WHERE YOU CAN FIND MORE INFORMATION

This prospectus supplement and the accompanying prospectus are part of the registration statement on Form S-3 we filed with the Commission under the Securities Act and do not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus supplement or the accompanying prospectus to any of our contracts,

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agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus supplement and the accompanying prospectus for a copy of such contract, agreement or other document. Because we are subject to the information and reporting requirements of the Exchange Act, we file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at http://www.sec.gov. You may also read and copy any document we file at the SEC’s Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information on the operation of the Public Reference Room.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

This prospectus supplement is part of a registration statement on Form S-3. The Commission allows this filing to “incorporate by reference” information that we previously have filed with the Commission. This means we can disclose important information to you by referring you to other documents that we have filed with the Commission. The information that is incorporated by reference is considered part of this prospectus supplement, and information that we file later will automatically update and may supersede this information. For further information about our company and the securities being offered, you should refer to the registration statement and the following documents that are incorporated by reference:

In addition, all documents filed by us under Sections 13(a), 13(a), 14 or 15(d) of the Exchange Act of 1934, as amended (the “Exchange Act”) (excluding, unless otherwise provided in this prospectus or in the applicable document, documents not deemed “filed” with the SEC and information furnished pursuant to Item 2.02 and Item 7.01 on any Current Report on Form 8-K or certain exhibits furnished pursuant to Item 9.01 of Form 8-K), after the date of this prospectus supplement but before the termination of the offering of the common stock covered by this prospectus supplement, are hereby incorporated by reference herein. We have not authorized anyone to provide you with any different or additional information other than that contained in or incorporated by reference into this prospectus supplement and the accompanying prospectus. We take no responsibility for, and can provide no assurance as to the reliability of, any information that others may provide.

Any statement contained in a document incorporated or deemed to be incorporated by reference into this prospectus supplement or the accompanying prospectus will be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement or any other subsequently filed document that is deemed to be incorporated by reference into this prospectus supplement modifies or supersedes the statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

The documents incorporated by reference into this prospectus supplement and the accompanying prospectus are available from us upon request. We will provide a copy of any and all of the documents incorporated by reference (excluding exhibits, unless the exhibits are specifically incorporated), without charge, upon written or oral request. Requests for any of these documents should be directed to:

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XOMA Corporation

2910 Seventh Street

Berkeley, California 94710

(510) 204-7200

Attn: Chief Financial Officer

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ANNEX A

SUBSCRIPTION AGREEMENT

This Subscription Agreement (this “ Agreement ”) is dated as of February 10, 2017 (the “ Effective Date ”), among XOMA Corporation, a Delaware corporation (the “ Company ”), and each purchaser identified on the signature pages hereto (each, including its permitted successors and assigns, a “ Purchaser ” and collectively the “ Purchasers ”).

WHEREAS, subject to the terms and conditions set forth in this Agreement and pursuant to an effective registration statement filed pursuant to the Securities Act (as defined below), the Company desires to issue and sell to each Purchaser, and each Purchaser, severally and not jointly, desires to purchase from the Company, shares of Series X Preferred Stock and Common Stock (each as defined below), as more fully described in this 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 each Purchaser agree as follows:

SECTION 1

DEFINITIONS

1.1 Definitions . In addition to the terms defined elsewhere in this Agreement, the following terms have the meanings set forth in this Section  1.1 :

“ Affiliate ” means any Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common control with a Person (as such terms are used in and construed under Rule 405 of the Securities Act). With respect to a Purchaser, any investment fund or managed account that is managed on a discretionary basis by the same investment manager as such Purchaser will be deemed to be an Affiliate of such Purchaser.

“ Amended and Restated Certificate of Incorporation ” means the Company’s Amended and Restated Certificate of Incorporation, as amended from time to time.

“ Closing ” means the closing of the purchase and sale of the Securities on the Closing Date pursuant to Section  2.1 of this Agreement.

“ Closing Date ” means the third Trading Day after the date hereof.

“ Commission ” means the U.S. Securities and Exchange Commission.

“ Common Stock ” means the common stock of the Company, $0.0075 par value per share, and any other class of securities into which such securities may hereafter be reclassified or changed into.

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“ Common Stock Equivalents ” means any securities of the Company or the Subsidiaries which would entitle the holder thereof, pursuant to the terms of such securities, 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 exercisable or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock.

“ Exchange Act ” means the Securities Exchange Act of 1934 and the rules and regulations promulgated thereunder.

“ Exempt Issuance ” means the issuance of (i) shares of Common Stock, options to purchase Common Stock and other securities convertible into or exchangeable for Common Stock pursuant to any plan or agreement, the issuance of securities under which would be eligible to be registered on Form S-8 under the Securities Act (regardless of whether such issuance is actually registered on Form S-8), (ii) issuances to financial institutions, equipment lessors, licensees, licensors, vendors, service providers, landlords, brokers or similar entities in connection with commercial credit arrangements, equipment financings, license or partnering arrangements, commercial services, commercial property lease transactions or similar transactions, the principal purpose of which is other than the raising of capital through the sale of equity securities of the Company and the terms of which are approved by the Board of Directors, (iii) securities issued in connection with the exercise or conversion of any Common Stock Equivalent that is outstanding as of the date of this Agreement or that is subsequently issued as an Exempt Issuance, and (iv) stock issued or issuable pursuant to any rights, agreements or Material Contracts outstanding as of the date of this Agreement.

“ Fundamental Transaction ” means (a) the Company effects any merger or consolidation of the Company with or into another person whereby the Company is not the surviving entity, (b) the Company effects any sale of all or substantially all of its assets in one transaction or a series of related transactions, (c) any tender offer or exchange offer (whether by the Company or another person) is completed pursuant to which holders of Common Stock are permitted to tender or exchange a material portion of the Company’s shares of Common Stock for other securities, cash or property, or (d) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property; provided , however , that for the purposes of clause (b) above, a “Fundamental Transaction” shall not include the Company entering into a license or other agreement that licenses or transfers any intellectual property in an arm’s length negotiated transaction so long as the Company and its subsidiaries continue to have bona fide, substantial and continuing business operations and activities after such transfer, license or other agreement is entered into; provided , further , however, that a “Fundamental Transaction” shall not include a reverse stock split with respect to the Common Stock.

“ Indebtedness ” means (a) any liabilities for borrowed money or amounts owed in excess of $250,000 (other than trade accounts payable incurred in the ordinary course of business), (b) all guaranties, endorsements and other contingent obligations in respect of Indebtedness of others, whether or not the same are or should be reflected in the Company’s balance sheet (or the notes thereto), except guaranties by endorsement of negotiable instruments for deposit or collection or similar transactions in the ordinary course of business, and (c) the present value of any lease payments in excess of $250,000 due under leases required to be capitalized in accordance with GAAP.

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“ Investment Company Act ” means the Investment Company Act of 1940, as amended.

“ Lead Investor ” means Biotechnology Value Fund, L.P.

“ Liens ” means a lien, charge, security interest, encumbrance, right of first refusal, preemptive right or other restriction (other than, in the case of the Securities, restrictions provided in the Transaction Documents or as otherwise agreed or imposed by a Purchaser).

“ Material Adverse Effect ” means any material adverse effect on (a) the enforceability of any Transaction Document, (b) the results of operations, assets, business or financial condition of the Company and its Subsidiaries, taken as a whole, or (c) the Company’s ability to perform in any material respect on a timely basis its obligations under any Transaction Document to be performed as of the date of determination, other than any such change, effect, event or circumstance, including, without limitation, any change in the stock price or trading volume of the Common Stock, that resulted directly or indirectly from (i) any change in the United States or foreign economies or securities or financial markets in general that does not have a disproportionate effect on the Company and its Subsidiaries, (ii) any change that generally affects the industry in which the Company and its Subsidiaries operate that does not have a disproportionate effect on the Company and its Subsidiaries, taken as a whole, (iii) any change arising in connection with natural disasters, hostilities, acts of war, sabotage or terrorism or military actions or any escalation or material worsening of any such natural disasters, hostilities, acts of war, sabotage or terrorism or military actions existing as of the date hereof, (iv) any action taken by the Purchaser, its Affiliates or its or their permitted successors and assigns with respect to the transactions contemplated by this Agreement, (v) the effect of any changes in applicable laws or accounting rules that does not have a disproportionate effect on the Company and its Subsidiaries, taken as a whole, and (vi) any change resulting from compliance with the terms of this Agreement or the consummation of the transactions contemplated by this Agreement.

“ Per Share Purchase Price ” means $4.03 per share of Common Stock and $4,030 per share of Series X Preferred Stock.

“ Person ” means an individual or corporation, partnership, trust, incorporated or unincorporated association, joint venture, limited liability company, joint stock company, government (or an agency or subdivision thereof) or other entity of any kind.

“ Proceeding ” means any action, claim, suit, investigation or proceeding whether commenced or threatened.

“ Prospectus ” means the final prospectus filed for the Registration Statement, including the documents incorporated by reference in the Registration Statement, including the documents incorporated by reference in such final prospectus.

“ Prospectus Supplement ” means the supplement to the Prospectus complying with Rule 424(b) of the Securities Act that is delivered by the Company to each Purchaser prior to the execution and delivery of this Agreement, including the documents incorporated by reference therein, and that is filed with the Commission.

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“ Registration Statement ” means the effective registration statement on Form S-3 (Commission File No. 333-201882) filed by the Company with the Commission pursuant to the Securities Act for the registration of the Securities, as such Registration Statement may be amended and supplemented from time to time (including pursuant to Rule 462(b) of the Securities Act), including all documents filed as part thereof or incorporated by reference therein, and including all information deemed to be a part thereof at the time of effectiveness pursuant to Rule 430B of the Securities Act.

“ Required Minimum ” means, as of any date, the maximum aggregate number of shares of Common Stock then issued or potentially issuable pursuant to the Transaction Documents, including all Underlying Shares, and without regard to any Blocker (as defined in Section  4.7 ).

“ 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.

“ Securities ” means the shares of the Common Stock and Series X Preferred Stock issued hereunder.

“ Securities Act ” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

“ Series X Preferred Stock ” means the Series X Convertible Preferred Stock of the Company, $0.05 par value per share, and any other class of securities into which such securities may hereafter be reclassified, converted or changed into, including the Common Stock.

“ Series X Preferred Stock Certificate of Designation ” means the Certificate of Designation of the Company, attached as
Exhibit A to this Agreement, setting forth the rights preferences and privileges of the Series X Preferred Stock.

“ Short Sales ” means all “short sales” as defined in Rule 200 of Regulation SHO of the Exchange Act, but shall be deemed to not include the location and/or reservation of borrowable shares of Common Stock.

“ Subscription Amount ” means, as to each Purchaser, the aggregate amount to be paid for the Common Stock and Series X Preferred Stock, respectively, purchased hereunder as specified below such Purchaser’s name on the signature page of this Agreement and next to the heading “Subscription Amount,” in United States dollars and in immediately available funds.

