AGREEMENT




                                 by and between



                                 ENTREMED, INC.



                                       and



                               CELGENE CORPORATION


Omitted portions (indicated by asterisks*) have been separately filed with the
United States Securities and Exchange Commission pursuant to a request for
confidential treatment.




                                                  TABLE OF CONTENTS




1 - DEFINITIONS...................................................................................................2
                                                                                                           
         1.1      AFFILIATE.......................................................................................2
         1.2      CALENDAR QUARTER................................................................................2
         1.3      CELGENE DEVELOPED INTELLECTUAL PROPERTY.........................................................2
         1.4      CELGENE DEVELOPED PATENT RIGHTS ................................................................2
         1.5      CELGENE DEVELOPED TECHNOLOGY RIGHTS ............................................................3
         1.6      CELGENE EXISTING INTELLECTUAL PROPERTY..........................................................3
         1.7      CELGENE EXISTING PATENT RIGHTS..................................................................3
         1.8      CELGENE EXISTING TECHNOLOGY RIGHTS .............................................................3
         1.9      CMCC AGREEMENT .................................................................................3
         1.10     ENTREMED DEVELOPED PATENT RIGHTS ...............................................................4
         1.11     ENTREMED DEVELOPED TECHNOLOGY RIGHTS ...........................................................4
         1.12     ENTREMED EXISTING PATENT RIGHTS.................................................................4
         1.13     ENTREMED EXISTING TECHNOLOGY RIGHTS.............................................................4
         1.14     ENTREMED INTELLECTUAL PROPERTY..................................................................5
         1.15     FIELD ..........................................................................................5
         1.16     FIRST COMMERCIAL SALE ..........................................................................5
         1.17     NCI AGREEMENT...................................................................................5
         1.18     NDA ............................................................................................6
         1.19     NET SALES ......................................................................................6
         1.20     PATENT RIGHT(s) ................................................................................7
         1.21     PRODUCT.........................................................................................7
         1.22     SUBLICENSEE.....................................................................................8
         1.23     TECHNOLOGY RIGHTS...............................................................................8
         1.24     TERRITORY ......................................................................................8
         1.25     THALIDOMIDE ....................................................................................8
         1.26     THIRD PARTY(IES) ...............................................................................8
         1.27     VALID CLAIM ....................................................................................8

2 - GRANT.........................................................................................................9
         2.1      Grant of ENTREMED EXISTING PATENT RIGHTS and ENTREMED EXISTING TECHNOLOGY RIGHTS................9
         2.2      Grant of ENTREMED DEVELOPED PATENT RIGHTS and ENTREMED DEVELOPED TECHNOLOGY RIGHTS..............9
         2.3      CELGENE'S Right To Sublicense..................................................................10
         2.4      Assignment Of Investigational New Drug and
                  Orphan Drug Status Applications................................................................10
         2.5      Assignment Of Agreements.......................................................................11
         2.6      Technology Transfer............................................................................11



         2.7      Understanding Regarding CMCC AGREEMENT. .......................................................12

3 - DUE DILIGENCE................................................................................................13
         3.1      In the United States...........................................................................13
         3.2      Outside the United States......................................................................15
         3.3      For PRODUCTS For Use In Animals................................................................17
         3.4      No Other ENTREMED Rights.......................................................................17
         3.5      Co-Promotion By CELGENE And ENTREMED...........................................................17
         3.6      Establishment Of A Scientific Committee........................................................19

4 - ROYALTIES....................................................................................................21
         4.1      Royalty Payments...............................................................................21
         4.2      Sublicensing Payments and Royalties.  .........................................................22
         4.3      Later-Issued VALID CLAIM.......................................................................23
         4.4      No Multiple Royalties..........................................................................24
         4.5      THIRD PARTY Sales..............................................................................24
         4.6      Recordkeeping..................................................................................25
         4.7      Quarterly Payments and Reports.................................................................25
         4.8      Accounting Reports.............................................................................26

5 - CONFIDENTIALITY..............................................................................................26
         5.1      Confidential Information. .....................................................................26
         5.2      Non-Confidential Information...................................................................27
         5.3      Disclosure To THIRD PARTIES. ..................................................................28
         5.4      Disclosure To Sublicensees. ...................................................................28
         5.5      Public Statements..............................................................................28

6 - ADVERSE MEDICAL EXPERIENCES..................................................................................29
         6.1      Adverse Medical Experience Reporting. .........................................................29

7 - PATENTS......................................................................................................29
         7.1      Patent Prosecution.............................................................................29
         7.2      Cooperation In Prosecution.....................................................................29
         7.3      Infringement and Declaratory Judgment Actions..................................................30

8 - REPRESENTATIONS AND WARRANTIES...............................................................................32
         8.1      By Both Parties................................................................................32
         8.2      By ENTREMED....................................................................................32

