beneficial owner, directly or indirectly, of a majority of the total voting power of Celgene Corp. or (iii) a Celgene Corp. conveys, transfers or leases all or substantially all of its assets to any Person other than a wholly owned Affiliate of Celgene Corp.

“ Closing ” means the closing of the purchase and sale of the Closing Shares pursuant to this Agreement.

“ Closing Date ” has the meaning set forth in Section 2.1(b) .

“ Closing Shares ” has the meaning set forth in the Recitals.

“ Collaboration Agreement ” means the Master Research and Collaboration Agreement by and among the Company and the Celgene Parties of even date herewith.

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“ Commission ” has the meaning set forth in the Recitals.

“ Common Stock ” has the meaning set forth in the Recitals, and also includes any other class of securities into which the Common Stock may hereafter be reclassified or changed into.

“ Common Stock Equivalents ” means any securities of the Company which would entitle the holder thereof to acquire at any time Common Stock, including, without limitation, any debt, preferred stock, rights, options, warrants or other instrument that is at any time convertible into or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock or other securities that entitle the holder to receive, directly or indirectly, Common Stock.

“ Company ” has the meaning set forth in the Preamble.

“ Company Counsel ” means Latham & Watkins LLP.

“ Company Cure Period ” has the meaning set forth in Section 6.1(b)(i) .

“ Company Deliverables ” has the meaning set forth in Section 2.2(a) .

“ Company FTU Notice ” has the meaning set forth in Section 2.3(a) .

“ Company’s Knowledge ” means the knowledge of the executive officers of the Company.

“ Company STU Notice ” has the meaning set forth in Section 2.3(b) .

“ Company TTU Notice ” has the meaning set forth in Section 2.3(c) .

“ Control ” (including the terms “controlling,” “controlled by” or “under common control with”) means the possession, direct or indirect, of the power to direct or cause the direction of the management and policies of a Person, whether through the ownership of voting securities, by contract or otherwise.

“ Development & Commercialization Agreement ” shall have the meaning given in the Collaboration Agreement.

“ Disclosure Materials ” has the meaning set forth in Section 3.1(g) .

“ Disclosure Schedules ” has the meaning set forth in Section 3.1 .

“ DTC ” has the meaning set forth in Section 4.1(c) .

“ Effective Date ” means the date on which the initial Registration Statement required by Section 2(a) of the Registration Rights Agreement is first declared effective by the Commission.

“ Eligible BD Program ” shall have the meaning set forth in the Collaboration Agreement.

“ Evaluation Date ” has the meaning set forth in Section 3.1(k) .

“ Exchange Act ” means the Securities Exchange Act of 1934, as amended, or any successor statute, and the rules and regulations promulgated thereunder.

“ Existing Rights Agreement ” has the meaning set forth in Section 3.1(o) .

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“ FAR Acquisition Percentage ” has the meaning set forth in Section 2.4(a) , as adjusted as set forth in Sections 2.4(a) and (e) .

“ FAR Catch-up Number ” means the additional number of shares that the Celgene Group would have needed to purchase on the date of delivery of the FAR Notice, such that, following such hypothetical purchase, the Celgene Group would have owned the Applicable FTU Percentage of the shares of Common Stock outstanding after giving effect to such hypothetical purchase.

“ FAR Notice ” has the meaning set forth in Section 2.4(a) .

“ FAR Termination Date ” means the fifth anniversary of the date of this Agreement.

“ First Acquisition Right ” has the meaning set forth in Section 2.4(a) .

“ First Acquisition Right Base Price ” has the meaning set forth in Section 2.4(b) .

“ First Acquisition Right Conditions ” means that prior to the FAR Termination Date a Celgene Party has exercised the Celgene Option with respect to at least [***] Juno Programs (which may include [***]) that remain in effect without having been terminated pursuant to Article 11 of the Collaboration Agreement or Section 10 of any Development & Commercialization Agreement, provided that each such Juno Program [***].

“ First Acquisition Right Shares ” has the meaning set forth in Section 2.4(a) .

“ First Top-Up Period ” has the meaning set forth in Section 2.3(a) .

“ First Top-Up Right ” has the meaning set forth in Section 2.3(a) .

“ First Top-Up Shares ” has the meaning set forth in Section 2.3(a) .

“ FTU Notice ” has the meaning set forth in Section 2.3(a) .

“ GAAP ” means U.S. generally accepted accounting principles, consistently applied.

“ Governmental Authority ” has the meaning set forth in Section 3.1(d) .

“ Governmental Order ” means any order, judgment, injunction, decree, writ, stipulation, determination or award, in each case, entered by or with any Governmental Authority.

“ HSR Act ” has the meaning set forth in Section 3.1(d) .

“ Immune Cell Target ” shall have the meaning given in the Collaboration Agreement.

“ Immune Modulatory Agent” or “IMA” shall have the meaning given in the Collaboration Agreement.

“ Intellectual Property ” means patents, patent applications, trademarks, trademark applications, service marks, tradenames, copyrights, trade secrets, licenses, domain names, mask works, or any other proprietary right or process.

“ Juno Lead Co-Co Agreement ” shall have the meaning given in the Collaboration Agreement.

[***] Certain information in this document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.

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“ Juno Option ” shall have the meaning given in the Collaboration Agreement.

“ Juno Program ” shall have the meaning given in the Collaboration Agreement.

“ Lien ” means any lien, charge, claim, encumbrance, security interest, right of first refusal, preemptive right or other restrictions of any kind.

“ Material Adverse Effect ” means a material adverse effect on the results of operations, assets, business or financial condition of the Company.

“ Material Contract ” means any contract of the Company that has been filed as an exhibit to the SEC Reports pursuant to Item 601(b)(4) or Item 601(b)(10) of Regulation S-K.

“ Minimum Percentage ” has the meaning set forth in Section 2.3(b) .

“ Minimum FAR Purchase Condition ” means that a Celgene Party has delivered a FAR Notice specifying a FAR Acquisition Percentage in excess of 17% and the closing of the sale of the First Acquisition Right Shares has occurred (except to the extent such closing does not occur as a result of a breach hereof by the Company or a failure to obtain the approval contemplated by Section 5.2(g) ).

“ Multi-Target IMA ” shall have the meaning given in the Collaboration Agreement.

“ New York Courts ” means the state and federal courts sitting in New York, New York.

“ Offering Party ” shall have the meaning given in the Collaboration Agreement.

“ OFAC ” has the meaning set forth in Section 3.1(v) .

“ Option Exercise Notice ” shall have the meaning given in the Collaboration Agreement.

“ Other Juno Program ” shall have the meaning given in the Collaboration Agreement.

“ Payee Party ” has the meaning set forth in Section 4.8(a) .

“ Paying Party ” has the meaning set forth in Section 4.8(a) .

“ Permitted Transferee ” has the meaning set forth in the Voting and Standstill Agreement.

“ Person ” means an individual, corporation, partnership, limited liability company, trust, business trust, association, joint stock company, joint venture, sole proprietorship, unincorporated organization, governmental authority or any other form of entity not specifically listed herein.

“ Principal Trading Market ” means the Trading Market on which the Common Stock is primarily listed on and quoted for trading, which, as of the date of this Agreement and the Closing Date, shall be the NASDAQ Global Select Market.

“ Proceeding ” means an action, claim, suit, investigation or proceeding (including, without limitation, an investigation or partial proceeding, such as a deposition), whether commenced or threatened.

“ Purchase Notice ” has the meaning set forth in Section 4.6(a) .

“ Qualified Notice ” shall have the meaning set forth in the Collaboration Agreement.

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“Registration Rights Agreement ” has the meaning set forth in the Recitals.

“ Registration Statement ” means a registration statement meeting the requirements set forth in the Registration Rights Agreement and covering the resale by the Celgene Parties of the Registrable Securities (as defined in the Registration Rights Agreement).

“ Regulation D ” has the meaning set forth in the Recitals.

“ Required Approvals ” has the meaning set forth in Section 3.1(d) .

“ Rule 144 ” means Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.

“ SAR Acquisition Percentage ” has the meaning set forth in Section 2.4(c) , as adjusted as set forth in Section 2.4(c).

“ SAR Catch-up Number ” means the additional number of shares that the Celgene Group would have needed to purchase on the date of delivery of the SAR Notice, such that, following such hypothetical purchase, the Celgene Group would have owned the Applicable STU Percentage of the shares of Common Stock outstanding after giving effect to such hypothetical purchase.

“ SAR Notice ” has the meaning set forth in Section 2.4(c) .

“ SAR Termination Date ” means the date that is the later of (a) the tenth anniversary of the date of this Agreement and (b) the earlier of (x) the date that is 6 months following the date that the Second Acquisition Right Conditions are satisfied and (y) the date that is 6 months following the tenth anniversary of the date of this Agreement.

“ SEC Report s” has the meaning set forth in Section 3.1(g) .

“ Second Acquisition Right ” has the meaning set forth in Section 2.4(c) .

“ Second Acquisition Right Base Price ” has the meaning set forth in Section 2.4(d) .

“ Second Acquisition Right Conditions ” means that, prior to the 10 ^th anniversary of the date hereof: (a) a Celgene Party has exercised the Celgene Option with respect to at least [***] Juno Programs (which may include [***]) that remain in effect without having been terminated pursuant to Article 11 of the Collaboration Agreement or Section 10 of any Development & Commercialization Agreement, provided that each such Juno Program [***], (b) the Minimum FAR Purchase Condition has been satisfied, and (c) following a Celgene Party’s timely delivery of an FAR Notice, the Company has made at least [***] “elections.” For purposes of the foregoing clause (c), [***].

“ Second Acquisition Right Shares ” has the meaning set forth in Section 2.4(c) .

“ Second Top-Up Period ” has the meaning set forth in Section 2.3(b) .

“ Second Top-Up Right ” has the meaning set forth in Section 2.3(b) .

“ Second Top-Up Shares ” has the meaning set forth in Section 2.3(b) .

“ Secretary’s Certificate ” has the meaning set forth in Section 2.2(a)(vi) .

[***] Certain information in this document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.

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“ Securities Act ” has the meaning set forth in the Recitals.

“ Sell-Down Period ” has the meaning set forth in Section 2.4(e) .

“ Shares ” has the meaning set forth in the Recitals.

“ STU Notice ” has the meaning set forth in Section 2.3(b) .

“ Subsequent Closing ” means any closing of a purchase by a Celgene Party of Top-Up Shares or Acquisition Right Shares.

“ Subsidiary ” means any subsidiary (within the meaning of Rule 405 under the Securities Act) of the Company formed or acquired after the date hereof.

“ Target ” shall have the meaning given in the Collaboration Agreement; provided, that, [***].

“ Tax Benefit ” has the meaning set forth in Section 4.8(d) .

“ Ten (10) Day VWAP ” means the volume-weighted average closing price of the Common Stock on the Principal Trading Market for the ten (10) consecutive Trading Days commencing on the first Trading Day after the Company files a Triggering Report (it being understood that if the Triggering Report is filed prior to the open of the Principal Trading Market on a given Trading Day, then such Trading Day shall count as the first Trading Day of the ten (10) Trading Day period).

“ Terminating Celgene Breach ” has the meaning set forth in Section 6.1(c)(i) .

“ Terminating Company Breach ” has the meaning set forth in Section 6.1(b)(i) .

“ Termination Date ” has the meaning set forth in Section 6.1(b)(ii) .

“ Third Top-Up Period ” has the meaning set forth in Section 2.3(c) .

“ Third Top-Up Right ” has the meaning set forth in Section 2.3(c) .

“ Third Top-Up Shares ” has the meaning set forth in Section 2.3(c) .

“ Top-Up Right ” has the meaning set forth in Section 2.3(c) .

“ Top-Up Shares ” has the meaning set forth in Section 2.3(d) .

“ Trading Day ” means (i) a day on which the Common Stock is listed or quoted and traded on its Principal Trading Market (other than the OTC Bulletin Board), or (ii) if the Common Stock is not listed on a Trading Market (other than the OTC Bulletin Board), a day on which the Common Stock is traded in the over-the-counter market, as reported by the OTC Bulletin Board, or (iii) if the Common Stock is not quoted on any Trading Market, a day on which the Common Stock is quoted in the over-the-counter market as reported in the “pink sheets” by Pink Sheets LLC (or any similar organization or agency succeeding to its functions of reporting prices); provided , that in the event that the Common Stock is not listed or quoted as set forth in (i), (ii) and (iii) hereof, then Trading Day shall mean a Business Day.

“ Trading Market ” means whichever of the New York Stock Exchange, the NYSE Amex Equities (formerly the American Stock Exchange), the NASDAQ Global Select Market, the NASDAQ Global Market, the NASDAQ Capital Market or the OTC Bulletin Board on which the Common Stock is listed or quoted for trading on the date in question.

[***] Certain information in this document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.

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“ Transaction Documents ” means this Agreement, the schedules and exhibits attached hereto, the Registration Rights Agreement, the Voting and Standstill Agreement, the Collaboration Agreement and any other documents or agreements explicitly contemplated hereunder or thereunder.

“ Transfer Agent ” means Wells Fargo Bank, N.A., the current transfer agent of the Company or any successor transfer agent for the Company.

“ Triggering Report ” has the meaning set forth in Section 2.3(a) .

“ TTU Notice ” has the meaning set forth in Section 2.3(c) .

“ Undesignated IMM BD Program ” shall have the meaning given in the Collaboration Agreement.

“ Undesignated IMM Internal Program ” shall have the meaning given in the Collaboration Agreement.

“ Undesignated IMM Programs ” shall have the meaning given in the Collaboration Agreement.

“ Undesignated IMM Qualified Notice ” shall have the meaning given in the Collaboration Agreement.

“Voting and Standstill Agreement ” has the meaning set forth in the Recitals.

ARTICLE II.

PURCHASE AND SALE; ACQUISITION RIGHTS

2.1 Closing .

(a) Amount . Subject to the terms and conditions set forth in this Agreement, at the Closing, the Company shall issue and sell to Celgene RIVOT, and Celgene RIVOT shall purchase from the Company, 9,137,672 shares of Common Stock, representing 10% of the outstanding shares of Common Stock as of 5 pm Pacific Time on the day prior to the date hereof.

(b) Closing . The Closing of the purchase and sale of the Closing Shares shall take place at the offices of Latham & Watkins LLP, 140 Scott Drive, Menlo Park, California 94025, on the date which is two Trading Days after the date on which all conditions set forth in Article V shall been satisfied or waived (other than those conditions that by their terms are to be satisfied at the Closing, but subject to the satisfaction or waiver of such conditions), but no earlier than July 1, 2015, or at such other locations or remotely by facsimile transmission or other electronic means as the parties may mutually agree. The date on which the Closing actually occurs is referred to in this Agreement as the “ Closing Date .”

(c) Form of Payment . On the Closing Date, Celgene RIVOT shall pay to the Company the cash purchase price for the Closing Shares in the amount of $93.00 per share, or $849,803,496.00 in aggregate, by wire transfer of immediately available funds, and the Company shall irrevocably instruct the Transfer Agent to deliver to Celgene RIVOT the Closing Shares in book-entry form, free and clear of all restrictive and other legends (except as expressly provided in Section 4.1(b) hereof).

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2.2 Closing Deliveries . (a) On or prior to the Closing, the Company shall issue, deliver or cause to be delivered to Celgene RIVOT the following (the “ Company Deliverables ”):

(i) this Agreement, duly executed by the Company;

(ii) the Closing Shares in book-entry form, free and clear of all restrictive and other legends (except as provided in Section 4.1(b) hereof);

(iii) a legal opinion of Company Counsel, dated as of the Closing Date, in form and substance reasonably satisfactory to Celgene RIVOT, executed by such counsel and addressed to Celgene RIVOT;

(iv) a certificate of the Secretary or Assistant Secretary of the Company (the “ Secretary’s Certificate ”), dated as of the Closing Date, (a) certifying the resolutions adopted by the Board of Directors of the Company or a duly authorized committee thereof approving the transactions contemplated by this Agreement and the other Transaction Documents and the issuance of the Shares, (b) certifying the current versions of the certificate of incorporation, as amended, and by-laws of the Company and (c) certifying as to the signatures and authority of persons signing the Transaction Documents and related documents on behalf of the Company, in the form attached hereto as Exhibit C ;

(v) a certificate evidencing the formation and good standing of the Company issued by the Secretary of State of Delaware, as of a date within five (5) Trading Days of the Closing Date; and

(vi) a certified copy of the Company’s restated certificate of incorporation, as certified by the Secretary of State of Delaware as of a date within five (5) Trading Days of the Closing Date.

(b) On or prior to the Closing, Celgene RIVOT shall deliver or cause to be delivered to the Company the following (the “ Celgene Deliverables ”):

(i) this Agreement, duly executed by the Celgene Parties; and

(ii) the purchase price for the Closing Shares as provided in Section 2.1(c) .

2.3 Additional Share Purchase Rights .

(a) On the eleventh Trading Day after each time the Company files an annual report on Form 10-K or the equivalent thereof at such time (such report, the “ Triggering Report ”) following Closing and prior to the FAR Termination Date (the “ First Top-Up Period ”), the Company will deliver written notice in accordance with Section 6.6 (the “ Company FTU Notice ”) to the Celgene Parties setting forth (i) the Ten (10) Day VWAP following the filing of the applicable Triggering Report, (ii) the Applicable FTU Percentage and (iii) the number of shares of Common Stock that the Celgene Group would need to purchase such that, following such purchase, the Celgene Group would own the Applicable FTU Percentage of the shares of Common Stock outstanding after giving effect to such purchase, but not giving effect to any other shares issued following the last Trading Day of the Ten (10) Day VWAP period, less the number of Shares, if any, previously sold, transferred, or otherwise disposed of by the Celgene Group to a Person other than a Permitted Transferee, to the extent the sale, transfer, or disposition of such Shares had not been previously reflected in an adjustment to the Applicable FTU Percentage as provided below in this Section 2.3(a) (e.g., if no adjustment to the Applicable FTU Percentage has yet occurred or if the sale, transfer, or disposition in question occurred following the last Trading Day of the associated Ten (10) Day VWAP period with respect

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to which the most recent adjustment to the Applicable FTU Percentage was made), where such number of Shares sold, transferred or otherwise disposed of is appropriately and equitably adjusted for any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization. Following receipt of the Company FTU Notice, a Celgene Party may (the “ First Top-Up Right ”), by written notice (the “ FTU Notice ”) delivered to the Company in accordance with Section 6.6 during each five Trading Day period following the receipt of the Company FTU Notice, elect to purchase from the Company the number of shares of Common Stock specified in such FTU Notice (the “ First Top-Up Shares ”) up to the number of shares set forth in the Company FTU Notice. If a Celgene Party does not deliver a FTU Notice electing to purchase the maximum number of shares to which it may be entitled in any given year during the First Top-Up Period (as set forth in the Company FTU Notice), then the Applicable FTU Percentage shall be adjusted downward to the percentage of outstanding shares of Common Stock the Celgene Group owned as of the end of the last Trading Day of the associated Ten (10) Day VWAP period assuming the issuance of any First Top-Up Shares from such year. The purchase price per share for the First Top-Up Shares will be equal to the Ten (10) Day VWAP following the filing of the applicable Triggering Report.

(b) If a Celgene Party has delivered an FAR Notice, then following the closing of the purchase of the First Acquisition Right Shares and prior to the SAR Termination Date (the “ Second Top-Up Period ”), the Company may elect, by written notice delivered to the Celgene Parties in accordance with Section 6.6 no later than the date that the Company files any Triggering Report during such period, to give notice to the Celgene Parties of its intention to offer the Celgene Parties the right to purchase additional shares of Common Stock under this Section 2.3(b) (the “ Second Top-Up Right ”). If the Company delivers such notice, then on the eleventh Trading Day following such notice, the Company will also deliver written notice in accordance with Section 6.6 (the “ Company STU Notice ”) to the Celgene Parties setting forth (i) the Ten (10) Day VWAP following the filing of the applicable Triggering Report, (ii) the Applicable STU Percentage and (iii) the number of shares of Common Stock that the Celgene Group would need to purchase such that, following such purchase, the Celgene Group would own the Applicable STU Percentage of the shares of Common Stock outstanding after giving effect to such purchase, but not giving effect to any other shares issued following the last Trading Day of the Ten (10) Day VWAP period less the number of Shares, if any, previously sold, transferred, or otherwise disposed of by the Celgene Group outside of a Sell-Down Period to a Person other than a Permitted Transferee following the purchase of the First Acquisition Right Shares, to the extent the sale, transfer, or disposition of such Shares had not been previously reflected in an adjustment to the Applicable STU Percentage as provided below in this Section 2.3(b) (e.g., if no adjustment to the Applicable STU Percentage has yet occurred or if the sale, transfer, or disposition in question occurred following the last Trading Day of the associated Ten (10) Day VWAP period with respect to which the most recent adjustment to the Applicable STU Percentage was made), where such number of Shares sold, transferred or otherwise disposed of is appropriately and equitably adjusted for any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization. Following receipt of the Company STU Notice, a Celgene Party may, by written notice (the “ STU Notice ”) delivered to the Company in accordance with Section 6.6 during the five Trading Day period following the receipt of the Company STU Notice, elect to purchase from the Company the number of shares of Common Stock specified in such STU Notice (the “ Second Top-Up Shares ”) up to the number of shares set forth in the Company STU Notice. The Company may elect to offer the Celgene Parties the Second Top-Up Right with respect to any, all, or none of the Triggering Reports filed during the Second Top-Up Period in its sole discretion. If a Celgene Party does not deliver a STU Notice electing to purchase the maximum number of shares to which it may be entitled in any given year in which the Company has offered the Celgene Parties a Second Top-Up Right (as set forth in the Company STU Notice), then the Applicable STU Percentage shall be adjusted downward to the percentage of outstanding shares of Common Stock the Celgene Group owned as of the end of the last Trading Day of the associated Ten (10) Day VWAP period assuming the issuance of any Second Top-Up Shares from such year. The purchase price per share for the Second Top-Up Shares will be equal to 105% of the Ten (10) Day VWAP following the filing of the applicable Triggering Report.

