EXECUTION VERSION

PURCHASE AGREEMENT

BETWEEN

BIOVENTURE INVESTMENTS KFT

and

ENTREMED, INC.

Dated as of June 14, 2001

THALIDOMIDE ROYALTY

[*] = CERTAIN INFORMATION CONTAINED IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS. OMITTED TEXT IS INDICATED BY A "*".

ARTICLE I - DEFINITIONS.....................................................1
   1.01.    Definitions.....................................................1


ARTICLE II - PURCHASE AND SALE..............................................5
   2.01.    Purchase and Sale...............................................5
   2.02.    No Assumed Obligations..........................................5
   2.03.    Purchase Price..................................................5
   2.04.    Closing.........................................................5
   2.05.    Contingent Purchase Price.......................................6
   2.06.    Shared Royalties................................................7
   2.07.    Offset..........................................................8


ARTICLE III - REPRESENTATIONS AND WARRANTIES OF SELLER......................8
   3.01.    Existence and Power.............................................8
   3.02.    Corporate Authorization.........................................9
   3.03.    Governmental Authorization......................................9
   3.04.    Non-Contravention...............................................9
   3.05.    Litigation......................................................9
   3.06.    Compliance with Laws...........................................10
   3.07.    No Prior Transfer..............................................10
   3.08.    Celgene Agreement..............................................10
   3.09.    CMCC Agreement.................................................11
   3.10.    Finders' Fees..................................................12


ARTICLE IV - REPRESENTATIONS AND WARRANTIES OF BUYER.......................12
   4.01.    Organization and Existence.....................................12
   4.02.    Corporate Authorization........................................13
   4.03.    Governmental Authorization.....................................13
   4.04.    Non-Contravention..............................................13
   4.05.    Finders' Fees..................................................13
   4.06.    Litigation.....................................................13
   4.07.    Ability to Perform Obligations.................................13


ARTICLE V - COVENANTS......................................................14
   5.01.    Preservation of the Celgene Payments...........................14
   5.02.    Access to Information..........................................14
   5.03.    Notices of Certain Events......................................14
   5.05.    Commercially Reasonable Efforts; Further Assurances............14
   5.06.    Seller's Continuing Covenants..................................15
   5.07.    Buyer's Continuing Covenants...................................16

   5.08.    Cash Received..................................................16
   5.09.    Notice of Payments.............................................16


ARTICLE VI - CONDITIONS TO CLOSING.........................................16
   6.01.    Conditions to Obligation of Buyer..............................16
   6.02.    Conditions to Obligation of Seller.............................17


ARTICLE VII - SURVIVAL; INDEMNIFICATION....................................19
   7.01.    Survival.......................................................19
   7.02.    Indemnification................................................19
   7.03.    Procedures; No Waiver; Exclusivity.............................20


ARTICLE VIII - TERMINATION.................................................20
   8.01.    Grounds for Termination........................................20
   8.02.    Effect of Termination..........................................20


ARTICLE IX - MISCELLANEOUS.................................................21
   9.01.    Notices........................................................21
   9.02.    Amendments; No Waivers.........................................22
   9.03.    Expenses.......................................................22
   9.04.    Successors and Assigns.........................................22
   9.05.    Governing Law; Jurisdiction, Etc...............................23
   9.06.    Counterparts; Effectiveness....................................24
   9.07.    Entire Agreement...............................................24
   9.08.    Captions.......................................................24

Schedules
---------
3.08(a)       Waivers under Celgene Agreement
3.08(g)       Third-Party Patents
3.09(a)       Patent Rights

Exhibits
--------

Exhibit A     Celgene Agreement
Exhibit B     Royalties Paid by Celgene to Seller under Celgene Agreement
              since December 9, 1998
Exhibit C     CMCC Agreement
Exhibit D     Form of Opinion of Seller's Counsel
Exhibit E     Form of IPO Agreement
Exhibit F     Form of Guaranty

PURCHASE AGREEMENT

AGREEMENT dated as of June 14, 2001 by and between EntreMed, Inc., a Delaware corporation ("Seller"), and Bioventure Investments kft, a company organized under the laws of Hungary and a wholly-owned subsidiary of Royalty Pharma AG, a Swiss stock corporation ("Buyer").

W I T N E S S E T H:

WHEREAS, Seller is a party to that certain License Agreement dated as of May 26, 1994 (the "CMCC Agreement"), by and between Children's Medical Center Corporation ("CMCC") and Seller, as amended by Amendment to License Agreement effective as of December 9, 1997, Amendment to Agreement effective as of August 23, 1995, Amendment to License Agreement effective as of December 3, 1998 and Amendment to License Agreement effective as of September 24, 1999;

WHEREAS, Seller is a party to that certain Agreement dated as of December 9, 1998 (the "Celgene Agreement"), by and between Seller and Celgene Corporation ("Celgene"); and

WHEREAS, Buyer desires to purchase Seller's rights to receive the Net Celgene Payments (as defined below) under the Celgene Agreement, and Seller desires to sell such rights to Buyer, upon the terms and subject to the conditions hereinafter set forth.

NOW, THEREFORE, in consideration of the foregoing and the representations, warranties, covenants and agreements herein contained, the parties hereto agree as follows:

ARTICLE I

DEFINITIONS

1.01. DEFINITIONS. The following terms, as used herein, have the following meanings:

"Accounting Referee" has the meaning set forth in Section 2.06.

"Affiliate" means with respect to any Person, any Person directly or indirectly controlling, controlled by or under common control with such other Person.

"Agreement" means this Purchase Agreement by and between Buyer and Seller.

"Applicable Net Celgene Payments" means (i) in respect of any period prior to the Closing Date, for any calendar year, an amount equal to the excess, if any, of (A) payments made or due by Celgene pursuant to

Sections 4.1, 4.2(a)(ii) and 4.3 (only, with respect to Section 4.3, to the extent such payments are royalty payments with royalty rates determined pursuant to Section 4.1 or 4.2(a)(ii)) of the Celgene Agreement on Shared Net Sales, net of payments made or due to CMCC pursuant to Sections 4.2 and 4.4 of the CMCC Agreement for such year, over (B) US$* and (ii) in respect of any period on or after the Closing Date, for any calendar year, an amount equal to the excess, if any, of (A) payments made or due by Celgene to Buyer pursuant to those sections of the New Thalidomide Agreement that are equivalent to Sections 4.1, 4.2(a)(ii) and 4.3 (only, with respect to Section 4.3, to the extent such payments are royalty payments with royalty rates determined pursuant to Section 4.1 or 4.2) of the Celgene Agreement on Shared Net Sales over (B) US$*; provided that, in the case of clause (ii) of this definition, if the royalty payment provisions of the New Thalidomide Agreement are amended or modified, or the New Thalidomide Agreement is terminated and a new agreement entered into in substitution thereof, then "Applicable Net Celgene Payments" shall be calculated based on the payment provisions of such amended, modified or substituted agreement.

"Applicable Net Sales" means (i) in respect of any period prior to the Closing, Net Sales on which any royalty payments are due under Section 4.1 (and, for greater certainty, not under any other provision) of the Celgene Agreement and (ii) in respect of any period on or after the Closing Date, Net Sales on which any royalty payments are due under those sections of the New Thalidomide Agreement that are equivalent to Section 4.1 (and, for greater certainty, not under any other provision) of the Celgene Agreement; provided that, in the case of clause (ii) of this definition, if the royalty payment provisions of the New Thalidomide Agreement are amended or modified, or the New Thalidomide Agreement is terminated and a new agreement entered into in substitution thereof, then "Applicable Net Sales" shall be calculated based on the net sales on which payments are due under such amended, modified or substituted agreement.

"Buyer's Consultants" has the meaning set forth in Section 5.02.

"Celgene" has the meaning set forth in the recitals hereto.

"Celgene Consent" means the acknowledgement and consent of Celgene in the form and substance satisfactory to Buyer and Seller in their sole discretion.

"Celgene Cumulative Net Sales" means Applicable Net Sales from and after December 9, 1998.

"Celgene Payments" means (i) in respect of any period prior to the Closing Date, all payments payable by Celgene under the Celgene Agreement commencing in respect of the calendar quarter ended June 30, 2001, which, in the absence of this Agreement, would otherwise have been made to Seller under Sections 4.1, 4.2 and 4.3 of the Celgene Agreement and (ii) in respect of any period on and after the Closing Date, all payments payable by Celgene under the New Thalidomide Agreement commencing in respect of the calendar quarter ended June 30, 2001, payable by Celgene under those sections of the New Thalidomide Agreement that are equivalent to Sections 4.1, 4.2 and 4.3 of the Celgene Agreement; provided that, in the case of clause (ii) of this definition, if the royalty payment provisions of the New Thalidomide Agreement are amended or modified, or the New Thalidomide Agreement is terminated and a

new agreement entered into in substitution thereof, then "Celgene Payments" shall be calculated based on the payment provisions of such amended, modified or substituted agreement.

"Closing" has the meaning set forth in Section 2.04.

"Closing Date" has the meaning set forth in Section 2.04.

"CMCC" has the meaning set forth in the recitals hereto.

"CMCC Agreement" has the meaning set forth in the recitals hereto.

"CMCC Consent" means the acknowledgment and consent of CMCC in form and substance satisfactory to Buyer and Seller in their sole discretion.

"Commencement Date" means, if Celgene Cumulative Net Sales exceed US$* at any time, the later of (i) January 1 of the calendar year following the calendar year in which Celgene Cumulative Net Sales exceed US$* and (ii) January 1, 2004. If Celgene Cumulative Net Sales do not exceed US$* at any time, then there shall be no Commencement Date.

"Contingent Purchase Price" has the meaning set forth in Section 2.05.

"Contingent Purchase Price Threshold" has the meaning set forth in
Section 2.05.

"Excluded Liabilities and Obligations" has the meaning set forth in
Section 2.02(a).

"Governmental Authority" means any government, court, regulatory or administrative agency or commission, or other governmental authority, agency or instrumentality, whether federal, state or local (domestic or foreign), including, without limitation, the U.S. Patent and Trademark Office and the U.S. National Institutes of Health.

"Guaranty" means the Guaranty by Royalty Pharma of the obligations of Buyer pursuant to this Agreement substantially in the form attached hereto as Exhibit F.

"Indemnified Party" has the meaning set forth in Section 7.03.

"Indemnifying Party" has the meaning set forth in Section 7.03.

"IPO Agreement" means the Agreement from Royalty Pharma to Seller substantially in the form attached hereto as Exhibit E.

"Licensed Products" (i) in respect of any period prior to the Closing Date, has the meaning set forth in the CMCC Agreement and (ii) in respect of any period after the Closing Date, has the meaning set forth in the New Thalidomide Agreement.

"Licensed Processes" (i) in respect of any period prior to the Closing Date, has the meaning set forth in the CMCC Agreement and (ii) in respect of any period after the Closing Date, has the meaning set forth in the New Thalidomide Agreement.

"Lien" means, with respect to any agreement or other asset, any mortgage, lien, pledge, charge, security interest or encumbrance of any kind in respect of such agreement or other asset.

"Loss" has the meaning set forth in Section 7.02.

"Net Celgene Payments" means (i) in respect of any period prior to the Closing Date, (A) all amounts payable by Celgene under the Celgene Agreement commencing in respect of the calendar quarter ended June 30, 2001, which, in the absence of this Agreement, would otherwise have been made to Seller under Sections 4.1, 4.2 and 4.3 of the Celgene Agreement less (B) any payments hereafter due CMCC under Sections 4.2 and 4.4 of the CMCC Agreement and (ii) in respect of any period on or after the Closing Date, all amounts payable by Celgene under the New Thalidomide Agreement commencing in respect of the calendar quarter ended June 30, 2001, under those sections of the New Thalidomide Agreement that are equivalent to Sections 4.1, 4.2 and 4.3 of the Celgene Agreement.

"Net Sales" (i) with respect to any period prior to the Closing Date, has the meaning set forth in the Celgene Agreement and (ii) with respect to any period on or after the Closing Date, has the meaning set forth in the New Thalidomide Agreement.

"New Analog Agreement" means the agreement between CMCC and Seller in form and substance satisfactory to Seller (and if Buyer is a party, to Buyer).

"New Thalidomide Agreement" means the agreement among CMCC, Celgene and Buyer (and, for a limited purpose, Seller) in form and substance satisfactory to Buyer and Seller.

"Patent Rights" (i) in respect of any period prior to the Closing Date, has the meaning set forth in the CMCC Agreement and (ii) in respect of any period after the Closing Date, has the meaning set forth in the New Thalidomide Agreement.

"Person" means an individual, corporation, partnership, association, trust or other entity or organization, but not including a government or political subdivision or any agency or instrumentality of such government or political subdivision.