9 - INDEMNIFICATION AND INSURANCE................................................................................34
         9.1      By CELGENE. ...................................................................................34
         9.2      By ENTREMED.  .................................................................................35
         9.3      Conditions to Indemnification. ................................................................36



10 - ASSIGNMENT AND SUCCESSORS...................................................................................37
         10.1     By Either Party................................................................................37
         10.2     By CELGENE.....................................................................................37
         10.3     CELGENE As Guarantor...........................................................................37
         10.4     Binding Effect.................................................................................37

11 - FORCE MAJEURE...............................................................................................38

12 - TERMINATION.................................................................................................38
         12.1     Term.  ........................................................................................38
         12.2     By Reason Of FDA Action........................................................................38
         12.3     Termination Of Royalty Obligations.  ..........................................................38
         12.4     Breach.........................................................................................39
         12.5     Insolvency.  ..................................................................................41
         12.6     Work-In-Progress. .............................................................................41
         12.7     Survival.......................................................................................41
         12.8     Reversion of Rights............................................................................41

13 - GENERAL PROVISIONS..........................................................................................42




                                    AGREEMENT

         This Agreement is effective this 9th day of December, 1998 (the
"EFFECTIVE DATE") by and between CELGENE CORPORATION, a Delaware corporation
located at 6 Powder Horn Drive, Warren, New Jersey 07059 ("CELGENE"), and
ENTREMED, INC., a Delaware Corporation located at 9610 Medical Center Drive,
Rockville, Maryland 20850 ("ENTREMED").

         WHEREAS, CELGENE is a company that develops, manufactures, markets and
sells pharmaceutical products for healthcare, and that has developed and owns
certain patents, patent applications, proprietary technology, know-how, and
United States Food and Drug Administration ("FDA") filings relating to PRODUCTS,
as hereinafter defined; and

         WHEREAS, ENTREMED is the owner or exclusive licensee of certain PATENT
RIGHTS as hereinafter defined, TECHNOLOGY RIGHTS, as hereinafter defined, and
FDA filings related to PRODUCTS, and has certain rights and obligations relating
to PRODUCTS pursuant to agreements with THIRD PARTIES, as hereinafter defined;
and

         WHEREAS, CELGENE desires to obtain assignments and/or exclusive rights
in the TERRITORY in and to all of ENTREMED's PATENT RIGHTS, TECHNOLOGY RIGHTS,
rights by agreement, and FDA filings, whether presently existing or subsequently
developed, for the commercial development, use, and sale of PRODUCTS; and

         WHEREAS, ENTREMED is willing to grant the assignments and/or exclusive
rights desired by CELGENE, as set forth herein, in order to transfer its entire
present and future right, title and interest in PRODUCTS to CELGENE.

         NOW, THEREFORE, in consideration of the mutual promises and other good
and valuable



 consideration, the parties agree as follows:

                             SECTION 1 - DEFINITIONS

         The terms used in this Agreement have the following meaning:

         1.1      The term "AFFILIATE" as applied to either party shall mean any
                  company or other legal entity other than the party in question
                  in whatever country organized, controlling controlled by or
                  under common control with that party. The term "control" means
                  ownership or control, directly or indirectly, of at least
                  fifty percent (50%) of the outstanding stock or voting rights
                  entitled to elect directors.

         1.2      The term "CALENDAR  QUARTER" shall mean the period of three
                  (3) consecutive  calendar months ending on March 31, June
                  30, September 30 or December 31, as the case may be.

         1.3      The term "CELGENE DEVELOPED INTELLECTUAL PROPERTY" shall mean
                  CELGENE DEVELOPED PATENT RIGHTS and CELGENE DEVELOPED
                  TECHNOLOGY RIGHTS.

         1.4      The term "CELGENE DEVELOPED PATENT RIGHTS" shall mean any
                  United States or foreign patents or patent applications filed
                  by CELGENE, or an AFFILIATE, successor or assign thereof at
                  any time subsequent to the EFFECTIVE DATE, in which CELGENE
                  has a transferrable interest, relating to a modification of a
                  PRODUCT described in any ENTREMED INTELLECTUAL PROPERTY or a
                  method of using such PRODUCT, which modification is (a)
                  necessary for the manufacture, use, or sale of such PRODUCT,
                  and (b) then currently in use by CELGENE at the time ENTREMED
                  exercises its rights under Section 0(b), for the manufacture,
                  use, or sale of such PRODUCT.



         1.5      The term "CELGENE DEVELOPED TECHNOLOGY RIGHTS" shall mean any
                  TECHNOLOGY RIGHTS developed, obtained, or acquired by CELGENE
                  or an AFFILIATE, successor or assign thereof at any time
                  subsequent to the EFFECTIVE DATE, in which CELGENE has a
                  transferrable interest, relating to a modification of a
                  PRODUCT described in any ENTREMED INTELLECTUAL PROPERTY or a
                  method of using or use of such PRODUCT, which modification is
                  (a) necessary for the manufacture, use, or sale of such
                  PRODUCT, and (b) then currently in use by CELGENE at the time
                  ENTREMED exercises its rights under Section 0(b), for the
                  manufacture, use, or sale of such PRODUCT.