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(c) On the eleventh Trading Day after each time the Company files a Triggering Report following the purchase of the Second Acquisition Right Shares until the expiration of the Restricted Period as provided as provided in the Voting and Standstill Agreement (the “ Third Top-Up Period ”), the Company will deliver written notice in accordance with Section 6.6 (the “ Company TTU Notice ”) to the Celgene Parties setting forth (i) the Ten (10) Day VWAP following the filing of the applicable Triggering Report, (ii) the Applicable TTU Percentage and (iii) the number of shares of Common Stock that the Celgene Group would need to purchase such that, following such purchase, the Celgene Group would own the Applicable TTU Percentage of the shares of Common Stock outstanding after giving effect to such purchase, but not giving effect to any other shares issued following the last day of the Ten (10) Day VWAP period, less the number of Shares, if any, previously sold, transferred, or otherwise disposed of by the Celgene Group to a Person other than a Permitted Transferee following the purchase of the Second Acquisition Right Shares, to the extent the sale, transfer, or disposition of such Shares had not been previously reflected in an adjustment to the Applicable TTU Percentage as provided below in this Section 2.3(b) (e.g., if no adjustment to the Applicable TTU Percentage has yet occurred or if the sale, transfer, or disposition in question occurred following the last Trading Day of the associated Ten (10) Day VWAP period with respect to which the most recent adjustment to the Applicable TTU Percentage was made), where such number of Shares sold, transferred or otherwise disposed of is appropriately and equitably adjusted for any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization. Following receipt of the Company TTU Notice, a Celgene Party may (the “ Third Top-Up Right, ” and together with the First Top-Up Right and the Second Top-Up Right, the “ Top-Up Rights ”), by written notice (the “ TTU Notice ”) delivered to the Company in accordance with Section 6.6 during the five Trading Day period following the Receipt of the Company TTU Notice, elect to purchase from the Company the number of shares of Common Stock set forth in such TTU Notice (the “ Third Top-Up Shares ”) up to the number of shares set forth in the Company TTU Notice. If a Celgene Party does not deliver a TTU Notice electing to purchase the maximum number of shares to which it may be entitled in any given year in which it is available (as set forth in the Company TTU Notice), then the Applicable TTU Percentage shall be adjusted downward to the percentage of outstanding shares of Common Stock the Celgene Group owned as of the end of the last Trading Day of the associated Ten (10) Day VWAP period assuming the issuance of any Third Top-Up Shares from such year. The purchase price per share for the Third Top-Up Shares will be equal to 105% of the Ten (10) Day VWAP following the filing of the applicable Triggering Report. Notwithstanding the foregoing, (x) if prior to the fifth anniversary of the delivery of the SAR Notice, the Celgene Group sells any Shares in reliance upon Section 3.1(B) of the Voting and Standstill Agreement, then the Applicable TTU Percentage shall be adjusted downward to equal the FAR Acquisition Percentage, and (y) the first time that the percentage of outstanding shares of Common Stock owned by the Celgene Group as of the end of the last Trading Day of the next Ten (10) Day VWAP period following such sales (after giving effect to the assumed exercise in full of the Third Top-Up Right for such period) declines below the FAR Acquisition Percentage as a result of any sales of Shares by the Celgene Group following the delivery of the SAR Notice, the Applicable TTU Percentage shall be adjusted downward, if necessary, to equal the FAR Acquisition Percentage.

(d) Upon the closing of any purchase of First Top-Up Shares, Second Top-Up Shares, or Third Top-Up Shares (collectively, the “ Top-Up Shares ”), the applicable Celgene Party shall pay to the Company the cash purchase price for the applicable Top-Up Shares calculated as set forth in Section 2.3(a) , (b)  or (c) , as applicable, by wire transfer of immediately available funds, and the Company shall irrevocably instruct the Transfer Agent to deliver to the applicable Celgene Party the applicable Top-Up Shares in book-entry form, free and clear of all restrictive and other legends (except as expressly provided in Section 4.1(b) hereof). For avoidance of doubt, when the Triggering Report is filed prior to the open of the Principal Trading Market on a Trading Day, such Trading Day shall be deemed to be the first Trading Day after the filing of the Triggering Report.

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2.4 First and Second Acquisition Rights .

(a) Once the First Acquisition Right Conditions have been satisfied, the Celgene Parties may, by written notice (the “ FAR Notice ”) delivered to the Company in accordance with Section 6.6 on a Trading Day at any one time following the fourth anniversary of the date hereof and prior to the FAR Termination Date, purchase from the Company (the “ First Acquisition Right ”) shares of Common Stock (the “ First Acquisition Right Shares ”) such that, after giving effect to such purchase, the Celgene Group would own the percentage (up to 19.99%, provided that the maximum number of shares that can be purchased shall be reduced from this percentage for any sales, transfers, or dispositions by the Celgene Group to any Person other than a Permitted Transferee that have occurred since the Closing Date, appropriately and equitably adjusted for any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization) specified in such notice (the “FAR Acquisition Percentage ”) of the shares of Common Stock outstanding as of the date of such notice. Upon receipt by the Company of the FAR Notice, the Company shall, within three (3) Trading Days, provide the Celgene Parties with written notice of the purchase price(s) per First Acquisition Right Share calculated in accordance with Section 2.4(b) , the number of First Acquisition Right Shares and the calculation of the aggregate purchase price for the First Acquisition Right Shares. In consideration for the First Acquisition Right Shares, the applicable Celgene Party shall pay to the Company the cash purchase price for the First Acquisition Right Shares set forth in such notice by wire transfer of immediately available funds, and the Company shall irrevocably instruct the Transfer Agent to deliver to the applicable Celgene Party the First Acquisition Right Shares in book-entry form, free and clear of all restrictive and other legends (except as expressly provided in Section 4.1(b) hereof). If the number of First Acquisition Right Shares is reduced as a result of the provision of this Section 2.4(a) providing that the maximum number of shares that can be purchased shall be reduced by sales, transfers, or dispositions by the Celgene Group, the FAR Acquisition Percentage (notwithstanding the percentage stated in the FAR Notice) shall be reduced to the percentage ownership of the Celgene Group after giving effect to the purchase, as of the date of the FAR Notice.

(b) The purchase price per First Acquisition Right Share will be equal to: (x) the closing price of the Common Stock on the Principal Trading Market on the date of delivery of the FAR Notice (the “ First Acquisition Right Base Price ”) with respect to the FAR Catch-Up Number of First Acquisition Right Shares and (y) the First Acquisition Right Base Price, plus the applicable premium set forth on Schedule 2.4(b) with respect to the remaining First Acquisition Right Shares.

(c) Once the Second Acquisition Right Conditions have been satisfied, Celgene Corp. may, by written notice delivered to the Company in accordance with Section 6.6 (the “ SAR Notice ”) on a Trading Day at any one time following the ninth anniversary of the date hereof and prior to the SAR Termination Date, purchase from the Company (the “ Second Acquisition Right ”) shares of Common Stock (the “ Second Acquisition Right Shares ”) such that, after giving effect to such purchase, the Celgene Group would own the percentage (up to 30%, provided that the maximum number of shares that can be purchased shall be reduced from this percentage for any sales, transfers, or dispositions by the Celgene Group to any Person other than a Permitted Transferee that have occurred since the Closing Date outside of a Sell-Down Period, appropriately and equitably adjusted for any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization) specified in such notice (the “ SAR Acquisition Percentage ”) of the shares of Common Stock outstanding as of the date of such notice. Upon receipt by the Company of the SAR Notice, the Company shall, within three (3) Trading Days, provide Celgene Corp. with written notice of the purchase price(s) per Second Acquisition Right Share calculated in accordance with Section 2.4(d) , the number of Second Acquisition Right Shares and the calculation of the aggregate purchase price for the Second Acquisition Right Shares. In consideration for the Second Acquisition Right Shares, Celgene Corp. shall pay to the Company the cash purchase price for the Second Acquisition Right Shares set forth in such notice by wire transfer of immediately available funds, and the Company shall irrevocably instruct the Transfer Agent to deliver to Celgene Corp. the Second Acquisition Right Shares in book-entry form, free and clear of all restrictive and other legends (except as expressly provided in Section 4.1(b) hereof). If the number of Second Acquisition Right Shares is reduced as a result of the provision of this Section 2.4(c) providing that

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the maximum number of shares that can be purchased shall be reduced by sales, transfers, or dispositions by the Celgene Group, the SAR Acquisition Percentage (notwithstanding the percentage stated in the SAR Notice) shall be reduced to the percentage ownership of the Celgene Group after giving effect to the purchase, as of the date of the SAR Notice.

(d) The purchase price per share of the Second Acquisition Right Shares will be equal to: (x) the closing price of the Common Stock on the Principal Trading Market on the date of delivery of the SAR Notice (the “ Second Acquisition Right Base Price ”) multiplied by 1.05 with respect to the SAR Catch-Up Number of First Acquisition Right Shares and (y) the Second Acquisition Right Base Price plus the applicable premium set forth on Schedule 2.4(d) with respect to the remaining Second Acquisition Right Shares.

(e) Upon satisfaction of the Minimum FAR Purchase Condition, the Celgene Parties will have the right to: (x) exercise the Celgene Co-Promote Right in accordance with Section 3.1.4 of the Collaboration Agreement for one (1) additional Juno Program, excluding the CD19 Program and the CD22 Program, but including any CAR/TCR Deferred Program, or any Undesignated IMM Program that becomes a Juno Program pursuant to Section 2.2.1 or Section 3.1.5, respectively, of the Collaboration Agreement (the “ Additional Co-Promote Option ”) and (y) by written notice to the Company during the Second Top-Up Period, reduce the FAR Acquisition Percentage to 16% until such time that the Celgene Group collectively owns 16% of the shares of Common Stock outstanding (the period from such notice to such time, the “ Sell-Down Period ”, immediately after which, the FAR Acquisition Percentage shall be 16%), and during such period, the Company shall use commercially reasonable efforts to assist the Celgene Group in reducing their ownership of the shares of outstanding Common Stock to 16%.

2.5 Subsequent Closings . Each Subsequent Closing shall take place at the offices of Latham & Watkins LLP, 140 Scott Drive, Menlo Park, California 94025, on the date which is two Trading Days after the date on which all conditions to such Subsequent Closing, as set forth in Article V, shall been satisfied or waived (other than those conditions that by their terms are to be satisfied at the Subsequent Closing, but subject to the satisfaction or waiver of such conditions), or at such other locations or remotely by facsimile transmission or other electronic means as the parties may mutually agree.

2.6 Limit on Issuance . The parties agree that the aggregate number of shares to be issued under this Agreement shall not exceed such number of Shares that is equal to 19.99% of the outstanding shares of Common Stock or the voting power of the Company as of immediately prior to the date hereof, except to the extent that the stockholders of the Company have approved any issuance of Shares in excess of that limit.

ARTICLE III.

REPRESENTATIONS AND WARRANTIES

3.1 Representations and Warranties of the Company . Except (A) as set forth in the schedules delivered herewith (the “ Disclosure Schedules ”), which Disclosure Schedules shall be deemed a part hereof and shall qualify any representation made herein to the extent of the disclosure contained in the corresponding section of the Disclosure Schedules, and which may be amended or supplemented by the Company in connection with any Subsequent Closing, or (B) disclosed in the SEC Reports, the Company hereby represents and warrants as of the date hereof to the Celgene Parties:

(a) Organization and Qualification . The Company is an entity duly incorporated or otherwise organized, validly existing and in good standing under the laws of the State of Delaware, with the requisite corporate power and authority to own or lease and use its properties and assets and to carry on its business as currently conducted. The Company is not in violation or default of any of the provisions of its certificate of incorporation or bylaws. The Company is duly qualified to conduct business and is in good

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standing as a foreign corporation or other entity in each jurisdiction in which the nature of the business conducted or property owned by it makes such qualification necessary, except where the failure to be so qualified or in good standing, as the case may be, would not have or reasonably be expected to result in a Material Adverse Effect, and no Proceeding has been instituted, is pending, or, to the Company’s Knowledge, has been threatened in writing in any such jurisdiction revoking, limiting or curtailing or seeking to revoke, limit or curtail such power and authority or qualification.

(b) Authorization; Enforcement; Validity . The Company has the requisite corporate power and authority to enter into and to consummate the transactions contemplated by each of the Transaction Documents to which it is a party and otherwise to carry out its obligations hereunder and thereunder. The Company’s execution and delivery of each of the Transaction Documents to which it is a party and the consummation by it of the transactions contemplated hereby and thereby (including, but not limited to, the sale and delivery of the Shares) have been duly authorized by all necessary corporate action on the part of the Company, and no further corporate action is required by the Company, its Board of Directors or its stockholders in connection therewith other than in connection with the Required Approvals. Each of the Transaction Documents to which it is a party has been (or upon delivery will have been) duly executed by the Company and is, or when delivered in accordance with the terms hereof, will constitute the legal, valid and binding obligation of the Company.

(c) No Conflicts . The execution, delivery and performance by the Company of the Transaction Documents to which it is a party and the consummation by the Company of the transactions contemplated hereby or thereby (including, without limitation, the issuance of the Shares) do not and will not (i) conflict with or violate any provisions of the Company’s certificate of incorporation or bylaws, (ii) conflict with, or constitute a default (or an event that with notice or lapse of time or both would result in a default) under, result in the creation of any Lien upon any of the properties or assets of the Company or give to others any rights of termination, amendment, acceleration or cancellation (with or without notice, lapse of time or both) of, any Material Contract, or (iii) subject to the Required Approvals, conflict with or result in a violation of any law, rule, regulation, order, judgment, injunction, decree or other restriction of any court or governmental authority to which the Company is subject (including federal and state securities laws and regulations and the rules and regulations, assuming the correctness of the representations and warranties made by the Celgene Parties herein, of any self-regulatory organization to which the Company or its securities are subject), or by which any property or asset of the Company is bound or affected, except in the case of clauses (ii) and (iii) such as would not, individually or in the aggregate, have or reasonably be expected to result in a Material Adverse Effect.

(d) Filings, Consents and Approvals . The Company is not required to obtain any consent, waiver, authorization or order of, give any notice to, or make any filing or registration with, any court or other federal, state, local or other governmental authority (“ Governmental Authority ”) or other Person in connection with the execution, delivery and performance by the Company of the Transaction Documents (including the issuance of the Shares), other than (i) the filing with the Commission of one or more Registration Statements in accordance with the requirements of the Registration Rights Agreement, (ii) filings required by applicable state securities laws, (iii) the filing of a Notice of Sale of Securities on Form D with the Commission under Regulation D of the Securities Act, (iv) the filing of any requisite notices and/or application(s) to the Principal Trading Market for the issuance and sale of the Shares and the listing of the Shares thereon in the time and manner required thereby, (v) as required by the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the rules and regulations promulgated thereunder (the “ HSR Act ”) or any similar foreign law, rule, or regulation, (vi) shareholder approval, as may be required under the NASDAQ Marketplace Rules, (vii) any consent, amendment, or waiver that may be required under the Existing Rights Agreement, and (viii) those that have been made or obtained prior to the date of this Agreement (the items referred to in clauses (i) through (viii) collectively, the “ Required Approvals ”).

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(e) Issuance of the Shares . The Shares have been duly authorized and, when issued and paid for in accordance with the terms of the Transaction Documents, will be validly issued, fully paid and nonassessable and free and clear of all Liens, other than restrictions on transfer provided for in the Transaction Documents or imposed by applicable securities laws, and shall not be subject to preemptive or similar rights. Assuming the accuracy of the representations and warranties of the Celgene Parties in this Agreement, the Shares will be issued in compliance with all applicable federal and state securities laws.

(f) Capitalization . The number of shares and type of all authorized, issued and outstanding capital stock, options and other securities of the Company (whether or not presently convertible into or exercisable or exchangeable for shares of capital stock of the Company) is set forth in Section 3.1(f) of the Disclosure Schedules. The Company has not issued any capital stock since the date of its most recently filed SEC Report other than to reflect stock option exercises or the vesting of restricted stock units. No Person has any right of first refusal, preemptive right, right of participation, or any similar right to participate in the transactions contemplated by the Transaction Documents that have not been effectively waived as of the Closing Date. Except as set forth on Section 3.1(f) of the Disclosure Schedules or as specifically disclosed in the most recently filed annual report on Form 10-K or subsequent SEC Reports, there are no outstanding options, warrants, scrip rights to subscribe to, calls or commitments of any character whatsoever relating to, or securities, rights or obligations convertible into or exercisable or exchangeable for, or giving any Person any right to subscribe for or acquire any shares of Common Stock, or contracts, commitments, understandings or arrangements by which the Company is or may become bound to issue additional shares of Common Stock or Common Stock Equivalents. The issuance and sale of the Shares will not obligate the Company to issue shares of Common Stock or other securities to any Person (other than the Celgene Parties) and will not result in a right of any holder of Company securities to adjust the exercise, conversion, exchange or reset price under any of such securities. Except for the Required Approvals, no further approval or authorization of any stockholder, the Board of Directors or others is required for the issuance and sale of the Shares. Except for the Voting and Standstill Agreement, as set forth on Section 3.1(f) of the Disclosure Schedules, or as specifically disclosed in the most recently filed annual report on Form 10-K or subsequent SEC Reports, there are no stockholders agreements, voting agreements or other similar agreements with respect to the Company’s capital stock to which the Company is a party or, to the Company’s Knowledge, between or among any of the Company’s stockholders.

(g) SEC Reports; Disclosure Materials . The Company has filed all reports, schedules, forms, statements and other documents required to have been filed by it under the Exchange Act as of the date hereof, including pursuant to Section 13(a) or 15(d) thereof, for the two years preceding the date hereof (or such shorter period as the Company was required by law or regulation to file such material) (the foregoing materials, including the exhibits thereto and documents incorporated by reference therein, and also including the Company’s prospectus dated December 19, 2014 filed with the Commission pursuant to Rule 424(b) under the Securities Act, being collectively referred to herein as the “ SEC Reports ,” and the SEC Reports, together with the Disclosure Schedules, being collectively referred to as the “ Disclosure Materials ”) on a timely basis or has received a valid extension of such time of filing and has filed any such SEC Reports prior to the expiration of any such extension, except where the failure to file on a timely basis would not have or reasonably be expected to result in a Material Adverse Effect (including, for this purpose only, any failure which would prevent the Celgene Parties from using Rule 144 to resell any Shares). As of their respective filing dates, or to the extent corrected by a subsequent restatement, the SEC Reports complied in all material respects with the requirements of the Securities Act and the Exchange Act and the rules and regulations of the Commission promulgated thereunder, and none of the SEC Reports, when filed, contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The Company has never been an issuer subject to Rule 144(i) under the Securities Act. Each of the Material Contracts to which the Company is a party or to which the property or assets of the Company are subject has been filed as an exhibit to the SEC Reports.

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(h) Financial Statements . The financial statements of the Company included in the SEC Reports comply in all material respects with applicable accounting requirements and the rules and regulations of the Commission with respect thereto as in effect at the time of filing (or to the extent corrected by a subsequent restatement). Such financial statements have been prepared in accordance with GAAP applied on a consistent basis during the periods involved, except as may be otherwise specified in such financial statements or the notes thereto and except that unaudited financial statements may not contain all footnotes required by GAAP, and fairly present in all material respects the financial position of the Company as of and for the dates thereof and the results of operations and cash flows for the periods then ended, subject, in the case of unaudited statements, to normal, immaterial year-end audit adjustments.

(i) Material Changes . Except as specifically disclosed in SEC Reports filed prior to the date hereof, (i) there have been no events, occurrences or developments that have had or would reasonably be expected to have, either individually or in the aggregate, a Material Adverse Effect, (ii) the Company has not incurred any material liabilities other than (A) trade payables and accrued expenses incurred in the ordinary course of business consistent with past practice and (B) liabilities not required to be reflected in the Company’s financial statements pursuant to GAAP or disclosed in filings made with the Commission, (iii) the Company has not altered materially its method of accounting or the manner in which it keeps its accounting books and records, (iv) the Company has not declared or made any dividend or distribution of cash, shares of capital stock or other property to its stockholders or purchased, redeemed or made any agreements to purchase or redeem any shares of its capital stock (other than in connection with repurchases of unvested stock issued to employees of the Company), and (v) the Company has not issued any equity securities to any officer, director or Affiliate, except Common Stock issued in the ordinary course as dividends on outstanding preferred stock or issued pursuant to existing Company stock option or stock purchase plans or executive and director compensation arrangements disclosed in the SEC Reports.

(j) Litigation . There is no Action which (i) adversely affects or challenges the legality, validity or enforceability of any of the Transaction Documents or the Shares or (ii) except as specifically disclosed in the SEC Reports, would, if there were an unfavorable decision, individually or in the aggregate, have or reasonably be expected to result in a Material Adverse Effect. Neither the Company nor, to the Company’s Knowledge, any director or officer thereof is or has been the subject of any Action involving a claim of violation of or liability under federal or state securities laws or a claim of breach of fiduciary duty relating to actions taken at the Company. There has not been, and to the Company’s Knowledge there is not pending or contemplated, any investigation by the Commission involving the Company. The Commission has not issued any stop order or other order suspending the effectiveness of any registration statement filed by the Company under the Exchange Act or the Securities Act.

(k) Sarbanes-Oxley; Disclosure Controls . The Company is in compliance in all material respects with all of the provisions of the Sarbanes-Oxley Act of 2002 which are applicable to it as an “emerging growth company,” as defined in Section 2(a) of the Securities Act, as of the Closing Date. The Company has established disclosure controls and procedures (as such term is defined in Rule 13a-15(e) and 15d-15(e) under the Exchange Act) for the Company and designed such disclosure controls and procedures to ensure that information required to be disclosed by the Company in the reports it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the Commission’s rules and forms. The Company’s certifying officers have evaluated the effectiveness of the Company’s disclosure controls and procedures as of the end of the period covered by the Company’s most recently filed periodic report under the Exchange Act (such date, the “ Evaluation Date ”). The Company presented in its most recently filed periodic report under the Exchange Act the conclusions of the certifying officers about the effectiveness of the disclosure controls and procedures based on their evaluations as of the Evaluation Date. Since the Evaluation Date, there have been no changes in the Company’s internal control over financial reporting (as such term is defined in the Exchange Act) that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

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(l) Certain Fees . Except for sublicense consideration payments that may be required under certain of Company’s license agreements due to the licenses and sublicenses granted under the Collaboration Agreement, no person or entity will have, as a result of the transactions contemplated by this Agreement, any valid right, interest or claim against or upon the Company or the Celgene Parties for any commission, fee or other compensation pursuant to any agreement, arrangement or understanding entered into by or on behalf of the Company, with respect to the offer and sale of the Shares.

(m) Private Placement . Assuming the accuracy of the Celgene Parties’ representations and warranties set forth in Section 3.2 of this Agreement, no registration under the Securities Act is required for the offer and sale of the Shares by the Company to the Celgene Parties under the Transaction Documents. The issuance and sale of the Shares hereunder does not contravene the rules and regulations of the Trading Market.

(n) Investment Company . The Company is not, and immediately after receipt of payment for the Shares, will not be or be an “investment company” within the meaning of the Investment Company Act of 1940, as amended. The Company shall conduct its business in a manner so that it will not become subject to the Investment Company Act of 1940, as amended.

(o) Registration Rights . Other than the Celgene Parties or as set forth in the Company’s Fourth Amended and Restated Investor Rights Agreement, dated December 5, 2014 (the “ Existing Rights Agreement ”) no Person has any right to cause the Company to effect the registration under the Securities Act of any securities of the Company other than those securities which are currently registered on an effective registration statement on file with the Commission.