"Purchase Price" has the meaning set forth in Section 2.03.

"PTO" means the United States Patent and Trademark Office.

"Royalty Pharma" shall mean Royalty Pharma AG, a Swiss stock corporation.

"Securities Act" means the United States Securities Act of 1933, as amended.

"Shared Net Sales", for any calendar year, means Net Sales during such year on which payments by Celgene are made or due under Sections 4.1, 4.2(a)(ii) and 4.3 (only, with respect to Section 4.3, to the extent such payments are royalty payments with royalty rates determined pursuant to
Section 4.1 or 4.2(a)(ii)) of the Celgene Agreement or those sections of the New Thalidomide Agreement that are equivalent to Sections 4.1, 4.2 and 4.3 (only, with respect to Section 4.3, to the extent of royalty payments with royalty rates determined pursuant to Section 4.1 or 4.2) of the Celgene Agreement.

"Transaction Documents" means, collectively, this Agreement, the New Thalidomide Agreement, the New Analog Agreement, the Celgene Consent, the CMCC Consent, the IPO Agreement and the Guaranty.

ARTICLE II

PURCHASE AND SALE

2.01. PURCHASE AND SALE. Upon the terms and subject to the conditions of this Agreement, Buyer agrees to purchase from Seller, and Seller agrees to sell, transfer, assign and deliver to Buyer, at Closing, free and clear of all Liens, all of Seller's right, title and interest in and to the Net Celgene Payments. It is understood and agreed that (a) the execution and delivery of the New Thalidomide Agreement is a condition to the Closing hereunder, (b) the Celgene Agreement will be terminated upon effectiveness of the New Thalidomide Agreement, (c) pursuant to the New Thalidomide Agreement, Celgene will pay Buyer directly all Net Celgene Payments, (d) the execution and delivery of the New Analog Agreement is a condition to the Closing hereunder, (e) the CMCC Agreement will be terminated upon effectiveness of the New Thalidomide Agreement and the New Analog Agreement and (f) effective upon the Closing, Celgene will pay CMCC directly any royalty payments due CMCC under the New Thalidomide Agreement pursuant to the terms thereof. After the Closing, subject to Sections 2.05 and 2.06 hereof, Seller will have no further right, title or interest in or to the Net Celgene Payments.

2.02. NO ASSUMED OBLIGATIONS. Notwithstanding any provision in this Agreement or any other writing to the contrary, Buyer is acquiring only the Net Celgene Payments and is not assuming any liability or obligation of Seller of whatever nature, whether presently in existence or arising or asserted hereafter, whether under the Celgene Agreement, the CMCC Agreement or otherwise (the "Excluded Liabilities and Obligations").

2.03. PURCHASE PRICE. The purchase price for the Net Celgene Payments is US$24,382,278 in cash (the "Purchase Price"). The Purchase Price shall be reduced by an amount equal to the aggregate Net Celgene Payments received by Seller after June 30, 2001 and prior to the Closing.

2.04. CLOSING. The closing (the "Closing") of the purchase and sale of the Net Celgene Payments hereunder shall take place at the offices of Testa, Hurwitz & Thibeault, LLP, 125 High Street, Boston, Massachusetts 02110 USA on the third business day after satisfaction of the

closing conditions in Sections 6.01 and 6.02 hereof (the "Closing Date"), or at such other time or place as the parties may mutually agree. At the Closing,

(a) Buyer shall pay the Purchase Price by wire transfer of immediately available funds to an account designated by Seller.

(b) Buyer and Seller shall also execute and deliver all instruments, documents and certificates as may be reasonably requested by the other party, each in form and substance reasonably satisfactory to the other party, that are necessary for the consummation at the Closing of the transactions contemplated by this Agreement.

2.05. CONTINGENT PURCHASE PRICE.(a) Buyer will make a one-time payment to Seller equal to US$3,000,000 in immediately available funds (the "Contingent Purchase Price") within thirty (30) days after satisfaction of the Contingent Purchase Price Threshold. The "Contingent Purchase Price Threshold" shall be deemed to be satisfied on the date on or before December 31, 2004 on which Celgene Cumulative Net Sales exceed US$*; provided, however, that Buyer shall have no obligation to pay the Contingent Purchase Price pursuant to this
Section 2.05(a) unless and until (i) Buyer shall have received all Net Celgene Payments then due on Cumulative Net Sales from the date of this Agreement to the date of satisfaction of the Contingent Purchase Price Threshold (and, for greater certainty, it is understood that the due date of the Contingent Purchase Price shall not occur until Buyer shall have received such Net Celgene Payments) and (ii) the New Thalidomide Agreement is in full force and effect at that time.

(b) Notwithstanding anything to the contrary in Section 2.05(a), in the event that the New Thalidomide Agreement is hereafter amended, modified or terminated, the Contingent Purchase Price Threshold shall be deemed satisfied on the date on which (i) Celgene Cumulative Net Sales exceed US$* and (ii) the sum of (A) Net Celgene Payments made to Buyer pursuant to the New Thalidomide Agreement prior to such amendment, modification or termination of the New Thalidomide Agreement and (B) all royalty payments made to Buyer on account of or in respect of thalidomide after such amendment, modification or termination of the New Thalidomide Agreement, is equal to or greater than US$*. For purposes of this Section 2.05(b), notwithstanding anything herein to the contrary,

(x) "Celgene Cumulative Net Sales" shall mean the sum of (i) Applicable Net Sales from December 9, 1998 to the date immediately preceding the date on which the New Thalidomide Agreement is amended, modified or terminated and (ii) net sales of thalidomide by Celgene from and after the date on which the New Thalidomide Agreement is amended, modified or terminated; and

(y) the New Thalidomide Agreement shall not be considered amended or modified unless such amendment or modification in any respect affects or could reasonably be expected to affect the calculation of Celgene Cumulative Net Sales.

2.06. SHARED ROYALTIES. (a) From and after the Commencement Date, Seller shall be entitled annually to *% of the Applicable Net Celgene Payments. Subject to Section 2.06(b) hereof, Buyer shall make any such payment to Seller within 10 business days after receipt by Buyer of all Net Celgene Payments then due it and the reports thereon for the applicable calendar year.

(b) If Buyer and Seller disagree as to the occurrence of the Commencement Date or the amount to which Seller is entitled pursuant to
Section 2.06(a) hereof, the parties shall use commercially reasonable best efforts to resolve their disagreement within 10 business days. The parties agree that commercially reasonable best efforts shall require the presence of the Chief Executive Officer and Chief Financial Officer of each of Buyer and Seller in person at a meeting in New York called for such purpose. If, notwithstanding such efforts, the parties remain in disagreement, the disagreement shall be referred to the New York City office of an independent accounting firm of nationally recognized standing, which shall not have performed services for Buyer or Seller or any of their respective Affiliates within the last two years (the "Accounting Referee"). The parties agree to submit written briefs to the Accounting Referee no later than 15 business days after the Accounting Referee notifies Buyer and Seller in writing of its acceptance of the engagement. All other procedures of the dispute resolution effort shall be determined by the Accounting Referee in its sole discretion. Costs of the Accounting Referee shall be borne equally by Buyer and Seller except as may be awarded otherwise by the Accounting Referee. Buyer and Seller shall instruct the Accounting Referee to award costs against either Buyer or Seller if the Accounting Referee determines that such party's position was frivolous or without reasonable commercial basis. The determination of the Accounting Referee shall be final and binding upon the parties.

(c) In the event that Buyer fails to make when due any payment due to Seller under Section 2.05 or this Section 2.06, Buyer shall pay Seller interest on such unpaid amount at the rate per annum equal to the Prime Rate (as reported in the Wall Street Journal) plus 2% from and after the 21st day after the date on which such payment was due to Buyer under Section 2.05 or 2.06, as applicable, until the date such payment is made in full. Buyer's obligation to pay interest shall not be construed as Seller's exclusive remedy for Buyer's breach of Section 2.05 or Section 2.06; provided that Seller shall not be entitled to greater interest than that set forth in this Section 2.06(c).

(d) Buyer will forward to Seller copies of any reports received from or on behalf of Celgene in any way relating to Applicable Net Sales, Celgene Cumulative Net Sales and/or the Net Celgene Payments within 10 business days after receipt thereof by Buyer. In the event that the New Thalidomide Agreement is hereafter amended, modified or terminated, Buyer shall promptly notify Seller of such event and shall provide to Seller copies of such documents, books and records as shall relate to the calculation to amounts due Seller under Section 2.05 hereof or this Section 2.06, including copies of any amendment or modification of the New Thalidomide Agreement or, if the New Thalidomide Agreement is terminated, of any agreement made in substitution of the New Thalidomide Agreement. Buyer shall keep full and accurate books of account containing all particulars relevant to its receipt of Applicable Net Celgene Payments and other records that may be necessary for the purpose of determining whether and when any

amounts are payable by Buyer to Seller under Section 2.05 hereof or this
Section 2.06. Such books of account shall be kept at a place of business in the United States and shall be open for inspection by an independent certified public accountant reasonably acceptable to Buyer upon reasonable notice during normal business hours at Seller's expense, for the sole purpose of verifying compliance with this Agreement; provided, however, that Buyer shall have no obligation to open such books of account for inspection until the earlier to occur of (i) such time as any amounts are payable by Buyer to Seller or (ii) such time as Seller reasonably believes that any payments should have been made to Seller by Buyer under Section 2.05 hereof or this Section 2.06. In the event the inspection determines that amounts due Seller for any period have been underpaid by five percent (5%) or more, then Buyer shall pay for all costs of the inspection. All information and data reviewed in the inspection shall be used only for the purpose of verifying royalties and shall be treated as confidential information. No inspection by an agent of Seller shall occur more frequently than once during any twelve (12) month period.

2.07. OFFSET. Notwithstanding anything to the contrary in Sections 2.05 and 2.06, the provisions of this Section 2.07 shall apply. If Seller owes any amount to Buyer or its Affiliates pursuant to Article VII of this Agreement, and such amount shall have been finally determined by written agreement with Seller or by final judgment for which the time of appeal has expired, then Buyer shall be entitled to offset against any amount payable to Seller under Section 2.05 or 2.06 the amount so owed to Buyer or its Affiliates. If Buyer or any of its Affiliates has claimed any amount from Seller pursuant to Article VII of this Agreement, but there shall not yet be any such written agreement or final judgment, Buyer shall pay to an escrow agent, which shall be a financial institution located in the United States with which neither Buyer nor Seller has a material relationship, out of the amount payable pursuant to Section 2.05 or 2.06, an amount equal to the amount claimed by Buyer or its Affiliates, such amount to be held in escrow subject to joint instructions from Buyer and Seller. If it shall be agreed or determined that Seller owes Buyer or its Affiliates any amount, then Buyer and Seller shall execute joint instructions to the escrow agent to deliver, out of the funds held in escrow, such amount to Buyer and the remaining amount, if any, to Seller. If it shall be agreed or determined that Seller owes no amount to Buyer or its Affiliates, then Buyer and Seller shall execute joint instructions to the escrow agent to deliver the entire amount of the funds held in escrow to Seller. Buyer shall bear the costs of the escrow agent if Seller is entitled to the escrowed funds. Seller shall bear the costs of the escrow agent if Buyer or its Affiliates are entitled to the escrowed funds. If any portion of the escrowed funds are payable to Buyer, then the costs of the escrow agent shall be borne pro rata, the largest portion by the Person paid the smallest portion of the escrowed funds.

ARTICLE III

REPRESENTATIONS AND WARRANTIES OF SELLER

Seller hereby represents and warrants to Buyer, as of the date hereof and as of the Closing Date, that:

3.01. EXISTENCE AND POWER. Seller is a corporation duly organized, validly existing and in good standing under the laws of the State of Delaware, and has all corporate powers and

all material licenses, authorizations, consents and approvals required to enter into and perform this Agreement and the transactions contemplated hereby.

3.02. CORPORATE AUTHORIZATION. The execution, delivery and performance by Seller of the Transaction Documents to which it is a party, and the consummation by Seller of the transactions contemplated thereby, are within Seller's corporate powers and have been duly authorized by all necessary corporate action on the part of Seller. This Agreement has been duly executed and delivered by, and constitutes the legal, valid and binding agreement of Seller, enforceable against Seller in accordance with its terms, subject to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights of creditors generally and to equitable principles. Effective at the Closing, the other Transaction Documents to which Seller is a party will have been duly executed and delivered by, and will constitute the legal, valid and binding agreements of Seller, enforceable against Seller in accordance with their terms, subject to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights of creditors generally and to equitable principles.

3.03. GOVERNMENTAL AUTHORIZATION. The execution, delivery and performance by Seller of the Transaction Documents to which it is a party do not require any notice to, action or consent by, or in respect of, or filing with, any Governmental Authority.