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

“ Trading Market ” means the following markets or exchanges on which (and if) the Common Stock is listed or quoted for trading on the date in question: the NYSE MKT; The NASDAQ Capital Market; The NASDAQ Global Market; The NASDAQ Global Select Market; or the New York Stock Exchange.

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“ Transaction Documents ” means this Agreement, the Series X Preferred Stock Certificate of Designation and any other documents or agreements executed and delivered to the Purchasers in connection with the transactions contemplated hereunder.

“ Underlying Shares ” means the shares of Common Stock issued and issuable upon conversion or exercise of the Series X Preferred Stock and any other shares of Common Stock issuable to the Purchasers in connection with or pursuant to the Transaction Documents.

SECTION 2

PURCHASE AND SALE

2.1 Closing . At the Closing, upon the terms set forth herein, the Company shall sell, and the Purchasers shall purchase, in the aggregate, severally and not jointly: (a) $20,162,090, in the aggregate, of Series X Preferred Stock, with each Purchaser purchasing Series X Preferred Stock with an aggregate purchase price equal to such Purchaser’s applicable Subscription Amount, and (b) $4,836,000, in the aggregate, of Common Stock, with each Purchaser purchasing Common Stock with an aggregate purchase price equal to such Purchaser’s applicable Subscription Amount. The aggregate number of shares of Series X Preferred Stock sold hereunder shall be 5,003 and the aggregate number of shares of Common Stock sold hereunder shall be 1,200,000. Each Purchaser shall deliver to the Company via wire transfer or certified check immediately available funds equal to its aggregate Subscription Amount and the Company shall deliver to each Purchaser its respective Securities as determined pursuant to Section  2.2 of this Agreement and the other items set forth in Section  2.2 of this Agreement deliverable at the Closing on the Closing Date. The Closing shall occur at 10:00 a.m. (Pacific Time) on the third Trading Day after the Effective Date, at the offices of Gibson, Dunn & Crutcher, LLP, 555 Mission Street, Suite 3000, San Francisco, California or such other time and location as the parties shall mutually agree.

2.2 Deliveries; Closing Conditions .

i. Prior to the Closing, the Company shall have adopted and filed with the Secretary of State of the State of Delaware the Series X Preferred Stock Certificate of Designation, and the Series X Preferred Stock Certificate of Designation shall be in full force and effect.

ii. At the Closing, the Company shall deliver or cause to be delivered to each Purchaser evidence that the number of Securities equal to such Purchaser’s Subscription Amount divided by the applicable Per Share Purchase Price have been recorded in the name of such Purchaser as beneficial owner on the records of the Company’s transfer agent, Wells Fargo Shareowner Services.

iii. At the Closing, each Purchaser shall deliver or cause to be delivered to the Company such Purchaser’s Subscription Amount by wire transfer to the account as specified in writing by the Company.

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iv. The respective obligations of the Company, on the one hand, and the Purchasers, on the other hand, hereunder in connection with the Closing are subject to the following conditions being met:

(i) the accuracy in all material respects on the Closing Date of the representations and warranties contained herein (unless made as of a specified date therein) of the Company (with respect to the obligations of the Purchasers) and the Purchasers (with respect to the obligations of the Company);

(ii) all obligations, covenants and agreements of the Company (with respect to the obligations of the Purchasers) and the Purchasers (with respect to the obligations of the Company) required to be performed at or prior to the Closing Date shall have been performed in all material respects;

(iii) the delivery by the Company (with respect to the obligations of the Purchasers) and the Purchasers (with respect to the obligations of the Company) of the items set forth in Sections 2.2(ii) and 2.2(iii) of this Agreement;

(iv) there shall have been no Material Adverse Effect with respect to the Company since the date hereof; and

(v) from the date hereof to the Closing Date, trading in the Common Stock shall not have been suspended on the Company’s principal U.S. Trading Market and, at any time prior to the Closing Date, trading in securities generally as reported by Bloomberg L.P. shall not have been suspended or limited, or minimum prices shall not have been established on securities whose trades are reported by such service, on any U.S. Trading Market.

SECTION 3

REPRESENTATIONS AND WARRANTIES

3.1 Representations and Warranties of the Company . Except as set forth in the SEC Reports, which shall qualify any representation or warranty otherwise made herein to the extent of such disclosure, the Company hereby makes the following representations and warranties set forth below to each Purchaser as of the date hereof and as of the Closing Date:

i. Subsidiaries . Each of the direct and indirect significant subsidiaries (each, a “ Subsidiary ”) of the Company are set forth on Exhibit 21.1 to the Company’s most recently filed Annual Report on Form 10-K for the fiscal year ended December 31, 2015. Except as disclosed in the SEC Reports, the Company owns, directly or indirectly, all of the capital stock or other equity interests of each Subsidiary free and clear of any Liens, except for such Liens as would not reasonably be expected to result in a Material Adverse Effect, and all the issued and outstanding shares of capital stock of each Subsidiary are validly issued and are fully paid, non-assessable and free of preemptive and similar rights to subscribe for or purchase securities of the Company.

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ii. Organization and Qualification . The Company and each of the Subsidiaries is an entity duly incorporated or otherwise organized, validly existing and in good standing under the laws of the jurisdiction of its incorporation or organization (as applicable), with the requisite power and authority to own and use its properties and assets and to carry on its business as currently conducted. Neither the Company nor any Subsidiary is in violation or default of any of the provisions of its respective certificate or articles of incorporation, bylaws or other organizational or charter documents. Each of the Company and the Subsidiaries is duly qualified to conduct business and is in good 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 in any such jurisdiction revoking, limiting or curtailing or seeking to revoke, limit or curtail such power and authority or qualification except where the revocation, limitation or curtailment could not have or reasonably be expected to result in a Material Adverse Effect.

iii. Authorization; Enforcement . The Company has the requisite corporate power and authority to enter into and to consummate the transactions contemplated by each of the Transaction Documents and otherwise to carry out its obligations hereunder and thereunder. The execution and delivery of each of the Transaction Documents to which it is a party by the Company and the consummation by it of the transactions contemplated hereby and thereby have been duly authorized by all necessary corporate action on the part of the Company and except as contemplated by this Agreement, no further corporate consent or action is required to be obtained by the Company, its Board of Directors or its shareholders in connection therewith other than in connection with the Required Approvals. Each Transaction Document has been (or upon delivery will have been) duly executed by the Company and, when delivered in accordance with the terms hereof and thereof, will constitute the legally valid and binding obligation of the Company enforceable against the Company in accordance with its terms except (i) as limited by general equitable principles and applicable bankruptcy, insolvency, reorganization, moratorium and other laws of general application affecting enforcement of creditors’ rights generally, (ii) as limited by laws relating to the availability of specific performance, injunctive relief or other equitable remedies and (iii) insofar as indemnification and contribution provisions may be limited by applicable law.

iv. No Conflicts . The execution, delivery and performance of the Transaction Documents to which it is a party by the Company, the issuance and sale of the Securities and the consummation by the Company of the other transactions contemplated hereby and thereby do not and will not (i) after giving effect to the Required Approvals, conflict with or violate any provision of the Company’s or any Subsidiary’s certificate or articles of incorporation, bylaws or other organizational or charter documents, or (ii) after giving effect to the Required Approvals, conflict with, or constitute a default (or an event that with notice or lapse of time or both would become a default) under, result in the creation of any Lien upon any of the properties or assets of the Company or any Subsidiary, or give to others any rights of termination, amendment, acceleration or cancellation (with or without notice, lapse of time or both) of, any agreement, credit facility, debt or other instrument (evidencing a Company or Subsidiary debt or otherwise) or other understanding to which the Company or any Subsidiary is a party or by which any property or asset of the Company or any Subsidiary is bound or affected, 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 or a Subsidiary is subject (including federal and state securities laws and regulations), or by which any property or asset of the Company or a Subsidiary is bound or affected, except in the case of each of clauses (ii)  and (iii) only, such as would not have or reasonably be expected to result in a Material Adverse Effect.

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v. Filings, Consents and Approvals . Except as disclosed in the SEC Reports and except where the failure to obtain any such consent, waiver, authorization or order, give any such notice or make any such filing or registration would not reasonably be expected to result in a Material Adverse Effect, 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 or other Person or other entity of any kind, including, without limitation, any Trading Market in connection with the execution, delivery and performance by the Company of the Transaction Documents, except for any filings required to be made under applicable federal and state securities laws and the listing applications with respect to the listing of the Securities required pursuant to Section  4.6 (collectively, the “ Required Approvals ”).

vi. Issuance of the Securities . The Securities are duly authorized and, when issued and paid for in accordance with the applicable Transaction Documents, will be duly and validly issued, fully paid and non-assessable, free and clear of all Liens imposed by the Company. The Securities are being issued pursuant to the Registration Statement and the issuance of the Securities will be registered by the Company pursuant to the Securities Act. The Company has prepared and filed with the Commission in accordance with the provisions of the Securities Act the Registration Statement. The Registration Statement is effective pursuant to the Securities Act and available for the issuance of the Securities thereunder and the Company has not received any written notice that the Commission has issued or intends to issue a stop-order or other order with respect to the Registration Statement or the Prospectus or that the Commission otherwise has (i) suspended or withdrawn the effectiveness of the Registration Statement or (ii) issued any order preventing or suspending the use of the Prospectus, in either case, either temporarily or permanently or intends or has threatened in writing to do so. The “Plan of Distribution” section of the Registration Statement permits the issuance of the Securities hereunder. Upon receipt of the Securities, the Purchasers will have good and marketable title to such Securities, the Common Stock will be immediately freely tradable on each Trading Market, and upon issuance in compliance with the terms of the Transaction Documents, the Underlying Shares will be immediately freely tradable on each Trading Market. At the time the Registration Statement and any amendments thereto became effective, at the date of this Agreement and at each deemed effective date thereof pursuant to Rule 430B(f)(2) of the Securities Act, the Registration Statement and any amendments thereto complied and will comply in all material respects with the requirements of the Securities Act and did not and 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 not misleading; and the Prospectus and any amendments or supplements thereto, at the time the Prospectus or any amendment or supplement thereto was issued and as of the Closing Date, complied and will comply in all material respects with the requirements of the Securities Act and did not and will not contain an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The Company meets all of the requirements for the use of a registration statement on Form S-3 (“ Form S-3 ”) pursuant to the Securities Act for the offering and sale of the Securities

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contemplated by this Agreement, and the Commission has not notified the Company of any objection to the use of the form of the Registration Statement pursuant to Rule 401(g)(1) of the Securities Act. The Registration Statement, as of its effective date, meets the requirements set forth in Rule 415(a)(1)(x) pursuant to the Securities Act. At the earliest time after the filing of the Registration Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2) of the Securities Act) relating to any of the Securities, the Company was not and is not an Ineligible Issuer (as defined in Rule 405 of the Securities Act). The offering of the Securities has been registered with the Commission on Form S-3 pursuant to the Securities Act pursuant to the standards for Form S-3 and the Securities are being offered pursuant to Rule 415 of the Securities Act.    