(p) Listing and Maintenance Requirements . The Company’s Common Stock is registered pursuant to Section 12(b) or 12(g) of the Exchange Act, and the Company has taken no action designed to terminate the registration of the Common Stock under the Exchange Act nor has the Company received any notification that the Commission is contemplating terminating such registration. The Company has not, in the twelve (12) months or such applicable shorter period preceding the date hereof, received written notice from any Trading Market on which the Common Stock is listed or quoted to the effect that the Company is not in compliance with the listing or maintenance requirements of such Trading Market. The Company is in compliance with all listing and maintenance requirements of the Principal Trading Market on the date hereof.

(q) Application of Takeover Protections; Rights Agreements . The Company and the Board of Directors have taken all necessary action, if any, in order to render inapplicable any control share acquisition, business combination, poison pill (including any distribution under a rights agreement) or other similar anti-takeover provision under the Company’s charter documents or the laws of the State of Delaware that is or would reasonably be expected to become applicable to the Celgene Parties as a result of the Celgene Parties and the Company fulfilling its obligations or exercising their rights under the Transaction Documents, including, without limitation, the Company’s issuance of the Shares and the Celgene Parties’ ownership of the Shares.

(r) No Integrated Offering . Assuming the accuracy of the Celgene Parties’ representations and warranties set forth in Section 3.2 , none of the Company nor, to the Company’s Knowledge, any of its Affiliates or any Person acting on its behalf has, directly or indirectly, at any time within the past six (6) months, made any offers or sales of any Company security or solicited any offers to buy any security under circumstances that would (i) eliminate the availability of the exemption from registration under Regulation D under the Securities Act in connection with the offer and sale by the Company of the Shares as contemplated hereby or (ii) cause the offering of the Shares pursuant to the Transaction Documents to be integrated with prior offerings by the Company for purposes of any applicable law, regulation or stockholder approval provisions, including, without limitation, under the rules and regulations of any Trading Market on which any of the securities of the Company are listed or designated.

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(s) No General Solicitation . Neither the Company nor, to the Company’s Knowledge, any person acting on behalf of the Company has offered or sold any of the Shares by any form of general solicitation or general advertising (within the meaning of Regulation D promulgated under the Securities Act).

(t) Foreign Corrupt Practices . Neither the Company nor any agent or other person acting on behalf of the Company, has: (i) directly or indirectly, used any funds for unlawful contributions, gifts, entertainment or other unlawful expenses related to foreign or domestic political activity, (ii) made any unlawful payment to foreign or domestic government officials or employees or to any foreign or domestic political parties or campaigns from corporate funds, (iii) failed to disclose fully any contribution made by the Company (or made by any person acting on its behalf of which the Company is aware) which is in violation of law or (iv) violated in any material respect any provision of the Foreign Corrupt Practices Act of 1977, as amended.

(u) PFIC . The Company is not a “passive foreign investment company” within the meaning of Section 1297 of the U.S. Internal Revenue Code of 1986, as amended.

(v) OFAC . Neither the Company nor any director, officer, agent, employee, Affiliate or Person acting on behalf of the Company is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“ OFAC ”); and the Company will not directly or indirectly use the proceeds of the sale of the Shares, or lend, contribute or otherwise make available such proceeds to any Subsidiary, joint venture partner or other Person or entity, towards any sales or operations in Cuba, Iran, Syria, Sudan, Myanmar or any other country sanctioned by OFAC or for the purpose of financing the activities of any Person currently subject to any U.S. sanctions administered by OFAC.

3.2 Representations and Warranties of the Celgene Parties . Each of the Celgene Parties hereby represents and warrants as of the date hereof to the Company as follows:

(a) Organization; Authority . Each Celgene Party is an entity duly organized, validly existing and in good standing under the laws of the jurisdiction of its organization with the requisite corporate or partnership power and authority to enter into and to consummate the transactions contemplated by the applicable Transaction Documents and otherwise to carry out its obligations hereunder and thereunder. The execution and delivery of this Agreement by each Celgene Party and performance by each Celgene Party of the transactions contemplated by this Agreement have been duly authorized by all necessary corporate action on the part of each Celgene Party. Each Transaction Document to which a Celgene Party is a party has been duly executed by such Celgene Party, and when delivered by such Celgene Party in accordance with the terms hereof, will constitute the valid and legally binding obligation of such Celgene Party, enforceable against it in accordance with its terms, except as such enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium, liquidation or similar laws relating to, or affecting generally the enforcement of, creditors’ rights and remedies or by other equitable principles of general application. As of the date of this Agreement, Celgene RIVOT is a direct or indirect wholly owned controlled subsidiary of Celgene Corp. As of the date of any Closing or Subsequent Closing where the purchaser of the Shares in such Closing or Subsequent Closing is Celgene RIVOT or a Permitted Transferee (pursuant to Section 6.10), such purchaser will be a direct or indirect wholly owned controlled subsidiary of Celgene Corp.

(b) No Conflicts . The execution, delivery and performance by each Celgene Party of this Agreement and the Registration Rights Agreement and the consummation by each Celgene Party of the transactions contemplated hereby and thereby will not (i) result in a violation of the organizational

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documents of either Celgene Party, (ii) conflict with, or constitute a default (or an event which with notice or lapse of time or both would become a default) under, or give to others any rights of termination, amendment, acceleration or cancellation of, any agreement, indenture or instrument to which either Celgene Party is a party, or (iii) result in a violation of any law, rule, regulation, order, judgment or decree (including federal and state securities laws) applicable to either Celgene Party, except in the case of clauses (ii) and (iii) above, for such conflicts, defaults, rights or violations which would not, individually or in the aggregate, reasonably be expected to have a material adverse effect on the ability of Celgene Parties to perform their obligations hereunder.

(c) Investment Intent . Each Celgene Party understands that the Shares are “restricted securities” and have not been registered under the Securities Act or any applicable state securities law and is acquiring the Shares for its own account and not with a view to, or for distributing or reselling such Shares or any part thereof in violation of the Securities Act or any applicable state securities laws. Each Celgene Party is acquiring the Shares hereunder in the ordinary course of business. Neither Celgene Party presently has any agreement, plan or understanding, directly or indirectly, with any Person to distribute or effect any distribution of any of the Shares (or any securities which are derivatives thereof) to or through any person or entity. Neither Celgene Party is a registered broker-dealer under Section 15 of the Exchange Act nor an entity engaged in a business that would require it to be so registered as a broker-dealer.

(d) Status . At the time each Celgene Party was offered the Shares, it was, and at the date hereof or any date in the future on which each Celgene Party purchases Shares, it is and will be an “accredited investor” as defined in Rule 501(a) under the Securities Act.

(e) General Solicitation . Neither Celgene Party is purchasing the Shares as a result of any advertisement, article, notice or other communication regarding Shares published in any newspaper, magazine or similar media or broadcast over television or radio or presented at any seminar or any other general advertisement.

(f) Experience . Each Celgene Party, either alone or together with its representatives, has such knowledge, sophistication and experience in business and financial matters so as to be capable of evaluating the merits and risks of the prospective investment in the Shares, and has so evaluated the merits and risks of such investment. Each Celgene Party is able to bear the economic risk of an investment in the Shares and, at the present time, is able to afford a complete loss of such investment.

(g) Access to Information . Each Celgene Party acknowledges that it has had the opportunity to review the Disclosure Materials and has been afforded (i) the opportunity to ask such questions as it has deemed necessary of, and to receive answers from, representatives of the Company concerning the terms and conditions of the offering of the Shares and the merits and risks of investing in the Shares; (ii) access to information about the Company and its financial condition, results of operations, business, properties, management and prospects sufficient to enable such Celgene Party to evaluate its investment; and (iii) the opportunity to obtain such additional information that the Company possesses or can acquire without unreasonable effort or expense that is necessary to make an informed investment decision with respect to the investment. Neither such inquiries nor any other investigation conducted by or on behalf of either Celgene Party or its representatives or counsel shall modify, amend or affect either Celgene Party’s right to rely on the truth, accuracy and completeness of the Disclosure Materials and the Company’s representations and warranties contained in the Transaction Documents. The Celgene Parties have sought such accounting, legal and tax advice as they have considered necessary to make an informed decision with respect to its acquisition of the Shares.

(h) Brokers and Finders . No Person will have, as a result of the transactions contemplated by this Agreement, any valid right, interest or claim against or upon the Company or either Celgene Party for any commission, fee or other compensation pursuant to any agreement, arrangement or understanding entered into by or on behalf of either Celgene Party.

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(i) Independent Investment Decision . Each Celgene Party has independently evaluated the merits of its decision to purchase Shares pursuant to the Transaction Documents and such Celgene Party has consulted such legal, tax and investment advisors as it, in its sole discretion, has deemed necessary or appropriate in connection with its purchase of the Shares.

(j) United States Investor . Celgene Corp. is a United States person (as defined by Section 7701(a)(30) of the Code).

The Company and the Celgene Parties acknowledge and agree that no party to this Agreement has made or makes any representations or warranties with respect to the transactions contemplated hereby other than those specifically set forth in this Article III and the Transaction Documents.

ARTICLE IV.

OTHER AGREEMENTS OF THE PARTIES

4.1 Transfer Restrictions .

(a) Compliance with Laws . Notwithstanding any other provision of this Article IV , the Celgene Parties acknowledge and agree that the Shares may be disposed of only pursuant to an effective registration statement under, and in compliance with the requirements of, the Securities Act, or pursuant to an available exemption from, or in a transaction not subject to, the registration requirements of the Securities Act, and in compliance with any applicable state and federal securities laws. In connection with any transfer of Shares other than (i) pursuant to an effective registration statement, (ii) to the Company or (iii) pursuant to Rule 144, the Company may require the transferor thereof to provide to the Company an opinion of counsel selected by the transferor and reasonably acceptable to the Company, the form and substance of which opinion shall be reasonably satisfactory to the Company, to the effect that such transfer does not require registration of such transferred Shares under the Securities Act. As a condition of transfer, any such transferee shall agree in writing to be bound by the terms of this Agreement and the Registration Rights Agreement and shall have the rights of the Celgene Parties under this Agreement and the Registration Rights Agreement with respect to such transferred Shares.

(b) Legends . In addition to any legend required under the Voting and Standstill Agreement, the book-entry or certificated form of the Shares shall bear any legend as required by the “blue sky” laws of any state and a restrictive legend in substantially the following form, until such time as they are not required under Section 4.1(c) :

THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THE SECURITIES UNDER SUCH ACT OR AN OPINION OF COUNSEL SATISFACTORY TO THE ISSUER THAT SUCH REGISTRATION IS NOT REQUIRED OR UNLESS SOLD PURSUANT TO RULE 144 OF SUCH ACT.

(c) Removal of Legends . Subject to the restrictions set forth in the Voting and Standstill Agreement, the legend set forth in Section 4.1(b) above shall be removed and the Company shall issue to such holder the applicable Shares in book-entry form free and clear of such legend or any other legends by electronic delivery at the applicable balance account at the Depository Trust Company (“ DTC ”),

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if (i) such Shares are sold under an effective registration statement under the Securities Act, (ii) such Shares are sold or transferred pursuant to Rule 144 (if the transferor is not an Affiliate of the Company), or (iii) such Shares are eligible for sale under Rule 144, without the requirement for the Company to be in compliance with the current public information required under Rule 144 as to such securities and without volume or manner-of-sale restrictions. Subject to the restrictions set forth in the Voting and Standstill Agreement, the Company agrees that it shall cause Company Counsel (i) after the Effective Date, to issue to the Transfer Agent, if required by the Transfer Agent, a “blanket” legal opinion or other letter to allow sales without restriction pursuant to the effective registration statement and (ii) provide all other opinions of Company Counsel as may reasonable be required by the Transfer Agent in connection with the removal of legends pursuant to this Section 4.1(c) following receipt of the certificates and documents contemplated below. Subject to the restrictions set forth in the Voting and Standstill Agreement, following Rule 144 becoming available for the resale of Shares, without the requirement for the Company to be in compliance with the current public information required under Rule 144 as to such securities and without volume or manner-of-sale restrictions, the Company, upon the request of a Celgene Party and delivery of the certificates and documents contemplated below, shall cause Company Counsel or other counsel satisfactory to the Transfer Agent to issue to the Transfer Agent a legal opinion stating that such Shares are eligible for sale under Rule 144 without the requirement for the Company to be in compliance with the current public information required under Rule 144 as to such securities and without volume or manner-of-sale restrictions. Any fees (with respect to the Transfer Agent, Company Counsel or otherwise) associated with the issuance of such opinion or the removal of such legend shall be borne by the Company. Except with respect to the restrictions set forth in the Voting and Standstill Agreement, the Company may not make any notation on its records or give instructions to the Transfer Agent that enlarge the restrictions on transfer set forth in this Section 4.1(c) .

(d) Acknowledgement . Each Celgene Party hereunder acknowledges its primary responsibilities under the Securities Act and accordingly will not sell or otherwise transfer the Shares or any interest therein without complying with the requirements of the Securities Act. Subject to the restrictions set forth in the Voting and Standstill Agreement, while the Registration Statement remains effective, a Celgene Party may sell the Shares accordance with the plan of distribution contained in the Registration Statement and if it does so it will comply therewith and with the related prospectus delivery requirements unless an exemption therefrom is available. Each Celgene Party agrees that if it is notified by the Company in writing at any time that the Registration Statement registering the resale of the Shares is not effective or that the prospectus included in such Registration Statement no longer complies with the requirements of Section 10 of the Securities Act, such Celgene Party will refrain from selling such Shares until such time as such Celgene Party is notified by the Company that such Registration Statement is effective or such prospectus is compliant with Section 10 of the Securities Act, unless such Celgene Party is able to, and does, sell such Shares pursuant to an available exemption from the registration requirements of Section 5 of the Securities Act.

4.2 Integration . The Company shall not, and shall use its commercially reasonable efforts to ensure that no Affiliate of the Company shall, sell, offer for sale or solicit offers to buy or otherwise negotiate in respect of any security (as defined in Section 2 of the Securities Act) that will be integrated with the offer or sale of the Shares in a manner that would require the registration under the Securities Act of the sale of the Shares to a Celgene Party, or that will be integrated with the offer or sale of the Shares for purposes of the rules and regulations of any Trading Market such that it would require stockholder approval prior to the closing of such other transaction unless stockholder approval is obtained before the closing of such subsequent transaction.

4.3 Shareholder Rights Plan . No claim will be made or enforced by the Company or, with the consent of the Company, any other Person, that a Celgene Party is an “ Acquiring Person ” under any control share acquisition, business combination, poison pill (including any distribution under a rights agreement) or similar anti-takeover plan or arrangement in effect or hereafter adopted by the Company, or that a Celgene Party could be deemed to trigger the provisions of any such plan or arrangement, in either case solely by virtue of purchasing the Shares under the Transaction Documents.

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4.4 Principal Trading Market Listing . In the time and manner required by the Principal Trading Market, the Company shall prepare and file with such Principal Trading Market an additional shares listing application covering all of the Shares and shall use its commercially reasonable efforts to take all steps necessary to cause all of the Shares to be approved for listing, and continue to be listed for so long as they are owned by a Celgene Party, on the Principal Trading Market as contemplated by the Registration Rights Agreement.

4.5 Form D . The Company agrees to timely file a Form D with respect to the Shares as required under Regulation D and to provide a copy thereof to the Celgene Parties.

4.6 HSR Act and Foreign Antitrust Approvals .

(a) In connection with the transactions contemplated by this Agreement, each of the parties hereto shall (i) comply promptly but in no event later than ten (10) Trading Days after the date hereof, or the date a FAR Notice, SAR Notice, FTU Notice, STU Notice or TTU Notice (each, a “ Purchase Notice ”), as applicable, is delivered if the purchase of the related Shares would trigger reporting requirements under the HSR Act, with the notification and reporting requirements of the HSR Act and use its reasonable best efforts to obtain early termination of the waiting period under the HSR Act provided, that there will be no obligation to seek such early termination in the event of any filing under the HSR Act with respect to the First Acquisition Right, Second Acquisition Right or Top-Up Right that is made prior to the applicable Purchase Notice; and (ii) as soon as practicable, make such other filings with any foreign Governmental Authorities as may be required under any applicable similar foreign law, rule or regulation. Each of the parties hereto shall use reasonable best efforts to substantially comply with any Antitrust Information or Document Requests.

(b) Each Celgene Party shall promptly furnish to the Company copies of any notices or written communications received by such Celgene Party from any third party or any Governmental Authority with respect to the transactions contemplated by this Agreement, and such Celgene Party shall permit counsel to the Company an opportunity to review in advance, and such Celgene Party shall consider in good faith the views of such counsel in connection with, any proposed written communications by such Celgene Party to any Governmental Authority concerning the transactions contemplated by this Agreement. Each Celgene Party agrees to provide the Company and its counsel the opportunity, on reasonable advance notice, to participate in any substantive meetings or discussions, either in person or by telephone, between such Celgene Party and/or any of its agents or advisors, on the one hand, and any Governmental Authority, on the other hand, concerning or in connection with the transactions contemplated hereby.

(c) The Celgene Parties shall be solely responsible for and pay all fees associated with the premerger filing under the HSR Act and any other filings required to be submitted to Governmental Authorities under applicable similar foreign law, rule, or regulation that are payable to the Antitrust Authorities in connection with the transactions contemplated by this Agreement.

4.7 Reservation of Shares and Stockholder Approvals and Waivers . Each of the parties (a) will make, or cause to be made, all filings and submissions under laws, rules and regulations applicable to it, or to its subsidiaries and Affiliates, as may be required for such party to consummate the transactions contemplated by this Agreement, (b) will use its respective commercially reasonable efforts to obtain, or cause to be obtained, all authorizations, approvals, consents, qualifications, orders and waivers from all Persons necessary to be obtained by it in order to consummate such transactions, and (c) will use its commercially reasonable efforts to take, or cause to be taken, all other actions necessary, proper or advisable in order for it to fulfill its respective obligations under this Agreement. In furtherance of the foregoing, the

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Company will: (i) keep authorized and reserved for issuance a sufficient number of shares of Common Stock to enable the issuance of the Shares to be issued at the Closing or any Subsequent Closing; (ii) seek any consent, amendment, or waiver that may be required under the Existing Rights Agreement with respect to the rights granted under the Registration Rights Agreement; and (iii) seek shareholder approval in compliance with the NASDAQ Marketplace Rules, including at the Company’s 2016 Annual Meeting of Stockholders, for the issuance of Top Up Shares, First Acquisition Right Shares, and Second Acquisition Right Shares on the terms and conditions in this Agreement until such approval is obtained; and (iv) use commercially reasonable efforts to timely file all reports, schedules, forms, statements and other documents required to be filed by it under the Exchange Act of 1934, including pursuant to Section 13(a) or 15(d) thereof, until the expiration or termination of the Celgene Parties’ registration right pursuant to Sections 6(i)(A) or (B) of the Registration Rights Agreement.

4.8 Tax Withholding .

(a) The Celgene Parties shall be entitled to deduct and withhold from any amounts payable under this Agreement such taxes as are required to be deducted or withheld therefrom under any provision of applicable law. The party that is required to make such withholding (the “ Paying Party ”) will: (i) deduct those taxes from such payment, (ii) timely remit the taxes to the proper taxing authority, and (iii) send evidence of the obligation together with proof of tax payment to the recipient party (the “ Payee Party ”) on a timely basis following that tax payment; provided, however, that before making any such deduction or withholding, the Paying Party shall give the Payee Party notice of the intention to make such deduction or withholding (such notice, which shall include the authority, basis and method of calculation for the proposed deduction or withholding, shall be given at least a reasonable period of time before such deduction or withholding is required, in order for such Payee Party to obtain reduction of or relief from such deduction or withholding). Each Party agrees to cooperate with the other Parties in claiming refunds or exemptions from such deductions or withholdings under any relevant agreement or treaty which is in effect to ensure that any amounts required to be withheld pursuant to this Section 4.8(a) are reduced in amount to the fullest extent permitted by applicable Laws.

(b) The parties acknowledge and agree that the Celgene Parties will not, absent a change in law or relevant circumstance between the date of this Agreement and the Closing Date, deduct or withhold from the amounts payable pursuant to Section 2.1(c) any amount in respect of any taxes provided that the Company provides the Celgene Parties with a properly completed and duly executed IRS Form W-9.

(c) In the event that a liability is imposed by a taxing authority upon the Celgene Parties in respect of a failure to withhold on an amount payable under Section 2.1(c) (except to the extent that, if Celgene had withheld on such amounts, it would have been required to gross-up such amounts under Section 4.8(d) ), then the Company shall indemnify and hold harmless the Celgene Parties from any and all liabilities, claims and losses with respect to such failure to withhold, provided that (1) the Celgene Parties shall notify the Company promptly upon the receipt of any claim from a taxing authority which might give rise to an indemnification under this Section 4.8(c) (although the Celgene Parties’ delay in promptly notifying The Company shall only reduce the Company’s liability to indemnify the Celgene Parties to the extent that the Company is prejudiced by such delay); (2) the Company shall be entitled to participate, at its own expense, and with counsel of its choosing, in the defense of any claim which may give rise to liability under this Section; and (3) the Celgene Parties may not settle any liability with a Taxing Authority, to the extent such settlement would create a liability for the Company under this Section 4.8(c) , without the prior written consent of the Company, which consent will not be unreasonably withheld, conditioned or delayed.

(d) Tax Gross-Up . Notwithstanding the foregoing, if (i) a Paying Party redomiciles or assigns its rights or obligations under this Agreement, (ii) as a result of such redomiciliation or assignment, such Paying Party (or its assignee) is required by applicable law to withhold taxes, and (iii) such withholding

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taxes exceed the amount of withholding taxes that would have been applicable but for such redomiciliation or assignment, then any such amount payable shall be increased to take into account such withholding taxes as may be necessary so that, after making all required withholdings (including withholdings on the additional amounts payable), as the case may be, the Payee Party (or its assignee) receives an amount equal to the sum it would have received had no such increased withholding been made. The obligation to pay additional amounts pursuant to the preceding sentence shall not apply, however, to the extent such increased withholding tax (A) would not have been imposed but for the assignment by the Payee Party of its rights or obligations under this Agreement or the redomiciliation of such Payee Party outside of the United States, to the extent such assignment or redomiciliation occurs after the redomiciliation or assignment by the Paying Party described in the first sentence of this Section 4.8(d) or (B) are attributable to the failure by the Payee Party to comply with the requirements of Section 4.8(e) . To the extent the Payee Party receiving additional amounts and the Payee Party’s Affiliates (for the avoidance of doubt, not including any deemed partnership for U.S. federal income tax purposes arising out of a Juno Lead Co-Co Agreement or a Celgene Lead Co-Co Agreement), taken as a whole, actually realize an overall reduction in cash taxes otherwise due (determined on a with and without basis and taking into account the overall tax liability of the Payee Party’s affiliates) as a result of a foreign tax credit or a tax refund attributable to withholding taxes in respect of which the Payee Party received additional amounts pursuant to this Section 4.8(d) (such reduction, a “ Tax Benefit ”), the Payee Party shall pay to the Paying Party that paid such additional amounts an amount equal to such Tax Benefit (but only to the extent of such additional amounts paid), net of all reasonable out-of-pocket expenses incurred by the Payee Party and its affiliates in connection with the obtaining or receipt of such Tax Benefit. The foregoing sentence shall not be construed to require the Payee Party to make available its tax returns to the Paying Party. Furthermore, the Payee Party and its affiliates agree not to take any action (including any tax position) principally for the purpose of reducing the amount of the Tax Benefit. Solely for purposes of this Section 4.8(d) , (X) a party’s “domicile” shall include its jurisdiction of incorporation or tax residence and a “redomiciliation” shall include a reincorporation or other action resulting in a change in tax residence of the applicable party or its assignee and (Y) Celgene RIVOT shall further be required under this Section 4.8(d) to gross-up the Payee (subject to the terms and conditions provided earlier in this paragraph) for any tax that would not be applicable had Celgene Corp. been the Payor Party.