3.04. NON-CONTRAVENTION. (a) The execution, delivery and performance by Seller of the Transaction Documents to which it is a party do not and will not (i) contravene or conflict with the organizational or constitutional documents of Seller; (ii) contravene or conflict with or constitute a violation of any provision of any law, rule or regulation binding upon or applicable to Seller or the Celgene Payments; (iii) contravene or conflict with or constitute a violation of any judgment, injunction, order or decree binding upon or applicable to Seller or the Celgene Payments; (iv) constitute a default under or give rise to any right of termination, cancellation or acceleration of any right or obligation of Seller, or to a loss of any benefit relating to, the Celgene Payments, except as contemplated by the Transaction Documents; (v) require the consent or permission of any Person, other than the Celgene Consent and the CMCC Consent; or (vi) result in the creation or imposition of any Lien on the Net Celgene Payments, except as contemplated by the Transaction Documents.

(b) Seller has not granted, and there does not exist, any Lien on the Celgene Payments or on any amounts payable to Seller under the Celgene Agreement, except for any rights of Celgene under the Celgene Agreement and any rights of CMCC under the CMCC Agreement.

3.05. LITIGATION. There is no action, suit, investigation or proceeding (or any basis therefor) pending or, to the knowledge of Seller, threatened before any Governmental Authority or arbitrator to which Seller is a party that has or could materially and adversely affect the Celgene Payments. To Seller's knowledge, there is no action, suit, investigation or proceeding (or any basis therefor) pending or threatened before any Governmental Authority or arbitrator, to which Seller is not a party, that has or could materially and adversely affect the Celgene Payments. Seller has not received notice in writing of any claim made by any Person with

respect to, or of any action, suit or other proceeding relating to, the Celgene Payments. There is no action, suit, investigation or proceeding pending against, or to the knowledge of Seller, threatened against or affecting, Seller before any Governmental Authority or arbitrator which in any manner challenges or seeks to prevent, enjoin, alter or materially delay the transactions contemplated hereby or which could reasonably be expected to materially and adversely affect Seller's ability to perform its obligations under this Agreement.

3.06. COMPLIANCE WITH LAWS. Seller is not in violation of, nor has Seller violated, and to the knowledge of Seller, Seller is not under investigation with respect to nor has Seller been threatened to be charged with or given notice of any violation of, any law, rule, ordinance or regulation, or judgment, order or decree entered by any Governmental Authority which violation, after the Closing, could materially and adversely affect Buyer's right, title and interest to the Net Celgene Payments.

3.07. NO PRIOR TRANSFER. Seller has not assigned and has not in any other way conveyed, transferred or encumbered all or any portion of its right, title and interest to the Net Celgene Payments. Celgene has made all payments required to be made to date under the Celgene Agreement. Seller has not received any notice from Celgene that could reasonably be construed to mean that any future payment from Celgene will not be timely made under the Celgene Agreement.

3.08. CELGENE AGREEMENT. (a) Terms Unmodified. A true, correct and complete copy of the Celgene Agreement is attached hereto as Exhibit A. The Celgene Agreement is in full force and effect in the form attached hereto as Exhibit A, and has not been altered or modified in any respect. Seller has not consented to any sublicense by Celgene of its rights under the Celgene Agreement. Except as set forth on Schedule 3.08(a) hereto, Seller has not granted any material waiver under the Celgene Agreement. Celgene has not been released, in whole or in part, from any of its obligations under the Celgene Agreement.

(b) Payments. Attached hereto as Exhibit B are true and correct copies of all accounting reports provided to Seller by Celgene under the Celgene Agreement since December 9, 1998. Except for the reports included in, and such other correspondence as may be further identified in Exhibit B, there has been no correspondence or other communication in writing provided to Seller by Celgene since December 9, 1998, the subject matter of which could reasonably be interpreted to mean that Celgene intends to take any action, or any event has occurred or circumstance is existing, that could materially and adversely affect the Net Celgene Payments. To Seller's knowledge, there have been no sales by Third Parties in excess of $1,000,000 per year of the Product (each as defined in the Celgene Agreement).

(c) No Defenses. No right of rescission, set-off, counterclaim or defense (including any off-set pursuant to Section 7.3(g) of the Celgene Agreement) has been asserted by Celgene under the Celgene Agreement. To Seller's knowledge, no event has occurred or circumstance exists that would entitle Celgene to exercise any right of rescission, set-off, counterclaim or defense, including any off-set pursuant to Section 7.3(g) of the Celgene Agreement or as of the

Closing, that section of the New Thalidomide Agreement that is equivalent to
Section 7.3(g) of the Celgene Agreement.

(d) No Satisfaction or Discharge; Entire Agreement. Except as contemplated by this Agreement, the Celgene Agreement has not been satisfied, discharged, canceled, terminated, subordinated or rescinded, in whole or in part. The Celgene Agreement is the entire agreement between Seller and Celgene relating to the subject matter thereof and, other than the CMCC Agreement and the Transaction Documents, constitutes the only agreement or instrument to which Seller is a party that relates to the Celgene Payments.

(e) Validity and Enforceability of Celgene Agreement. The Celgene Agreement is the legal, valid and binding obligation of Seller enforceable against Seller in accordance with its terms, subject to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights of creditors generally and to equitable principles.

(f) No Material Adverse Effect. Except as set forth on Schedule 3.08(f) hereto, to Seller's knowledge, there has not been any event or development, and there does not exist any set of circumstances, which could reasonably be expected to have a material adverse effect on the Celgene Payments.

(g) No Notice of Infringement. Except as set forth on Appendix D to the Celgene Agreement and Schedule 3.08(g), to Seller's knowledge, there does not exist any Third Party patent or patent application that contains any interfering subject matter, nor any issued Third Party patents that would be infringed by the making, using, selling, offering for sale, or importing by Celgene of Products covered by the EntreMed Existing Patent Rights or the EntreMed Existing Technology Rights in any country in the Territory, nor by the exercise by Celgene of any right granted to it under the Celgene Agreement. All capitalized terms used in this Section 3.08(g) but not defined herein shall have the meanings ascribed to such terms in the Celgene Agreement.

3.09. CMCC AGREEMENT. (a) Terms Unmodified. A true, correct and complete copy of the CMCC Agreement is attached hereto as Exhibit C. The CMCC Agreement is in full force and effect in the form attached hereto as Exhibit C, and has not been altered or modified in any respect. Other than pursuant to the Celgene Agreement, Seller has not sublicensed any rights under the CMCC Agreement. Seller has not granted any material waiver under the CMCC Agreement. CMCC has not been released, in whole or in part, from any of its material obligations under the CMCC Agreement. Except for the transactions contemplated hereby, Seller has not received any notice of CMCC's intention to terminate the CMCC Agreement, in whole or in part, or requesting any amendment, alteration or modification of the CMCC Agreement or any sublicense or assignment thereunder. Except as set forth on Schedule 3.09(a), which is intended to be an appendix to the New Thalidomide Agreement, there are no Patent Rights under the CMCC Agreement.

(b) Payments. Seller has made all payments required to be made to CMCC under the CMCC Agreement prior to the date hereof and will make all payments required to be made to

CMCC under the CMCC Agreement prior to the Closing Date. There has been no correspondence or other communication in writing provided to Seller by CMCC, the subject matter of which could reasonably be interpreted to mean that CMCC intends to take any action, or any event has occurred or circumstance is existing, that could materially and adversely affect the Net Celgene Payments.

(c) No Satisfaction or Discharge; Entire Agreement. The CMCC Agreement has not been satisfied, discharged, canceled, terminated, subordinated or rescinded, in whole or in part. The CMCC Agreement is the entire agreement between Seller and CMCC relating to the subject matter thereof and, other than the Celgene Agreement, constitutes the only agreement or instrument to which Seller is a party that relates to the Net Celgene Payments.

(d) Validity and Enforceability of CMCC Agreement. The CMCC Agreement is the legal, valid and binding obligation of Seller enforceable against Seller in accordance with its terms, subject to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights of creditors generally and to equitable principles.

(e) License. Seller has, pursuant to the CMCC Agreement, the exclusive worldwide right and license to use, lease and sell the Licensed Products (which are sublicensed to Celgene pursuant to the Celgene Agreement), and to practice the Licensed Processes (which are sublicensed to Celgene pursuant to the Celgene Agreement) to the end of the term for which the Patent Rights are granted unless sooner terminated. On the Closing Date, after consummation of the transactions contemplated by this Agreement, Seller will no longer have any such right or license. To the knowledge of Seller, Seller, CMCC and each inventor of the Patent Rights has complied with the PTO duty of candor and good faith in dealing with the PTO, including the duty to disclose to the PTO all information known to be material to the patentability of each claim of the Patent Rights.

3.10. FINDERS' FEES. There is no investment banker, broker, finder or other intermediary which has been retained by or is authorized to act on behalf of Seller who might be entitled to any fee or commission from Buyer or any of its Affiliates upon consummation of the transactions contemplated by this Agreement.

ARTICLE IV

REPRESENTATIONS AND WARRANTIES OF BUYER

Buyer hereby represents and warrants to Seller that:

4.01. ORGANIZATION AND EXISTENCE. Buyer is a company, duly and validly organized and existing under the laws of Hungary and has all applicable powers and all material governmental licenses, authorizations, consents and approvals required to carry on its business as now conducted.

4.02. CORPORATE AUTHORIZATION. The execution, delivery and performance by Buyer of the Transaction Documents to which it is a party, and the consummation by Buyer of the transactions contemplated thereby, are within Buyer's corporate powers and have been duly authorized by all necessary corporate action on the part of Buyer. This Agreement has been duly executed and delivered by, and constitutes the legal, valid and binding agreement of, Buyer, enforceable against Buyer in accordance with its terms, subject to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights of creditors generally and to equitable principles. Effective at the Closing, the other Transaction Documents to which Buyer is a party will have been duly executed and delivered by, and will constitute the legal, valid and binding agreements of Buyer, enforceable against Buyer in accordance with their terms, subject to bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the rights of creditors generally and to equitable principles.

4.03. GOVERNMENTAL AUTHORIZATION. The execution, delivery and performance by Buyer of this Agreement does not require any notice to, action or consent by, or in respect of, or filing with, any Governmental Authority.

4.04. NON-CONTRAVENTION. The execution, delivery and performance by Buyer of this Agreement does not and will not (i) contravene or conflict with the organizational documents of Buyer, (ii) contravene or conflict with or constitute a violation of any provision of any law, rule or regulation binding upon or applicable to Buyer, (iii) contravene or conflict with or constitute a violation of any judgment, injunction, order or decree binding upon or applicable to Buyer, (iv) constitute a default under or give rise to any right of termination, cancellation or acceleration of any right or obligation of Buyer or (v) require the consent or permission of any Person.

4.05. FINDERS' FEES. There is no investment banker, broker, finder or other intermediary that has been retained by or is authorized to act on behalf of Buyer who might be entitled to any fee or commission from Seller upon consummation of the transactions contemplated by this Agreement.

4.06. LITIGATION. There is no action, suit, investigation or proceeding pending against, or to the knowledge of Buyer, threatened against or affecting, Buyer before any Governmental Authority or arbitrator which in any manner challenges or seeks to prevent, enjoin, alter or materially delay the transactions contemplated hereby or which could reasonably be expected to materially and adversely affect Buyer's ability to perform its obligations under this Agreement.

4.07. ABILITY TO PERFORM OBLIGATIONS. There has not been filed with respect to Buyer a petition in bankruptcy, insolvency, receivership or similar proceedings. Buyer has sufficient assets to perform its obligations under this Agreement.

ARTICLE V

COVENANTS

Buyer and Seller agree that:

5.01. PRESERVATION OF THE CELGENE PAYMENTS. From the date hereof until the Closing Date, Seller shall not:

(a) sell, lease, license, sublicense, assign, transfer or otherwise dispose of, or incur or suffer to exist any Lien on, the Celgene Payments, or agree to commit to do any of the foregoing; or

(b) take or agree or commit to take any action that would make any representation and warranty of Seller hereunder inaccurate at, or as of any time prior to, the Closing Date.

5.02. ACCESS TO INFORMATION. From the date hereof until the Closing Date, Seller (a) will give Buyer, its Affiliates, counsel and accountants (collectively, "Buyer's Consultants") reasonable commercial access during normal business hours to the offices, properties, books and records of Seller related to the Celgene Payments; and (b) will furnish to Buyer and Buyer's Consultants such information relating to the Celgene Payments as such Persons may reasonably request.