vii. Capitalization . As of February 9, 2017, there were 6,320,882 shares of Common Stock issued and outstanding and no shares of preferred stock outstanding. Except as disclosed in the SEC Reports, the Company has not issued any capital stock since its most recently filed periodic report pursuant to the Exchange Act, other than pursuant to a certain at the market sales agreement with Cowen & Company, LLC, the exercise of stock options pursuant to the Company’s equity incentive plans, the issuance of shares of Common Stock to employees, directors and consultants pursuant to the Company’s equity incentive plans and stock purchase plans, and pursuant to the conversion or exercise of Common Stock Equivalents outstanding as of the date of the most recently filed periodic report pursuant to the Exchange Act. 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. Except for various outstanding series of convertible debt, options and warrants described in the SEC Reports, there are no outstanding series of convertible stock, 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 or any Subsidiary is or may become bound to issue additional shares of Common Stock or Common Stock Equivalents. The issuance and sale of the Securities will not obligate the Company to issue shares of Common Stock or other securities to any Person other than the Purchasers, 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. All of the outstanding shares of capital stock of the Company are validly issued, fully paid and non-assessable, have been issued in compliance with all federal and state securities laws, and none of such outstanding shares were issued in violation of any preemptive rights or similar rights to subscribe for or purchase securities. Other than the Required Approvals, no further approval or authorization after the date hereof of any shareholder, the Board of Directors of the Company or others is required for the issuance and sale of the Securities. Except as disclosed in the SEC Reports or as contemplated by this Agreement or as otherwise agreed by a Purchaser, there are no shareholder 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 knowledge of the Company, between or among any of the Company’s shareholders.

viii. SEC Reports; Financial Statements . The Company has complied in all material respects with requirements to file all reports, schedules, forms, statements and other documents required to be filed by it pursuant to the Securities Act and the Exchange Act, including, without limitation, pursuant to Section 13(a) or 15(d) thereof, for the two years

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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, together with the Prospectus and the Prospectus Supplement, being collectively referred to herein as the “ SEC Reports ”) 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. As of their respective dates, the SEC Reports complied in all material respects with the requirements of the Securities Act and the Exchange Act, as applicable, the rules and regulations of the Commission promulgated thereunder and other federal, state and local laws, rules and regulations applicable to it, 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 the light of the circumstances under which they were made, not misleading. The financial statements of the Company included in the SEC Reports, together with the related notes and schedules thereto, comply in all material respects with applicable accounting requirements and the rules and regulations of the Commission and all other applicable rules and regulations with respect thereto as in effect at the time of filing. Such financial statements, together with the related notes and schedules, have been prepared in accordance with United States generally accepted accounting principles (“ 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 and its consolidated subsidiaries 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.

ix. Material Changes; Undisclosed Events, Liabilities or Developments . Except as disclosed in the SEC Reports or as otherwise contemplated by this Agreement, since the date of the latest audited financial statements included within the SEC Reports, (i) there has been no event, occurrence or development that has had or that could reasonably be expected to result in a Material Adverse Effect, (ii) the Company has not incurred any liabilities (contingent or otherwise) 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 required to be disclosed in filings made with the Commission, (iii) the Company has not altered its method of accounting, and (iv) the Company has not issued any equity securities to any officer, director or Affiliate except pursuant to existing Company equity incentive and incentive compensation plans. Except for the issuance of the Securities contemplated by this Agreement, or as set forth in the SEC Reports, or as otherwise disclosed to the Purchasers, no event, liability or development has occurred or exists with respect to the Company or its Subsidiaries or their respective business, properties, operations or financial condition, that would be required to be disclosed by the Company under applicable securities laws at the time this representation is made that has not been publicly disclosed at least one (1) Trading Day prior to the date that this representation is made.

x. Litigation . Except as disclosed in the SEC Reports, there is no Proceeding pending or, to the knowledge of the Company, threatened against or affecting the Company, any Subsidiary or any of their respective properties before or by any court, arbitrator, governmental or administrative agency or regulatory authority (federal, state, county, local or foreign)

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(collectively, an “ Action ”) which (i) adversely affects or challenges the legality, legal validity or enforceability of any of the Transaction Documents or the Securities or (ii) would, if there were an unfavorable decision, reasonably be expected to result in a Material Adverse Effect. Except as disclosed in the SEC Reports, neither the Company nor any Subsidiary, nor 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. Except as disclosed in the SEC Reports, there has not been, and to the knowledge of the Company, there is not pending or contemplated, any investigation by the Commission involving the Company or any current or former director or officer of the Company. The Commission has not issued any stop order or other order suspending the effectiveness of any registration statement filed by the Company or any Subsidiary pursuant to the Exchange Act or the Securities Act.    

xi. Labor Relations . No material labor dispute exists or, to the knowledge of the Company, is imminent with respect to any of the employees of the Company which would reasonably be expected to result in a Material Adverse Effect. The Company and its Subsidiaries believe that their relationships with their employees are good. No executive officer, to the knowledge of the Company, is, or is now expected to be, in violation of any material term of any employment contract, confidentiality, disclosure or proprietary information agreement or non-competition agreement, or any other contract or agreement or any restrictive covenant, and the continued employment of each such executive officer does not subject the Company or any of its Subsidiaries to any liability with respect to any of the foregoing matters. The Company and its Subsidiaries are in compliance with all U.S. federal, state, local and foreign laws and regulations relating to employment and employment practices, terms and conditions of employment and wages and hours, except where the failure to be in compliance would not, individually or in the aggregate, reasonably be expected to have a Material Adverse Effect.

xii. Compliance . Except as disclosed in the SEC Reports, neither the Company nor any Subsidiary (i) is in default under or in violation of (and no event has occurred that has not been waived that, with notice or lapse of time or both, would result in a default by the Company or any Subsidiary under), nor has the Company or any Subsidiary received notice of a claim that it is in default under or that it is in violation of, any indenture, loan or credit agreement or any other agreement or instrument to which it is a party or by which it or any of its properties is bound (whether or not such default or violation has been waived), (ii) is in violation of any order of any court, arbitrator or governmental body, or (iii) is or has been in violation of any statute, rule or regulation of any governmental authority, including without limitation all foreign, federal, state and local laws applicable to its business and all such laws that affect the environment, except as disclosed herein and except in each case as would not reasonably be expected to have a Material Adverse Effect.

xiii. Regulatory Permits . Except as disclosed in the SEC Reports, (i) the Company and the Subsidiaries possess all certificates, authorizations and permits issued by the appropriate federal, state, local or foreign regulatory authorities necessary to conduct their respective businesses as described in the SEC Reports, except where the failure to possess such permits would not have or reasonably be expected to result in a Material Adverse Effect (“ Material Permits ”), and (ii) neither the Company nor any Subsidiary has received any notice of proceedings relating to the revocation or modification of any Material Permit.

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xiv. Title to Assets . Except as disclosed in the SEC Reports, the Company and the Subsidiaries have good and marketable title in fee simple to all real property owned by them that is material to the business of the Company and the Subsidiaries and good and marketable title in all personal property owned by them that is material to the business of the Company and the Subsidiaries, in each case free and clear of all Liens, except for Liens which do not materially affect the value of such property and do not materially interfere with the use made and proposed to be made of such property by the Company and the Subsidiaries and Liens for the payment of federal, state or other taxes, the payment of which is neither delinquent nor subject to penalties or for taxes that are being contested in good faith and by appropriate proceedings, and except for Liens which would not reasonably be expected to result in a Material Adverse Effect. Any real property and facilities held under lease by the Company and the Subsidiaries are held by them under valid, subsisting and enforceable leases with which the Company and the Subsidiaries are in compliance.

xv. Patents and Trademarks . To its knowledge, the Company and the Subsidiaries have, or have rights to use, all patents, patent applications, trademarks, trademark applications, service marks, trade names, trade secrets, inventions, copyrights, licenses and other similar intellectual property rights currently owned by or licensed to them in connection with the business currently operated by them that are necessary for use in the conduct of their respective businesses as described in the SEC Reports, except where the failure to so have would not reasonably be expected to have a Material Adverse Effect (collectively, the “ Intellectual Property Rights ”). Neither the Company nor any Subsidiary has received any written notice that any of the Intellectual Property Rights used by the Company or any Subsidiary violates or infringes upon the rights of any Person, except for such as would not reasonably be expected to have a Material Adverse Effect. To the knowledge of the Company, all such Intellectual Property Rights are enforceable and there is no existing infringement by another Person of any of the Intellectual Property Rights of the Company or any Subsidiaries.

xvi. Insurance . The Company and the Subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which the Company and the Subsidiaries are engaged, including, but not limited to, directors and officers insurance coverage. To the Company’s knowledge, such insurance contracts are accurate and complete. Neither the Company nor any Subsidiary has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business without a significant increase in cost, except for such renewals or failures to obtain similar coverage from similar insurers as would not reasonably be expected to have a Material Adverse Effect or as affect the industry generally.

xvii. Transactions With Affiliates and Employees . None of the officers or directors of the Company and, to the knowledge of the Company, none of the employees of the Company is presently a party to any transaction with the Company or any Subsidiary (other than for services as employees, officers and directors) that is required to be disclosed and is not disclosed in the SEC Reports, including any contract, agreement or other arrangement providing for the furnishing of services to or by, providing for rental of real or personal property to or from, or otherwise requiring payments to or from any officer, director or such employee or, to the

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knowledge of the Company, any entity in which any officer, director, or any such employee has a substantial interest or is an officer, director, trustee or partner, other than for (i) payment of salary, consulting fees or financial advisory fees for services rendered, (ii) reimbursement for expenses incurred on behalf of the Company and (iii) other employee benefits, including restricted stock programs and stock option agreements under any stock option plan of the Company.

xviii. Sarbanes-Oxley . The Company is in material compliance with all provisions of the Sarbanes-Oxley Act of 2002, as amended, which are applicable to it as of the date hereof.

xix. Certain Fees . Other than as disclosed in the Prospectus Supplement, no brokerage or finder’s fees or commissions are or will be payable by the Company to any broker, financial advisor or consultant, finder, placement agent, investment banker, bank or other Person with respect to the transactions contemplated by the Transaction Documents.

xx. Investment Company . The Company is not, and immediately after receipt of payment for the Securities will not be, an “investment company” within the meaning of the Investment Company Act.

xxi. Registration Rights . No Person has any right to cause the Company to effect the registration pursuant to the Securities Act of any securities of the Company, which rights will interfere with the transactions contemplated hereunder.

xxii. Listing and Maintenance Requirements . The 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, or which to its knowledge is likely to have the effect of, terminating the registration of the Common Stock pursuant to the Exchange Act nor has the Company received any notification that the Commission is currently contemplating terminating such registration. The Company is currently in compliance with all applicable NASDAQ listing and maintenance requirements and, except as disclosed in the SEC Reports, the Company has not, in the 12 months preceding the date hereof, received notice from NASDAQ to the effect that the Company is not in compliance with the listing or maintenance requirements of such Trading Market.

xxiii. Application of Takeover Protections . The Company and its 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 pursuant to the Amended and Restated Certificate of Incorporation (or similar charter documents) or the laws of its state of incorporation that is or could become applicable to the Purchasers as a result of the Purchasers and the Company fulfilling their obligations or exercising their rights pursuant to the Transaction Documents, including without limitation, as a result of the Company’s issuance of the Securities and the Purchasers’ ownership of the Securities. All such anti-takeover provisions in effect as of the Effective Date are summarized generally in the Prospectus under the caption, “ Description of Capital Stock – Anti-Takeover Effects of Our Charter Documents and Some Provisions of Delaware Law .”