(e) Tax Documentation . The Company has provided a properly completed and duly executed IRS Form W-9 to the Celgene Parties. Each Payee Party shall provide to the other party, at the time or times reasonably requested by such other parties or as required by applicable Law, such properly completed and duly executed documentation (for example, IRS Forms W-8 or W-9) as will permit payments made under this Agreement to be made without, or at a reduced rate of, withholding for taxes.

ARTICLE V.

CONDITIONS PRECEDENT TO CLOSING

5.1 Conditions Precedent to the Obligation to Purchase Shares . The obligation of the applicable Celgene Party to acquire Shares at the Closing (or upon any Subsequent Closing) is subject to the fulfillment, on or prior to the Closing Date (or the date of a Subsequent Closing), of each of the following conditions, any of which may be waived by the applicable Celgene Party:

(a) Representations and Warranties . For the Closing, the representations and warranties made by the Company in Section 3.1 hereof shall have been true and correct in all material respects as of the date of this Agreement. For each Subsequent Closing, the representations and warranties made by the Company in Section 3.1 hereof (as qualified by any amended or supplemented Disclosure Schedules in accordance with Section 3.1 ) shall be true and correct in all material respects as of the date of such Subsequent Closing as if made on such date rather than on the date of this Agreement.

(b) Performance . The Company shall have performed, satisfied and complied in all material respects with all covenants, agreements and conditions required by this Agreement to be performed, satisfied or complied with by it at or prior to the Closing (or Subsequent Closing).

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(c) No Injunction . No statute, rule, regulation, executive order, decree, ruling or injunction shall have been enacted, entered, promulgated or endorsed by any Governmental Authority of competent jurisdiction that prohibits the consummation of any of the transactions contemplated by the Transaction Documents.

(d) Regulatory Approvals and Filings . All waiting periods under the HSR Act applicable to the purchase of the applicable Shares by the applicable Celgene Party shall have expired or been terminated, and the parties shall have made all other material filings and submissions with, and obtained all material authorizations, approvals, consents, qualifications, orders and waivers from, all Governmental Authorities necessary to be obtained in order to effect the Closing (or Subsequent Closing).

(e) No Suspensions of Trading in Common Stock . The Common Stock shall not have been suspended, as of the Closing Date (or the applicable closing date of a Subsequent Closing), by the Commission or the Principal Trading Market from trading on the Principal Trading Market nor shall suspension by the Commission or the Principal Trading Market have been threatened, as of the Closing Date (or the applicable closing date of a Subsequent Closing), either (A) in writing by the Commission or the Principal Trading Market or (B) by falling below the minimum listing maintenance requirements of the Principal Trading Market.

(f) Company Deliverables . The Company shall have delivered the Company Deliverables in accordance with Section 2.2(a) (provided that the only Company Deliverables with respect to a Subsequent Closing shall be the applicable Shares, in book-entry form, the certificates set forth in Section 2.2(a)(iv) , (v)  and (vi) , and with respect to a closing of the First Acquisition Right or Second Acquisition Right, an appropriate legal opinion of Company Counsel).

(g) Compliance Certificate . The Company shall have delivered to the applicable Celgene Party a certificate, dated as of the Closing Date (or the applicable closing date of a Subsequent Closing) and signed by its Chief Executive Officer or its Chief Financial Officer, certifying to the fulfillment of the conditions specified in Sections 5.1(a) and (b)  in the form attached hereto as Exhibit D .

(h) Neither the Voting and Standstill Agreement nor the Registration Rights Agreement has been terminated in its entirety.

5.2 Conditions Precedent to the Obligations of the Company to sell Shares . The Company’s obligation to sell and issue the Shares at the Closing (or upon any Subsequent Closing) to the applicable Celgene Party is subject to the fulfillment, on or prior to the Closing Date (or the date of a Subsequent Closing), of each of the following conditions, any of which may be waived by the Company:

(a) Representations and Warranties . For the Closing, the representations and warranties made by the Celgene Parties in Section 3.2 hereof shall be true and correct in all material respects. For each Subsequent Closing, the representations and warranties made by the Celgene Parties in Section 3.2 hereof shall be true and correct in all material respects as of the date of such Subsequent Closing as if made on such date rather than on the date of this Agreement (except that, for the purposes of the representations and warranties in Sections 3.2(c) through (g) , “Celgene Parties” shall mean only the purchasers of shares at such Subsequent Closing).

(b) Performance . The Celgene Parties shall have performed, satisfied and complied in all material respects with all covenants, agreements and conditions required by this Agreement to be performed, satisfied or complied with by the Celgene Parties at or prior to the Closing (or Subsequent Closing, except that “Celgene Parties” shall mean only the purchasers of shares at such Subsequent Closing).

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(c) No Change of Control of Celgene . Celgene Corp. shall not have undergone any Change of Control, and if the purchaser of Shares at the applicable Closing or Subsequent Closing is Celgene RIVOT or a Permitted Transferee, then such purchaser is a direct or indirect wholly owned controlled subsidiary of Celgene Corp.

(d) Collaboration Agreement . The Collaboration Agreement shall still be in effect, without any expiration or termination thereof pursuant to Article 11 thereof.

(e) No Injunction . No statute, rule, regulation, executive order, decree, ruling or injunction shall have been enacted, entered, promulgated or endorsed by any Governmental Authority of competent jurisdiction that prohibits the consummation of any of the transactions contemplated by the Transaction Documents.

(f) Regulatory Approvals and Filings . All waiting periods under the HSR Act applicable to the purchase of the applicable Shares by the applicable Celgene Party shall have expired or been terminated, and the parties shall have made all other material filings and submissions with, and obtained all material authorizations, approvals, consents, qualifications, orders and waivers from, all Governmental Authorities necessary to be obtained in order to effect the Closing (or Subsequent Closing).

(g) Shareholder Approval . With respect to any Subsequent Closing, to the extent required by the NASDAQ Marketplace Rules, the Company shall have obtained shareholder approval of the issuance of Top-Up Shares or Acquisition Right Shares, as applicable, to the applicable Celgene Party.

(h) Celgene Deliverables . The applicable Celgene Party shall have delivered the Celgene Deliverables in accordance with Section 2.2(b) (provided that the only Celgene Deliverable with respect to a Subsequent Closing shall be the applicable purchase price).

(i) Compliance Certificate . The applicable Celgene Party shall have delivered to the Company a certificate, dated as of the Closing Date (or the applicable closing date of a Subsequent Closing) and signed by Celgene Corp.’s treasurer or other corporate officer, certifying to the fulfillment of the conditions specified in Sections 5.2(a) and (b)  in the form attached hereto as Exhibit E .

(j) Neither the Voting and Standstill Agreement nor the Registration Rights Agreement has been terminated in its entirety.

ARTICLE VI.

MISCELLANEOUS

6.1 Termination . This Agreement may be terminated and the transactions contemplated hereby abandoned:

(a) by written consent of the Company and the Celgene Parties;

(b) prior to the Closing, by written notice to the Company from the Celgene Parties if:

(i) there is any material breach of any representation, warranty, covenant or agreement on the part of the Company set forth in this Agreement, such that the conditions specified in Section 5.1 would not be satisfied at the Closing (a “ Terminating Company Breach ”), except that, if such

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Terminating Company Breach is curable by the Company through the exercise of its reasonable best efforts, then, for a period of up to thirty (30) days after receipt by the Company of notice from the Celgene Parties of such breach, but only as long as the Company continues to use its reasonable best efforts to cure such Terminating Company Breach (the “ Company Cure Period ”), such termination shall not be effective and the Termination Date shall be automatically extended until the end of the Company Cure Period, and such termination shall become effective only if the Terminating Company Breach is not cured within the Company Cure Period;

(ii) the Closing has not occurred on or before December 31, 2015 (subject to Sections 6.1(b)(i) and 6.1(c)(i) , the “ Termination Date ”), unless a Celgene Party’s willful breach is the primary reason for the Closing not occurring on or before such date; or

(iii) the consummation of any of the transactions contemplated hereby is permanently enjoined or prohibited by the terms of a final, non-appealable order of a court of competent jurisdiction; or

(c) prior to the Closing, by written notice to the Celgene Parties from the Company if:

(i) there is any material breach of any representation, warranty, covenant or agreement on the part of either of the Celgene Parties set forth in this Agreement, such that the conditions specified in Section 5.2 would not be satisfied at the Closing (a “ Terminating Celgene Breach ”), except that, if any such Terminating Celgene Breach is curable by the Celgene Parties through the exercise of its reasonable best efforts, then, for a period of up to thirty (30) days after receipt by the Celgene Parties of notice from the Company of such breach, but only as long as the Celgene Parties continues to exercise such reasonable best efforts to cure such Terminating Celgene Breach (the “ Celgene Cure Period ”), such termination shall not be effective and the Termination Date shall be automatically extended until the end of the Celgene Cure Period, and such termination shall become effective only if the Terminating Celgene Breach is not cured within the Celgene Cure Period;

(ii) the Closing has not occurred on or before the Termination Date, unless the Company’s willful breach is the primary reason for the Closing not occurring on or before such date; or

(iii) the consummation of any of the transactions contemplated hereby is permanently enjoined or prohibited by the terms of a final, non-appealable order of a court of competent jurisdiction.

6.2 Termination of Purchase Rights . The Company will have the unilateral right to terminate the rights of the Celgene Parties set forth in Sections 2.3 and 2.4 of this Agreement upon written notice to the Celgene Parties (a) if the Company has exercised its termination rights under Section 2.2 of the Voting and Standstill Agreement, (b) if Celgene Corp. undergoes a Change of Control, or (c) upon the expiration of the Term (as defined in the Collaboration Agreement) or the earlier termination of the Collaboration Agreement pursuant to Article 11 thereof. The Company will have the unilateral right to terminate the rights of Celgene RIVOT set forth in Sections 2.3 and 2.4 of this Agreement upon written notice to the Celgene Parties if Celgene RIVOT ceases to be a direct or indirect wholly owned controlled subsidiary of Celgene Corp.

6.3 Effect of Termination . In the event of the termination of this Agreement pursuant to Section 6.1 , this Agreement shall forthwith become void and have no effect, without any liability on the part of any party hereto or its respective Affiliates, officers, directors or stockholders, other than liability of the Company or either Celgene Party, as the case may be, for any intentional and willful breach of this Agreement occurring prior to such termination; provided, however, that, a failure of a Party to

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consummate the purchase of Shares in breach of this Agreement shall be deemed to be intentional and willful. The termination of this Agreement pursuant to Section 6.1 shall also result in a termination of all other Transaction Documents.

6.4 Fees and Expenses . The Company and the Celgene Parties shall each pay the fees and expenses of their respective advisers, counsel, accountants and other experts, if any, and all other expenses incurred by such party in connection with the negotiation, preparation, execution, delivery and performance of this Agreement. The Company shall pay all Transfer Agent fees and stamp taxes levied in connection with the sale and issuance of the Shares to the Celgene Parties.

6.5 Entire Agreement . The Transaction Documents, together with the exhibits and schedules thereto, contain the entire understanding of the parties with respect to the subject matter hereof and supersede all prior agreements, understandings, discussions and representations, oral or written, with respect to sale of the Shares, which the parties acknowledge have been merged into such documents, exhibits and schedules. At or after the Closing, and without further consideration, the Company and the Celgene Parties will execute and deliver to the other such further documents as may be reasonably requested in order to give practical effect to the intention of the parties under the Transaction Documents.

6.6 Notices . Any and all notices or other communications or deliveries required or permitted to be provided hereunder shall be in writing and shall be deemed given and effective on the earliest of (a) the date of transmission, if such notice or communication is delivered via facsimile (provided the sender receives a machine-generated confirmation of successful transmission) at a facsimile number specified in this Section 6.6 prior to 5:00 P.M., New York City time, on a Trading Day, (b) the next Trading Day after the date of transmission, if such notice or communication is delivered via facsimile at a facsimile number specified in this Section 6.6 on a day that is not a Trading Day or later than 5:00 P.M., New York City time, on any Trading Day, (c) the Trading Day following the date of mailing, if sent by U.S. nationally recognized overnight courier service with next day delivery specified, (d) upon confirmation via electronic return receipt if such notice or communication is delivered via email at an email address specified in this Section 6.6 or (e) upon actual receipt by the party to whom such notice is required to be given. The address for such notices and communications shall be as follows:

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or such other address as may be designated in writing hereafter, in the same manner, by such Person.

Any Company FTU Notice, Company STU Notice, or Company TTU Notice shall be sent by facsimile, and any Purchase Notice shall be sent by e-mail (in each case with a copy by U.S. nationally recognized overnight courier service with next day delivery), and shall be deemed received by Company or the applicable Celgene Party, as applicable, upon the date of receipt Pacific Time of such facsimiles or e-mails, as applicable (whether or not such facsimile or e-mail, as applicable, is checked or read by the recipient), for purposes of determining the date of delivery of such notices hereunder.

6.7 Amendments; Waivers . No provision of this Agreement may be waived, modified, supplemented or amended except in a written instrument signed, in the case of an amendment, by the Company and the Celgene Parties. No waiver of any default with respect to any provision, condition or requirement of this Agreement shall be deemed to be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the exercise of any such right.

6.8 Specific Performance . The parties hereby acknowledge and agrees that the rights of the parties hereunder are special, unique and of extraordinary character, and that if any party refuses or otherwise fails to act, or to cause its Affiliates to act, in accordance with the provisions of this Agreement, such refusal or failure would result in irreparable injury to the Company or the Celgene Parties, as the case may be, the exact amount of which would be difficult to ascertain or estimate and the remedies at law for which would not be reasonable or adequate compensation. Accordingly, if any party refuses or otherwise fails to act, or to cause its Affiliates to act, in accordance with the provisions of this Agreement, then, in addition to any other remedy which may be available to any damaged party at law or in equity, such damaged party will be entitled to seek specific performance and injunctive relief, without posting bond or other security, and without the necessity of proving actual or threatened damages, which remedy such damaged party will be entitled to seek in any court of competent jurisdiction.

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6.9 Construction . The headings herein are for convenience only, do not constitute a part of this Agreement and shall not be deemed to limit or affect any of the provisions hereof. The language used in this Agreement will be deemed to be the language chosen by the parties to express their mutual intent, and no rules of strict construction will be applied against any party. This Agreement shall be construed as if drafted jointly by the parties, and no presumption or burden of proof shall arise favoring or disfavoring any party by virtue of the authorship of any provisions of this Agreement or any of the Transaction Documents.

6.10 Successors and Assigns . The provisions of this Agreement shall inure to the benefit of and be binding upon the parties and their successors and permitted assigns. This Agreement, or any rights or obligations hereunder, may not be assigned by either party without the prior written consent of the other; provided that a Celgene Party may assign its right to purchase Shares hereunder, in whole or in part, to one or more Permitted Transferees, provided that any such Permitted Transferee shall be deemed to be a “Celgene Party” hereunder for purposes of (i) representations and warranties to be made hereunder as of the Closing or Subsequent Closing at which such Permitted Transferee purchases Shares, (ii) covenants to be performed hereunder with respect to such closing, and (iii) the provisions of Article IV, and such Permitted Transferee shall agree in writing to be bound by such covenants and provisions.

6.11 No Third-Party Beneficiaries . This Agreement is intended for the benefit of the parties hereto and their respective successors and permitted assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other Person.

6.12 Governing Law . All questions concerning the construction, validity, enforcement and interpretation of this Agreement shall be governed by and construed and enforced in accordance with the internal laws of the State of New York, without regard to the principles of conflicts of law thereof. Each party agrees that all Proceedings concerning the interpretations, enforcement and defense of the transactions contemplated by this Agreement and any other Transaction Documents (whether brought against a party hereto or its respective Affiliates, employees or agents) shall be commenced exclusively in the New York Courts. Each party hereto hereby irrevocably submits to the exclusive jurisdiction of the New York Courts for the adjudication of any dispute hereunder or in connection herewith or with any transaction contemplated hereby or discussed herein (including with respect to the enforcement of any of the Transaction Documents), and hereby irrevocably waives, and agrees not to assert in any Proceeding, any claim that it is not personally subject to the jurisdiction of any such New York Court, or that such Proceeding has been commenced in an improper or inconvenient forum. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such Proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this Agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by law. EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

6.13 Survival . The representations, warranties, agreements and covenants contained herein shall survive the Closing and the delivery of the Shares.

6.14 Execution . This Agreement may be executed in two or more counterparts, all of which when taken together shall be considered one and the same agreement and shall become effective when counterparts have been signed by each party and delivered to the other party, it being understood that both parties need not sign the same counterpart. In the event that any signature is delivered by facsimile

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transmission, or by e-mail delivery of a “.pdf” data file, such signature shall create a valid and binding obligation of the party executing (or on whose behalf such signature is executed) with the same force and effect as if such facsimile signature page were an original thereof.

6.15 Severability . If any provision of this Agreement is held to be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Agreement shall not in any way be affected or impaired thereby and the parties will attempt to agree upon a valid and enforceable provision that is a reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Agreement.

6.16 Celgene Parties . The Company and the Celgene Parties hereby acknowledge and agree that (a) Celgene Corp. is the party to this Agreement with respect to all rights and obligations (including payment obligations) under this Agreement with respect to the Second Acquisition Right; (b) Celgene RIVOT is the party to this Agreement with respect to all rights and obligations (including payment obligations) under this Agreement with respect to the Closing Shares; and (c) Celgene Corp. or Celgene RIVOT, at the discretion of Celgene Corp., shall undertake all other actions permitted or required to be taken by Celgene. Notwithstanding the foregoing, Celgene Corp. shall cause Celgene RIVOT to perform Celgene RIVOT’s obligations hereunder.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

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IN WITNESS WHEREOF, the parties hereto have caused this Share Purchase Agreement to be duly executed by their respective authorized signatories as of the date first indicated above.

IN WITNESS WHEREOF, the parties hereto have caused this Share Purchase Agreement to be duly executed by their respective authorized signatories as of the date first indicated above.

EXHIBITS

EXHIBIT A

FORM OF VOTING AND STANDSTILL AGREEMENT

EXHIBIT B

FORM OF REGISTRATION RIGHTS AGREEMENT

EXHIBIT C

FORM OF SECRETARY’S CERTIFICATE

The undersigned hereby certifies that he is the duly elected, qualified and acting Secretary of Juno Therapeutics, Inc., a Delaware corporation (the “ Company ”), and that as such he is authorized to execute and deliver this certificate in the name and on behalf of the Company and in connection with the Share Purchase Agreement, dated as of             , 2015, by and among the Company, Celgene Corporation and Celgene RIVOT Ltd. (the “Share Purchase Agreement” ), and further certifies solely in his official capacity, in the name and on behalf of the Company, the items set forth below. Capitalized terms used but not otherwise defined herein shall have the meaning set forth in the Share Purchase Agreement.

Latham & Watkins LLP, special counsel to the Company, is entitled to rely on this certificate in connection with the opinion that such firm is rendering pursuant to the Share Purchase Agreement.

IN WITNESS WHEREOF, the undersigned has hereunto set his hand as of this      day of             , 20    .

EXHIBIT A

Resolutions

EXHIBIT B

Restated Certificate of Incorporation

EXHIBIT C

Bylaws

EXHIBIT D

FORM OF OFFICER’S CERTIFICATE

The undersigned, the [Chief Executive Officer][Chief Financial Officer] of Juno Therapeutics, Inc., a Delaware corporation (the “ Company ”), pursuant to Section 5.1(g) of the Share Purchase Agreement, dated as of                     , by and among the Company, Celgene Corporation and Celgene RIVOT Ltd. (the “ Share Purchase Agreement ”), hereby represents, warrants and certifies as follows (capitalized terms used but not otherwise defined herein shall have the meaning set forth in the Share Purchase Agreement):

Latham & Watkins LLP, special counsel to the Company, is entitled to rely on this certificate in connection with the opinion that such firm is rendering pursuant to the Share Purchase Agreement.

IN WITNESS WHEREOF, the undersigned has executed this certificate this      day of             , 20    .

EXHIBIT E

FORM OF OFFICER’S CERTIFICATE

The undersigned, the [                    ] of Celgene Corporation, a Delaware corporation (“ Celgene ”), pursuant to Section 5.2(i) of the Share Purchase Agreement, dated as of                     , by and among Juno Therapeutics, Inc., Celgene and Celgene RIVOT Ltd. (the “ Share Purchase Agreement ”), hereby represents, warrants and certifies as follows (capitalized terms used but not otherwise defined herein shall have the meaning set forth in the Share Purchase Agreement):

Latham & Watkins LLP, special counsel to Juno Therapeutics, Inc., is entitled to rely on this certificate in connection with the opinion that such firm is rendering pursuant to the Share Purchase Agreement.

IN WITNESS WHEREOF, the undersigned has executed this certificate this      day of             , 20    .

Schedule 2.4(b)

If the First Acquisition Right Base Price is less than or equal to $[***], the premium shall be [***]% (reduced to [***]% if the FAR Opt-In Condition has been met) of the First Acquisition Right Base Price. If the First Acquisition Right Base Price is more than $[***], the premium shall be the greater of (i) [***]% (reduced to [***]% if the FAR Opt-In Condition has been met) of the First Acquisition Right Base Price and (ii) $[***] (reduced to $[***] if the FAR Opt-In Condition has been met), provided that the foregoing dollar amounts shall be appropriately and equitably adjusted for any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization that occurs subsequent to the date hereof but prior to the delivery of the FAR Notice.

For the purposes hereof, “FAR Opt-In Condition” means the Company has, on or before the timely delivery of the FAR Notice, exercised the Juno Option with respect to at least [***] Celgene Programs (which may include [***]), provided that each such Celgene Program [***].

[***] Certain information in this document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.