5.03. NOTICES OF CERTAIN EVENTS. From the date hereof until the Closing Date, Seller shall promptly notify Buyer of:

(a) any notice or other communication from any person or entity that the consent of such person or entity is or may be required in connection with the transactions contemplated by this Agreement;

(b) any notice or other communication from any Governmental Authority in connection with the transactions contemplated by this Agreement or from Celgene or CMCC to the extent that such notice or communication relates to the Celgene Payments, and expressly excluding any notices or communication which do not relate to thalidomide; and

(c) any actions, suits, claims, investigations or proceedings to its knowledge commenced or threatened against, relating to or involving or otherwise affecting the Celgene Agreement, the CMCC Agreement or the Celgene Payments.

5.04. [RESERVED.]

5.05. COMMERCIALLY REASONABLE EFFORTS; FURTHER ASSURANCES. Subject to the terms and conditions of this Agreement, each party will use its commercially reasonable efforts to take, or cause to be taken, all actions and to do, or cause to be done, all things necessary under applicable laws and regulations to consummate the transactions contemplated by this Agreement;

provided that Buyer shall not be obligated to pay any amount of money or deliver any goods or services to Seller or any third party except as otherwise expressly provided in this Agreement. Buyer and Seller agree to execute and deliver such other documents, certificates, agreements and other writings (including any UCC filings requested by Buyer) and to take such other actions as may be reasonably necessary in order to consummate or implement expeditiously the transactions contemplated by this Agreement.

5.06. SELLER'S CONTINUING COVENANTS.

(a) If Celgene should exercise its right to reduce any royalty payments pursuant to Section 7.3(g) of the Celgene Agreement or that section of the New Thalidomide Agreement that is equivalent to Section 7.3(g) of the Celgene Agreement, and such exercise results in a reduction in any Net Celgene Payments, then Seller shall, promptly after notice from Buyer that such right to reduce royalty payments has been exercised, pay to Buyer the amount that Celgene applied in such reduction. Seller's obligations under this Section 5.06(a) shall expire on the due date, if it shall occur, for payment of the Contingent Purchase Price pursuant to Section 2.05(a) hereof.

(b) From and after the Closing Date until such time as Buyer shall have received the last Net Celgene Payment under the New Thalidomide Agreement (or any amendment, modification or successor agreement thereto), Seller shall:

(i) Upon the request of Buyer, from time to time execute, acknowledge and deliver, or cause to be executed, acknowledged and delivered, such further instruments and take such further action as may be reasonably necessary to effectuate the intention, performance and provisions of this Agreement;

(ii) Provide Buyer, as promptly as practicable (and in any event within three business days of Seller's receipt thereof), of (A) copies of any correspondence or other written communication from CMCC relating to thalidomide or from Celgene relating to thalidomide and (B) notice (in writing in reasonable detail) of any oral communication from CMCC or Celgene which could reasonably be understood to be a material development with respect to thalidomide; and

(iii) Cooperate and provide assistance as reasonably requested and to the extent reasonably necessary in connection with any litigation, arbitration or other proceeding (whether threatened, existing, initiated, or contemplated prior to, on or after the date hereof) to which Buyer, its affiliates or any of its officers, directors, shareholders, agents or employees is or may become a party or is or may become otherwise directly or indirectly affected or as to which any such Persons have a direct or indirect interest relating to this Agreement, the Net Celgene Payments or the transactions described herein or therein. With respect to the foregoing obligations, it is understood that, as result of the New Thalidomide Agreement, Buyer may bring actions against Celgene directly and, therefore, it is expected that the need for Seller's cooperation and assistance, if any, will be limited. Buyer shall reimburse Seller for reasonable out-of-pocket expenses (including

the reasonable fees and expenses of counsel) incurred by Seller in connection with the foregoing cooperation and assistance.

5.07. BUYER'S CONTINUING COVENANTS. From and after the Closing Date, upon the request of Seller, from time to time execute, Buyer shall acknowledge and deliver, or cause to be executed, acknowledged and delivered, such further instruments and take such further action as may be reasonably necessary to effectuate the intention, performance and provisions of this Agreement.

5.08. CASH RECEIVED. At and after the Closing, if, notwithstanding the provisions of the Transaction Documents, in respect of the transactions contemplated hereby, Seller shall receive any Net Celgene Payment, Seller shall pay over to Buyer such Net Celgene Payment.

5.09. NOTICE OF PAYMENTS. Prior to the Closing Date, Seller will notify Buyer of the receipt by Seller of any payment from Celgene under Sections 4.1, 4.2 or 4.3 of the Celgene Agreement and of any payment by Seller pursuant to the CMCC Agreement.

ARTICLE VI

CONDITIONS TO CLOSING

6.01. CONDITIONS TO OBLIGATION OF BUYER. The obligation of Buyer to effect the Closing shall be subject to the satisfaction of each of the following conditions, any of which may be waived by Buyer in its sole discretion:

(a) Seller shall have performed and complied in all material respects with all agreements, covenants, obligations and conditions required to be performed and complied by it under this Agreement prior to the Closing Date and Buyer shall have received a certificate executed by a duly authorized officer of Seller to such effect on the Closing Date.

(b) The representations and warranties of Seller contained in Article III which are qualified as to materiality shall be true and correct, and the representations and warranties of Seller which are not qualified as to materiality shall be true and correct in all material respects, in each case, as of the date of this Agreement and as of the Closing Date as though made at and as of the Closing Date, except to the extent any such representation or warranty expressly speaks of a particular date, in which case it shall be true and correct as of such date, and Buyer shall have received a certificate executed by a duly authorized officer of Seller to such effect on the Closing Date.

(c) There shall not have been issued and be in effect any order, decree or judgment of any Governmental Authority enjoining, preventing or restricting the consummation of the transactions contemplated hereby.

(d) There shall not have been instituted or pending any action or proceeding (other than any actions or proceedings that are demonstrably frivolous) by any Governmental Authority or any other Person (i) challenging or seeking to make illegal, to delay materially or otherwise directly or indirectly to restrain or prohibit the consummation of the transactions contemplated hereby, or seeking to obtain material damages in connection with the transactions contemplated hereby, or (ii) seeking to restrain or prohibit Buyer's acquisition or future receipt of the Net Celgene Payments.

(e) There shall not have occurred any event or development, and there shall not be existing any circumstance, which could reasonably be expected to materially and adversely affect future expected Net Sales or the Celgene Payments.

(f) Buyer shall have received an opinion of counsel to Seller in substantially the form attached hereto as Exhibit D.

(g) Buyer shall have received the Celgene Consent duly executed and delivered by the parties thereto.

(h) Buyer shall have received the CMCC Consent duly executed and delivered by the parties thereto.

(i) Buyer shall have received the New Thalidomide Agreement duly executed and delivered by the parties thereto.

(j) Buyer and Seller shall have entered into a mutually satisfactory agreement pursuant to which Buyer and Seller shall identify those sections of the New Thalidomide Agreement that are equivalent to those sections of the Celgene Agreement, for purposes of the definitions of "Applicable Net Celgene Payments", "Applicable Net Sales", "Celgene Payments", "Net Celgene Payments" and "Shared Net Sales", Section 3.08(c) and Section 5.06 hereof.

6.02. CONDITIONS TO OBLIGATION OF SELLER. The obligation of Seller to effect the Closing shall be subject to the satisfaction of each of the following conditions, any of which may be waived by Seller in its sole discretion:

(a) Buyer shall have performed and complied in all material respects with all agreements, covenants, obligations and conditions required to be performed and complied by it under this Agreement prior to the Closing Date and Seller shall have received a certificate executed by a duly authorized officer of Buyer to such effect on the Closing Date.

(b) The representations and warranties of Buyer contained in Article IV which are qualified as to materiality shall be true and correct, and the representations and warranties of Buyer which are not qualified as to materiality shall be true and correct in all material respects, in each case, as of the date of this Agreement and as of the Closing Date as though made at and as of the Closing Date, except to the extent any such representation or warranty expressly speaks of

a particular date, in which case it shall be true and correct as of such date, and Seller shall have received a certificate executed by a duly authorized officer of Buyer to such effect on the Closing Date.

(c) There shall not have been issued and be in effect any order, decree or judgment of any Governmental Authority enjoining, preventing or restricting the consummation of the transactions contemplated hereby.

(d) There shall not have been instituted or pending any action or proceeding (other than any actions or proceedings that are demonstrably frivolous) by any Governmental Authority or any other Person (i) challenging or seeking to make illegal, to delay materially or otherwise directly or indirectly to restrain or prohibit the consummation of the transactions contemplated hereby, or seeking to obtain material damages in connection with the transactions contemplated hereby, or (ii) seeking to restrain or prohibit Buyer's acquisition or future receipt of the Net Celgene Payments.

(e) Seller shall have received the Guaranty duly executed by the parties thereto.

(f) Seller shall have received the New Analog Agreement duly executed and delivered by the parties thereto.

(g) Seller shall have received the IPO Agreement duly executed by the parties thereto.

(h) Seller shall have received the Celgene Consent duly executed and delivered by the parties thereto.

(i) Seller shall have received the CMCC Consent duly executed and delivered by the parties thereto.

(j) Seller shall have received the New Thalidomide Agreement duly executed and delivered by the parties thereto.

(k) Buyer and Seller shall have entered into a mutually satisfactory agreement pursuant to which Buyer and Seller shall identify those sections of the New Thalidomide Agreement that are equivalent to those sections of the Celgene Agreement, for purposes of the definitions of "Applicable Net Celgene Payments", "Applicable Net Sales", "Celgene Payments", "Net Celgene Payments" and "Shared Net Sales", Section 3.08(c) and Section 5.06 hereof.

ARTICLE VII

SURVIVAL; INDEMNIFICATION

7.01. SURVIVAL. The representations, warranties, covenants and agreements of the parties hereto contained in this Agreement or in any certificate or other writing delivered pursuant hereto or in connection herewith shall survive the Closing for a period of five years; provided that
(i) the representations and warranties in Sections 3.01, 3.02, 3.07, 3.08, 3.09, 4.01 and 4.02 and the agreements in Article II, this Article VII, Article VIII and Section 9.03 shall survive the Closing indefinitely; and (ii) each of the covenants and agreements in Article V shall survive for the period of time stated in such covenant or agreement or, if no such period is specified, indefinitely; provided that any expiration shall not terminate or limit in any manner whatsoever any liabilities any person has or may have hereunder for criminal activity, willful misstatements, willful omissions, willful breaches, willful nonfulfillments and willful violations or for common law fraud. Notwithstanding the time limits set forth above, any covenant, agreement, representation or warranty in respect of which indemnity may be sought under Section 7.02 shall survive the time at which it would otherwise terminate pursuant to the preceding sentence if notice of the inaccuracy or breach thereof giving rise to such right to indemnity shall have been given to the party against whom such indemnity may be sought prior to such time and such notice was delivered in accordance with the procedures described in
Section 7.03 below. The covenants, agreements, representations and warranties of Seller and the rights and remedies that may be exercised by Buyer shall not be limited, diminished or otherwise affected by or as a result of any information that may have been provided, any investigation or examination that may have been made by, or any knowledge of, Buyer or any other party on behalf of Buyer.

7.02. INDEMNIFICATION.

(a) Seller hereby indemnifies Buyer and its Affiliates against and agrees to hold each of them harmless from any and all damage, loss, liability and expense (including, without limitation, reasonable expenses of investigation and reasonable attorneys' fees and expenses in connection with any action, suit or proceeding) (collectively, "Loss") incurred or suffered by Buyer or any of its Affiliates arising out of any misrepresentation or breach of warranty, covenant or agreement made or to be performed by Seller pursuant to this Agreement, including any failure by Seller to satisfy any of the Excluded Liabilities and Obligations. A misrepresentation or breach of warranty of the last sentence of Section 3.09(e) hereof shall be deemed not to have occurred except upon the issuance of a non-appealable final determination or judgment by the PTO or any court of competent jurisdiction in an action not initiated by Buyer to the effect that Seller, CMCC or any inventor of the Patent Rights failed to comply with the PTO duty of candor and good faith in dealing with the PTO, including the duty to disclose to the PTO all information known to be material to the patentability of each claim of the Patent Rights.

(b) Buyer hereby indemnifies Seller and its Affiliates against and agrees to hold each of them harmless from any and all Loss incurred or suffered by Seller or any of its Affiliates

arising out of any misrepresentation or breach of warranty, covenant or agreement made or to be performed by Buyer pursuant to this Agreement.