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xxiv. No Integrated Offering . Assuming the accuracy of the Purchasers’ representations and warranties set forth in Section  3.2 of this Agreement, neither the Company, nor any of its Affiliates, nor any Person acting on its or their behalf has, directly or indirectly, made any offers or sales of any security or solicited any offers to buy any security, under circumstances that would cause this offering of the Securities to be integrated with prior offerings by the Company in a manner that would require shareholder approval pursuant to the rules of any Trading Market on which any of the securities of the Company are listed or designated. The issuance and sale of the Securities hereunder does not contravene the rules and regulations of any Trading Market.

xxv. Indebtedness . The SEC Reports set forth as of the dates thereof all outstanding secured and unsecured Indebtedness of the Company or any Subsidiary, or for which the Company or any Subsidiary has commitments. Neither the Company nor any Subsidiary is in default with respect to any Indebtedness disclosed to the Purchasers except for any such default that would not have or reasonably be expected to result in a Material Adverse Effect.

xxvi. Tax Status . Except for matters that would not, individually or in the aggregate, have or reasonably be expected to result in a Material Adverse Effect and except as disclosed in the SEC Reports, the Company and each Subsidiary have filed (or requested valid extensions thereof) all necessary federal, state and foreign income and franchise tax returns (unless and only to the extent that the Company and each of its Subsidiaries has set aside on its books provisions reasonably adequate for the payment of all unpaid and unreported taxes) and have paid or accrued all taxes shown as due thereon, and the Company has no knowledge of a tax deficiency which has been asserted or threatened against the Company or any Subsidiary.

xxvii. Foreign Corrupt Practices.  Neither the Company, nor to the knowledge of the Company, 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.

xxviii. Accountants . Ernst & Young LLP (i) to the knowledge of the Company, is an independent public accountant as required by the Exchange Act and is an independent registered public accounting firm within the meaning of the Sarbanes-Oxley Act of 2002, as amended, as required by the rules of the Public Company Accounting Oversight Board and (ii) expressed its opinion with respect to the audited financial statements and related schedules as of December 31, 2014 and 2015 and for fiscal years 2013, 2014 and 2015 included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2015.

xxix. Acknowledgment Regarding Purchasers’ Purchase of Securities . The Company acknowledges and agrees that each of the Purchasers is acting solely in the capacity of an arm’s length purchaser with respect to the Transaction Documents and the transactions contemplated thereby. The Company further acknowledges that no Purchaser is acting as a

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financial advisor or fiduciary of the Company (or in any similar capacity) with respect to the Transaction Documents and the transactions contemplated thereby and any advice given by any Purchaser or any of their respective representatives or agents in connection with the Transaction Documents and the transactions contemplated thereby is merely incidental to the Purchasers’ purchase of the Securities. The Company further represents to each Purchaser that the Company’s decision to enter into this Agreement and the other Transaction Documents has been based solely on the independent evaluation of the transactions contemplated hereby by the Company and its representatives.

xxx. Regulation  M Compliance . The Company has not, and to its knowledge no one acting on its behalf has, (i) taken, directly or indirectly, any action designed to cause or to result in the stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of any of the Securities, (ii) sold, bid for, purchased, or, paid any compensation for soliciting purchases of, any of the Securities, or (iii) paid or agreed to pay to any Person any compensation for soliciting another to purchase any other securities of the Company.

xxxi. Shell Company Status . The Company is not, and has never been, an issuer identified in Rule 144(i)(1) of the Securities Act.

xxxii. Office of Foreign Assets Control . Neither the Company nor any Subsidiary nor, to the Company’s knowledge, any director, officer, agent, employee or Affiliate of the Company or any Subsidiary is currently subject to any U.S. sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department.

xxxiii. Money Laundering . The operations of the Company and its Subsidiaries are and have been conducted at all times in compliance with applicable financial record-keeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, applicable money laundering statutes and applicable rules and regulations thereunder (collectively, the “ Money Laundering Laws ”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any Subsidiary with respect to the Money Laundering Laws is pending or, to the knowledge of the Company or any Subsidiary, threatened.

xxxiv. Material Contracts . All material contracts as defined under Item 601(b)(10) of Regulation S-K that were required to be filed as exhibits to the SEC Reports under Item 601 of Regulation S-K (collectively, the “ Material Contracts ”) to which the Company is a party, or the property or assets of the Company is subject, have been filed as exhibits to the SEC Reports. All Material Contracts are legally valid and enforceable against the Company in accordance with their respective terms, except (i) as limited by general equitable principles and applicable bankruptcy, insolvency, reorganization, moratorium and other laws of general application affecting enforcement of creditors’ rights generally, (ii) as limited by laws relating to the availability of specific performance, injunctive relief or other equitable remedies and (iii) insofar as indemnification and contribution provisions may be limited by applicable law. The Company is not in breach of or default under any of the Material Contracts, and to the Company’s knowledge, no other party to a Material Contract is in breach of or default under such Material Contract, except in each case, for such breaches or defaults as would not reasonably be expected to have a Material Adverse Effect. The Company has not received a

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notice of termination or material modification nor is the Company otherwise aware of any threats to terminate or materially modify any of the Material Contracts. Schedule 3.1( ll ) , previously provided to the Purchasers, sets forth a complete and accurate list of all material licenses, joint ventures and other partnership agreements to which the Company is a party and involving any drug or drug candidate (the “ Assets ”).

xxxv. Disclosure Controls and Procedures . Except as disclosed in the SEC Reports, the Company has established and maintains disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) that are effective in all material respects to ensure that material information relating to the Company, including any consolidated Subsidiaries, is made known to its principal executive officer and principal financial officer by others within those entities. 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 most recently filed quarterly or annual periodic report under the Exchange Act (such date, the “ Evaluation Date ”). The Company presented in its most recently filed quarterly or annual 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 significant changes in the Company’s internal control over financial reporting (as such term is defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) or, to the Company’s knowledge, in other factors that could significantly affect the Company’s internal control over financial reporting.

xxxvi. Accounting Controls . Except as disclosed in the SEC Reports, the Company maintains a system of internal accounting controls sufficient to provide reasonable assurances that (i) transactions are executed in accordance with management’s general or specific authorization, (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with GAAP and to maintain accountability for assets, (iii) access to assets is permitted only in accordance with management’s general or specific authorization, and (iv) the recorded accountability for assets is compared with existing assets at reasonable intervals and appropriate action is taken with respect to any differences.

xxxvii. Placement Agent . The Company has taken no action that would give rise to any claim by any Person for brokerage commissions, placement agent’s fees or similar payments relating to this Agreement or the transactions contemplated hereby.

xxxviii. No Disagreements with Accountants . The Company is not presently under any Advisement (as defined below) from the independent registered public accounting firm presently employed by the Company and the Company is current with respect to any fees owed to such firm that could affect the Company’s ability to perform any of its obligations under this Agreement. “ Advisement ” means (i) the accountant’s having advised the Company that the internal controls necessary for the Company to develop reliable financial statements do not exist, (ii) the accountant’s having advised the Company that information has come to the accountant’s attention that has led it to no longer be able to rely on management’s representations, or that has made it unwilling to be associated with the financial statements prepared by management, (iii) the accountant’s having advised the Company of the need to expand significantly the scope of its audit, or (iv) the accountant’s having advised the Company that information has come to the accountant’s attention that it has concluded materially impacts the fairness or reliability of either:

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(A) a previously issued audit report or the underlying financial statements, or (B) the financial statements issued or to be issued covering the fiscal period(s) subsequent to the date of the most recent financial statements covered by an audit report (including information that, unless resolved to the accountant’s satisfaction, would prevent it from rendering an unqualified audit report on those financial statements).

3.2 Representations, Warranties and Covenants of the Purchasers . Each Purchaser, for itself and for no other Purchaser, hereby represents, warrants and covenants as of the execution and delivery of this Agreement on the date first above written in this Agreement to the Company as follows:

i. Organization; Authority . Such Purchaser is an entity duly organized, validly existing and in good standing under the laws of the jurisdiction of its organization with full right, corporate or partnership power and authority to enter into and to consummate the transactions contemplated by the Transaction Documents and otherwise to carry out its obligations hereunder and thereunder. The execution, delivery and performance by such Purchaser of the transactions contemplated by this Agreement have been duly authorized by all necessary corporate or similar action on the part of such Purchaser. Each Transaction Document to which it is a party has been duly executed by such Purchaser, and when delivered by such Purchaser in accordance with the terms hereof, will constitute the valid and legally binding obligation of such Purchaser, enforceable against it in accordance with its terms, except (i) as limited by general equitable principles and applicable bankruptcy, insolvency, reorganization, moratorium and other laws of general application affecting enforcement of creditors’ rights generally, (ii) as limited by laws relating to the availability of specific performance, injunctive relief or other equitable remedies and (iii) insofar as indemnification and contribution provisions may be limited by applicable law.

ii. No Intent to Take Over . Such Purchaser is not a party to any voting agreements or similar arrangements with respect to the Securities. Except as expressly disclosed in a Schedule 13D or Schedule 13G (or amendments thereto) filed by such Purchaser with the Commission with respect to the beneficial ownership of the Company’s Common Stock, such Purchaser is not a member of a partnership, limited partnership, syndicate, or other group for the purpose of acquiring, holding, voting or disposing of the Securities. Each Purchaser represents and warrants that it (i) is not, and has no present intention to become, a party to (A) any agreement, arrangement or understanding with, and has not given any commitment or assurance to, any Person as to how such Person, if serving as a director or if elected as a director of the Company, will act or vote on any issue or question (a “ Voting Commitment ”) or (B) any Voting Commitment that could limit or interfere with such Person’s ability to comply, if serving as or elected as a director of the Company, with such Person’s fiduciary duties under applicable law; (ii) is not, and has no present intention to become, a party to any agreement, arrangement or understanding with any Person other than the corporation with respect to any direct or indirect compensation, reimbursement or indemnification in connection with service or action as a director of the Company. Such Purchaser has no present actual intent to seek to effect, or to assist others in effecting, a hostile acquisition of the Company.