Schedule 2.4(d)

If the Second Acquisition Right Base Price is less than or equal to $[***], the premium shall be [***]% of the Second Acquisition Right Base Price. If the Second Acquisition Right Base Price is more than $[***], the premium shall be the greater of (i) [***]% of the Second Acquisition Right Base Price and (ii) $[***], provided that the foregoing dollar amounts shall be appropriately and equitably adjusted for any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization that occurs subsequent to the Closing but prior to the delivery of the SAR Notice.

[***] Certain information in this document has been omitted and filed separately with the Securities and Exchange Commission. Confidential treatment has been requested with respect to the omitted portions.

Disclosure Schedules

These Disclosure Schedules have been prepared and delivered by Juno Therapeutics, Inc. (the “ Company ”) in accordance with the Share Purchase Agreement (the “ Agreement ”), dated as of June 29, 2015, by and among the Company. Celgene RIVOT Ltd. (“ Celgene RIVOT ”) and Celgene Corporation (“ Celgene ”).

These Disclosure Schedules are part of and are incorporated into the Agreement, and, unless the context otherwise requires, all capitalized terms used herein and not otherwise defined have the same meanings given to them in the Agreement. Headings and subheadings have been inserted herein for convenience of reference only and will not have the effect of amending or changing the express description of any portion hereof as set forth in the Agreement. The disclosure of any information will not be deemed or interpreted to constitute an acknowledgment that such information is material or is otherwise required to be disclosed in connection with the representations and warranties made by the Company in the Agreement. No disclosure in any section of the Disclosure Schedules relating to any possible breach or violation of any contract or any law, regulation, order or similar legal requirement will be construed as an admission or indication that any such breach or violation exists or has actually occurred.

Section 3.1(f)

Capitalization

Common Stock, par value $0.0001 per share

Authorized: 495,000,000 shares

Outstanding: 91,376,720 shares, excluding any options that may have been exercised on the date hereof, which shares are included in the option numbers below

Preferred Stock, par value $0.0001 per share

Authorized: 5,000,000 shares

Outstanding: No shares

Number of shares of Common Stock reserved for future issuance under the Company’s 2014 Equity Incentive Plan pursuant to future awards, exercise of outstanding stock options, or vesting of outstanding restricted stock units: 10,296,851 shares, less any such options that may have been exercised on the date hereof

Number of shares of Common Stock reserved for future issuance under the Company’s 2014 Employee Stock Purchase Plan: 2,856,395 shares

Options to acquire Common Stock outstanding under the Company’s 2014 Equity Incentive Plan: 1,634,803 shares, less any such options that may have been exercised on the date hereof

Options to acquire Common Stock outstanding under the Company’s 2013 Equity Incentive Plan: 2,632,286 shares, less any such options that may have been exercised on the date hereof

Restricted stock units (Common Stock) outstanding under the Company’s 2014 Equity Incentive Plan: 158,516 shares

See the SEC Reports regarding success payment obligations to Memorial Sloan Kettering Cancer Center and Fred Hutchinson Cancer Center, and certain milestone obligations to Opus Bio, Inc., which may be paid in shares of Common Stock.

Section 3.1(g)

SEC Reports; Disclosure Materials

The following Material Contracts (or amendments to Material Contracts) have not yet been filed as exhibits to the SEC Reports, each of which are to be filed with the Company’s next quarterly report on Form 10-Q:

Exhibit 10.2

VOTING AND STANDSTILL AGREEMENT

This Voting and Standstill Agreement (this “ Agreement ”) is dated as of June 29, 2015, by and between Juno Therapeutics, Inc., a Delaware corporation (the “ Company ”), Celgene RIVOT Ltd. (“ Celgene RIVOT ”) and Celgene Corporation (“ Celgene Corporation ”, and together with Celgene RIVOT, the “ Investors ”).

A. The Share Purchase Agreement, dated as of June 29, 2015, by and between the Company and the Investor (the “ Purchase Agreement ”), provides for the issuance and sale by the Company to the Investors, and the purchase by the Investors, of shares of the Company’s common stock, par value $0.0001 per share (the “ Common Stock ”), including shares of Common Stock that may be purchased by the Celgene RIVOT at an initial Closing as well as pursuant to certain Top-Up Rights and a First Acquisition Right and a Second Acquisition Right, each as defined in the Purchase Agreement (collectively, the “ Purchased Shares ”); and

B. As a condition to consummating the transactions contemplated by the Purchase Agreement, the Investors and the Company have agreed upon certain rights and restrictions as set forth herein with respect to the Purchased Shares and other securities of the Company beneficially owned by each Investor and its Affiliates, and it is a condition to the closing under the Purchase Agreement that this Agreement be executed and delivered by the Investors and the Company.

NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the Company and the Investors agree as follows:

ARTICLE 1.

DEFINITIONS

As used in this Agreement, the following terms shall have the following meanings:

1.1 “ Acquisition Proposal ” shall have the meaning set forth in Section 2.1(c).

1.2 “ Affiliate ” shall mean (i) any Person that directly or indirectly beneficially owns a majority of the voting securities of or voting interests in an Investor or (ii) any direct or indirect majority owned subsidiaries of an Investor or of such a Person.

1.3 “ Agreement ” shall have the meaning set forth in the Preamble to this Agreement, including all Exhibits attached hereto.

1.4 “ beneficial owner ,” “ beneficially owns ,” “ beneficial ownership ” and terms of similar import used in this Agreement shall, with respect to a Person, have the meaning set forth in Rule 13d-3 under the Exchange Act (i) assuming the full conversion into, and exercise and exchange for, shares of Common Stock of all Common Stock Equivalents beneficially owned by such Person and (ii) determined without regard for the number of days in which such Person has the right to acquire such beneficial ownership.

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1.5 “ Business Day ” shall mean a day on which commercial banking institutions in New York, New York are open for business.

1.6 “ Celgene Group ” shall have the meaning set forth in the Purchase Agreement.

1.7 “ Change of Control ” shall mean, with respect to the Company, any of the following events: (i) any Person is or becomes the beneficial owner (except that a Person shall be deemed to have beneficial ownership of all shares that any such Person has the right to acquire, whether such right which may be exercised immediately or only after the passage of time), directly or indirectly, of a majority of the total voting power represented by all Shares of Then Outstanding Common Stock; (ii) the Company consolidates with or merges into another corporation or entity, or any corporation or entity consolidates with or merges into the Company, other than (A) a merger or consolidation which would result in the voting securities of the Company outstanding immediately prior to such merger or consolidation continuing to represent (either by remaining outstanding or by being converted into voting securities of the surviving entity or any parent thereof) a majority of the combined voting power of the voting securities of the Company or such surviving entity or any parent thereof outstanding immediately after such merger or consolidation, or (B) a merger or consolidation effected to implement a recapitalization of the Company (or similar transaction) in which no Person becomes the beneficial owner, directly or indirectly, of a majority of the total voting power of all Shares of Then Outstanding Common Stock; (iii) the Company conveys, transfers or leases all or substantially all of its assets to any Person other than a wholly owned Affiliate of the Company or (iv) individuals who constitute Continuing Directors cease for any reason to constitute at least a majority of the Board of Directors of the Company.

1.8 “ Closing Date ” shall have the meaning set forth in the Purchase Agreement.

1.9 “ Collaboration Agreement ” shall mean the Master Research and Collaboration Agreement by and among the Company and Investors of even date herewith, as the same may be amended from time to time.

1.10 “ Common Stock ” shall have the meaning set forth in the Preamble to this Agreement.

1.11 “ Common Stock Equivalents ” shall mean any options, warrants or other securities or rights convertible into or exercisable or exchangeable for, whether directly or following conversion into or exercise or exchange for other options, warrants or other securities or rights, shares of Common Stock.

1.12 “ Company ” shall have the meaning set forth in the Preamble to this Agreement.

1.13 “ Competitor ” shall mean any operating company with a biopharmaceutical business, or any other Person that directly or indirectly beneficially owns a majority of the voting securities of or voting interests in such a company, or any direct or indirect majority-owned subsidiary of such a company or of such a Person.

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1.14 “ Continuing Directors ” shall mean the directors of the Company on the date hereof, and each other director, if in each case, such other director’s nomination for election to the Board of Directors was recommended by, or whose appointment to the Board of Directors was approved by, at least a majority of the other Continuing Directors.

1.15 “ Disposition ” or “ Dispose of ” shall mean any (i) offer, pledge (other than pledges in connection with bona fide debt financing transactions involving a general lien on assets of an Investor), sale, contract to sell, sale of any option or contract to purchase, purchase of any option or contract to sell, grant of any option, right or warrant for the sale of, or other disposition of or transfer of any shares of Common Stock, or any Common Stock Equivalents, including, without limitation, any “short sale” or similar arrangement, or (ii) swap, hedge, derivative instrument, or any other agreement or any transaction that transfers, in whole or in part, directly or indirectly, the economic consequence of ownership of shares of Common Stock, whether any such swap or transaction is to be settled by delivery of securities, in cash or otherwise.

1.16 “ Exchange Act ” shall mean the Securities Exchange Act of 1934, as amended, and the rules and regulations of the SEC promulgated thereunder.

1.17 “ FAR Acquisition Percentage ” shall have the meaning set forth in the Purchase Agreement.

1.18 “ FAR Notice ” shall have the meaning set forth in the Purchase Agreement.

1.19 “ FAR Termination Date ” shall have the meaning set forth in the Purchase Agreement.

1.20 “ First Subsequent Designee ” shall have the meaning set forth in Section 4.4.

1.21 “ Governmental Authority ” shall mean any court, agency, authority, department, regulatory body or other instrumentality of any government or country or of any national, federal, state, provincial, regional, county, city or other political subdivision of any such government or country or any supranational organization of which any such country is a member.

1.22 “ Initial Designee ” shall have the meaning set forth in Section 4.4.

1.23 “ Investors ” shall have the meaning set forth in the Preamble to this Agreement.

1.24 “ Investor Designee ” shall have the meaning set forth in Section 4.4.

1.25 “ Law ” or “ Laws ” shall mean all laws, statutes, rules, regulations, orders, judgments, injunctions and/or ordinances of any Governmental Authority.

1.26 “ Lock-Up Agreement ” shall have the meaning set forth in Section 3.4.

1.27 “ Lock-Up Period ” shall have the meaning set forth in Section 3.1.

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1.28 “ Modified Clause ” shall have the meaning set forth in Section 6.7.

1.29 “ Offeror ” shall have the meaning set forth in Section 2.1(c).

1.30 “ Organizational Documents ” shall have the meaning set forth in the Purchase Agreement.

1.31 “ Permitted Transferee ” shall mean a controlled Affiliate of an Investor that is wholly owned, directly or indirectly, by such Investor; it being understood that for purposes of this definition “wholly owned” shall mean an Affiliate in which an Investor owns, directly or indirectly, at least ninety-nine percent (99%) of the outstanding capital stock or ownership interests of such Affiliate; provided, however, that no such Person shall be deemed a Permitted Transferee for any purpose under this Agreement unless: (a) such Investor shall have, within five (5) days prior to such transfer, furnished to the Company written notice of the name and address of such Permitted Transferee, details of its status as a Permitted Transferee and details of the Shares of Then Outstanding Common Stock and/or Common Stock Equivalents to be transferred, (b) the Permitted Transferee, prior to or simultaneously with such transfer, shall have agreed in writing to be subject to and bound by all restrictions and obligations set forth in this Agreement as though it were such Investor hereunder, and (c) such Investor acknowledges that it continues to be bound by all restrictions and obligations set forth in this Agreement.

1.32 “ Person ” shall mean any individual, partnership, firm, corporation, association, trust, unincorporated organization, government or any department or agency thereof or other entity, as well as any syndicate or group that would be deemed to be a Person under Section 13(d)(3) of the Exchange Act.

1.33 “ Purchase Agreement ” shall have the meaning set forth in the Preamble to this Agreement, and shall include all Exhibits attached thereto.

1.34 “ Purchased Shares ” shall have the meaning set forth in the Preamble to this Agreement, and shall be adjusted for (i) any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization and (ii) any Common Stock issued as (or issuable upon the exercise of any warrant, right or other security that is issued as) a dividend or other distribution with respect to, or in exchange or in replacement of, the Purchased Shares.

1.35 “ Qualified Investor Designee ” shall have the meaning set forth in Section 4.4.

1.36 “ Registration Rights Agreement ” shall mean the Registration Rights Agreement by and among the Company and the Investors of even date herewith.

1.37 “ Replacement Designee ” shall have the meaning set forth in Section 4.4.

1.38 “ Restricted Period ” shall mean the period from and after the date of this Agreement until the later of (i) the fifth (5 ^th ) anniversary of the date of this Agreement and (ii) the expiration of the Term (as defined in the Collaboration Agreement) or the earlier termination of the Collaboration Agreement pursuant to Article 11 thereof (other than as a result

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of its termination pursuant to Section 2.2 of this Agreement). For the avoidance of doubt, the termination of one or more Programs under the Collaboration Agreement shall not be deemed a termination of the Collaboration Agreement unless and until the Collaboration Agreement is terminated in its entirety.

1.39 “ Sale Process ” shall mean any process undertaken by the Company that is designed to result in a Change of Control.

1.40 “ SAR Notice ” shall have the meaning set forth in the Purchase Agreement.

1.41 “ SAR Termination Date ” shall have the meaning set forth in the Purchase Agreement.

1.42 “ SEC ” shall mean the United States Securities and Exchange Commission.

1.43 “ Second Acquisition Right ” shall have the meaning set forth in the Purchase Agreement.

1.44 “ Securities Act ” shall mean the Securities Act of 1933, as amended, and the rules and regulations of the SEC promulgated thereunder.

1.45 “ Sell-Down Period ” shall have the meaning set forth in the Purchase Agreement.

1.46 “ Shares of Then Outstanding Common Stock ” shall mean, at any time, the issued and outstanding shares of Common Stock at such time, as well as all capital stock issued and outstanding as a result of any stock split, stock dividend, or reclassification of Common Stock distributable, on a pro rata basis, to all holders of Common Stock, as applicable.

1.47 “ Standstill Parties ” shall have the meaning set forth in Section 2.1.

1.48 “ Third Party ” shall mean any Person other than an Investor, the Company or any of their respective Affiliates.

1.49 “ Top-Up Right ” shall have the meaning set forth in the Purchase Agreement.

ARTICLE 2.

RESTRICTIONS ON BENEFICIAL OWNERSHIP

2.1 Standstill . During the Restricted Period, neither Investor nor any of their Affiliates or executive officers or directors (collectively, the “ Standstill Parties ”) shall (and each Investor shall cause its Affiliates and executive officers and directors not to), except as expressly contemplated by the Purchase Agreement or hereunder or approved or invited in writing by the Company, including in connection with a Sale Process:

(a) directly or indirectly, acquire beneficial ownership of Shares of Then Outstanding Common Stock and/or Common Stock Equivalents, or make a tender, exchange or other offer to acquire Shares of Then Outstanding Common Stock and/or Common Stock Equivalents, except as contemplated by the Purchase Agreement;

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(b) directly or indirectly, seek to have called any meeting of the stockholders of the Company, propose or nominate for election to the Company’s Board of Directors any person whose nomination has not been approved by a majority of the Company’s Board of Directors or cause to be voted in favor of such person for election to the Company’s Board of Directors any Shares of Then Outstanding Common Stock other than as contemplated by Sections 4.1 or 4.4 hereof;

(c) directly or indirectly, encourage or support a tender, exchange or other offer or proposal by any Third Party (an “ Offeror ”) the consummation of which would result in a Change of Control of the Company (an “ Acquisition Proposal ”);

(d) directly or indirectly, solicit proxies or consents or become a participant in a solicitation (as such terms are defined in Regulation 14A under the Exchange Act) in opposition to the recommendation of a majority of the Company’s Board of Directors with respect to any matter, or seek to advise or influence any Third Party, with respect to voting of any Shares of Then Outstanding Common Stock of the Company;

(e) deposit any Shares of Then Outstanding Common Stock in a voting trust or subject any Shares of Then Outstanding Common Stock to any arrangement or agreement with respect to the voting of such Shares of Then Outstanding Common Stock other than as contemplated by Section 4.1 hereof;

(f) act in concert with any Third Party to take any action in clauses (a) through (e) above, or form, join or in any way participate in a “partnership, limited partnership, syndicate, or other group” with any Third Party within the meaning of Section 13(d)(3) of the Exchange Act with respect to the equity securities of the Company;

(g) enter into discussions, negotiations, arrangements or agreements with any Third Party relating to the foregoing actions referred to in (a) through (e) above; or

(h) request or propose in writing to the Company’s Board of Directors, any member(s) thereof or any officer of the Company that the Company amend, waive, or consider the amendment or waiver of, any provisions set forth in this Section 2.1; provided, however, that the mere voting in accordance with Section 4 hereof of any voting securities of the Company held by an Investor, its executive officers or directors, or its Affiliates shall not constitute a violation of any of clauses (a) through (h) above.

Notwithstanding the foregoing, (A) none of an Investor’s executive officers or directors shall be restricted from purchasing shares of the Common Stock for his or her personal account (other than through a tender or exchange offer), tendering his or her shares into a Third Party tender or exchange offer, voting his or her shares in any way he or she determines, or depositing his or her shares into a voting trust or subjecting them to any arrangement or agreement with respect to the voting of such shares; and (B) if any executive officer or director of an Investor serves as a

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member of the Company’s Board of Directors, any action he or she takes in the performance of his or her duties as a member of the Company’s Board of Directors shall not be deemed to violate this Section 2.1, except if he or she takes such action at the direction of an Investor or an Affiliate thereof.

2.2 Notwithstanding anything to the contrary herein or in the Collaboration Agreement, the Company will have the unilateral right to terminate all of (a) the rights of the Investors set forth in Section 4.4 of this Agreement, (b) the rights of the Investors set forth in Sections 2.3 and 2.4 of the Purchase Agreement, (c) the Registration Rights Agreement, and (d) the Collaboration Agreement, and any Development & Commercialization Agreement entered into pursuant to the Collaboration Agreement, in their entirety (as provided therein), upon written notice to the Investors, if any of the Standstill Parties shall have breached Section 2.1 of the Agreement in any material respect and, if such breach is susceptible of cure, failed to cure such breach within 48 hours after receiving written notice of such alleged breach from the Company, and upon such termination the terminated rights or agreements shall have no further force or effect (except, in the case of termination of the Collaboration Agreement and any Development & Commercialization Agreement, as provided therein). For the avoidance of doubt, the Company shall not have the termination rights set forth in the preceding sentence as a result of a de minimis breach of Section 2.1(a) of the Agreement or an inadvertent breach of Section 2.1(g) of the Agreement arising from informal discussions covering general corporate or other business matters the purpose of which is not intended to effectuate or lead to any of the actions referred to in paragraphs (a) through (e) of Section 2.1 of the Agreement.

2.3 The Company shall provide the Investors with a reasonable opportunity to reasonably participate in any Sale Process.

ARTICLE 3.

RESTRICTIONS ON DISPOSITIONS

3.1 Lock-Up . During (i) the 364 day period following the Closing Date, (ii) each 364 day period following the date of any other closing of purchase of shares of Common Stock under the Purchase Agreement, (iii) if an Investor is eligible to deliver a FAR Notice under Section 2.4(a) of the Purchase Agreement and fails to do so prior to the FAR Termination Date, the 364 day period following the FAR Termination Date, and (iv) if an Investor is eligible to deliver a SAR Notice under Section 2.4(c) of the Purchase Agreement and fails to do so prior to the SAR Termination Date, the 364 day period following the SAR Termination Date (each such period, a “ Lock-Up Period ”), without the prior approval of a majority of the Company’s Board of Directors or as contemplated by Section 3.3 , each Investor shall not, and shall cause its Affiliates not to, Dispose of (x) any of the Purchased Shares or any shares of Common Stock beneficially owned by such Investor or any of its Affiliates as of the date of this Agreement, together with any shares of Common Stock issued in respect thereof as a result of any stock split, stock dividend, share exchange, merger, consolidation or similar recapitalization, and (y) any Common Stock issued as (or issuable upon the exercise of any warrant, right or other security that is issued as) a dividend or other distribution with respect to, or in exchange or in replacement of, the shares of Common Stock described in clause (x) of this sentence; provided, however, that the foregoing shall not prohibit an Investor or its Affiliates from (A) transferring Purchased Shares

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to a Permitted Transferee or to the Company, (B) subject to the limitations set forth in Section 3.2, offering, selling, contracting to sell or offering to sell any Shares of Then Outstanding Common Stock as an Investor or its Affiliates may hold from time to time in order to reduce the beneficial ownership of the Celgene Group to the FAR Acquisition Percentage of the Shares of Then Outstanding Common Stock, or (C) offering, selling, contracting to sell or offering to sell any Shares of Then Outstanding Common Stock as an Investor or its Affiliates may hold from time to time in order to reduce the beneficial ownership of the Celgene Group to 16% during a Sell-Down Period. For the avoidance of doubt, any transfer, or issuance, of any capital stock or ownership interests in Celgene RIVOT or any controlled Affiliate of Celgene Corporation that causes Celgene RIVOT or any Permitted Transferee that then holds Purchased Shares to no longer be a direct or indirect wholly owned controlled subsidiary of Celgene Corporation shall be deemed a Disposition for all purposes under this Agreement.

3.2 Sale Limitations . Subject to the restrictions set forth in Section 3.1, each Investor agrees that, except for any transfer of Shares of Then Outstanding Common Stock and/or Common Stock Equivalents by such Investor to a Permitted Transferee or the Company, it shall not, and shall cause its Affiliates not to, Dispose of any Shares of Then Outstanding Common Stock and/or Common Stock Equivalents at any time: (a) except (i) pursuant to a registered public offering in accordance with the Registration Rights Agreement, (ii) pursuant to Rule 144 under the Securities Act or (iii) pursuant to privately negotiated sales in transactions exempt from the registration requirements under the Securities Act, (b) if such Dispositions, in any rolling 3-month period, exceed one percent (1%) of the Shares of Then Outstanding Common Stock of the Company or (c) to any Person that such Investor or Affiliate knows (after a reasonable inquiry in a private placement) is a Competitor of the Company. Notwithstanding this Section 3.2, if an Investor or any of its Affiliates knowingly Dispose of any shares of Common Stock prior to the fifth anniversary of the exercise of the Second Acquisition Right or, if the Second Acquisition Right expires unexercised or does not become exercisable, the fifth anniversary of the SAR Termination Date, in a manner that would have breached Section 3.1 if such Disposition had occurred during a Lock-Up Period, then (A) such Investor or its Affiliates shall promptly notify the Company in writing of such Disposition in accordance with Section 6.3 and (B) the Company shall have the right within 90 days of learning of such Disposition to terminate (by notice to the Investors in accordance with Section 6.3) all of the Investors’ and their Permitted Transferees’ future rights under the Purchase Agreement to acquire any shares of Common Stock.