7.03. PROCEDURES; NO WAIVER; EXCLUSIVITY. The party seeking indemnification under Section 7.02 (the "Indemnified Party") agrees to give prompt notice to the party against whom indemnity is sought (the "Indemnifying Party") of the assertion of any claim, or the commencement of any suit, action or proceeding in respect of which indemnity may be sought under such Section; provided, that the failure to give such notice shall not affect the Indemnified Party's rights hereunder except to the extent the Indemnifying Party is materially prejudiced by such failure. The Indemnifying Party may, and at the request of the Indemnified Party shall, participate in and control the defense of any third party suit, action or proceeding at its own expense. The Indemnifying Party shall not be liable under Section 7.02 for any settlement effected without its prior consent of any claim, litigation or proceeding in respect of which indemnity may be sought hereunder; provided that such consent may not be unreasonably withheld.

ARTICLE VIII

TERMINATION

8.01. GROUNDS FOR TERMINATION. This Agreement may be terminated at any time prior to the Closing:

(a) by mutual written agreement of Buyer and Seller; or

(b) by either Buyer or Seller if the Closing shall not have been consummated on or before July 15, 2001 due to non-satisfaction of a condition set forth in Section 6.01 or 6.02 hereof that has not been waived; provided, that neither Buyer nor Seller shall have the right to terminate this Agreement pursuant to this Section 8.01(b) if such party has failed to perform its obligations hereunder.

8.02 EFFECT OF TERMINATION. If this Agreement is terminated as permitted by Section 8.01, such termination shall be without liability of any party (or any stockholder, director, officer, employee, agent, consultant or representative of such party) to any other party to this Agreement; provided, that if such termination shall result from the breach by a party of the terms of this Agreement, which breach results in the failure of a condition to the performance of the obligations of another party, such party shall be fully liable for any and all Losses incurred or suffered by the other party as a result of such failure or breach.

ARTICLE IX

MISCELLANEOUS

9.01. NOTICES. All notices, requests and other communications to any party hereunder shall be in writing (including telex, telecopy, or similar writing) and shall be given,

(a) if to Buyer, to:

c/o Royalty Pharma Management 675 Third Avenue
Suite 3000
New York, NY 10017
USA

Attention:        Pablo Legorreta
                  David Madden
Telephone:        (917) 368-0020
Telecopy:         (917) 368-0021

with copies to:

Testa, Hurwitz & Thibeault, LLP 125 High Street
Boston, MA 02110

Attention:        F. George Davitt, Esq.
Telephone:        (617) 248-7000
Telecopy:         (617) 248-7100

         CH-8006 Zurich
         Switzerland
         Attention:        Claude Lambert
         Telephone:        +41-1-265 35 35
         Telecopy:         +41-1-265 35 11

(b)      if to Seller, to:

         EntreMed, Inc.

9640 Medical Center Drive Rockville, MD 20850

Attention:        Thomas P. Russo
Telephone:        (301) 217-9858

                   -21-

Telecopy:         (301) 217-9594

with copies to:

EntreMed, Inc.
9640 Medical Center Drive Rockville, MD 20850

Attention:        Donald S. Brooks, Esq.
Telephone:        (561) 998-4774
Telecopy:         (561) 998-2960

Arnold & Porter
555 12th Street NW
Washington, DC  20004-1202
USA
Attention:        Kenneth Schwartz, Esq.
Telephone:        (202) 942-5595
Telecopy:         (202) 942-5999

or to such other address as any party may have furnished to the others in writing in accordance herewith, except that notices of change of address shall only be effective upon receipt. All notices and other communications given to any party hereto in accordance with the provisions of this Agreement shall be deemed to have been given on the date of receipt if delivered by hand or overnight courier service or sent by fax prior to 1:00 p.m. (New York time) or on the date five business days after dispatch by certified or registered mail if mailed, in each case delivered, sent or mailed (properly addressed) to such party as provided in this Section 9.01.

9.02. AMENDMENTS; NO WAIVERS. (a) Any provisions of this Agreement may be amended or waived if, and only if, such amendment or waiver is in writing and signed by all parties hereto, or, in the case of a waiver, by the party against whom the waiver is to be effective.

(b) No failure or delay by either Buyer or Seller in exercising any right, power or privilege hereunder shall operate as a waiver thereof nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege. The rights and remedies herein provided shall be cumulative and not exclusive of any rights or remedies provided by law.

9.03. EXPENSES. Except as otherwise provided herein, all costs and expenses incurred in connection with this Agreement shall be paid by the party incurring such cost or expense.

9.04. SUCCESSORS AND ASSIGNS. The provisions of this Agreement shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns. Without

limiting the generality of the foregoing, nothing herein shall prohibit or restrict Buyer from assigning any of its rights and obligations hereunder.

9.05. GOVERNING LAW; JURISDICTION, ETC. (a) THIS AGREEMENT SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAW OF THE STATE OF NEW YORK.

(b) EACH OF BUYER AND SELLER HEREBY IRREVOCABLY AND UNCONDITIONALLY SUBMITS, FOR ITSELF AND ITS PROPERTY AND ASSETS, TO THE EXCLUSIVE JURISDICTION OF ANY NEW YORK STATE COURT OR FEDERAL COURT OF THE UNITED STATES OF AMERICA SITTING IN NEW YORK CITY, NEW YORK, AND ANY APPELLATE COURT THEREOF, IN ANY ACTION OR PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT, OR FOR RECOGNITION OR ENFORCEMENT OF ANY JUDGMENT IN RESPECT THEREOF, AND BUYER AND SELLER HEREBY IRREVOCABLY AND UNCONDITIONALLY AGREE THAT ALL CLAIMS IN RESPECT OF ANY SUCH ACTION OR PROCEEDING MAY BE HEARD AND DETERMINED IN ANY SUCH NEW YORK STATE COURT OR, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, IN SUCH FEDERAL COURT. BUYER AND SELLER HEREBY AGREE THAT A FINAL JUDGMENT IN ANY SUCH ACTION OR PROCEEDING SHALL BE CONCLUSIVE AND MAY BE ENFORCED IN OTHER JURISDICTIONS BY SUIT ON THE JUDGMENT OR IN ANY OTHER MANNER PROVIDED BY APPLICABLE LAW. EACH OF BUYER AND SELLER HEREBY SUBMITS TO THE EXCLUSIVE PERSONAL JURISDICTION AND VENUE OF SUCH NEW YORK STATE AND FEDERAL COURTS. BUYER AND SELLER AGREE, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, THAT PROCESS MAY BE SERVED ON BUYER OR SELLER IN THE SAME MANNER THAT NOTICES MAY BE GIVEN PURSUANT TO SECTION 9.01 HEREOF. BUYER HEREBY APPOINTS, IN THE CASE OF ANY SUCH ACTION OR PROCEEDING BROUGHT IN THE COURTS OF OR IN THE STATE OF NEW YORK, CT CORPORATION SYSTEMS, WITH OFFICES ON THE DATE HEREOF AT 111 EIGHTH AVENUE, NEW YORK, NEW YORK 10011, TO RECEIVE, FOR IT AND ON ITS BEHALF, SERVICE OF PROCESS IN THE STATE OF NEW YORK WITH RESPECT THERETO, PROVIDED THAT BUYER MAY APPOINT ANY OTHER PERSON WITH OFFICES IN THE STATE OF NEW YORK TO REPLACE SUCH AGENT FOR SERVICE OF PROCESS UPON DELIVERY TO SELLER OF NOTICE PURSUANT TO SECTION 9.01 HEREOF.

(c) EACH OF BUYER AND SELLER HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES, TO THE FULLEST EXTENT IT MAY LEGALLY AND EFFECTIVELY DO SO, ANY OBJECTION THAT IT MAY NOW OR HEREAFTER HAVE TO THE LAYING OF VENUE OF ANY ACTION OR PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT IN ANY NEW YORK STATE OR FEDERAL COURT. EACH OF BUYER AND SELLER HEREBY IRREVOCABLY WAIVES TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, THE DEFENSE OF AN INCONVENIENT FORUM TO THE MAINTENANCE OF SUCH ACTION OR PROCEEDING IN ANY SUCH COURT.

(d) IT IS FURTHER UNDERSTOOD AND AGREED THAT MONEY DAMAGES WOULD NOT BE A SUFFICIENT REMEDY FOR ANY BREACH OF THIS AGREEMENT BY SELLER AND THAT BUYER MAY BE ENTITLED TO EQUITABLE RELIEF, INCLUDING INJUNCTION AND SPECIFIC PERFORMANCE, AS A REMEDY FOR ANY SUCH BREACH. SUCH REMEDIES SHALL NOT BE DEEMED TO BE THE EXCLUSIVE REMEDIES FOR A BREACH BY SELLER BUT SHALL BE IN ADDITION TO ALL OTHER REMEDIES AVAILABLE AT LAW OR EQUITY TO BUYER.

(e) BUYER AND SELLER HEREBY IRREVOCABLY WAIVE ALL RIGHT TO TRIAL BY JURY IN ANY ACTION, PROCEEDING OR CLAIM (WHETHER IN CONTRACT, TORT OR OTHERWISE) ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREBY.

9.06. COUNTERPARTS; EFFECTIVENESS. This Agreement may be signed in any number of counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement shall become effective when each party hereto shall have received a counterpart hereof signed by the other party hereto.

9.07. ENTIRE AGREEMENT. This Agreement and the Exhibits hereto constitute the entire agreement between the parties with respect to the subject matter hereof and supersede all prior agreements, understandings and negotiations, both written and oral, between the parties with respect to the subject matter of this Agreement. No representation, inducement, promise, understanding, condition or warranty not set forth herein has been made or relied upon by either party hereto. None of this Agreement, nor any provision hereof, is intended to confer upon any Person other than the parties hereto any rights or remedies hereunder.

9.08. CAPTIONS. The captions herein are included for convenience of reference only and shall be ignored in the construction or interpretation hereof.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]

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

ENTREMED, INC.

By: /s/ James D. Johnson
    ------------------------------------
    Name:  James Dean Johnson
    Title: General Counsel

BIOVENTURE INVESTMENTS KFT

By: /s/ I Zentai
    ------------------------------------
    Name:  Istvan Zentai
    Title: Managing Director

Title:

AMENDMENT NO. 1 TO
PURCHASE AGREEMENT
BETWEEN
BIOVENTURE INVESTMENTS KFT
AND
ENTREMED, INC.

THIS AMENDMENT NO. 1 TO PURCHASE AGREEMENT (the "Amendment") is made and entered into on this 13th day of July, 2001 by and between EntreMed, Inc., a Delaware corporation ("Seller") and Bioventure Investments kft, a company organized under the laws of Hungary and a wholly-owned subsidiary of Royalty Pharma AG, a Swiss stock corporation ("Buyer").

WHEREAS, Seller and Buyer are parties to that certain Purchase Agreement dated as of June 15, 2001 (the "Purchase Agreement") pursuant to which Seller agreed, subject to the terms thereof, to sell, transfer, assign and deliver to Buyer all of Seller's right, title and interest in and to the Net Celgene Payments;

WHEREAS, Seller and Buyer wish to amend the Purchase Agreement to provide that the Purchase Agreement may be terminated at any time prior to the Closing by either Buyer or Seller if the Closing shall not have been consummated on or before July 30, 2001;

NOW, THEREFORE, in consideration of the mutual promises and covenants contained in this Amendment and in the Purchase Agreement, and pursuant to
Section 9.02(a) of the Purchase Agreement, Seller and Buyer do hereby amend the Purchase Agreement, as follows:

1. Section 8.01(b) of the Purchase Agreement is hereby amended by deleting the reference to "July 15, 2001" wherever it appears in said Section 8.01(b) and replacing it with "July 30, 2001."

2. Definitions. All capitalized terms used, but not defined herein, shall have the respective meanings ascribed to them in the Purchase Agreement.

3. Governing Law. This Amendment shall be governed by, construed in accordance with, the laws of the State of New York (without regard to conflict of laws provisions).

4. Entire Agreement. The Purchase Agreement, as amended hereby, constitutes the full and entire understanding between the parties regarding the subject matter herein. Except as otherwise expressly provided herein, the provisions hereof shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns.

5. Full Force and Effect. Except as amended hereby, the Purchase Agreement shall remain in full force and effect.

6. Counterparts. This Amendment may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

7. Headings. Headings in this Amendment are included for reference only and have no effect upon the construction or interpretation of any part of this Amendment.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

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

ENTREMED, INC.

By: /s/ James D. Johnson
   -------------------------------------------
   Name:  James Dean Johnson
   Title: General Counsel

BIOVENTURE INVESTMENTS KFT

By: /s/ I Zentai
   -------------------------------------------
   Name:  Istvan Zentai
   Title: Managing Director

AMENDMENT NO. 2 TO
PURCHASE AGREEMENT
BETWEEN
BIOVENTURE INVESTMENTS KFT
AND
ENTREMED, INC.