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iii. Short Sales and Confidentiality Prior to the Date Hereof . Other than consummating the transactions contemplated hereunder, such Purchaser has not directly or indirectly, nor has any Person acting on behalf of or pursuant to any understanding with such Purchaser, executed any purchases or sales, including Short Sales, of the securities of the Company during the period commencing as of the time that such Purchaser first learned of the specific purchase and sale transaction being effected pursuant to this Agreement and ending immediately prior to the execution and delivery hereof. Notwithstanding the foregoing, in the case of a Purchaser that is a multi-managed investment vehicle whereby separate portfolio managers manage separate portions of such Purchaser’s assets and the portfolio managers have no direct knowledge of the investment decisions made by the portfolio managers managing other portions of such Purchaser’s assets, the representation set forth above shall only apply with respect to the portion of assets managed by the portfolio manager that made the investment decision to purchase the Securities covered by this Agreement. Other than to other Persons party to this Agreement and to its counsel, such Purchaser has maintained the confidentiality of all disclosures made to it in connection with the transaction expressly contemplated by this Agreement (including the existence and terms of this transaction). Notwithstanding the foregoing, for avoidance of doubt, nothing contained herein shall constitute a representation or warranty, or preclude any actions, with respect to the identification of the availability of, or securing of, available shares to borrow in order to effect Short Sales or similar transactions in the future.

iv. Lock Up . The Purchaser agrees that for 180 days following the Closing, neither the Purchaser nor any of its Affiliates shall offer, sell, contract to sell, pledge, grant any option to purchase, make any Short Sale or otherwise dispose of in any manner, either directly or indirectly, any Securities purchased under this Agreement or any securities of the Company currently owned by the Purchaser, other than transfers of securities between and among the Purchaser and any one or more of its Affiliates.

v. No Government Review . Such Purchaser understands that no U.S. federal or state agency or any other government or governmental agency has passed upon or made any recommendation or endorsement of the Securities purchased hereunder.

vi. Beneficial Ownership . Immediately following such Purchaser’s purchase of Securities hereunder, such Purchaser, together with its Affiliates, will not beneficially own more than 19.99% of the Common Stock. For purposes hereof, beneficial ownership and all determinations and calculations (including, without limitation, with respect to calculations of percentage ownership) shall be determined in accordance with Section 13(d) of the Exchange Act and the rules and regulations promulgated thereunder.

vii. Interested Stockholders . To the extent applicable, any Purchaser that is an “Interested Stockholder” (as such term is defined in Section 203 of the General Corporation Law of the State of Delaware) represents and warrants that it has been an Interested Stockholder for at least three years prior to the date hereof.

viii. Standstill . The Purchaser agrees that during the 180 day period following the Closing, neither the Purchaser nor any of its Affiliates shall take any of the following actions, provided that nothing herein shall interfere with the rights or duties of the BVF Designee to serve in his/her capacity as a member of the Board of Directors, and in such capacity, act in accord with applicable fiduciary duties:

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(i) make any statement or proposal to any of the Company’s stockholders regarding, or make any public announcement, proposal or offer (including any “solicitation” of “proxies” as such terms are defined or used in Regulation 14A of the Exchange Act) with respect to, or otherwise solicit, seek or offer to effect (including, for the avoidance of doubt, indirectly by means of communication with the press or media): (i) any business combination, merger, tender offer, exchange offer or similar transaction involving the Company or any of its subsidiaries, (ii) any restructuring, recapitalization, liquidation or similar transaction involving the Company or any of its subsidiaries, or (iii) any acquisition of any of the Company’s loans, debt securities, equity securities or all or substantially all of the Company’s assets, or rights or options to acquire interests in any of the foregoing;

(ii) instigate, encourage or assist any third party (including forming a “group,” as defined in the Exchange Act, with any such third party) to do, or enter into any discussions or agreements with any third party with respect to, any of the actions set forth in clause (i) above;

(iii) take any action which would reasonably be expected to require the Company or any of its Affiliates to make a public announcement regarding any of the actions set forth in clause (i) above; or

(iv) acquire (or propose or agree to acquire), of record or beneficially, by purchase or otherwise, any loans, equity securities or all or substantially all of the assets of the Company or any of its subsidiaries, or rights or options to acquire interests in any of the foregoing, but excluding the acquisition of the Securities at the Closing and/or the conversion of any portion of the Series X Preferred Stock.

SECTION 4

OTHER AGREEMENTS OF THE PARTIES

4.1 Integration . After this transaction, the Company shall not 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 would be integrated with the offer or sale of the Securities such that the rules of the Trading Market would require shareholder approval of this transaction prior to the closing of such other transaction unless shareholder approval is obtained before the closing of such subsequent transaction.

4.2 Securities Laws Disclosure; Publicity . The Company shall: (a) issue a press release disclosing the material terms of the transactions by no later than 8:30 a.m. (Eastern Time) the next Trading Day following the execution and delivery of this Agreement (the “ Press Release ”), and (b) by 5:30 p.m. (Eastern Time) on the fourth Trading Day following the date hereof, file a Current Report on Form 8-K disclosing the material terms of the transactions contemplated hereby and including the Transaction Documents as exhibits thereto (the “ Form 8-K ”). From and after the issuance of the Press Release, no Purchaser shall be in possession of any material, non-public information received from the Company, any of its Subsidiaries or any of their respective officers, directors or employees that is not disclosed in the Press Release. The Company and each Purchaser shall consult with each other in issuing any other press releases with respect to the transactions contemplated hereby, and, except as may be required by law,

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neither the Company nor any Purchaser shall issue any such press release or otherwise make any such public statement without the prior consent of the Company, with respect to any press release of any Purchaser, or without the prior consent of each Purchaser, with respect to any press release of the Company, which consent shall not unreasonably be withheld or delayed, except if such disclosure is required by law, in which case the disclosing party shall promptly provide the other party with prior notice of such public statement or communication. Notwithstanding the foregoing, the Company shall not publicly disclose the name of any Purchaser, or include the name of any Purchaser in any filing with the Commission or any regulatory agency or any Trading Market, without the prior written consent of such Purchaser, except (i) in the Press Release, (ii) the filing of this Agreement (including the signature pages hereto), the Prospectus Supplement, the Press Release and the Form 8-K with the Commission, and (iii) to the extent such disclosure is required by law or any Trading Market regulations, in which case the Company shall provide the Purchasers with prior notice of such disclosure permitted under this sub clause (iii).

4.3 Non-Public Information . Except with respect to the material terms and conditions of the transactions contemplated by the Transaction Documents, the Company covenants and agrees that neither it nor any other Person acting on its behalf will provide any Purchaser or its agents or counsel with any information that the Company believes constitutes material non-public information. Notwithstanding the foregoing, to the extent the Company delivers any material, non-public information to a Purchaser without such Purchaser’s consent, the Company hereby covenants and agrees that such Purchaser shall not have any duty of confidentiality with respect to, or a duty not to trade on the basis of, such material, non-public information. The Company understands and confirms that each Purchaser shall be relying on the foregoing covenant in effecting transactions in securities of the Company.

4.4 Use of Proceeds . The Company will use the proceeds from the offering as described in the Prospectus Supplement.

4.5 Indemnification of Purchasers . Subject to the provisions of this Section  4.5 , the Company will indemnify and hold each Purchaser and its directors, officers, shareholders, members, partners, employees and agents (and any other Persons with a functionally equivalent role of a Person holding such titles notwithstanding a lack of such title or any other title), each Person who controls such Purchaser (within the meaning of Section 15 of the Securities Act and Section 20 of the Exchange Act), and the directors, officers, shareholders, agents, members, partners or employees (and any other Persons with a functionally equivalent role of a Person holding such titles notwithstanding a lack of such title or any other title) of such controlling Persons (each, a “ Purchaser Party ”) harmless from any and all losses, liabilities, obligations, claims, contingencies, damages, costs and expenses, including all judgments, amounts paid in settlements, court costs and reasonable attorneys’ fees and costs of investigation that any such Purchaser Party may suffer or incur as a result of or relating to (a) any breach of any of the representations, warranties, covenants or agreements made by the Company in this Agreement or in the other Transaction Documents or (b) any action instituted against a Purchaser, or any of them or their respective Affiliates, by any shareholder of the Company who is not an Affiliate of such Purchaser or any governmental or regulatory agency, with respect to any of the transactions contemplated by the Transaction Documents (unless such action is based upon a material breach of such Purchaser’s representations, warranties or covenants of the Transaction Documents or

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any agreements or understandings such Purchaser may have with any such shareholder or any material violations by the Purchaser of state or federal securities laws or any conduct by such Purchaser which constitutes fraud, gross negligence, willful misconduct or malfeasance). If any action shall be brought against any Purchaser Party in respect of which indemnity may be sought pursuant to this Agreement, such Purchaser Party shall promptly notify the Company in writing, and the Company shall have the right to assume the defense thereof with counsel of its own choosing reasonably acceptable to the Purchaser Party. Any Purchaser Party shall have the right to engage separate counsel in any such action and participate in the defense thereof, but the fees and expenses of such counsel shall be at the expense of such Purchaser Party except to the extent that (i) the engagement thereof has been specifically authorized by the Company in writing, (ii) the Company has failed after a reasonable period of time to assume such defense and to employ counsel or (iii) in such action there is, in the reasonable opinion of such separate counsel, a material conflict on any material issue between the position of the Company and the position of such Purchaser Party, in which case the Company shall be responsible for the reasonable fees and expenses of no more than one such separate counsel. The Company will not be liable to any Purchaser Party under this Agreement (i) for any settlement by a Purchaser Party effected without the Company’s prior written consent, which shall not be unreasonably withheld or delayed or (ii) to the extent, but only to the extent, that a loss, claim, damage or liability is attributable to any Purchaser Party’s breach of any of the representations, warranties, covenants or agreements made by such Purchaser Party in this Agreement or in the other Transaction Documents. To the extent that a Purchaser Party wishes to seek indemnification under this Section  4.5 , such Purchaser Party must provide the Company with written notice asserting a claim under this Section  4.5 , with such notice to be provided within one year from the Closing. If a Purchaser Party fails to provide such written notice within this one-year period, the Purchaser Party shall no longer be entitled to indemnification by the Company hereunder.

4.6 Reservation and Listing of Securities .

i. At all times from and after the Closing, the Company shall maintain a reserve from its duly authorized shares of Common Stock for issuance pursuant to the Transaction Documents in such amount as may then be required to fulfill its obligations in full under the Transaction Documents, but not less than the Required Minimum.

ii. If, on any date, the number of authorized but unissued (and otherwise unreserved) shares of Common Stock is less than the Required Minimum on such date (such date, the “ Authorized Share Failure ”), then the Company shall promptly take all action necessary to increase the Company’s authorized shares of Common Stock to an amount sufficient to allow the Company to reserve and have available the Required Minimum as of such date. Without limiting the generality of the foregoing sentence, as soon as practicable after the date of the occurrence of an Authorized Share Failure, but in no event later than 90 days after the occurrence of such Authorized Share Failure, the Company shall hold a meeting of its stockholders or conduct a consent solicitation for the approval of an increase in the number of authorized shares of Common Stock to have available the Required Minimum

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iii. The Company shall: (i) in the time and manner required by the principal Trading Market, prepare and file with such Trading Market a Notification of Listing of Additional Shares (“ LAS ”) application covering a number of shares of Common Stock at least equal to the Required Minimum on the date of such application, (ii) provide to each Purchaser evidence of filing the LAS, (iii) use commercially reasonable efforts to maintain the listing of the Common Stock on a Trading Market, and (iv) receive written or oral confirmation from NASDAQ prior to the Closing that it has completed its review of the LAS without raising any substantive objections to the offering and sale of the Securities. The Company further agrees that if the Company applies to have the Common Stock traded on any other Trading Market, it will include in such application all of the Underlying Shares and will take such other action as is necessary to cause all of the Underlying Shares to be listed on such other Trading Market as promptly as possible. The Company will take all action reasonably necessary to continue the listing and trading of its Common Stock on a Trading Market, other than in connection with a Fundamental Transaction in which the Company is not the surviving entity or in which all of the capital stock of the Company is acquired by an unaffiliated and unrelated Person, and will comply in all respects with the Company’s reporting, filing and other obligations under the bylaws or rules of such Trading Market.