3.3 Certain Tender Offers . Notwithstanding any other provision of this Section 3, this Section 3 shall not prohibit or restrict any Disposition of Shares of Then Outstanding Common Stock and/or Common Stock Equivalents by the Standstill Parties into (a) a tender offer by a Third Party that if completed in accordance with its terms would result in a Change of Control or (b) an issuer tender offer by the Company.

3.4 Offering Lock-Up . Each Investor shall, if requested by the Company and an underwriter of Common Stock of the Company in connection with any public offering involving an underwriting of Common Stock of the Company, agree not to Dispose of any Shares of Then Outstanding Common Stock and/or Common Stock Equivalents for a specified period of time, such period of time not to exceed ninety (90) days (a “ Lock-Up Agreement ”), provided that such agreement shall not restrict the Investor’s ability to Dispose of any Shares of Then Outstanding Common Stock and/or Common Stock Equivalents in accordance with Section 3.3. Following the exercise of the Second Acquisition Right, the Investors shall not be obligated to enter into a

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Lock-Up Agreement more than once in any 12 month period. Any Lock-Up Agreement shall be in writing in a form reasonably satisfactory to the Company and the underwriter(s) in such offering. The Company may impose stop transfer instructions with respect to the Shares of Then Outstanding Common Stock and/or Common Stock Equivalents subject to the foregoing restrictions until the end of the specified period of time. The foregoing provisions of this Section 3.4 shall not apply (i) if the Investors and their Affiliates collectively own less than 5% of Shares of Then Outstanding Common Stock and/or Common Stock Equivalents, or (ii) to the sale of any shares to an underwriter pursuant to an underwriting agreement, and shall be applicable to the Investors only if all officers and directors and all stockholders individually owning more than five percent (5%) of the outstanding Common Stock (excluding any investment companies other than venture capital firms) are subject to the same restrictions. Any discretionary waiver or termination of the restrictions of any or all of such agreements by the Company or the underwriters shall apply pro rata to the Investors, based on the number of shares subject to such agreements, excluding any waivers granted that fall within a customary de minimis exemption set forth in the associated Lock-Up Agreement.

3.5 Transactions for Personal Account . For the avoidance of doubt, nothing in this Article 3 will restrict any Disposition of shares of Common Stock held by an executive officer or director of an Investor for his or her personal account.

3.6 Legend . For so long as the Purchased Shares are subject to any of the restrictions set forth in this Article 3, the book-entry or certificated form of the Purchased Shares shall bear the following legend:

THE SHARES ARE SUBJECT TO RESTRICTIONS ON TRANSFER PURSUANT TO THE PROVISIONS OF A VOTING AND STANDSTILL AGREEMENT DATED AS OF JUNE 29, 2015. A COPY OF THE VOTING AND STANDSTILL AGREEMENT MAY BE OBTAINED FROM THE COMPANY. ANY TRANSFER IN VIOLATION OF THE VOTING AND STANDSTILL AGREEMENT IS VOID AND OF NO EFFECT.

ARTICLE 4.

VOTING AGREEMENT

4.1 Voting of Securities . From and after the date of this Agreement, other than as permitted by Section 4.2 with respect to a transaction the consummation of which would result in a Change of Control of the Company, in any vote or action by written consent of the stockholders of the Company (including, without limitation, with respect to the election of directors), each Investor shall, and shall cause its Affiliates to, vote or execute a written consent with respect to all voting securities of the Company as to which it is entitled to vote or execute a written consent in accordance with the recommendation of a majority of the Company’s Board of Directors. In furtherance of this Section 4.1, each Investor shall, and shall cause its Affiliates to, if and when requested by the Company from time to time, promptly execute and deliver to the Company an irrevocable proxy, substantially in the form of Exhibit A attached hereto, and

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irrevocably appoint the Company or its designees, with full power of substitution, its attorney, agent and proxy to vote (or cause to be voted) or to give consent with respect to, all of the voting securities of the Company as to which the Investor or Affiliate of the Investor is entitled to vote, in the manner and with respect to the matters set forth in this Section 4.1. Each Investor acknowledges, and shall cause its Affiliates to acknowledge, that any such proxy executed and delivered shall be coupled with an interest, shall constitute, among other things, an inducement for the Company to enter into this Agreement, shall be irrevocable and binding on any successor in interest of the Investor or Affiliate of the Investor, as applicable, and shall not be terminated by operation of Law upon the occurrence of any event. Such proxy shall operate to revoke and render void any prior proxy as to any voting securities of the Company heretofore granted by each Investor or Affiliate of such Investor, as applicable, to the extent it is inconsistent herewith. Such proxy shall terminate upon the earlier of the expiration or termination of this Section 4.1. For the avoidance of doubt, this Section 4.1 shall not apply to any shares of Common Stock held by an executive officer or director of an Investor for his or her personal account.

4.2 Change of Control . Notwithstanding Section 4.1, each Investor and its Affiliates may vote, or execute a written consent with respect to, any or all of the voting securities of the Company as to which they are entitled to vote or execute a written consent, as they may determine in their sole discretion with respect to any transaction the consummation of which would result in a Change of Control of the Company.

4.3 Quorum . In furtherance of Section 4.1, each Investor shall be, and shall cause each of its Affiliates to be, present in person or represented by proxy at all meetings of stockholders to the extent necessary so that all voting securities of the Company as to which they are entitled to vote shall be counted as present for the purpose of determining the presence of a quorum at such meeting.

4.4 Board Nomination Right . Beginning on the Closing Date and until the fifth (5 ^th ) anniversary of the date of this Agreement, and thereafter for so long as the Investors and their Affiliates collectively beneficially own voting securities representing at least 7.5% of the voting power of the Shares of Then Outstanding Common Stock (assuming full exercise of the next available Top-Up Right), at each annual meeting of the stockholders of the Company or at any meeting of the stockholders of the Company at which members of the Board of Directors are to be elected (or, for so long as the Company has a classified Board, at any meeting of the stockholders of the Company at which Class III members of the Board are to be elected), or whenever such action is to be taken by written consent for such purposes, the Company agrees to nominate for election one individual designated by Celgene Corporation (an “ Investor Designee ”) who (a) is a person other than an officer or employee of the Standstill Parties or any other individual having a relationship that, in the opinion of the Company’s board of directors, would interfere with the exercise of independent judgment in carrying out the responsibilities of a director, (b) is an Independent Director within the meaning of Rule 5605(a)(ii) of the NASDAQ Marketplace Rules, and (c) otherwise is reasonably acceptable to the nominating and governance committee of the Company’s Board of Directors (an Investor Designee who satisfied such requirements, a “ Qualified Investor Designee ”). Notwithstanding (a) and (b) above, for Celgene Corporation’s initial designee under this Agreement, Celgene Corporation may designate Dr. Thomas O. Daniel (the “ Initial Designee ”), and, in replacement of the Initial Designee, may subsequently designate one person as a Replacement Designee that is an “officer” of Celgene Corporation for purposes of Section 16 of the Exchange Act within the meaning of Rule 16a-1(f) thereunder (the “ First Subsequent Designee ”), if such Initial Designee and/or First Subsequent Designee, as applicable, satisfies (c) above to qualify as a

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Qualified Investor Designee hereunder (and such person will continue to be a Qualified Investor Designee, including for purposes of nomination for election and reelection as director, so long as (c) remains satisfied); provided that for any subsequent designee (other than the First Subsequent Designee), including any Replacement Designee (other than the First Subsequent Designee), (a) and (b) shall be reinstituted as required for such designee. Promptly following the date of this Agreement, the Company shall take all actions necessary (including, if necessary, by approving an enlargement of its Board of Directors to create a vacancy thereon) to cause the appointment to the Company’s Board of Directors of the Qualified Investor Designee designated as aforesaid and thereafter, for so long as Celgene Corporation’s board nomination right under the first sentence of this Section 4.4 continues, the Company will use its commercially reasonable efforts to cause the election and reelection of such individual to the Company’s Board of Directors for so long as he or she is a Qualified Investor Designee (including recommending that the Company’s stockholders vote in favor of the election of such an individual and otherwise supporting him or her for election in a manner no less rigorous and favorable than the manner in which the Company supports its other nominees), provided that if Celgene Corporation determine to designate a different individual (“ Replacement Designee ”) as its Investor Designee, and such Replacement Designee is a Qualified Investor Designee, such obligation shall instead apply to the Replacement Designee. If any Investor Designee vacates the Company’s Board of Directors, the Company shall take all actions necessary to cause the appointment to the Company’s Board of Directors of a Qualified Investor Designee nominated by Celgene Corporation to fill the vacancy and thereafter the Company will use its commercially reasonable efforts to cause the election such an individual to the Company’s Board of Directors, subject to the same conditions and limitations as set forth in the foregoing sentence. For avoidance of doubt, Celgene Corporation shall be limited to only one designee serving on the Board at any time pursuant to this Section 4.4. Such designee shall be entitled to the same level of directors’ and officers’ indemnity insurance coverage and indemnity and exculpation protection (including under any indemnification agreement) as the other members of the Board of Directors. Any Investor Designee shall be subject to the same Company policies and procedures as the other directors on the Company’s Board of Directors, including with respect to conflicts of interest and recusal from deliberations and voting.

ARTICLE 5.

TERMINATION OF CERTAIN RIGHTS AND OBLIGATIONS

5.1 Termination of Standstill Agreement . Section 2 shall terminate and have no further force or effect, upon the earliest to occur of:

(a) the public announcement by an Offeror of an Acquisition Proposal for the Company as long as none of the Standstill Parties had violated Section 2.1(c), 2.1(d) or 2.1(f) with respect to such Offeror;

(b) the public announcement by the Company of any definitive agreement providing for a Change of Control of the Company, or of any process designed to result in a Change of Control of the Company;

(c) any material breach by the Company of its obligations under Section 2.3, provided that an Investor has provided written notice to the Company of such breach;

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(d) the expiration of the Restricted Period (other than as a result of the termination of the Collaboration Agreement pursuant to Section 2.2 of this Agreement);

(e) the date on which the Common Stock ceases to be registered pursuant to Section 12 of the Exchange Act; and

(f) a liquidation or dissolution of the Company;

provided, however, that if any of the transactions referred to in (a) or (b) above terminates and the Company has not made a public announcement of its intent to solicit or engage in a transaction (or has announced its decision to discontinue pursuing such a transaction) the consummation of which would result in a Change of Control of the Company, then the restrictions contained in Section 2 shall again be applicable, unless a Standstill Party has announced an Acquisition Proposal for the Company prior to such termination, provided that if such Acquisition Proposal is terminated or if such Standstill Party has ceased to actively pursue such Acquisition Proposal, the restrictions contained in Section 2 shall again be applicable.

5.2 Termination of Restrictions on Dispositions . Section 3 shall terminate and have no further force or effect upon the earliest to occur of:

(a) a Change of Control of the Company;

(b) a liquidation or dissolution of the Company; and

(c) the date on which the Common Stock ceases to be registered pursuant to Section 12 of the Exchange Act.

5.3 Termination of Voting Agreement and Board Nomination Right . Section 4 shall terminate and have no further force or effect upon the earliest to occur of:

(a) a Change of Control of the Company; and

(b) a liquidation or dissolution of the Company.

5.4 Termination of Entire Agreement . This Agreement will terminate in its entirety (subject to Section 5.5) upon any termination of the Purchase Agreement with the effect set forth in Section 6.3 of the Purchase Agreement.

5.5 Effect of Termination . No termination pursuant to any of Sections 5.1, 5.2 or 5.3 or 5.4 shall relieve any of the parties (or the Permitted Transferee, if any) for liability for breach of or default under any of their respective obligations or restrictions under any terminated provision of this Agreement, which breach or default arose out of events or circumstances occurring or existing prior to the date of such termination.

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ARTICLE 6.

MISCELLANEOUS

6.1 Governing Law; Submission to Jurisdiction . This Agreement shall be governed by and construed in accordance with the Laws of the State of New York, without regard to the conflict of laws principles thereof that would require the application of the Law of any other jurisdiction. The parties irrevocably and unconditionally submit to the exclusive jurisdiction of the state and federal courts of New York solely and specifically for the purposes of any action or proceeding arising out of or in connection with this Agreement.

6.2 Waiver . Waiver by a party of a breach hereunder by another party shall not be construed as a waiver of any subsequent breach of the same or any other provision. No delay or omission by a party in exercising or availing itself of any right, power or privilege hereunder shall preclude the later exercise of any such right, power or privilege by such party. No waiver shall be effective unless made in writing with specific reference to the relevant provision(s) of this Agreement and signed by a duly authorized representative of the party granting the waiver.

6.3 Notices . All notices, instructions and other communications hereunder or in connection herewith shall be in writing, shall be sent to the address of the relevant party set forth on Exhibit B attached hereto and shall be (a) delivered personally, (b) sent by registered or certified mail, return receipt requested, postage prepaid, (c) sent via a reputable nationwide overnight courier service, (d) sent by facsimile transmission (if a facsimile number is provided in Exhibit B ), with a confirmation copy to be sent by registered or certified mail, return receipt requested, postage prepaid, or (e) sent by email (if an email address is provided in Exhibit B ). Any such notice, instruction or communication shall be deemed to have been delivered upon receipt if delivered by hand, three (3) Business Days after it is sent by registered or certified mail, return receipt requested, postage prepaid, one (1) Business Day after it is sent via a reputable nationwide overnight courier service or when transmitted with electronic confirmation of receipt, if transmitted by facsimile or email (if such transmission is made during regular business hours of the recipient on a Business Day; or otherwise, on the next Business Day following such transmission). Any party may change its address by giving notice to the other parties in the manner provided above.

6.4 Entire Agreement . This Agreement and the Purchase Agreement contain the entire agreement among the parties with respect to the subject matter hereof and thereof and supersede all prior and contemporaneous arrangements or understandings, whether written or oral, with respect hereto and thereto.

6.5 Amendments . No provision in this Agreement shall be supplemented, deleted or amended except in a writing executed by an authorized representative of each of the parties hereto.

6.6 Headings; Nouns and Pronouns; Section References . Headings in this Agreement are for convenience of reference only and shall not be considered in construing this Agreement. Whenever the context may require, any pronouns used herein shall include the corresponding masculine, feminine or neuter forms, and the singular form of names and pronouns shall include the plural and vice-versa. References in this Agreement to a section or subsection shall be deemed to refer to a section or subsection of this Agreement unless otherwise expressly stated.

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6.7 Severability . If, under applicable Laws, any provision hereof is invalid or unenforceable, or otherwise directly or indirectly affects the validity of any other material provision(s) of this Agreement in any jurisdiction (“ Modified Clause ”), then, it is mutually agreed that this Agreement shall endure and that the Modified Clause shall be enforced in such jurisdiction to the maximum extent permitted under applicable Laws in such jurisdiction; provided that the parties shall consult and use all reasonable efforts to agree upon, and hereby consent to, any valid and enforceable modification of this Agreement as may be necessary to avoid any unjust enrichment of either party and to match the intent of this Agreement as closely as possible, including the economic benefits and rights contemplated herein.

6.8 Assignment . Neither this Agreement nor any rights or duties of a party hereto may be assigned by such party, in whole or in part, without (a) the prior written consent of the Company in the case of any assignment by an Investor; or (b) the prior written consent of the Investors in the case of an assignment by the Company.

6.9 Successors and Assigns . This Agreement shall be binding upon and inure to the benefit of the parties hereto and their respective successors and permitted assigns.

6.10 Counterparts . This Agreement may be executed in counterparts, each of which shall be deemed an original but which together shall constitute one and the same instrument.

6.11 Third Party Beneficiaries . None of the provisions of this Agreement shall be for the benefit of or enforceable by any Third Party. No Third Party shall obtain any right under any provision of this Agreement or shall by reason of any such provision make any claim in respect of any debt, liability or obligation (or otherwise) against any party hereto.

6.12 No Strict Construction . This Agreement has been prepared jointly and will not be construed against any party.

6.13 Remedies . The rights, powers and remedies of the parties under this Agreement are cumulative and not exclusive of any other right, power or remedy which such parties may have under any other agreement or Law. No single or partial assertion or exercise of any right, power or remedy of a party hereunder shall preclude any other or further assertion or exercise thereof.

6.14 Specific Performance . The parties hereby acknowledge and agree that the rights of the parties hereunder are special, unique and of extraordinary character, and that if any party refuses or otherwise fails to act, or to cause its affiliates to act, in accordance with the provisions of this Agreement, such refusal or failure would result in irreparable injury to the Company or the Investors, as the case may be, the exact amount of which would be difficult to ascertain or estimate and the remedies at law for which would not be reasonable or adequate compensation. Accordingly, if any party refuses or otherwise fails to act, or to cause its affiliates to act, in accordance with the provisions of this Agreement, then, in addition to any other remedy which

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may be available to any damaged party at law or in equity, such damaged party will be entitled to seek specific performance and injunctive relief, without posting bond or other security, and without the necessity of proving actual or threatened damages, which remedy such damaged party will be entitled to seek in any court of competent jurisdiction.

6.15 No Conflicting Agreements . Each Investor hereby represents and warrants to the Company that neither it nor any of its Affiliates is, as of the date of this Agreement, a party to, and agrees that neither it nor any of its Affiliates shall, on or after the date of this Agreement, enter into any agreement that conflicts with the rights granted to the Company in this Agreement. The Company hereby represents and warrants to the Investors that it is not, as of the date of this Agreement, a party to, and agrees that it shall not, on or after the date of this Agreement, enter into, any agreement or approve any amendment to its Organizational Documents with respect to its securities that conflicts with the rights granted to the Investors in this Agreement. The Company further represents and warrants that the rights granted to the Investors hereunder do not in any way conflict with the rights granted to any other holder of the Company’s securities under any other agreements.

(Signature Page Follows)

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IN WITNESS WHEREOF, the parties have executed and delivered this Agreement as of the date first above written.

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IN WITNESS WHEREOF, the parties have executed and delivered this Agreement as of the date first above written.

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EXHIBIT A — FORM OF IRREVOCABLE PROXY

In order to secure the performance of the duties of the undersigned pursuant to Section 4.1 of the Voting and Standstill Agreement, dated as of June 29, 2015 (the “ Agreement ”), by and among Juno Therapeutics, Inc. (the “ Company ”), Celgene RIVOT Ltd. (“ Celgene RIVOT ”) and Celgene Corporation (“Celgene Corp.”, and together with Celgene RIVOT, the “ Investors ”), the undersigned hereby irrevocably appoints [            ] and [            ], and each of them, the attorneys, agents and proxies, with full power of substitution in each of them, for the undersigned, and in the name, place and stead of the undersigned, to vote (or cause to be voted) or, if applicable, to give consent, in such manners as each such attorney, agent and proxy or his substitute shall in his sole discretion deem proper to record such vote (or consent) in the manners, and with respect to such matters as set forth in Section 4.1 of the Agreement (but in any case, in accordance with any written instruction from the undersigned, properly delivered under Section 4.1 of the Agreement, to vote or give consent as contemplated by Section 4.1(b) of the Agreement) with respect to all voting securities (whether taking the form of shares of Common Stock, par value $0.0001 per share, or other voting securities of the Company), which the undersigned is or may be entitled to vote at any meeting of the Company held after the date hereof, whether annual or special and whether or not an adjourned meeting or, if applicable, to give written consent with respect thereto. This proxy is coupled with an interest, shall be irrevocable and binding on any successor in interest of the undersigned and shall not be terminated by operation of law upon the occurrence of any event. This proxy shall operate to revoke and render void any prior proxy as to voting securities heretofore granted by the undersigned which is inconsistent herewith. This proxy shall terminate upon the earlier of the expiration or termination of the voting agreement set forth in Section 4.1 of the Agreement.

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Exhibit 10.3

REGISTRATION RIGHTS AGREEMENT

This Registration Rights Agreement (this “ Agreement ”) is dated as of June 29, 2015, by and among Juno Therapeutics, Inc., a Delaware corporation (the “ Company ”), Celgene Corporation, a Delaware corporation (“ Celgene Corp. ”) and Celgene RIVOT Ltd (“ Celgene RIVOT ” and together with Celgene Corp., the “ Investors ”).

This Agreement is made pursuant to the Share Purchase Agreement, dated as of June 29, 2015, by and among the Company and the Investors (the “ Purchase Agreement ”).

NOW, THEREFORE, IN CONSIDERATION of the mutual covenants contained in this Agreement, and for other good and valuable consideration the receipt and adequacy of which are hereby acknowledged, the Company and the Investor agree as follows:

1. Definitions. Capitalized terms used and not otherwise defined herein that are defined in the Purchase Agreement shall have the meanings given such terms in the Purchase Agreement. As used in this Agreement, the following terms shall have the respective meanings set forth in this Section 1:

“ Advice ” shall have the meaning set forth in Section 6(e).

“ Affiliate ” shall have the meaning set forth in the Voting and Standstill Agreement.

“ Celgene Group ” shall have the meaning set forth in the Purchase Agreement.

“ Commission ” means the Securities and Exchange Commission.

“ Common Stock ” means the common stock, par value $0.001 per share, of the Company.

“ Effective Date ” means the date that a Registration Statement filed pursuant to Section 2 is first declared effective by the Commission.

“ Effectiveness Date ” means: (a) with respect to a Registration Statement that may be required pursuant to Section 2(a) hereof, the 60 ^th day following the Filing Date (or the 90 ^th day following the Filing Date in the event such Registration Statement is reviewed by the Commission), and (b) with respect to any Registration Statement that may be required pursuant to Section 2(b) hereof, the 90 ^th day following the date on which the Company first knows that such additional Registration Statement is required under such Section (or the 120 ^th day following the date on which the Company first knows that such additional Registration Statement is required in the event the additional Registration Statement is reviewed by the Commission). If an Effectiveness Date falls on a Saturday, Sunday or other date that the Commission is closed for business, the Effectiveness Date shall be extended to the next day on which the Commission is open for business.

“ Effectiveness Period ” shall have the meaning set forth in Section 2(a).

“ Exchange Act ” means the Securities Exchange Act of 1934, as amended.

“ Existing Holders ” shall mean the Holders as defined in the Existing Rights Agreement.

“ Existing Rights Agreement ” means any agreement entered into by the Company and existing as of the date hereof that provides for any registration rights with respect to any of the Company’s securities.

“ FAR Acquisition Percentage ” shall have the meaning set forth in the Purchase Agreement.

“ Filing Date ” means: (a) with respect to a Registration Statement that may be required pursuant to Section 2(a) hereof, a date which is no later than the 20 ^th day following receipt by the Company of a written request from a Holder that the Company effect a registration of all or a portion of the Registrable Securities, and (b) with respect to any Registration Statement that may be required pursuant to Section 2(b) hereof, the 30 ^th day following the date on which the Company first knows that such additional Registration Statement is required under such Section.

“ Holder ” means a holder from time to time of Registrable Securities, but only if such holder is either of the Investors or any assignee thereof in accordance with Section 6(k).