THIS AMENDMENT NO. 2 TO PURCHASE AGREEMENT (the "Amendment") is made and entered into on this 30th day of July, 2001 by and between EntreMed, Inc., a Delaware corporation ("Seller") and Bioventure Investments kft, a company organized under the laws of Hungary and a wholly-owned subsidiary of Royalty Pharma AG, a Swiss stock corporation ("Buyer").

WHEREAS, Seller and Buyer are parties to that certain Purchase Agreement dated as of June 15, 2001, as amended by Amendment No. 1 dated as of July 13, 2001 (as so amended, the "Purchase Agreement") pursuant to which Seller agreed, subject to the terms thereof, to sell, transfer, assign and deliver to Buyer all of Seller's right, title and interest in and to the Net Celgene Payments;

WHEREAS, Seller and Buyer wish to amend the Purchase Agreement to provide that the Purchase Agreement may be terminated at any time prior to the Closing by either Buyer or Seller if the Closing shall not have been consummated on or before August 3, 2001;

NOW, THEREFORE, in consideration of the mutual promises and covenants contained in this Amendment and in the Purchase Agreement, and pursuant to
Section 9.02(a) of the Purchase Agreement, Seller and Buyer do hereby amend the Purchase Agreement, as follows:

1. Section 8.01(b) of the Purchase Agreement is hereby amended by deleting the reference to "July 30, 2001" wherever it appears in said Section 8.01(b) and replacing it with "August 3, 2001."

2. Definitions. All capitalized terms used, but not defined herein, shall have the respective meanings ascribed to them in the Purchase Agreement.

3. Governing Law. This Amendment shall be governed by, construed in accordance with, the laws of the State of New York (without regard to conflict of laws provisions).

4. Entire Agreement. The Purchase Agreement, as amended hereby, constitutes the full and entire understanding between the parties regarding the subject matter herein. Except as otherwise expressly provided herein, the provisions hereof shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns.

5. Full Force and Effect. Except as amended hereby, the Purchase Agreement shall remain in full force and effect.

6. Counterparts. This Amendment may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

7. Headings. Headings in this Amendment are included for reference only and have no effect upon the construction or interpretation of any part of this Amendment.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

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

ENTREMED, INC.

By: /s/ James D. Johnson
   -------------------------------------------
   Name:  James Dean Johnson
   Title: General Counsel

BIOVENTURE INVESTMENTS KFT

By: /s/ I Zentai
   -------------------------------------------
   Name:  Istvan Zentai
   Title: Managing Director

AMENDMENT NO. 3 TO
PURCHASE AGREEMENT
BETWEEN
BIOVENTURE INVESTMENTS KFT
AND
ENTREMED, INC.

THIS AMENDMENT NO. 3 TO PURCHASE AGREEMENT (the "Amendment") is made and entered into on this 3rd day of August, 2001 by and between EntreMed, Inc., a Delaware corporation ("Seller") and Bioventure Investments kft, a company organized under the laws of Hungary and a wholly-owned subsidiary of Royalty Pharma AG, a Swiss stock corporation ("Buyer").

WHEREAS, Seller and Buyer are parties to that certain Purchase Agreement dated as of June 15, 2001, as amended by Amendment No. 1 dated as of July 13, 2001 and by Amendment No. 2 dated as of July 31, 2001(as so amended, the "Purchase Agreement") pursuant to which Seller agreed, subject to the terms thereof, to sell, transfer, assign and deliver to Buyer all of Seller's right, title and interest in and to the Net Celgene Payments;

WHEREAS, Seller and Buyer wish to amend the Purchase Agreement to provide that the Purchase Agreement may be terminated at any time prior to the Closing by either Buyer or Seller if the Closing shall not have been consummated on or before August 8, 2001;

NOW, THEREFORE, in consideration of the mutual promises and covenants contained in this Amendment and in the Purchase Agreement, and pursuant to
Section 9.02(a) of the Purchase Agreement, Seller and Buyer do hereby amend the Purchase Agreement, as follows:

1. Section 8.01(b) of the Purchase Agreement is hereby amended by deleting the reference to "August 3, 2001" wherever it appears in said Section 8.01(b) and replacing it with "August 8, 2001."

2. Definitions. All capitalized terms used, but not defined herein, shall have the respective meanings ascribed to them in the Purchase Agreement.

3. Governing Law. This Amendment shall be governed by, construed in accordance with, the laws of the State of New York (without regard to conflict of laws provisions).

4. Entire Agreement. The Purchase Agreement, as amended hereby, constitutes the full and entire understanding between the parties regarding the subject matter herein. Except as otherwise expressly provided herein, the provisions hereof shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns.

5. Full Force and Effect. Except as amended hereby, the Purchase Agreement shall remain in full force and effect.

6. Counterparts. This Amendment may be executed in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

7. Headings. Headings in this Amendment are included for reference only and have no effect upon the construction or interpretation of any part of this Amendment.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

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

ENTREMED, INC.

By: /s/ James D. Johnson
   -----------------------------------------
   Name:  James D. Johnson
   Title: General Counsel

BIOVENTURE INVESTMENTS KFT

By: /s/ I Zentai
   -----------------------------------------
   Name:  Istvan Zentai
   Title: Managing Director

ANALOG AGREEMENT

This Analog Agreement (the "Agreement") dated as of August 6, 2001 (the "Effective Date"), is entered into by and between CHILDREN'S MEDICAL CENTER CORPORATION, a corporation duly organized and existing under the laws of the Commonwealth of Massachusetts and having its principal office at 300 Longwood Avenue, Boston, Massachusetts 02115, U.S.A. (hereinafter referred to as "CMCC"), and ENTREMED, INC., a corporation duly organized under the laws of Delaware and having its principal office at 9640 Medical Center Drive, Rockville, MD 20850 (hereinafter referred to as "ENTREMED").

WITNESSETH

WHEREAS, CMCC is the owner of certain "Patent Rights" (as later defined herein), and has the right to grant licenses under said Patent Rights;

WHEREAS, the Patent Rights were originally licensed by CMCC to ENTREMED pursuant to that certain License Agreement made and entered into May 26, 1994, by and between CMCC and ENTREMED, as amended on August 23, 1995, December 2, 1997, December 3, 1998 and September 24, 1999 (as so amended, the "Original License Agreement");

WHEREAS, ENTREMED sublicensed the Patent Rights relating to Thalidomide to Celgene Corporation, a corporation duly organized under the laws of Delaware and having its principal office at 6 Powder Horn Drive, Warren, New Jersey 07059 ("CELGENE"), pursuant to that certain Agreement dated as of December 9, 1998 by and between ENTREMED and CELGENE (the "Celgene Agreement");

WHEREAS, pursuant to that certain Purchase Agreement dated as of June 15, 2001 (the "Purchase Agreement") by and between ENTREMED and Bioventure Investments kft, a company organized under the laws of Hungary ("BIOVENTURE"), ENTREMED has agreed to sell, transfer and assign to BIOVENTURE all of its right, title and interest relating to the Net Celgene Payments, as defined in the Purchase Agreement, under the Celgene Agreement;

WHEREAS, the Original License Agreement will be terminated, and CMCC and ENTREMED will enter into this Agreement, pursuant to which CMCC will grant a license to ENTREMED to the Patent Rights for use in the Non-Thalidomide Field (as defined below).

[*] = CERTAIN INFORMATION CONTAINED IN THIS EXHIBIT HAS BEEN OMITTED AND FILED SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS. OMITTED TEXT IS INDICATED BY A "*".

WHEREAS, CMCC desires to have the Patent Rights utilized in the public interest and is willing to grant a license thereunder;

WHEREAS, CMCC has consented to the Purchase Agreement pursuant to the CMCC Acknowledgment and Consent (the "CMCC Consent");

WHEREAS, ENTREMED desires to obtain a license under the Patent Rights upon the terms and conditions hereinafter set forth;

NOW, THEREFORE, in consideration of the premises and the mutual covenants herein, the parties hereto agree as follows:

ARTICLE I - DEFINITIONS

For the purpose of this Agreement, the following words and phrases shall have the following meanings:

1.1 "LICENSEE" shall mean ENTREMED and any Subsidiary or joint venture of ENTREMED.

1.2 "Sublicensee" shall mean any corporation, partnership or business organization which is not controlled directly or indirectly by LICENSEE but to whom LICENSEE transfers know-how, rights or products to enable said party to sell Licensed Products and/or Licensed Processes.

1.3 "Subsidiary" shall mean any corporation, company or other entity more than fifty percent (50%) of whose voting stock is owned or controlled directly or indirectly by ENTREMED.

1.4 "Patent Rights" shall mean all of the following CMCC intellectual property:

1.4.1    United States and foreign patents and/or patent applications
         listed in Appendix A;

1.4.2    United States and foreign patents issued from the applications
         listed in Appendix A and from divisionals and continuations of
         these applications;

1.4.3    Claims of U.S. and foreign continuation-in-part applications,
         and of the resulting patents, which are directed to subject
         matter that is described in the U.S. and foreign applications
         listed in Appendix A in a manner that meets the requirements
         of 35 U.S.C. Section 112;

1.4.4    Claims of all later filed foreign patent applications, and of
         the resulting patents, which are directed to subject matter
         that is described in the United States patent and/or patent
         applications listed in Appendix A in a manner that meets the
         requirements of 35 U.S.C. Section 112; and

1.4.5 Any reissues of United States patents described in Sections 1.4.1, 1.4.2 and 1.4.3 above.

1.5 A "Licensed Product" shall mean any product or part thereof which does not contain Thalidomide, alone or in combination, and which:

1.5.1    Is covered in whole or in part by an issued, unexpired claim
         or a pending claim contained in the Patent Rights in the
         country in which any Licensed Product is made, used, or sold;

1.5.2    Is manufactured by using a process which is covered in whole
         or in part by an issued, unexpired claim or a pending claim
         contained in the Patent Rights in the country in which any
         Licensed Process is used or in which the Licensed Product is
         used or sold.

1.6 A "Licensed Process" shall mean any process with application solely in the Non-Thalidomide Field and which is covered in whole or in part by an issued, unexpired claim or a pending claim contained in the Patent Rights.

1.7 "Net Sales" shall mean the gross amount invoiced for all sales of Licensed Products by LICENSEE or its Sublicensees or for any practice of the Licensed Processes by LICENSEE or its Sublicensees less:

1.7.1    trade, quantity and cash discounts, allowed, incurred or
         actually taken;

1.7.2    sales taxes directly related to the sale to the extent
         included in the gross invoice price;

1.7.3    the portion of freight, postage and shipping insurance
         expenses paid by LICENSEE;

1.7.4    value added tax, sales or turnover tax, or excise taxes or
         duties which are included in said invoiced amount;

1.7.5    rebates accrued, incurred or paid to Federal Medicaid or State
         Medicare and amounts exactly repaid or credited by reason of
         rejections or the return of Licensed Products (due to recalls,
         dating or other reasons) and retroactive deductions; and

1.7.6    cost of export licenses and any taxes, fees or other charges
         associated with the exportation or importation of Licensed
         Products.

1.7.7    No deductions shall be made for commissions paid to
         individuals whether they be with independent sales agencies or
         regularly employed by LICENSEE and on its payroll, or for the
         cost of collections.

1.7.8    Licensed Products shall be considered "sold" when billed out
         or invoiced.

1.8      "New Thalidomide Agreement" shall mean that certain Agreement of even
         date herewith by and among CMCC, BIOVENTURE, CELGENE, and, for limited
         purposes thereof, LICENSEE.

1.9      "Non-Thalidomide Field" shall mean the use of any compound other than
         Thalidomide, alone or in combination, in humans or animals, including
         without limitation any and all diagnostic, prophylactic, therapeutic,
         and research and development uses.

1.10     "Thalidomide" shall mean a compound with the chemical structure
         described as 2-(2,6-Dioxo-3-piperidinyl)-1H-isoindole-1,3(2H)-dione, or
         as otherwise defined in the Merck Index, entry 9390, 12th ed., and
         pharmaceutically acceptable salts thereof.

                         ARTICLE II - GRANT OF LICENSE

2.1      CMCC hereby grants to LICENSEE an exclusive worldwide right and license
         in the Non-Thalidomide Field, subject to the provisions of Articles 2.3
         and 2.9 herein, to make, have made, use, lease, and sell the Licensed
         Products and to practice the Licensed Processes under the Patent
         Rights. CMCC shall retain a royalty-free, nonexclusive, irrevocable
         license to practice the Patent Rights for research purposes only.

2.2      LICENSEE agrees that it will use its best efforts to manufacture
         substantially in the United States the Licensed Products leased or sold
         in the United States.