4.7 Appointment of Designee to Board of Directors . Promptly after the Closing, the Board of Directors of the Company shall take such actions as are necessary to appoint Matthew Perry (or another representative nominated by the Lead Investor and reasonably acceptable to the Company) (the “ BVF Nominee ”) to the Board of Directors of the Company and, subject to confirmation of the BVF Nominee’s eligibility under NASDAQ rules to serve as a member of the Compensation Committee of the Board of Directors of the Company, appoint that BVF Nominee as a member of the Compensation Committee. The BVF Nominee’s appointment shall be subject to reasonable confirmation that such nominee is not prohibited from such service pursuant to the applicable legal, regulatory and stock market requirements. For so long as the Lead Investor continues to beneficially own in excess of 19.9% of the Company’s outstanding Common Stock (with beneficial ownership to be determined without regard to conversion blockers, such as the “Beneficial Ownership Limitation” set forth in the Series X Preferred Stock Certificate of Designation (a “ Blocker ”) as of the record date for such Annual Meeting of Stockholders ): (a) the Board of Directors of the Company shall consist of no more than seven members after the date of 2017 Annual Meeting of Stockholders, and (b), the Lead Investor shall have the right (but not the obligation) to nominate a single director for inclusion in the Company’s proxy statement on Schedule 14A for use in soliciting proxies for each Annual Meeting of Stockholders after the Effective Date, but only if the BVF Nominee is not already named in such proxy statement as a director nominee put forth by the Board of Directors for reelection at such meeting. Within 90 days following the Closing, the Board of Directors shall undertake a review of its composition and compensation.

4.8 Preemptive Right .

i. From the date hereof for so long as at least 50% of the authorized shares of the Series X Preferred Stock remain issued and outstanding, upon any proposed issuance by the Company or any of its Subsidiaries of Common Stock, or Common Stock Equivalents for cash consideration, Indebtedness or a combination thereof, other than an Exempt Issuance (a “ Subsequent Financing ”), the Purchasers shall have the right to participate in such Subsequent Financing up to its pro rata amount, calculated as its percentage equity ownership of the Company’s outstanding equity (including the assumed conversion of all outstanding Series X Preferred Stock into shares of Common Stock without regard to any Blockers) (the “ Participation

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Maximum ”) on the same terms, conditions and price provided for in the Subsequent Financing (provided that if the Purchaser is limited or chooses to be limited in its ability to purchase beyond a given level of beneficial ownership (e.g., due to applicable NASDAQ limits or due to a desire to stay below 10% beneficial ownership), then the Company shall instead offer the Purchaser the right to purchase a comparable security with a Blocker and otherwise substantially similar economic rights and interests). Notwithstanding anything in this Section  4.8 , in the event a Subsequent Financing is an offering registered under the Securities Act, the Company shall offer the Purchasers the same right to participate in such registered offering (up to its pro rata amount) only when it is lawful for the Company to do so.

ii. Subject to compliance with any applicable laws, at least three Trading Days prior to the closing of the Subsequent Financing, the Company shall deliver to the Purchasers a written notice of its intention to effect a Subsequent Financing
(“ Pre-Notice ”), which Pre-Notice shall inquire with the Purchasers whether it wishes to review the details of such proposed financing (such additional notice, a “ Subsequent Financing Notice ”). Upon the request of the Purchasers, and only upon a request by the Purchasers, for a Subsequent Financing Notice, the Company shall promptly, but no later than one Trading Day after such request, deliver a Subsequent Financing Notice to the Purchasers. The requesting Purchasers shall be deemed to have acknowledged that the Subsequent Financing Notice may contain material non-public information. Subject to compliance with any applicable laws, the Subsequent Financing Notice shall describe in reasonable detail the proposed terms of such Subsequent Financing, the amount of proceeds intended to be raised thereunder and the Person or Persons through or with whom such Subsequent Financing is proposed to be effected and shall include a term sheet or similar document relating thereto as an attachment.

iii. If a Purchaser wishes to participate in such Subsequent Financing, it must provide written notice to the Company by not later than 5:30 p.m. (Pacific Time) on the second Trading Day after the Purchasers have received the Subsequent Financing Notice, that such Purchaser is willing to participate in the Subsequent Financing and the amount of such Purchaser’s participation. If the Company receives no such notice from a given Purchaser as of such second Trading Day, that Purchaser shall be deemed to have notified the Company that it does not elect to participate and the Company may effect the Subsequent Financing on the terms and with the Persons (including any participating Purchasers) set forth in the Subsequent Financing Notice.

iv. If by 5:30 p.m. (Pacific Time) on the second Trading Day after the Purchasers have received the Subsequent Financing Notice, the Company has received written notification by one or more Purchasers of their willingness to participate in the Subsequent Financing (or to cause its designees to participate), then the Company shall effect the Subsequent Financing with such Purchaser(s) (in the amount indicated in its notification up to the Participation Maximum) and, with respect to the remaining portion of such Subsequent Financing on the terms and with the Persons set forth in the Subsequent Financing Notice, subject to compliance with any applicable laws.

v. The Company must provide the Purchasers with a second Subsequent Financing Notice, and the Purchasers will again have the right of participation set forth above in this Section 4.8, if the Subsequent Financing subject to the initial Subsequent Financing Notice is amended in any material respect or is not consummated for any reason on the terms set forth in such Subsequent Financing Notice within 30 days after the date of the initial Subsequent Financing Notice.

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vi. Notwithstanding anything to the contrary in this Section  4.8 and unless otherwise agreed to by the Purchasers, the Company shall either confirm in writing to the Purchasers that the transaction with respect to the Subsequent Financing has been abandoned or shall publicly disclose its intention to issue the securities in the Subsequent Financing, in either case in such a manner such that the Purchasers will not be in possession of any material, non-public information, by the third Business Day following delivery of the Subsequent Financing Notice. If by such third Business Day, no public disclosure regarding a transaction with respect to the Subsequent Financing has been made, and no notice regarding the abandonment of such transaction has been received by the Purchasers, such transaction shall be deemed to have been abandoned and the Purchasers shall not be deemed to be in possession of any material, non-public information with respect to the Company or any of its Subsidiaries.

4.9 Equity Plan Increase . At the 2017 Annual Meeting of Stockholders, the Company will seek stockholder approval of an increase in the available pool of shares of Common Stock available for grant under the Company’s Amended and Restated 2010 Long Term Incentive and Stock Award Plan (the “ 2010 Plan ”), with the aggregate number of shares authorized for issuance under all equity plans currently or previously maintained by the Company (including the 2010 Plan) and all outstanding equity awards to equal, in total, approximately 12.5% of the total number of issued and outstanding shares of Common Stock immediately after the Closing (calculated on a pro forma basis, and assuming the conversion of all Series X Preferred Stock, without giving effect to any Blockers). No new issuances of awards shall be made under the 2010 Plan between the Effective Date and the Closing Date. Following the Closing Date, any new awards grants to the Company’s principal executive officer or principal financial officer issued under the 2010 Plan shall be made solely in accordance with the conditions set forth in Section 4(b) of the Series X Certificate of Designations.

SECTION 5

MISCELLANEOUS

5.1 Termination . This Agreement may be terminated by any Purchaser, as to such Purchaser’s obligations hereunder only and without any effect whatsoever on the obligations between the Company and the other Purchasers, by written notice to the other parties, if the Closing has not been consummated within ten calendar days from the Effective Date through no fault of such Purchaser; provided , however , that no such termination will affect the right of any party to sue for any breach by the other party (or parties).

5.2 Fees and Expenses . Except as expressly set forth in the Transaction Documents to the contrary, each party shall pay the fees and expenses of its advisers, counsel, accountants and other experts, if any, and all other expenses incurred by such party incident to the negotiation, preparation, execution, delivery and performance of this Agreement; provided, however , that the Company shall pay the Purchasers’ reasonable and documented legal fees and expenses incurred in connection with the transactions contemplated by this Agreement (including any post-Closing expenses) up to an aggregate amount of $100,000. The Company shall pay all transfer agent fees, stamp taxes and other taxes and duties levied in connection with the delivery of any Securities to the Purchasers.

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5.3 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 and understandings, oral or written, with respect to such subject matter, which the parties acknowledge have been merged into such documents, exhibits and schedules; provided that the foregoing shall not have any effect on any agreements that a Purchaser has entered into with the Company or any of its Subsidiaries prior to the date hereof with respect to any prior investment made by such Purchaser in the Company.

5.4 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 upon actual receipt via mail, courier or confirmed email by the party to whom such notice is required to be given. The address for such notices and communications shall be as set forth on the signature pages attached hereto.

5.5 Amendments; Waivers . No provision of this Agreement may be waived or amended except in a written instrument signed, in the case of an amendment, by the Company and the Lead Investor or, in the case of a waiver, by the party against whom enforcement of any such waived provision is sought. 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 any party to exercise any right hereunder in any manner impair the exercise of any such right.

5.6 Headings . 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.

5.7 Successors and Assigns . This Agreement shall be binding upon and inure to the benefit of the parties and their permitted successors and assigns. The Company may not assign this Agreement or any rights or obligations hereunder without the prior written consent of each Purchaser (other than by merger). The Purchasers may not assign this Agreement or any rights or obligations hereunder without the prior written consent of the Company (other than by merger).

5.8 No Third-Party Beneficiaries . This Agreement is intended for the benefit of the parties hereto and their respective permitted successors and assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other Person, except as otherwise set forth in Section  4.5 of this Agreement.

5.9 Governing Law . All questions concerning the construction, validity, enforcement and interpretation of the Transaction Documents shall be governed by and construed and enforced in accordance with the internal laws of the State of Delaware, without regard to the principles of conflicts of law thereof. Each party agrees that all legal 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

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respective Affiliates, directors, officers, shareholders, employees or agents) shall be commenced exclusively in the state and federal courts sitting in the State of Delaware. Each party hereby irrevocably submits to the exclusive jurisdiction of the state and federal courts sitting in the State of Delaware 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 suit, action or proceeding, any claim that it is not personally subject to the jurisdiction of any such court, that such suit, action or proceeding is improper or is an inconvenient venue for such proceeding. Each party hereby irrevocably waives personal service of process and consents to process being served in any such suit, action or 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 other manner permitted by law. If either party shall commence an action or proceeding to enforce any provisions of the Transaction Documents, then the prevailing party in such action or proceeding shall be reimbursed by the other party for its reasonable attorneys’ fees and other costs and expenses incurred with the investigation, preparation and prosecution of such action or proceeding.