“ Indemnified Party ” shall have the meaning set forth in Section 5(c).

“ Indemnifying Party ” shall have the meaning set forth in Section 5(c).

“ Lock-Up Period ” shall have the meaning set forth in the Voting and Standstill Agreement.

“ Losses ” shall have the meaning set forth in Section 5(a).

“ Other Registration Statement ” shall have the meaning set forth in Section 6(d).

“ Permitted Transferee ” shall have the meaning set forth in the Voting and Standstill Agreement.

“ Proceeding ” means an action, claim, suit, investigation or proceeding (including, without limitation, an investigation or partial proceeding, such as a deposition), whether commenced or threatened.

“ Prospectus ” means the prospectus included in a Registration Statement (including, without limitation, a prospectus that includes any information previously omitted from a prospectus filed as part of an effective registration statement in reliance upon Rule 430A

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or Rule 430B promulgated under the Securities Act), as amended or supplemented by any prospectus supplement, with respect to the terms of the offering of any portion of the Registrable Securities covered by a Registration Statement, and all other amendments and supplements to the Prospectus, including post-effective amendments, and all material incorporated by reference or deemed to be incorporated by reference in such Prospectus.

“ Reduction Securitie s” shall have the meaning set forth in Section 2(b).

“ register ,” “ registered ,” and “ registration ” refer to a registration effected by preparing and filing a registration statement or similar document (including any pre- or post-effective amendment or supplement thereto) in compliance with the Securities Act, and, as applicable, the declaration or ordering of effectiveness of such registration statement or document.

“ Registrable Securities ” means (a) the Shares issued pursuant to the Purchase Agreement, and (b) any other shares of Common Stock issued as (or issuable upon conversion or exercise of any warrant, right or other security which is issued as) a dividend or other distribution with respect to, in exchange for or in replacement of the Shares; provided, however , that no shares of Common Stock shall be deemed Registrable Securities for purposes of this Agreement to the extent such shares (x) have been sold to the public through a registration statement or pursuant to Rule 144 or (y) have been sold, transferred or otherwise disposed of by a Person in a transaction in which its rights under this Agreement were not assigned in accordance with Section 6(k).

“ Registration Statement ” means each of the following: (a) a Registration Statement contemplated by Section 2(a) hereof and (b) each additional registration statement, if any, contemplated by Section 2(b) hereof, and including, in each case, the Prospectus, amendments and supplements to each such registration statement or Prospectus, including pre- and post-effective amendments, all exhibits thereto, and all material incorporated by reference or deemed to be incorporated by reference in such registration statement.

“ Restricted Period ” shall have the meaning set forth in the Voting and Standstill Agreement.

“ Rule 144 ” means Rule 144 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.

“ Rule 415 ” means Rule 415 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.

“ Rule 424 ” means Rule 424 promulgated by the Commission pursuant to the Securities Act, as such Rule may be amended from time to time, or any similar rule or regulation hereafter adopted by the Commission having substantially the same effect as such Rule.

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“ SAR Termination Date ” shall have the meaning set forth in the Purchase Agreement.

“ Second Acquisition Right ” shall have the meaning set forth in the Purchase Agreement.

“ Securities Act ” means the Securities Act of 1933, as amended.

“ Selling Stockholder Questionnaire ” shall have the meaning set forth in Section 2(c).

“ Shares ” shall have the meaning set forth in the Purchase Agreement.

“ Shares of Then Outstanding Common Stock ” shall have the meaning set forth in the Voting and Standstill Agreement.

“ Trading Day ” means any day on which the Common Stock is traded on its Trading Market.

“ Underwritten Offering ” shall mean a registration in which Registrable Securities are sold to an underwriter for reoffering to the public.

“ Voting and Standstill Agreement ” shall mean the Voting and Standstill Agreement by and among the Company and the Investors.

2. Registration.

(a) Following the fifth (5 ^th ) anniversary of the exercise of the Second Acquisition Right or, if the Second Acquisition Right expires unexercised or does not become exercisable, the fifth (5 ^th ) anniversary of the SAR Termination Date, and at any time that a Holder chooses to sell or offer to sell any Shares of Then Outstanding Common Stock as such Holder may hold in order to reduce the beneficial ownership of the Celgene Group to the FAR Acquisition Percentage of the Shares of Then Outstanding Common Stock pursuant to Section 3.1(B) of the Voting and Standstill Agreement, the Company shall prepare and file with the Commission a Registration Statement on Form S-3 covering the resale of all or such portion of Registrable Securities as are permitted to be sold pursuant to Section 3 of the Voting and Standstill Agreement and are specified in a written request from a Holder to the Company not already covered by an existing and effective Registration Statement (except as provided in Section 2(b)) for an offering to be made on a continuous basis pursuant to Rule 415. If the Company is not at such time eligible for the use of Form S-3, then the Company will use its commercially reasonable efforts to prepare and file a Registration Statement on a Form S-1 or alternative form that permits the resale of the Registrable Securities. The Registration Statement shall contain (except if otherwise required pursuant to written comments received from the Commission upon a review of such Registration Statement) the “Plan of Distribution” in substantially the form attached hereto as Annex A . The Company shall use its commercially reasonable efforts to cause each Registration Statement to be declared effective under the

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Securities Act as soon as possible but, in any event, no later than the Effectiveness Date for such Registration Statement, and shall use its commercially reasonable efforts to keep the Registration Statement continuously effective under the Securities Act until the earlier of (i) such time as all Registrable Securities covered by such Registration Statement have been publicly sold by a Holder or (ii) the date that all shares of Common Stock covered by such Registration Statement cease to be Registrable Securities hereunder (the “ Effectiveness Period ”), subject to Section 6(c) hereof. The Company shall not be required to effect more than two registrations pursuant to this Section 2(a) in any 12-month period; provided, that the Company will not have been deemed to effect a registration unless and until the Registration Statement requested under this Section 2(a) becomes effective.

(b) Notwithstanding anything contained herein to the contrary, in the event that, following the filing of a Registration Statement pursuant to Section 2(a) above, the Commission limits the amount of Registrable Securities that may be included and sold by a Holder in any Registration Statement, including any such Registration Statement filed pursuant to Section 2(a) above, pursuant to Rule 415 or any other basis, the Company may reduce the number of Registrable Securities included in such Registration Statement on behalf of such Holder (such Registrable Securities so reduced, the “ Reduction Securities ”). In such event the Company shall give such Holder prompt written notice of the number of such Reduction Securities. The Company shall use its commercially reasonable efforts at the first opportunity that is permitted by the Commission to register for resale the Reduction Securities. Such new Registration Statement shall be filed on or prior to the applicable Filing Date, shall be on Form S-3 (except if the Company is not then eligible to register for resale the Registrable Securities on Form S-3, in which case such registration shall be on another appropriate form for such purpose) and shall contain (except if otherwise required pursuant to written comments received from the Commission upon a review of such Registration Statement) the “Plan of Distribution” in substantially the form attached hereto as Annex A . The Company shall use its commercially reasonable efforts to cause each such Registration Statement to be declared effective under the Securities Act as soon as possible but, in any event, no later than the Effectiveness Date for such Registration Statement, and shall use its commercially reasonable efforts to keep such Registration Statement continuously effective under the Securities Act during the entire Effectiveness Period, subject to Section 6(c) hereof.

(c) Any Holder exercising its rights under this Section 2 agrees to furnish to the Company a completed notice and questionnaire containing such information regarding such Holder, the Registrable Securities held by such Holder and the distribution proposed by such Holder as the Company may reasonably request and as shall be required in connection with any registration referred to in this Agreement (a “ Selling Stockholder Questionnaire ”) on a date that is not less than five Trading Days prior to the date of filing of a Registration Statement. Such Holder further agrees that it shall not be entitled to be named as a selling securityholder in a Registration Statement or use the Prospectus for offers and resales of Registrable Securities at any time, unless such Holder has returned to the Company a completed and signed Selling Stockholder Questionnaire. If such Holder of Registrable Securities returns a Selling Stockholder Questionnaire after the deadline specified in the previous sentence, the Company shall use its commercially reasonable efforts to take such actions as are required to name such Holder as a selling security holder in the Registration Statement or any pre-effective or post-

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effective amendment thereto and to include (to the extent not theretofore included) in the Registration Statement the Registrable Securities identified in such late Selling Stockholder Questionnaire. Such Holder acknowledges and agrees that the information in the Selling Stockholder Questionnaire will be used by the Company in the preparation of the Registration Statement and hereby consents to the inclusion of such information in the Registration Statement.

(d) In the event that the Company is not eligible to register the resale of Registrable Securities on Form S-3 at any time after the Company initially qualifies to use Form S-3, the Company shall (i) use commercially reasonable efforts to resume its eligibility to use Form S-3 and (ii) undertake to register any Registrable Securities pursuant to this Section 2 on Form S-3 as soon as such form becomes available.

(e) Until the Company obtains a waiver from the Existing Holders under the Existing Rights Agreement, the registration rights granted to the Investors under this Section 2 are subject to the prior, senior right of the Existing Holders, including without limitation under Sections 2.2 and 2.12 of the Existing Rights Agreement. The Company shall use its commercially reasonable efforts to seek and obtain a waiver from the Existing Holders to allow the Investors to exercise their rights under this Section 2 without being subject to the rights of the Existing Holders thereto.

(f) If Celgene RIVOT or any former Permitted Transferee that holds Registrable Securities ceases to be a direct or indirect “wholly owned” (within the meaning of Section 1.27 of the Voting and Standstill Agreement) controlled subsidiary of Celgene Corp., then Celgene RIVOT or such former Permitted Transferee, as applicable, will cease to have any rights under this Agreement.

3. Registration Procedures.

In connection with the Company’s registration obligations hereunder, the Company shall:

(a) Not less than three Trading Days prior to the filing of a Registration Statement or any related Prospectus or any amendment or supplement thereto, furnish to the selling Holder or Holders copies of all such documents proposed to be filed (other than those incorporated by reference). Notwithstanding the foregoing, the Company shall not be required to furnish to the Holders any prospectus supplement being prepared and filed solely to name new or additional selling securityholders unless any such Holder is named in such prospectus supplement. The Company shall duly consider any comments made by a Holder and received by the Company not later than two Trading Days prior to the filing of the Registration Statement, but shall not be required to accept any such comments to which it reasonably objects.

(b) Subject to Section 6(c), (i) prepare and file with the Commission such amendments, including post-effective amendments, to each Registration Statement and the Prospectus used in connection therewith as may be necessary to keep such Registration Statement continuously effective as to the applicable Registrable Securities for its Effectiveness

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Period and prepare and file with the Commission such additional Registration Statements in order to register for resale under the Securities Act all of the Registrable Securities; (ii) cause the related Prospectus to be amended or supplemented by any required Prospectus supplement, and as so supplemented or amended to be filed pursuant to Rule 424; (iii) respond as promptly as reasonably possible to any comments received from the Commission with respect to each Registration Statement or any amendment thereto and, as promptly as reasonably possible provide each selling Holder true and complete copies of all correspondence from and to the Commission relating to such Registration Statement that pertains to such Holder as a selling stockholder but not any comments that would result in the disclosure to such Holder of material and non-public information concerning the Company; and (iv) comply in all material respects with the provisions of the Securities Act and the Exchange Act with respect to the Registration Statements and the disposition of all Registrable Securities covered by each Registration Statement.

(c) Notify the Holders as promptly as reasonably possible (and, in the case of (i)(A) below, not less than three Trading Days prior to such filing) and (if requested by any such Person) confirm such notice in writing no later than one Trading Day following the day: (i)(A) when a Prospectus or any prospectus supplement (but only to the extent notice is required under Section 3(a) above) or post-effective amendment to a Registration Statement is proposed to be filed; (B) when the Commission notifies the Company whether there will be a “review” of such Registration Statement and whenever the Commission comments in writing on such Registration Statement (in which case the Company shall provide true and complete copies thereof and all written responses thereto to each Holder that pertain to such Holder as a selling stockholder or to the Plan of Distribution, but not information which the Company reasonably believes would constitute material and non-public information); and (C) with respect to each Registration Statement or any post-effective amendment, when the same has been declared effective; (ii) of any request by the Commission or any other Federal or state governmental authority for amendments or supplements to a Registration Statement or Prospectus or for additional information that pertains to a Holder as a selling stockholder or the Plan of Distribution; (iii) of the issuance by the Commission of any stop order suspending the effectiveness of a Registration Statement covering any or all of the Registrable Securities or the initiation of any Proceedings for that purpose; (iv) of the receipt by the Company of any notification with respect to the suspension of the qualification or exemption from qualification of any of the Registrable Securities for sale in any jurisdiction, or the initiation or threatening of any Proceeding for such purpose; (v) of the occurrence of any event or passage of time that makes the financial statements included or incorporated by reference in a Registration Statement ineligible for inclusion or incorporation by reference therein or any statement made in such Registration Statement or Prospectus or any document incorporated or deemed to be incorporated therein by reference untrue in any material respect or that requires any revisions to such Registration Statement, Prospectus or other documents so that, in the case of such Registration Statement or the Prospectus, as the case may be, it will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus, or any form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading; and (vi) of the occurrence or existence of any pending development with respect to the Company that the Company believes may be material and that, in the determination of the Company, makes it not in the best interest

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of the Company to allow continued availability of a Registration Statement or Prospectus; provided , that any and all of such information shall remain confidential to each Holder until such information otherwise becomes public, unless disclosure by such Holder is required by law; provided, further , that notwithstanding such Holder’s agreement to keep such information confidential, such Holder makes no acknowledgement that any such information is material, non-public information.

(d) Use its reasonable best efforts to avoid the issuance of, or, if issued, obtain the withdrawal of (i) any order suspending the effectiveness of a Registration Statement, or (ii) any suspension of the qualification (or exemption from qualification) of any of the Registrable Securities for sale in any jurisdiction, at the earliest practicable moment.

(e) Furnish to the selling Holder, without charge, at least one conformed copy of each Registration Statement and each amendment thereto and all exhibits to the extent reasonably requested by such Person (including those previously furnished or incorporated by reference) promptly after the filing of such documents with the Commission; provided , that the Company shall have no obligation to provide any document pursuant to this clause that is available on the EDGAR system.

(f) Promptly deliver to the selling Holder, without charge, as many copies of each Prospectus or Prospectuses (including each form of prospectus) and each amendment or supplement thereto as such Persons may reasonably request. Subject to Section 6(c) hereof, the Company hereby consents to the use of such Prospectus and each amendment or supplement thereto by the selling Holder in connection with the offering and sale of the Registrable Securities covered by such Prospectus and any amendment or supplement thereto.

(g) Prior to any public offering of Registrable Securities, use its commercially reasonable efforts to register or qualify or cooperate with the selling Holder in connection with the registration or qualification (or exemption from such registration or qualification) of such Registrable Securities for offer and sale under the securities or Blue Sky laws of those jurisdictions within the United States as such Holder reasonably requests in writing to keep each such registration or qualification (or exemption therefrom) effective during the Effectiveness Period and to do any and all other acts or things necessary or advisable to enable the disposition in such jurisdictions of the Registrable Securities covered by the Registration Statements; provided , that the Company shall not be required to qualify generally to do business in any jurisdiction where it is not then so qualified or subject the Company to any material tax in any such jurisdiction where it is not then so subject.

(h) Cooperate with the selling Holder to facilitate the timely delivery of the Registrable Securities in book-entry form to a transferee pursuant to the Registration Statements, free, to the extent permitted by the Purchase Agreement and under applicable law, of all restrictive legends, and to enable such Registrable Securities to be in such denominations and registered in such name as such Holder may request.

(i) Upon the occurrence of any event contemplated by Section 3(c)(v), as promptly as reasonably possible, prepare a supplement or amendment, including a post-effective

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amendment, to the affected Registration Statements or a supplement to the related Prospectus or any document incorporated or deemed to be incorporated therein by reference, and file any other required document so that, as thereafter delivered, no Registration Statement nor any Prospectus will contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus, or any form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading.

(j) If required by the FINRA Corporate Financing Department or any similar entity, promptly effect a filing with FINRA pursuant to FINRA Rule 5110 with respect to the public offering contemplated by resales of securities under the Registration Statement (an “ Issuer Filing ”), and pay the filing fee required by such Issuer Filing.

(k) Following expiration of the Restricted Period, if requested by the selling Holder, the Company shall use its reasonable efforts to engage an underwriter with respect to the sale of the Registrable Securities under the Registration Statement and in connection therewith:

(i) enter into and perform its obligations under an underwriting agreement, in usual and customary form, with the managing underwriter of the Underwritten Offering pursuant to which such Registrable Securities are being offered;

(ii) use reasonable efforts to obtain: (A) at the time of effectiveness of the Registration Statement covering such Registrable Securities, a “cold comfort letter” from the Company’s independent certified public accountants covering such matters of the type customarily covered by “cold comfort letters” as the underwriters may reasonably request; and (B) at the time of any underwritten sale pursuant to such Registration Statement, a “bring-down comfort letter,” dated as of the date of such sale, from the Company’s independent certified public accountants covering such matters of the type customarily covered by “bring-down comfort letters” as the underwriters may reasonably request;

(iii) in connection with any Underwritten Offering, use reasonable efforts to obtain an opinion or opinions addressed to the underwriter or underwriters in customary form and scope from counsel for the Company; and

(iv) use reasonable efforts to participate, to the extent requested by the managing underwriter, in efforts extending for no more than two (2) days scheduled by such managing underwriter and reasonably acceptable to the Company’s senior management, to sell the Registrable Securities being offered pursuant to such Required Registration (including participating during such period in customary “roadshow” meetings with prospective investors).

4. Registration Expenses. All fees and expenses incident to the Company’s performance of or compliance with its obligations under this Agreement (excluding any underwriting discounts and selling commissions) shall be borne by the Company whether or not any Registrable Securities are sold pursuant to a Registration Statement. The fees and expenses referred to in the foregoing sentence shall include, without limitation, (i) all registration and filing fees (including, without limitation, fees and expenses (A) with respect to filings required to be made with the Trading Market on which the Common Stock is then listed for trading, and (B)

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in compliance with applicable state securities or Blue Sky laws), (ii) printing expenses (including, without limitation, expenses of printing prospectuses if the printing of prospectuses is reasonably requested by the holders of a majority of the Registrable Securities included in the Registration Statement), (iii) messenger, telephone and delivery expenses, (iv) reasonable fees and disbursements of counsel for the Company, (v) Securities Act liability insurance, if the Company so desires such insurance, (vi) reasonable fees and expenses of all other Persons retained by the Company in connection with the consummation of the transactions contemplated by this Agreement and (vii) reasonable legal fees and expenses of one legal counsel for the Holders, up to a maximum of $10,000 per Registration Statement. In addition, the Company shall be responsible for all of its internal expenses incurred in connection with the consummation of the transactions contemplated by this Agreement (including, without limitation, all salaries and expenses of its officers and employees performing legal or accounting duties), the expense of any annual audit and the fees and expenses incurred in connection with the listing of the Registrable Securities on any securities exchange as required hereunder. In no event shall the Company be responsible for any underwriting, broker or similar commissions of the Holders or any legal fees or other costs of the Holders (except as set forth in clause (vii)).

5. Indemnification.

(a) Indemnification by the Company. The Company shall, notwithstanding any termination of this Agreement, indemnify and hold harmless each Holder, the officers, directors, agents, partners, members, stockholders and employees of such Holder, each Person who controls such Holder (within the meaning of Section 15 of the Securities Act or Section 20 of the Exchange Act) and the officers, directors, agents, partners, members, stockholders and employees of each such controlling Person, to the fullest extent permitted by applicable law, from and against any and all losses, claims, damages, liabilities, costs (including, without limitation, reasonable costs of preparation and reasonable attorneys’ fees) and expenses (collectively, “ Losses ”), as incurred, arising out of or relating to any untrue or alleged untrue statement of a material fact contained in any Registration Statement, any Prospectus or any form of prospectus or in any amendment or supplement thereto (it being understood that each Holder has approved Annex A hereto for this purpose), or arising out of or relating to any omission or alleged omission of a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus or form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading or any violation or alleged violation by the Company of the Securities Act or any other similar federal or state securities law or any rule or regulation promulgated thereunder applicable to the Company relating to any such registration, qualification or compliance, except to the extent, but only to the extent, that (1) such untrue statements, alleged untrue statements, omissions or alleged omissions are based solely upon information regarding such Holder furnished in writing to the Company by such Holder expressly for use therein, or to the extent that such information relates to such Holder or such Holder’s proposed method of distribution of Registrable Securities and was reviewed and expressly approved in writing by such Holder expressly for use in the Registration Statement, such Prospectus or such form of Prospectus or in any amendment or supplement thereto (it being understood that each Holder has approved Annex A hereto for this purpose) or (2) in the case of an occurrence of an event of the type specified in Section 3(c)(ii)-(vi), the use by such Holder of an outdated or defective Prospectus after such Holder has received written

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notice from the Company that the Prospectus is outdated or defective and prior to the receipt by such Holder of an Advice (as defined below) or an amended or supplemented Prospectus, but only if and to the extent that following the receipt of the Advice or the amended or supplemented Prospectus the misstatement or omission giving rise to such Loss would have been corrected. The Company shall notify each Holder promptly of the institution, threat or assertion of any Proceeding of which the Company is aware in connection with the transactions contemplated by this Agreement.

(b) Indemnification by Holder. Each Holder shall, notwithstanding any termination of this Agreement, severally and not jointly, indemnify and hold harmless the Company, its directors, officers, agents and employees, each Person who controls the Company (within the meaning of Section 15 of the Securities Act and Section 20 of the Exchange Act), and the directors, officers, agents, partners, members, stockholders or employees of such controlling Persons, to the fullest extent permitted by applicable law, from and against all Losses, as incurred, arising solely out of or based solely upon: (x) for so long as the prospectus delivery requirements of the Securities Act apply to sales by such Holder, such Holder’s failure to comply with the prospectus delivery requirements of the Securities Act or (y) any untrue statement of a material fact contained in any Registration Statement, any Prospectus, or any form of prospectus, or in any amendment or supplement thereto, or arising solely out of or based solely upon any omission of a material fact required to be stated therein or necessary to make the statements therein (in the case of any Prospectus, or any form of prospectus or supplement thereto, in light of the circumstances under which they were made) not misleading to the extent, but only to the extent that, (1) such untrue statements or omissions are based solely upon information regarding such Holder furnished in writing to the Company by such Holder expressly for use therein, or to the extent that such information relates to such Holder or such Holder’s proposed method of distribution of Registrable Securities and was reviewed and expressly approved in writing by such Holder expressly for use in the Registration Statement, such Prospectus or such form of Prospectus or in any amendment or supplement thereto (it being understood that each Holder has approved Annex A hereto for this purpose) or (2) in the case of an occurrence of an event of the type specified in Section 3(c)(ii)-(vi), the use by such Holder of an outdated or defective Prospectus after such Holder has received written notice from the Company that the Prospectus is outdated or defective and prior to the receipt by such Holder of an Advice or an amended or supplemented Prospectus, but only if and to the extent that following the receipt of the Advice or the amended or supplemented Prospectus the misstatement or omission giving rise to such Loss would have been corrected. In no event shall the liability of any Holder hereunder be greater in amount than the dollar amount of the net proceeds received by such Holder upon the sale of the Registrable Securities giving rise to such indemnification obligation.