2.3      The license granted in Article 2.1 is subject to a reserved
         nonexclusive right in CMCC to license the Patent Rights, including
         Licensed Products and Licensed Processes, to non-profit, non-commercial
         institutions for research purposes only. CMCC agrees to notify ENTREMED
         in writing of any such license grant. Subject only to this Article 2.3
         and Article 2.9 herein, CMCC hereby agrees that it shall not grant any
         other licenses, to make, have made, use, lease and/or sell Licensed
         Products or to utilize Licensed Processes during the period of time in
         which this Agreement is in effect.

2.4      LICENSEE shall have the right to enter into sublicensing agreements for
         the rights, privileges, and licenses granted hereunder. Such
         sublicenses will expire upon the expiration of LICENSEE's rights
         granted herein except as provided in Section 13.7.

2.5      LICENSEE agrees that any sublicense granted by it shall provide that
         the obligations to CMCC of Articles II, V, VII, VIII, IX, X, XII, XIII,
         and XV of this Agreement shall be binding upon the Sublicensee as if it
         were a party to this Agreement. LICENSEE further agrees to attach
         copies of such Articles to sublicense agreements. Further, LICENSEE
         hereby agrees that every

sublicensing agreement to which it shall be a party and which shall relate to the rights, privileges and license granted hereunder shall contain a statement setting forth the event or date upon which LICENSEE'S exclusive rights, privileges and license hereunder shall terminate.

2.6 LICENSEE agrees to forward to CMCC a copy of any and all fully executed sublicense agreements, and further agrees to forward to CMCC annually a copy of such reports received by LICENSEE from its Sublicensees during the preceding twelve (12) month period under the sublicenses as shall be pertinent to a royalty accounting under said sublicense agreements.

2.7 LICENSEE shall not receive from Sublicensees anything of value in lieu of cash payments based upon payment obligations of any sublicense under this Agreement, without the express prior written permission of CMCC.

2.8 The license granted hereunder shall not be construed to confer any rights upon LICENSEE by implication, estoppel or otherwise as to any technology not specifically set forth in Appendix A hereof. Without limiting the generality of the foregoing, LICENSEE may not use the Patent Rights outside the Non-Thalidomide Field. Any use by LICENSEE of the Patent Rights outside the Non-Thalidomide Field shall constitute a breach of this Agreement and grounds for termination of this Agreement.

2.9 The license granted in Article 2.1 is subject to, and expressly limited by, any rights the United States government may have pursuant to Public Laws 96-517 and 98-620.

ARTICLE III - DUE DILIGENCE

3.1 LICENSEE shall use its best efforts to bring one or more Licensed Products or Licensed Processes to market through a thorough, vigorous and diligent program for exploitation of the Patent Rights. CMCC agrees that LICENSEE shall have complete control over all regulatory submissions of Licensed Products to the appropriate regulatory agencies worldwide. For each Licensed Product which LICENSEE intends to commercialize, LICENSEE shall provide CMCC with written notice of LICENSEE's interest in such commercialization (each such notice, a "Notice of Intent to Commercialize" and the date of each such notice, a "Product Notice Date"). LICENSEE shall provide CMCC with a Notice of Intent to Commercialize the first Licensed Product ("First Licensed Product") upon the Effective Date. Due diligence shall be demonstrated by LICENSEE or its Sublicensee attaining the following milestones for each Licensed Product:

3.1.1    within * of the applicable Product Notice Date, the filing of
         an IND (Investigational New Drug application) in the U.S. for
         such Licensed Product;

3.1.2    within * of the applicable Product Notice Date, the initiation
         of Phase II trials of such Licensed Product;

3.1.3    within * of the applicable Product Notice Date, the initiation
         of Phase III trials of such Licensed Product; and

3.1.4    within * of the applicable Product Notice Date, the submission
         of an NDA (New Drug Application) or similar application to
         gain regulatory approval for the marketing of such Licensed
         Product.

3.2 LICENSEE acknowledges that the primary objective of CMCC with respect to the Licenses granted hereby is to promote the development and marketing of Licensed Products and Licensed Processes for the public good. To this end, CMCC shall have the right to terminate this Agreement pursuant to Section 13.4 if LICENSEE fails to attain any of the above milestones with respect to the First Licensed Product or if it suspends diligence in meeting any of the above milestones for more than three (3) months with respect to the First Licensed Product because of business circumstances such as lack of funds, merger acquisition, or the like ("Business Circumstances"). CMCC shall have the right to terminate this Agreement pursuant to Section 13.4 with respect to one or more Licensed Products except the First Licensed Product ("Other Licensed Product(s)"), if LICENSEE fails to attain any of the above milestones with respect to such Other Licensed Product(s) or if it suspends its diligence in meeting of any of the above milestones for more than three (3) months with respect to such Other Licensed Product(s) because of Business Circumstances. In the event of any such termination, LICENSEE shall grant to CMCC, to the extent not prohibited by the United States government or by prior contractual obligations to any third party, solely to the extent necessary to permit CMCC to exercise its rights under such terminated Patent Rights, immunity from suit for any causes of action LICENSEE may have arising out of or in connection with any intellectual property controlled by LICENSEE. However, if LICENSEE can demonstrate to the satisfaction of CMCC, at CMCC's sole discretion, that circumstances beyond LICENSEE's control precluded LICENSEE from fulfilling its diligence obligations with respect to the First Licensed Product or an Other Licensed Product, and that it is unlikely that any third party could overcome these circumstances better than LICENSEE, then CMCC shall not exercise its termination rights under this Section for one (1) year from the date on which CMCC gives notice of termination and, if LICENSEE reestablishes diligence towards it objectives during such one year period, any prior lack of diligence will be deemed cured with respect to the First Licensed Product or such Other Licensed Product(s), as applicable.

3.3 If (a) CMCC provides LICENSEE with written notice of research results that CMCC believes reasonably indicate that a compound covered under the Patent Rights has commercial potential but for which compound LICENSEE has not yet submitted to CMCC a Notice of Intent to Commercialize ("Compound Notice");

or (b) CMCC provides written notice to LICENSEE of a third party having approached CMCC seeking a right to commercialize any compound covered under the Patent Rights for which LICENSEE has not yet submitted to CMCC a Notice of Intent to Commercialize ("Sublicensee Notice"), then LICENSEE must within ninety (90) days after receipt of such notice either submit to CMCC a Notice of Intent to Commercialize with respect to such compound and comply with the obligations of Sections 3.1 and 3.2, or identify and enter into a sublicensing arrangement with a sublicensee to commercialize such compound. If LICENSEE does not submit a Notice of Intent to Commercialize to CMCC or fails to identify and enter into a sublicensing arrangement with such a sublicensee candidate as required above, CMCC shall have the right to terminate this Agreement pursuant to Section 13.4 with respect to such compound. In the event of such termination, LICENSEE shall grant to CMCC, to the extent not prohibited by the United States government or by prior contractual obligations to any third party, solely to the extent necessary to permit CMCC to exercise its rights under such terminated Patent Rights, immunity from suit for any causes of action LICENSEE may have arising out of or in connection with any intellectual property controlled by LICENSEE.

4.1.1    $* (* dollars) due * the applicable Product Notice Date for
         such Licensed Product;

4.1.2    $* (* dollars) due *submission of the first Phase I/II IND
         (Investigational New Drug application) for any indication for
         such Licensed Product;

4.1.3    $* (* dollars) due * completion of a Phase II clinical trials
         for any indication for such Licensed Product; and

4.1.4    $* (* dollars) due * submission of a PLA (Product License
         Application) or an NDA (New Drug Application) for any
         indication for such Licensed Product.

4.2 LICENSEE shall pay to CMCC a royalty based on the Net Sales with respect to the Licensed Products or Licensed Processes used, leased or sold by LICENSEE, which said royalty shall be *% (* percent), or such lower rate as may be agreed upon in writing by the parties, of such Net Sales.

4.3 Where sublicenses have been granted, or strategic partnerships entered into, LICENSEE shall pay to CMCC *% (* percent) of any and all sublicensing payments, or such lower percentage as may be agreed upon in writing by the parties. Sublicensing payments are defined as any and all payments made to LICENSEE by the Sublicensee or strategic partner except for payments to support research and development conducted by LICENSEE, for purchases of equity, for payments for goods and services or for royalties based on the Net Sales with respect to the Licensed Product or Licensed Process. LICENSEE shall pay to CMCC *% of the royalty income paid to LICENSEE up to $* of cumulative Net Sales with respect to the Licensed Product or Licensed Process. After $* of cumulative Net Sales, LICENSEE shall pay to CMCC *% of royalty income to LICENSEE from the Sublicensee with a minimum payment of *% of Net Sales for sales of the Licensed Product made or the practice of the Licensed Process by the Sublicensee. If the royalty rate paid by the Sublicensee is reduced because of third party, non-infringing sales of a Thalidomide analog, the minimum payment of at least *% of Net Sales of the Licensed Product will be reduced proportional to the reduction of the royalty rate paid to LICENSEE by the Sublicensee. Milestone payments from LICENSEE to CMCC shall be credited against CMCC's share of milestone payments made to LICENSEE by Sublicensee.

4.4 [Intentionally Omitted.]

4.5 No multiple royalties shall be payable because any Licensed Product, its manufacture, use, lease or sale, are or shall be covered by more than one of the Patent Rights licensed under this Agreement.

4.6 Royalty payments shall be paid in United States dollars in Boston, Massachusetts, or at such other place as CMCC may reasonably designate consistent with the laws and regulations controlling in any foreign country. If any currency conversion shall be required in connection with the payment of royalties hereunder, such conversion shall be made by using the exchange rate prevailing at the Fleet Bank of Boston on the last business day of the calendar quarterly reporting period to which such royalty payments relate.

ARTICLE V - REPORTS AND RECORDS

5.1 LICENSEE shall keep full, true and accurate books of account containing all particulars that may be necessary for the purpose of showing the amounts payable to CMCC hereunder. Said books of account shall be kept at LICENSEE's principal place of business or the principal place of business of the appropriate division of LICENSEE to which this Agreement relates. Said books and the supporting data shall be open at all reasonable times for five (5) years following the end of the calendar year to which they pertain, to the inspection of CMCC or its agents for the purpose of verifying LICENSEE's royalty statement or

compliance in other respects with this Agreement. CMCC can request auditing of said books and supporting data no more than once each calendar year.

5.2 LICENSEE, within thirty (30) days after March 31, June 30, September 30 and December 31, of each year, shall deliver to CMCC true and accurate reports, giving such particulars of the business conducted by LICENSEE and its Sublicensees during the preceding three-month period under this Agreement as shall be pertinent to a royalty accounting hereunder. These shall include at least the following:

5.2.1    Number of Licensed Products manufactured and sold.

5.2.2    Total billings for Licensed Products sold and Licensed
         Processes practiced.

5.2.3    Accounting for all Licensed Products used or sold and Licensed
         Processes practiced.

5.2.4    Deductions applicable as provided in Section 1.7.

5.2.5    Total royalties due.

5.2.6    Names and addresses of all Sublicensees of LICENSEE.

5.3 With each such report submitted, LICENSEE shall pay to CMCC the royalties due and payable under this Agreement. If no royalties shall be due, LICENSEE shall so report. On or before the ninetieth (90th) day following the close of LICENSEE's fiscal year, LICENSEE shall provide CMCC with LICENSEE's certified financial statements for the preceding fiscal-year including at a minimum, a Balance Sheet and an Operating Statement.

5.4 The royalty payments set forth in this Agreement shall, if overdue, bear interest until payment at a per annum rate of two percent (2%) above the prime rate in effect at the Fleet Bank of Boston on the due date. The payment of such interest shall not foreclose CMCC from exercising any other rights it may have as a consequence of the lateness of any payment.

ARTICLE VI - PATENT PROSECUTION

The rights and obligations of the parties with respect to the prosecution of the Patent Rights during the term of this Agreement shall be governed by the applicable provisions of Section 7 of the New Thalidomide Agreement, and such provisions of Section 7 shall survive and remain in effect during the term of this Agreement with respect to the parties' rights to the Patent Rights after a termination of the New Thalidomide Agreement prior to termination or expiration of this Agreement.

ARTICLE VII - INFRINGEMENT

The rights and obligations of the parties with respect to infringement of the Patent Rights during the term of this Agreement shall be governed by the applicable provisions of Section 7 of the New Thalidomide Agreement, and such provisions of Section 7 shall survive and remain in effect during the term of this Agreement with respect to the parties' rights to the Patent Rights after a termination of the New Thalidomide Agreement prior to termination or expiration of this Agreement.

8.1      Indemnification

         8.1.1    LICENSEE shall indemnify, defend and hold harmless CMCC and
                  its trustees, officers, medical and professional staff,
                  employees, and agents and their respective successors, heirs
                  and assigns (the "Indemnitees"), against any liability,
                  damage, loss or expense (including reasonable attorney's fees
                  and expenses of litigation) incurred by or imposed upon the
                  Indemnitees or any one of them in connection with any claims,
                  suits, actions, demands or judgments arising out of any theory
                  of product liability (including, but not limited to, actions
                  in the form of tort, warranty, or strict liability) concerning
                  any product, process or service made, used or sold pursuant to
                  any right or license granted under this Agreement.