5.10 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 each other party, it being understood that the parties need not sign the same counterpart. In the event that any signature on this Agreement or any instrument pursuant to Section  5.5 hereof is delivered by facsimile transmission or by e-mail delivery of a “.pdf” format data file, such signature shall create a legally 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 or “.pdf” signature page were an original thereof.

5.11 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 commercially reasonable 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.

5.12 Rescission and Withdrawal Right . Notwithstanding anything to the contrary contained in (and without limiting any similar provisions of) any of the other Transaction Documents, whenever any Purchaser exercises a right, election, demand or option under a Transaction Document and the Company does not timely perform its related obligations within the periods therein provided, then such Purchaser may rescind or withdraw, in its sole discretion from time to time upon written notice to the Company, any relevant notice, demand or election in whole or in part without prejudice to its future actions and rights.

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5.13 Replacement of Securities . If any certificate or instrument evidencing any Securities is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation thereof (in the case of mutilation), or in lieu of and substitution therefor, a new certificate or instrument, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction and customary and reasonable indemnity or bond, if requested. The applicant for a new certificate or instrument under such circumstances shall also pay any reasonable third-party costs (including customary indemnity) associated with the issuance of such replacement Securities.

5.14 Remedies . In addition to being entitled to exercise all rights provided herein or granted by law, including recovery of damages, each of the Purchasers and the Company will be entitled to specific performance pursuant to the Transaction Documents. The parties agree that monetary damages may not be adequate compensation for any loss incurred by reason of any breach of obligations contained in the Transaction Documents and hereby agrees to waive and not to assert in any action for specific performance of any such obligation the defense that a remedy at law would be adequate.

5.15 Independent Nature of Purchasers ’ Obligations and Rights . The obligations of each Purchaser under any Transaction Document are several and not joint with the obligations of any other Purchaser, and no Purchaser shall be responsible in any way for the performance or non-performance of the obligations of any other Purchaser under any Transaction Document. Nothing contained herein or in any other Transaction Document, and no action taken by any Purchaser pursuant thereto, shall be deemed to constitute the Purchasers as a partnership, an association, a joint venture or any other kind of entity, or create a presumption that the Purchasers are in any way acting in concert or as a group with respect to such obligations or the transactions contemplated by the Transaction Documents. Each Purchaser shall be entitled to independently protect and enforce its rights, including without limitation, the rights arising out of this Agreement or out of the other Transaction Documents, and it shall not be necessary for any other Purchaser to be joined as an additional party in any proceeding for such purpose. Each Purchaser has been represented by its own separate legal counsel in their review and negotiation of the Transaction Documents.

5.16 Construction . The parties agree that each of them and/or their respective counsel has reviewed and had an opportunity to revise the Transaction Documents and, therefore, the normal rule of construction to the effect that any ambiguities are to be resolved against the drafting party shall not be employed in the interpretation of the Transaction Documents or any amendments hereto.

5.17 WAIVER OF JURY TRIAL . IN ANY ACTION, SUIT, OR PROCEEDING IN ANY JURISDICTION BROUGHT BY ANY PARTY AGAINST ANY OTHER PARTY, THE PARTIES EACH KNOWINGLY AND INTENTIONALLY, TO THE GREATEST EXTENT PERMITTED BY APPLICABLE LAW, HEREBY ABSOLUTELY, UNCONDITIONALLY, IRREVOCABLY AND EXPRESSLY WAIVES FOREVER TRIAL BY JURY.

*     *     *

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

REMAINDER OF PAGE INTENTIONALLY LEFT BLANK;

PURCHASER SIGNATURE PAGES FOLLOW

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

Name of Purchaser: Biotechnology Value Fund, L.P.

Signature of Authorized Signatory of Purchaser : /s/ Mark Lampert    

Name of Authorized Signatory: Mark Lampert

Title of Authorized Signatory: President of BVF, Inc., itself GP of BVF Partners L.P., itself GP of Biotechnology Value Fund, L.P.

Address for Notice of Purchaser:

One Sansome Street, 30 ^th Floor

San Francisco, CA 94104

Attention: Spike Loy

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

Gibson, Dunn & Crutcher, LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105

Attn: Ryan A. Murr

Address for delivery of Securities for Purchaser (if not same as address for notice):

The Depository Trust Company

570 Washington Blvd – 5 ^th floor

Jersey City, NJ 07310                

Attention: BNY Mellon/Branch Deposit Department for the account of 478898

Subscription Amount Common Stock: $2,249,396.89

Shares of Common Stock: 558,163

Subscription Amount Series X Preferred Stock: $9,321,390.00

Shares of Series X Preferred Stock: 2,313

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

Name of Purchaser: Biotechnology Value Fund II, L.P.

Signature of Authorized Signatory of Purchaser : /s/ Mark Lampert

Name of Authorized Signatory: Mark Lampert

Title of Authorized Signatory: President of BVF, Inc., itself GP of BVF Partners L.P., itself GP of Biotechnology Value Fund II, L.P.

Address for Notice of Purchaser:

One Sansome Street, 30 ^th Floor

San Francisco, CA 94104

Attention: Spike Loy

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

Gibson, Dunn & Crutcher, LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105

Attn: Ryan A. Murr

Address for delivery of Securities for Purchaser (if not same as address for notice):

The Depository Trust Company

570 Washington Blvd – 5 ^th floor

Jersey City, NJ 07310                

Attention: BNY Mellon/Branch Deposit Department for the account of 478899

Subscription Amount Common Stock: $1,467,496.29

Shares of Common Stock: 364,143

Subscription Amount Series X Preferred Stock: $6,069,180.00

Shares of Series X Preferred Stock: 1,506

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

Name of Purchaser: Biotechnology Value Trading Fund OS, L.P.

Signature of Authorized Signatory of Purchaser : /s/ Mark Lampert    

Name of Authorized Signatory: Mark Lampert

Title of Authorized Signatory: President of BVF, Inc., itself GP of BVF Partners L.P., itself Sole Member of BVF Partners OS, Ltd., itself GP of Biotechnology Value Trading Fund OS, L.P.

Address for Notice of Purchaser:

One Sansome Street, 30 ^th Floor

San Francisco, CA 94104

Attention: Spike Loy

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

Gibson, Dunn & Crutcher, LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105

Attn: Ryan A. Murr

Address for delivery of Securities for Purchaser (if not same as address for notice):

The Depository Trust Company

570 Washington Blvd – 5 ^th floor

Jersey City, NJ 07310                

Attention: BNY Mellon/Branch Deposit Department for the account of 478087

Subscription Amount Common Stock: $391,655.55

Shares of Common Stock: 97,185

Subscription Amount Series X Preferred Stock: $1,660,360.00

Shares of Series X Preferred Stock: 412

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

Name of Purchaser: Investment 10, LLC

Signature of Authorized Signatory of Purchaser : /s/ Mark Lampert

Name of Authorized Signatory: Mark Lampert

Title of Authorized Signatory: President of BVF, Inc., itself GP of BVF Partners L.P., itself the investment advisor of Investment 10, LLC.

Address for Notice of Purchaser:

One Sansome Street, 30 ^th Floor

San Francisco, CA 94104

Attention: Spike Loy

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

Gibson, Dunn & Crutcher, LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105

Attn: Ryan A. Murr

Address for delivery of Securities for Purchaser (if not same as address for notice):

The Depository Trust Company

570 Washington Blvd – 5 ^th floor

Jersey City, NJ 07310                

Attention: BNY Mellon/Branch Deposit Department for the account of Investment 10, LLC

Subscription Amount Common Stock: $230,781.98

Shares of Common Stock: 57,266

Subscription Amount Series X Preferred Stock: $975,260.00

Shares of Series X Preferred Stock: 242

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

Name of Purchaser: MSI BVF SPV, L.L.C.

Signature of Authorized Signatory of Purchaser : /s/ Mark Lampert    

Name of Authorized Signatory: Mark Lampert

Title of Authorized Signatory: President of BVF, Inc., itself GP of BVF Partners L.P., itself attorney-in-fact for MSI BVF SPV, L.L.C.

Address for Notice of Purchaser:

One Sansome Street, 30 ^th Floor

San Francisco, CA 94104

Attention: Spike Loy

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

Gibson, Dunn & Crutcher, LLP

555 Mission Street, Suite 3000

San Francisco, CA 94105

Attn: Ryan A. Murr

Address for delivery of Securities for Purchaser (if not same as address for notice):

BNP Paribas Prime Brokerage

787 Seventh Avenue, 8 ^th Floor

New York, NY 10019                

Telephone: (212) 471-6836                

Attention: Jose Nevarez                

Subscription Amount Common Stock: $496,669.29

Shares of Common Stock: 123,243

Subscription Amount Series X Preferred Stock: $2,135,900.00

Shares of Series X Preferred Stock: 530

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PROSPECTUS

$300,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

We may, from time to time, offer and sell up to $300,000,000 of any combination of our common stock, preferred stock, debt securities or warrants described in this prospectus, either individually or in combination with other securities, at prices and on terms described in one or more supplements to this prospectus. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings.

This prospectus describes some of the general terms that may apply to an offering of our securities. The specific terms and any other information relating to a specific offering will be set forth in a post-effective amendment to the registration statement of which this prospectus is a part, in a supplement to this prospectus, or in a free writing prospectus or may be set forth in one or more documents incorporated by reference in this prospectus. You should read this prospectus, the information incorporated by reference in this prospectus and any applicable prospectus supplement or free writing prospectus carefully before you invest.

Securities may be sold by us to or through underwriters or dealers, directly to purchasers or through agents designated from time to time. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus and in the applicable prospectus supplement. If any underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such underwriters and any applicable discounts or commissions and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

Our common stock is listed on the NASDAQ Global Market under the symbol “XOMA” On February 3, 2015, the last reported sale price of our common stock on the NASDAQ Global Market was $3.51 per share.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “ Risk Factors ” contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the documents that are incorporated by reference into this prospectus .

This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is February 13, 2015.

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You should rely only on the information contained in or incorporated by reference into this prospectus or any applicable prospectus supplement or free writing prospectus. We have not authorized anyone to provide you with different information. We are not making an offer to sell or seeking an offer to buy securities under this prospectus or any applicable prospectus supplement or free writing prospectus in any jurisdiction where the offer or sale is not permitted. The information contained in this prospectus, any applicable prospectus supplement or free writing prospectus and the documents incorporated by reference herein and therein are accurate only as of their respective dates, regardless of the time of delivery of this prospectus or any sale of a security.