(c) Conduct of Indemnification Proceedings. If any Proceeding shall be brought or asserted against any Person entitled to indemnity hereunder (an “ Indemnified Party ”), such Indemnified Party shall promptly notify the Person from whom indemnity is sought (the “ Indemnifying Party ”) in writing, and the Indemnifying Party shall assume the defense thereof, including the employment of counsel reasonably satisfactory to the Indemnified Party and the payment of all fees and expenses incurred in connection with defense thereof; provided , that the failure of any Indemnified Party to give such notice shall not relieve the Indemnifying Party of its obligations or liabilities pursuant to this Agreement, except (and only) to the extent that it

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shall be finally determined by a court of competent jurisdiction (which determination is not subject to appeal or further review) that such failure shall have proximately and materially adversely prejudiced the Indemnifying Party.

An Indemnified Party shall have the right to employ separate counsel in any such Proceeding and to participate in the defense thereof, but the fees and expenses of such counsel shall be at the expense of such Indemnified Party or Parties unless: (1) the Indemnifying Party has agreed in writing to pay such fees and expenses; (2) the Indemnifying Party shall have failed promptly to assume the defense of such Proceeding and to employ counsel reasonably satisfactory to such Indemnified Party in any such Proceeding; or (3) the named parties to any such Proceeding (including any impleaded parties) include both such Indemnified Party and the Indemnifying Party, and such Indemnified Party shall have been advised by counsel that a conflict of interest is likely to exist if the same counsel were to represent such Indemnified Party and the Indemnifying Party (in which case, if such Indemnified Party notifies the Indemnifying Party in writing that it elects to employ separate counsel at the expense of the Indemnifying Party, the Indemnifying Party shall not have the right to assume the defense thereof and such counsel shall be at the expense of the Indemnifying Party); provided , that the Indemnifying Party shall not be liable for the fees and expenses of more than one separate firm of attorneys at any time for all Indemnified Parties pursuant to this Section 5(c). The Indemnifying Party shall not be liable for any settlement of any such Proceeding effected without its written consent, which consent shall not be unreasonably withheld. No Indemnifying Party shall, without the prior written consent of the Indemnified Party, effect any settlement of any pending Proceeding in respect of which any Indemnified Party is a party, unless such settlement includes an unconditional release of such Indemnified Party from all liability on claims that are the subject matter of such Proceeding.

All fees and expenses of the Indemnified Party (including reasonable fees and expenses to the extent incurred in connection with investigating or preparing to defend such Proceeding in a manner not inconsistent with this Section) shall be paid to the Indemnified Party, as incurred, within ten Trading Days of written notice thereof to the Indemnifying Party (regardless of whether it is ultimately determined that an Indemnified Party is not entitled to indemnification hereunder; provided , that the Indemnifying Party may require such Indemnified Party to undertake to reimburse all such fees and expenses to the extent it is finally judicially determined that such Indemnified Party is not entitled to indemnification hereunder).

(d) Contribution. If a claim for indemnification under Section 5(a) or 5(b) is unavailable to an Indemnified Party (by reason of public policy or otherwise), then each Indemnifying Party, in lieu of indemnifying such Indemnified Party, shall contribute to the amount paid or payable by such Indemnified Party as a result of such Losses, in such proportion as is appropriate to reflect the relative fault of the Indemnifying Party and Indemnified Party in connection with the actions, statements or omissions that resulted in such Losses as well as any other relevant equitable considerations. The relative fault of such Indemnifying Party and Indemnified Party shall be determined by reference to, among other things, whether any action in question, including any untrue or alleged untrue statement of a material fact or omission or alleged omission of a material fact, has been taken or made by, or relates to information supplied by, such Indemnifying Party or Indemnified Party, and the parties’ relative intent, knowledge,

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access to information and opportunity to correct or prevent such action, statement or omission. The amount paid or payable by a party as a result of any Losses shall be deemed to include, subject to the limitations set forth in Section 5(c), any reasonable attorneys’ or other reasonable fees or expenses incurred by such party in connection with any Proceeding to the extent such party would have been indemnified for such fees or expenses if the indemnification provided for in this Section was available to such party in accordance with its terms.

The parties hereto agree that it would not be just and equitable if contribution pursuant to this Section 5(d) was determined by pro rata allocation or by any other method of allocation that does not take into account the equitable considerations referred to in the immediately preceding paragraph. Notwithstanding the provisions of this Section 5(d), no Holder shall be required to contribute, in the aggregate, any amount in excess of the amount by which the proceeds actually received by such Holder from the sale of the Registrable Securities subject to the Proceeding exceeds the amount of any damages that such Holder has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation.

The indemnity and contribution agreements contained in this Section are in addition to any liability that the Indemnifying Parties may have to the Indemnified Parties and are not in diminution or limitation of the indemnification provisions under the Purchase Agreement.

6. Miscellaneous.

(a) Remedies. In the event of a breach by the Company or by any Holder, of any of their obligations under this Agreement, such Holder or the Company, as the case may be, in addition to being entitled to exercise all rights granted by law and under this Agreement, including recovery of damages, will be entitled to specific performance of its rights under this Agreement. The Company and each Holder agree that monetary damages would not provide adequate compensation for any losses incurred by reason of a breach by it of any of the provisions of this Agreement and hereby further agree that, in the event of any action for specific performance in respect of such breach, it shall waive the defense that a remedy at law would be adequate.

(b) Compliance. Each Holder covenants and agrees that it will comply with the prospectus delivery requirements of the Securities Act as applicable to it in connection with sales of Registrable Securities pursuant to the Registration Statement and shall sell the Registrable Securities only in accordance with a method of distribution described in the Registration Statement.

(c) Furnishing of Information. The Company may require each selling Holder to furnish to the Company a certified statement as to (i) the number of shares of Common Stock beneficially owned by such selling Holder and any Affiliate thereof, (ii) any FINRA affiliations, (iii) any natural persons who have the power to vote or dispose of the common stock and (iv) any other information as may be requested by the Commission, FINRA or any state securities commission.

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(d) Subsequent Registration Rights. Without the written consent of the Holder of a majority of the then outstanding Registrable Securities, the Company shall not file any registration statement covering the resale of any Company securities held by any Person (other than any of the Holders) (an “ Other Registration Statement ”) unless prior to or concurrently with the filing of such Other Registration Statement, a Registration Statement required by Section 2(a) hereof is or has been filed with, and declared effective by, the Commission; provided , that this Section 6(d) shall not prohibit the Company from fulfilling its obligations under any Existing Rights Agreement.

(e) Discontinued Disposition. Each Holder agrees by its acquisition of such Registrable Securities that, upon receipt of a notice from the Company of the occurrence of any event of the kind described in Section 3(c), such Holder will forthwith discontinue disposition of such Registrable Securities under the Registration Statement until such Holder’s receipt of the copies of the supplemented Prospectus and/or amended Registration Statement or until it is advised in writing (the “ Advice ”) by the Company that the use of the applicable Prospectus may be resumed, and, in either case, has received copies of any additional or supplemental filings that are incorporated or deemed to be incorporated by reference in such Prospectus or Registration Statement. The Company may provide appropriate stop orders to enforce the provisions of this paragraph.

(f) Piggy-Back Registrations. If at any time following the Effectiveness Date with respect to a Registration Statement filed pursuant to Section 2(a) hereof and continuing through the applicable Effectiveness Period, except as contemplated by Section 2(b) hereof, there is not an effective Registration Statement covering all of the Registrable Securities and the Company shall determine to prepare and file with the Commission a registration statement (other than a post-effective amendment to an existing registration statement) relating to an offering for its own account or the account of others under the Securities Act of any of its equity securities, other than a registration statement on Form S-4 or Form S-8 (each as promulgated under the Securities Act) or their then equivalents relating to equity securities to be issued solely in connection with any acquisition of any entity or business or equity securities issuable in connection with the stock option or other employee benefit plans, then the Company shall send to the Holders a written notice of such determination and, if within 10 days after the date of such notice, any Holder shall so request in writing, the Company shall include in such registration statement all or any part of such Registrable Securities such Holder requests to be registered; provided, however , that the Company shall not be required to register any Registrable Securities pursuant to this Section 6(f) that are the subject of a then effective Registration Statement; and provided further that the Company shall only be required to register any Holder’s Registrable Securities pursuant to this Section 6(f) to the extent that the inclusion of such Registrable Securities will not reduce the amount of securities to be registered on such registration statement by any holders with registration rights provided in any Existing Rights Agreement. A registration under this Section 6(f) shall not constitute a registration for purposes of Section 2(a).

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(g) Reports Under the Exchange Act. With a view to making available to the Holders the benefits of Rule 144 and any other rule or regulation of the Commission that may at any time permit the Holders to sell securities of the Company to the public without registration, the Company agrees, for so long as the Holders hold (i) all or any portion of the Shares issued pursuant to the Purchase Agreement, and (ii) any other shares of Common Stock issued as (or issuable upon conversion or exercise of any warrant, right or other security which is issued as) a dividend or other distribution with respect to, in exchange for or in replacement of the Shares, to use its commercially reasonable efforts to:

(A) make and keep public information available, as those terms are understood and defined in Rule 144, at all times on and after the date hereof;

(B) file with the Commission in a timely manner all reports and other documents required of the Company under the Securities Act and the Exchange Act (or obtain extensions in respect thereof and file within the applicable grace period); and

(C) furnish to each Holder, so long as the Holder owns (1) all or any portion of the Shares issued pursuant to the Purchase Agreement, and (2) any other shares of Common Stock issued as (or issuable upon conversion or exercise of any warrant, right or other security which is issued as) a dividend or other distribution with respect to, in exchange for or in replacement of the Shares, forthwith upon request (x) a written statement by the Company that it has complied with the reporting requirements of Rule 144, the Securities Act and the Exchange Act and (y) such other information as may be reasonably requested to avail such Holder of any rule or regulation of the Commission that permits the selling of any such securities without registration.

(h) Amendments and Waivers. No provision of this Agreement may be waived or amended except in a written instrument signed by the Company and the Holder of a majority of the then outstanding Registrable Securities. The Company shall provide prior notice to the Holders of any proposed waiver or amendment. No waiver of any default with respect to any provision, condition or requirement of this Agreement shall be deemed to be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the exercise of any such right.

(i) Termination of Registration Rights. For the avoidance of doubt, it is expressly agreed and understood that (i) in the event that there are no Registrable Securities outstanding as of a Filing Date, then the Company shall have no obligation to file, caused to be declared effective or to keep effective any Registration Statement hereunder (including any Registration Statement previously filed pursuant to this Agreement) and (ii) all registration rights granted to the Holders hereunder (including the rights set forth in Sections 6(d) and 6(f)), shall terminate in their entirety effective on the first date on which there shall cease to be any Registrable Securities outstanding. If not previously terminated pursuant to the foregoing sentence, it is expressly agreed and understood that all registration rights granted to the Holders pursuant to this Agreement shall terminate as to each Holder on the earlier of (A) 36 cumulative months (which need not be consecutive) during which one or more Registration Statements continues to be effective, or (B) the expiration of the Effectiveness Period. Additionally, the Company will have the unilateral right to terminate this Agreement in its entirety in accordance

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with Section 2.2 of the Voting and Standstill Agreement upon written notice to any Investor. In the event that the Company determines that the registration rights granted to the Holders hereunder have terminated as to any Holder, it shall notify such Holder of such determination, which notice shall set forth in reasonable detail the basis for such determination; provided , that the failure to provide any such notice shall not affect whether any Registrable Securities are outstanding or whether the registration rights granted to such Holder hereunder have terminated. For the avoidance of doubt, it is expressly agreed and understood that the Company’s determination of whether such registration rights shall have terminated shall not be deemed to be conclusive or determinative of such matter.

(j) Notices. All notices, requests, consents and other communications hereunder shall be in writing, shall be sent by confirmed facsimile, electronic mail, by first-class registered or certified airmail, or nationally recognized overnight express courier, postage prepaid, and shall be deemed given when so sent in the case of facsimile or electronic mail transmission, or when so received in the case of mail or courier, and addressed as follows:

if to the Company, to:

Juno Therapeutics, Inc.

Attention: General Counsel

307 Westlake Avenue N., Suite 300

Seattle, Washington 98109

E-mail: [omitted]

with a copy (which shall not constitute notice) to:

Latham & Watkins LLP

140 Scott Drive

Menlo Park, California 94025

Facsimile: (650) 463-2600

Attention: Robert A. Koenig

or to such other Person at such other place as the Company shall designate to the Investor in writing;

if to either Investor, to:

Celgene Corporation

86 Morris Avenue

Summit, New Jersey 07901

Facsimile: [omitted]

Attention: Senior Vice President, Business Development

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with a copy to:

Celgene Legal

86 Morris Avenue

Summit, New Jersey 07901

Facsimile: [omitted]

Attention: General Counsel

with a copy (which shall not constitute notice) to:

Dechert LLP

1900 K Street, NW

Washington, DC 20006

Facsimile: (202) 261-3333

Attention: David E. Schulman

or to such other Person at such other place as any Investor shall designate to the Company in writing; and

if to any other Person who is then a registered Holder, to the address of such Holder as it appears in the stock transfer books of the Company, or to such other place as such Holder shall designate to the Company in writing.

(k) Successors and Assigns. This Agreement shall inure to the benefit of and be binding upon the successors and permitted assigns of each of the parties and shall inure to the benefit of the Holders. The Company may not assign its rights or obligations hereunder without the prior written consent of the Holder of a majority of the then outstanding Registrable Securities (other than by merger or consolidation or to an entity which acquires the Company including by way of acquiring all or substantially all of the Company’s assets). The rights of the Holders hereunder, including the right to have the Company register Registrable Securities pursuant to this Agreement, may be assigned by any Holders to a Permitted Transferee of such Holder, but only if (i) such Holder agrees in writing with such Permitted Transferee to assign such rights and related obligations under this Agreement, and for such Permitted Transferee to assume such obligations, and a copy of such agreement is furnished to the Company, (ii) the Company is furnished with written notice of the name and address of such Permitted Transferee and the securities with respect to which such registration rights are being transferred or assigned, (iii) such Permitted Transferee agrees in writing with the Company to be bound by all of the provisions contained herein and (iv) such Permitted Transferee is an “accredited investor,” as that term is defined in Rule 501 of Regulation D.

(l) Counterparts. This Agreement may be executed in counterparts, each of which shall constitute an original, but all of which, when taken together, shall constitute but one instrument, and shall become effective when one or more counterparts have been signed by each party hereto and delivered to the other party.

(m) Governing Law. This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York.

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(n) Cumulative Remedies. The remedies provided herein are cumulative and not exclusive of any remedies provided by law.

(o) Severability. If any term, provision, covenant or restriction of this Agreement is held by a court of competent jurisdiction to be invalid, illegal, void or unenforceable, the remainder of the terms, provisions, covenants and restrictions set forth herein shall remain in full force and effect and shall in no way be affected, impaired or invalidated, and the parties hereto shall use their best efforts to find and employ an alternative means to achieve the same or substantially the same result as that contemplated by such term, provision, covenant or restriction. It is hereby stipulated and declared to be the intention of the parties that they would have executed the remaining terms, provisions, covenants and restrictions without including any of such that may be hereafter declared invalid, illegal, void or unenforceable.

(p) Headings. The headings in this Agreement are for convenience of reference only and shall not limit or otherwise affect the meaning hereof.

[signature pages follow]

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IN WITNESS WHEREOF , the parties hereto have caused this Agreement to be executed by their duly authorized representatives as of the day and year first above written.

IN WITNESS WHEREOF , the parties hereto have caused this Agreement to be executed by their duly authorized representatives as of the day and year first above written.

ANNEX A

PLAN OF DISTRIBUTION

We are registering the shares of common stock issued to the selling stockholders to permit the resale of these shares of common stock by the holders of the shares of common stock from time to time after the date of this prospectus. We will not receive any of the proceeds from the sale by the selling stockholders of the shares of common stock. We will bear all fees and expenses incident to our obligation to register the shares of common stock.

The selling stockholders and any of their transferees, donees, pledgees or other successors in interest may, from time to time, sell all or a portion of the shares of common stock beneficially owned by them and offered hereby from time to time directly or through one or more underwriters, broker-dealers or agents. If the shares of common stock are sold through underwriters or broker-dealers, the selling stockholders will be responsible for underwriting discounts or commissions or agent’s commissions. The shares of common stock may be sold on any national securities exchange or quotation service on which the securities may be listed or quoted at the time of sale, in the over-the-counter market or in transactions otherwise than on these exchanges or systems or in the over-the-counter market and in one or more transactions at fixed prices, at prevailing market prices at the time of the sale, at varying prices determined at the time of sale, or at negotiated prices. These sales may be effected in transactions, which may involve crosses or block transactions. The selling stockholders may use any one or more of the following methods when selling shares:

A-1

The selling stockholders also may resell all or a portion of the shares in open market transactions in reliance upon Rule 144 under the Securities Act, as permitted by that rule, or Section 4(a)(1) under the Securities Act, if available, rather than under this prospectus, provided that they meet the criteria and conform to the requirements of those provisions.

Broker-dealers engaged by the selling stockholders may arrange for other broker-dealers to participate in sales. If the selling stockholders effect such transactions by selling shares of common stock to or through underwriters, broker-dealers or agents, such underwriters, broker-dealers or agents may receive commissions in the form of discounts, concessions or commissions from the selling stockholders or commissions from purchasers of the shares of common stock for whom they may act as agent or to whom they may sell as principal. Such commissions will be in amounts to be negotiated, but, except as set forth in a supplement to this Prospectus, in the case of an agency transaction will not be in excess of a customary brokerage commission in compliance with FINRA Rule 2440 (and any successor); and in the case of a principal transaction a markup or markdown in compliance with FINRA IM-2440-1.

In connection with sales of the shares of common stock or otherwise, the selling stockholders may enter into hedging transactions with broker-dealers or other financial institutions, which may in turn engage in short sales of the shares of common stock in the course of hedging in positions they assume. The selling stockholders may also sell shares of common stock short and if such short sale shall take place after the date that the registration statement of which this prospectus is a part is declared effective by the Commission, the selling stockholders may deliver shares of common stock covered by this prospectus to close out short positions and to return borrowed shares in connection with such short sales. The selling stockholders may also loan or pledge shares of common stock to broker-dealers that in turn may sell such shares, to the extent permitted by applicable law. The selling stockholders may also enter into option or other transactions with broker-dealers or other financial institutions or the creation of one or more derivative securities which require the delivery to such broker-dealer or other financial institution of shares offered by this prospectus, which shares such broker-dealer or other financial institution may resell pursuant to this prospectus (as supplemented or amended to reflect such transaction). Notwithstanding the foregoing, the selling stockholders have been advised that they may not use shares registered on the registration statement of which this prospectus forms a part to cover short sales of our common stock made prior to the date the registration statement, of which this prospectus forms a part, has been declared effective by the Commission.

The selling stockholders may, from time to time, pledge or grant a security interest in some or all of the shares of common stock owned by them and, if they default in the performance of their secured obligations, the pledgees or secured parties may offer and sell the shares of common stock from time to time pursuant to this prospectus or any amendment to this prospectus under Rule 424(b)(3) or other applicable provision of the Securities Act, as amended, amending, if necessary, the list of selling stockholders to include the pledgee, transferee or other successors in interest as selling stockholders under this prospectus. The selling stockholders also may transfer and donate the shares of common stock in other circumstances in which case the transferees, donees, pledgees or other successors in interest will be the selling beneficial owners for purposes of this prospectus.

A-2

The selling stockholders and any broker-dealer or agents participating in the distribution of the shares of common stock may be deemed to be “underwriters” within the meaning of Section 2(11) of the Securities Act in connection with such sales. In such event, any commissions paid, or any discounts or concessions allowed to, any such broker-dealer or agent and any profit on the resale of the shares purchased by them may be deemed to be underwriting commissions or discounts under the Securities Act. Selling stockholders who are “underwriters” within the meaning of Section 2(11) of the Securities Act will be subject to the prospectus delivery requirements of the Securities Act and may be subject to certain statutory liabilities of, including but not limited to, Sections 11, 12 and 17 of the Securities Act and Rule 10b-5 under the Securities Exchange Act of 1934, as amended, or the Exchange Act.

Each selling stockholder has informed us that it is not a registered broker-dealer and does not have any written or oral agreement or understanding, directly or indirectly, with any person to distribute the common stock. Upon our being notified in writing by a selling stockholder that any material arrangement has been entered into with a broker-dealer for the sale of common stock through a block trade, special offering, exchange distribution or secondary distribution or a purchase by a broker or dealer, a supplement to this prospectus will be filed, if required, pursuant to Rule 424(b) under the Securities Act, disclosing:

In no event shall any broker-dealer receive fees, commissions and markups, which, in the aggregate, would exceed eight percent (8%).

Under the securities laws of some states, the shares of common stock may be sold in such states only through registered or licensed brokers or dealers. In addition, in some states the shares of common stock may not be sold unless such shares have been registered or qualified for sale in such state or an exemption from registration or qualification is available and is complied with.

There can be no assurance that any selling stockholder will sell any or all of the shares of common stock registered pursuant to the registration statement, of which this prospectus forms a part.

Each selling stockholder and any other person participating in such distribution will be subject to applicable provisions of the Exchange Act, as amended, and the rules and regulations thereunder, including, without limitation, Regulation M of the Exchange Act, which may limit

A-3

the timing of purchases and sales of any of the shares of common stock by the selling stockholder and any other participating person. Regulation M may also restrict the ability of any person engaged in the distribution of the shares of common stock to engage in market-making activities with respect to the shares of common stock. All of the foregoing may affect the marketability of the shares of common stock and the ability of any person or entity to engage in market-making activities with respect to the shares of common stock.

We will pay all expenses of the registration of the shares of common stock pursuant to the registration rights agreement, including, without limitation, Securities and Exchange Commission filing fees and expenses of compliance with state securities or “blue sky” laws; provided, however , that each selling stockholder will pay all underwriting discounts and selling commissions, if any. We will indemnify the selling stockholders against certain liabilities, including some liabilities under the Securities Act, in accordance with a registration rights agreement, or the selling stockholders will be entitled to contribution. We may be indemnified by the selling stockholders against civil liabilities, including liabilities under the Securities Act, that may arise from any written information furnished to us by the selling stockholders specifically for use in this prospectus, in accordance with the related registration rights agreements, or we may be entitled to contribution.

A-4