         8.1.2    LICENSEE's indemnification under Section 8.1.1 shall not apply
                  to any liability, damage, loss or expense to the extent that
                  it is directly attributable to the negligent activities,
                  reckless misconduct or intentional misconduct of the
                  Indemnitees.

         8.1.3    LICENSEE agrees, at its own expense, to provide attorneys
                  reasonably acceptable to CMCC to defend against any actions
                  brought or filed against any party indemnified hereunder with
                  respect to the subject of indemnity contained herein, whether
                  or not such actions are rightfully brought.

         8.1.4    This Section 8.1 shall survive expiration or termination of
                  this Agreement.

8.2      Insurance

         8.2.1    Beginning at the time as any such product, process or service
                  is being commercially distributed or sold (other than for the
                  purpose of obtaining regulatory approvals) by LICENSEE or by a
                  Sublicensee or agent of LICENSEE, LICENSEE shall, at its sole
                  cost and expense, procure and maintain comprehensive general
                  liability insurance in amounts not less than $2,000,000 per
                  incident and $2,000,000 annual aggregate and naming

         the Indemnitees as additional insureds. Such comprehensive
         general liability insurance shall provide (i) product
         liability coverage and (ii) broad form contractual liability
         coverage for LICENSEE's indemnification under Section 8.1. If
         LICENSEE elects to self-insure all or part of the limits
         described above (including deductibles or retentions which are
         in excess of $250,000 annual aggregate) such self-insurance
         program must be acceptable to the CMCC and the Risk Management
         Foundation of the Harvard Medical Institutions, Inc. The
         minimum amount of insurance coverage required under this
         Section 8.2 shall not be construed to create a limit of
         LICENSEE's liability with respect to its indemnification under
         Section 8.1.

8.2.2    LICENSEE shall provide CMCC with written evidence of such
         insurance upon request of CMCC. LICENSEE shall provide CMCC
         with written notice at lease fifteen (15) days prior to the
         cancellation, non-renewal or material change in such
         insurance; if LICENSEE does not obtain replacement insurance
         providing comparable coverage within such fifteen (15) day
         period, CMCC shall have the right to terminate this Agreement
         effective at the end of such fifteen (15) day period without
         notice of any additional waiting periods.

8.2.3    LICENSEE shall maintain such comprehensive general liability
         insurance during (i) the period that any such product, process
         or service is being commercially distributed or sold (other
         than for the purpose of obtaining regulatory approvals) by
         LICENSEE or by a Sublicensee or agent of LICENSEE and (ii) a
         reasonable period after the period referred to above, which in
         no event shall be less than fifteen (15) years.

8.2.4    This Section 8.2 shall survive expiration or termination of
         this Agreement.

ARTICLE IX - EXPORT CONTROLS

It is understood that CMCC is subject to United States laws and regulations controlling the export of technical data, computer software, laboratory prototypes and other commodities (including the Arms Export Control Act, as amended and the Export Administration Act of 1979) and that its obligations hereunder are contingent on compliance with applicable United States export laws and regulations. The transfer of certain technical data and commodities may require a license from the cognizant agency of the United States Government and/or written assurances by LICENSEE that LICENSEE shall not export data or commodities to certain foreign countries without prior approval of such agency. CMCC neither represents that a license shall not be required nor that, if required, it shall be issued.

ARTICLE X - NON-USE OF NAMES

LICENSEE shall not use the names of the Children's Medical Center Corporation nor of any of its employees, nor any adaptation thereof, in any advertising, promotional or sales literature without prior written consent obtained from CMCC in each case except that LICENSEE may state that it is licensed by CMCC under one or more of the patents and/or applications comprising the Patent Rights, and LICENSEE may comply with disclosure requirements of all applicable laws relating to its business, including United States and state security laws.

ARTICLE XI - ASSIGNMENT

Subject to the restrictions set forth herein, this Agreement, and each and every provision hereof, shall be binding upon and shall inure to the benefit of the parties, their respective successors, successors-in-title, heirs and assigns, and each and every successor-in-interest to any party, whether such successor acquires such interest by way of gift, inheritance, purchase, foreclosure, or by any other method, shall hold such interest subject to all the terms and provisions of this Agreement; provided however that LICENSEE shall not assign or transfer the whole or any part of this Agreement or its rights hereunder without the express written agreement of CMCC which agreement shall not be unreasonably withheld except that LICENSEE may assign this Agreement in connection with the transfer or sale of all or substantially all of its assets or business or its merger or consolidation with another organization.

12.1     Any and all claims, disputes or controversies arising under, out of, or
         in connection with this Agreement, which have not been resolved by good
         faith negotiations between the parties, shall be resolved by final and
         binding arbitration in Boston, Massachusetts, under patent arbitration
         rules of the American Arbitration Association then obtaining. The
         arbitrators shall have no power to add to, subtract from or modify any
         of the terms or conditions of this Agreement. Any award rendered in
         such arbitration may be enforced by either party in either the courts
         of the Commonwealth of Massachusetts or in the United States District
         Court for the District of Massachusetts, to whose jurisdiction for such
         purposes CMCC and LICENSEE each hereby irrevocably consents and
         submits.

12.2     Notwithstanding the foregoing, nothing in this Article shall be
         construed (i) to waive any rights or timely performance of any
         obligations existing under this Agreement or (ii) to apply to the
         provisions of Section 7.3 (Infringement Actions) (other than the fourth
         sentence of Section 7.3(a)) or Section 7.4 (Declaratory Judgment
         Actions) of the New Thalidomide Agreement.

13.1     Unless earlier terminated as hereinafter provided, this Agreement shall
         remain in full force and effect for the life of the last to expire
         patent issued under the Patent Rights.

13.2     Pursuant to Section 8.2.2, or if LICENSEE shall cease to carry on its
         business, this Agreement shall terminate upon notice by CMCC.

13.3     Should LICENSEE fail to pay CMCC royalties due and payable hereunder,
         CMCC shall have the right to terminate this Agreement on sixty (60)
         days' notice, unless LICENSEE shall pay CMCC within the sixty (60) day
         period, all such royalties and interest due and payable. Upon the
         expiration of the sixty (60) day period, if LICENSEE shall not have
         paid all such royalties and interest due and payable, the rights,
         privileges and license granted hereunder shall terminate.

13.4     Upon any material breach or default of this Agreement by LICENSEE,
         other than those occurrences set out in Sections 13.2 and 13.3, which
         shall always take precedence in that order over any material breach or
         default referred to in this Section 13.4, CMCC shall have the right to
         terminate this Agreement (or, in the case of a breach with respect to
         Other Licensed Products and/or compounds as set forth in Sections 3.2
         and 3.3, respectively, terminate the Agreement with respect to such
         Other Licensed Products and/or compounds) and the rights, privileges
         and license granted hereunder by ninety (90) days' notice to LICENSEE.
         Such termination shall become effective unless LICENSEE shall have
         cured any such breach or default prior to the expiration of the ninety
         (90) day period.

13.5     LICENSEE shall have the right to terminate this Agreement at any time
         on six (6) months' notice to CMCC, and upon payment of all amounts due
         CMCC through the effective date of termination.

13.6     Upon termination of this Agreement for any reason, nothing herein shall
         be construed to release either party from any obligation that matured
         prior to the effective date of such termination. LICENSEE and any
         Sublicensee thereof may, however, after the effective date of such
         termination, sell all Licensed Products, and complete Licensed Products
         in the process of manufacture at the time of such termination and sell
         the same, provided that LICENSEE shall pay to CMCC the royalties
         thereon as required by Article IV of this Agreement and shall submit
         the reports required by Article V hereof on the sales of Licensed
         Products.

13.7     CMCC agrees that if LICENSEE has provided to CMCC notice that LICENSEE
         has granted a sublicense to a Sublicensee under this Agreement, then in
         the event CMCC terminates this Agreement for any reason, CMCC shall
         provide to such Sublicensee no less than thirty (30) days prior to the
         effective date of said termination, written notice of said termination
         at the address specified by LICENSEE to CMCC in LICENSEE's notice to
         CMCC under Article XIV.

CMCC agrees that upon the Sublicensee's notice as described below and provided the Sublicensee is not in breach of its sublicense, CMCC shall grant to such Sublicensee license rights and terms equivalent to the sublicense rights and terms which the sublicense shall have granted to said Sublicensee; provided that the Sublicensee shall remain a Sublicensee under this Agreement for a period of at least sixty (60) days following receipt of notice from CMCC. Sublicensees shall during said sixty (60) day period provide to CMCC notice wherein the Sublicensee: (i) reaffirms the terms and conditions of this Agreement as it relates to the rights the Sublicensee has been granted under the sublicense; (ii) agrees to abide by all of the terms and conditions of this Agreement applicable to Sublicensees and to discharge directly all pertinent obligations of LICENSEE which LICENSEE is obligated hereunder to discharge, excluding any financial obligations; and (iii) acknowledges that CMCC shall have no obligations to the Sublicensee other than its obligations set forth in this Agreement with regard to LICENSEE.

13.8     The following provisions shall survive the expiration or termination of
         this Agreement: Article I, Sections 5.1 and 5.4, Articles VIII, X and
         XII, Sections 13.6, 13.7, 13.8 and 13.9, and Articles XIV and XV.

13.9     Termination shall be in addition to, and shall not prejudice, any of
         the parties' remedies at law or in equity.

ARTICLE XIV - PAYMENTS, NOTICES, AND OTHER COMMUNICATIONS

Any payment, notice or other communication pursuant to this Agreement shall be sufficiently made or given on the date of the mailing if sent to a party by certified first class mail, postage prepaid, addressed to it at its address below or as it shall designate by written notice given to the other party:

In the case of CMCC:
Chief Intellectual Property Officer
Intellectual Property Office
CHILDREN'S HOSPITAL BOSTON
300 Longwood Avenue
Boston, MA 02115
Fax: (617) 232-7485

With a copy to:
Hale and Dorr LLP
60 State Street
Boston, MA 02109
Attn: Steven D. Singer, Esq.
Fax: (617) 526-5000

In the case of LICENSEE:
Chief Executive Officer
ENTREMED, INC.
9640 Medical Center Drive, Suite 200
Rockville, MD 20850
Fax: (302) 217-9594

With a copy to:
Kilpatrick Stockton LLP
37th Floor
191 Peachtree Street
Atlanta, GA 30303
Attn: James Dean Johnson, Ph.D.
Fax: 404-949-2499

15.1     This Agreement shall be construed, governed, interpreted and applied in
         accordance with the laws of the Commonwealth of Massachusetts, U.S.A.
         excluding its conflicts of laws provisions, except that questions
         affecting the construction and effect of any patent shall be determined
         by the law of the country in which the patent was granted.

15.2     The parties hereto acknowledge that this Agreement, the CMCC Consent
         and the applicable provisions of Section 7 of the New Thalidomide
         Agreement set forth the entire Agreement and understanding of the
         parties hereto as to the subject matter hereof, and shall not be
         subject to any change or modification except by the execution of a
         written instrument subscribed to by the parties hereto.

15.3     The provisions of this Agreement are severable, and in the event that
         any provisions of this Agreement shall be determined to be invalid or
         unenforceable under any controlling body of law, such invalidity or
         unenforceability shall not in any way affect the validity or
         enforceability of the remaining provisions hereof.

15.4     LICENSEE agrees to mark the Licensed Products sold in the United States
         with all applicable United States patent numbers. All Licensed Products
         shipped to or sold in other countries shall be marked in such a manner
         as to conform with the patent laws and practice of the country of
         manufacture or sale.

15.5     The failure of either party to assert a right hereunder or to insist
         upon compliance with any term or condition of this Agreement shall not
         constitute a waiver of that

right or excuse a similar subsequent failure to perform any such term or condition by the other party.

[REMAINDER OF PAGE LEFT INTENTIONALLY BLANK]

IN WITNESS WHEREOF, the parties have hereunto set their hands and seals and duly executed this Agreement the day and year set forth below.

CHILDREN'S MEDICAL CENTER CORPORATION

By       /s/ Stuart J. Novick
         --------------------------------------------
Name         Stuart J. Novick
         --------------------------------------------
Title        S.R. V.P. / General Counsel
         --------------------------------------------
Date
         --------------------------------------------

ENTREMED, INC.

By       /s/ John W. Holaday
         --------------------------------------------
Name         John W. Holaday
         --------------------------------------------
Title        CHM & CEO
         --------------------------------------------
Date         July 28, 2001
         --------------------------------------------