About this Prospectus

This prospectus is part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, using a “shelf” registration process. Under this shelf registration statement, we may sell from time to time in one or more offerings up to a total dollar amount of $300,000,000 of common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination with other securities as described in this prospectus. Each time we sell any type or series of securities under this prospectus, we will provide a prospectus supplement that will contain more specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. We may also add, update or change in a prospectus supplement or free writing prospectus any of the information contained in this prospectus or in documents we have incorporated by reference into this prospectus. This prospectus, together with any applicable prospectus supplement or free writing prospectus and the documents incorporated by reference into this prospectus, include all material information relating to this offering. You should carefully read both this prospectus and any applicable prospectus supplement and any related free writing prospectus together with the additional information described under “Where You Can Find More Information” before buying securities in this offering.

You should rely only on the information contained in, or incorporated by reference into, this prospectus and the applicable prospectus supplement, along with the information contained in any free writing prospectuses we have authorized for use in connection with a specific offering. We have not authorized anyone to provide you with different or additional information. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so.

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The information appearing in this prospectus, any applicable prospectus supplement and any related free writing prospectus is accurate only as of the date on the front of the document and any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, the applicable prospectus supplement or any related free writing prospectus, or any sale of a security. Our business, financial condition, results of operations and prospects may have changed since those dates.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the section entitled “Where You Can Find More Information.”

Unless otherwise specified or required by context, references in this prospectus to “XOMA,” “the Company,” “we,” “us” and “our” refer to XOMA Corporation, a Delaware corporation and its consolidated subsidiaries, if any, unless otherwise specified.

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Summary

The following summary highlights information contained elsewhere in this prospectus or incorporated by reference herein and does not contain all the information that may be important to purchasers of our securities. Prospective purchasers of our securities should review this entire prospectus carefully, including the risks of investing discussed under “Risk Factors” on page 7, the financial statements and related notes, and the information to which we refer you and the information incorporated into this prospectus by reference, for a complete understanding of our business and this offering.

This prospectus and the information incorporated herein by reference include trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included or incorporated by reference into this prospectus, any applicable prospectus supplement or any related free writing prospectus are the property of their respective owners.

XOMA CORPORATION

Overview

XOMA Corporation (“XOMA”), a Delaware corporation, discovers and develops innovative antibody-based therapeutics. Several of our antibodies have unique properties due to their interaction at allosteric sites on specific protein rather than the orthosteric, or active sites. The compounds are designed to either enhance or diminish the protein’s activity as desired. We believe allosteric-modulating antibodies may be more selective or offer a safety advantage in certain disease indications when compared to more traditional modes of action.

Our lead drug candidate, gevokizumab, is a proprietary potent, humanized allosteric-modulating monoclonal antibody that binds to the inflammatory cytokine interleukin-1 beta (“IL-1 beta”). We believe that by targeting IL-1 beta, gevokizumab has the potential to address the underlying inflammatory causes of a wide range of diseases that have been identified as having unmet medical needs.

Together with our development partner, Les Laboratoires Servier (“Servier”), an independent French pharmaceutical research company, we have initiated four pivotal clinical trials evaluating gevokizumab for the treatment of non-infectious intermediate, posterior or pan-uveitis (“NIU”) and Behçet’s disease uveitis. We are responsible for all of the clinical study sites in the United States, and Servier is responsible for all of the clinical study sites outside of the United States. These studies are known as the EYEGUARD™ program, which includes EYEGUARD-A (patients with active NIU), EYEGUARD-B (patients with Behçet’s disease uveitis outside of the United States), EYEGUARD-C (patients with a history of NIU currently controlled with systemic treatment), and EYEGUARD-US (patients with Behçet’s disease uveitis being conducted at study centers in the United States).

Our strategy is to pursue Behçet’s disease uveitis as our first indication for gevokizumab in the United States. Upon the successful completion of SERVIER’s EYEGUARD-B study, we intend to meet with the U.S. Food and Drug Administration (“FDA”) to review the Phase 3 EYEGUARD-B data together with the data from the two Behçet’s disease uveitis Phase 2 studies conducted independently by XOMA and Servier. We believe the seriousness of this disease and the small patient population warrant consideration for approval based upon positive data from a single pivotal study. There is significant precedence for regulatory approval based upon a single study for indications of similar seriousness in patient populations. Should EYEGUARD-B successfully demonstrate patients with Behçet’s disease uveitis receiving gevokizumab took longer to exacerbate than the placebo-treated patients during the tapering of administered steroids, we believe we will be in position to begin the Biologics License Application (“BLA”) submission process.

In addition to the EYEGUARD studies, we are evaluating gevokizumab in pyoderma gangrenosum (“PG”), a rare ulcerative skin disease that is a specific indication under the umbrella of diseases known as neutrophilic dermatosis. Patients experience painful expanding skin ulcers that have a significant impact on their quality of life. The U.S. Department of Health and Human Services’ National Institutes of Health’s Office of Rare Disease Research lists PG occurring in about one per 100,000 people. Claims data compiled

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over the past three years indicate the number of diagnosed PG patients in the U.S. ranges between 11,000 and 14,000 annually. Based upon what we believe are compelling data from our pilot study in patients with PG, we initiated a Phase 3 clinical program in October 2014. The PG Phase 3 program includes two double-blind, placebo-controlled clinical studies, each of which is designed to enroll 58 patients with active PG to receive gevokizumab 60 mg or placebo dosed subcutaneously once monthly, in addition to their current treatment regimen of low-dose corticosteroids and/or immunosuppressants. The primary endpoint is the complete closure of the PG target ulcer determined at Day 126 and confirmation of complete closure a minimum of two weeks later on or after Day 140.

We and Servier also have an active gevokizumab Proof-of-Concept (“POC”) development program to identify other illnesses for late-stage development.

Gevokizumab has been generally well tolerated across all of our clinical studies. The most common adverse events were headache, pain, arthralgia, urinary tract infections, upper respiratory tract infections and pneumonia, and they were comparable between gevokizumab and placebo.

Our proprietary pipeline includes classes of allosteric modulating antibodies that activate, sensitize or deactivate the insulin receptor in vivo, which we have named XOMA Metabolism or XMet. Insulin is the major hormone for lowering blood glucose levels. Abnormal increases in insulin secretion can lead to profound hypoglycemia (low blood sugar), a state that may result in significant morbidities including cerebral damage and epilepsy. In some instances, profound hypoglycemia can result in fatality. There are three programs in the XMet portfolio, XOMA 358, which is designed to deactivate the insulin receptor, XMetA, which is designed to activate the insulin receptor, and XMetS, which is designed to sensitize the insulin receptor when in an insulin resistant state. These programs are highly novel as the antibodies bind to different sites on the insulin receptor than currently marketed drugs.

XOMA 358 is a fully human monoclonal allosteric modulating antibody that binds to insulin receptors and attenuates insulin action. It is designed to negatively modulate the insulin receptor and its downstream signaling capabilities. We launched clinical development activities for XOMA 358 in October 2014, with the first patient dosed in our Phase 1 safety and tolerability study. We intend to investigate this compound as a novel treatment for non-drug-induced, endogenous hyperinsulinemic hypoglycemia (low blood glucose caused by excessive insulin produced by the body). A therapy that safely and effectively mitigates insulin-induced hypoglycemia has the potential to address a significant unmet therapeutic need for certain rare medical conditions associated with hyperinsulinism.

We intend to retain full ownership of the XOMA 358, as it aligns with our focus to develop products for diseases with significant unmet medical need and treated by the specialist prescriber. We intend to license XMetA and XMetS to a pharmaceutical company with expertise in developing and commercializing compounds for Types 1 and 2 diabetes. This portfolio of antibodies represents potential new therapeutic approaches to the treatment of diabetes and several rare diseases that have insulin involvement.

Risks Associated with our Business

Our business is subject to numerous risks, as described under the heading “Risk Factors” contained in the applicable prospectus supplement and in any free writing prospectuses we have authorized for use in connection with a specific offering, and under similar headings in the documents that are incorporated by reference into this prospectus.

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Company Information

We were incorporated in Delaware in 1981 and became a Bermuda exempted company in December 1998. Effective December 31, 2011, we changed our jurisdiction of incorporation from Bermuda to Delaware and changed our name from XOMA Ltd. to XOMA Corporation.

Our principal executive offices are located at 2910 Seventh Street, Berkeley, California 94710, and we maintain a registered office located at Corporation Trust Center, 1209 Orange Street, Wilmington, Delaware 19801. Our telephone number at our principal executive offices is (510) 204-7200. Our website address is www.xoma.com. Information found on, or accessible through, our website is not a part of, and is not incorporated into, this prospectus, and you should not consider it part of this prospectus or part of any prospectus supplement. Our website address is included in this document as an inactive textual reference only.

NASDAQ Global Market Listing

Our common stock is listed on The NASDAQ Global Market under the symbol “XOMA.”

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The Securities We May Offer

We may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in combination with other securities, with a total value of up to $300,000,000 from time to time under this prospectus at prices and on terms to be determined at the time of any offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus or in documents we have incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

This prospectus may not be used to offer or sell securities unless it is accompanied by a prospectus supplement.

We may sell the securities directly to investors or to or through agents, underwriters or dealers. We, and our agents, underwriters or dealers reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities to or through agents, underwriters or dealers, we will include in the applicable prospectus supplement:

Common Stock. We may issue shares of our common stock from time to time. Common stockholders are entitled to one vote per share for the election of directors and on all other matters that require common stockholder approval. Holders of our common stock are entitled to share in an equal amount per

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share in any dividends declared by our board of directors on the common stock and paid out of legally available assets. Subject to any preferential rights of any outstanding preferred stock, in the event of our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in the assets remaining after payment of liabilities and the liquidation preferences of any outstanding preferred stock. Our common stock does not carry any preemptive rights enabling a holder to subscribe for, or receive shares of, any class of our common stock or any other securities convertible into shares of any class of our common stock, or any redemption rights.

Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Our board of directors will determine the designations, voting powers, preferences and rights of the preferred stock, as well as the qualifications, limitations or restrictions thereof, including dividend rights, conversion rights, preemptive rights, terms of redemption or repurchase, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of any series. Convertible preferred stock will be convertible into our common stock or exchangeable for other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

If we sell any series of preferred stock under this prospectus, we will fix the designations, voting powers, preferences and rights of such series of preferred stock, as well as the qualifications, limitations or restrictions thereof, in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock that we are offering before the issuance of the related series of preferred stock. We urge you to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.

Debt Securities. We may issue debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsecured and unsubordinated debt. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all of our senior indebtedness. Convertible debt securities will be convertible into or exchangeable for our common stock or other securities. Conversion may be mandatory or at your option and would be at prescribed conversion rates.

Any debt securities issued under this prospectus will be issued under one or more documents called indentures, which are contracts between us and a national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. Forms of indentures have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.

Warrants. We may issue warrants for the purchase of common stock, preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities. In this prospectus, we have summarized certain general features of the warrants. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of warrants being offered, as well as any warrant agreements and warrant certificates that contain the terms of the warrants. We will file as exhibits to the registration statement

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of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, any forms of warrant agreements and forms of warrant certificates containing the terms of the warrants being offered, and any supplemental warrant agreements and forms of warrant certificates containing the terms of the warrants being offered.

Any warrants issued under this prospectus may be evidenced by warrant certificates. Warrants also may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.

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