         1.6      The term "CELGENE EXISTING INTELLECTUAL PROPERTY" shall mean
                  CELGENE EXISTING PATENT RIGHTS and CELGENE EXISTING TECHNOLOGY
                  RIGHTS.

         1.7      The term "CELGENE EXISTING PATENT RIGHTS" shall mean the
                  United States and foreign patents and patent applications
                  relating to PRODUCTS in which CELGENE has an interest, jointly
                  or solely, as owner, assignee, or licensee, whether exclusive
                  or nonexclusive, as of the EFFECTIVE DATE.

         1.8      The term "CELGENE EXISTING TECHNOLOGY RIGHTS" shall mean any
                  TECHNOLOGY RIGHTS developed, obtained, or acquired, solely or
                  jointly, exclusively or non-exclusively, by CELGENE or an
                  AFFILIATE, successor or assign thereof as of the EFFECTIVE
                  DATE.

         1.9      The term "CMCC AGREEMENT" shall mean that certain License
                  Agreement entered into by and between ENTREMED and Children's
                  Medical Center Corporation ("CMCC"), dated May 26, 1994, as
                  amended to the date hereof, attached hereto as Exhibit A.

         1.10     The term "ENTREMED DEVELOPED PATENT RIGHTS" shall mean any
                  United



                  States or foreign patent applications relating to PRODUCTS
                  assigned to, licensed to or filed, solely or jointly, by
                  ENTREMED, or an AFFILIATE, successor or assign thereof at
                  any time subsequent to the EFFECTIVE DATE, including any
                  United States or foreign patent applications filed pursuant
                  to the CMCC AGREEMENT or NCI AGREEMENT, and the patents
                  issuing therefrom, which patent applications and patents
                  shall be added to Appendix A and shall be included in this
                  Agreement as PATENT RIGHTS and licensed to CELGENE in
                  accordance with Section 2 of this Agreement.

         1.11     The term "ENTREMED DEVELOPED TECHNOLOGY RIGHTS" shall mean any
                  TECHNOLOGY RIGHTS developed, obtained, or acquired, solely or
                  jointly, exclusively or non-exclusively, by ENTREMED, or an
                  AFFILIATE, successor or assign thereof at any time subsequent
                  to the EFFECTIVE DATE, including any TECHNOLOGY RIGHTS
                  developed or obtained pursuant to the CMCC AGREEMENT or NCI
                  AGREEMENT, which TECHNOLOGY RIGHTS shall be included in this
                  Agreement and licensed to CELGENE in accordance with Section 2
                  of this Agreement.

         1.12     The term "ENTREMED EXISTING PATENT RIGHTS" shall mean the
                  PATENT RIGHTS in which ENTREMED has an interest, jointly or
                  solely, as owner, assignee, or licensee, whether exclusive or
                  nonexclusive, as of the EFFECTIVE DATE.

         1.13     The term "ENTREMED EXISTING TECHNOLOGY RIGHTS" shall mean any
                  TECHNOLOGY RIGHTS developed, obtained, or acquired, solely or
                  jointly, exclusively or non-exclusively, by ENTREMED, or an
                  AFFILIATE, successor or assign thereof as of the EFFECTIVE
                  DATE, including without limitation any TECHNOLOGY RIGHTS
                  developed or obtained pursuant to the CMCC AGREEMENT or NCI
                  AGREEMENT. ENTREMED EXISTING TECHNOLOGY RIGHTS expressly
                  includes any regulatory data and filings,



                  including without limitation all FDA Investigational New
                  Drug and Orphan Drug Status applications, as set forth in
                  Appendix C.

         1.14     The term "ENTREMED INTELLECTUAL PROPERTY" shall mean and
                  include ENTREMED DEVELOPED PATENT RIGHTS, ENTREMED DEVELOPED
                  TECHNOLOGY RIGHTS, ENTREMED EXISTING PATENT RIGHTS, and
                  ENTREMED EXISTING TECHNOLOGY RIGHTS.

         1.15     The term "FIELD" shall mean the use of THALIDOMIDE in humans
                  and animals, including without limitation any and all
                  diagnostic, prophylactic, therapeutic, and research and
                  development uses.

         1.16     The term "FIRST COMMERCIAL SALE" shall mean, in each country
                  of the TERRITORY, the first sale after the EFFECTIVE DATE in
                  such country to a THIRD PARTY in connection with the
                  nationwide introduction of any PRODUCT by CELGENE, its
                  AFFILIATES or SUBLICENSEES following marketing and/or pricing
                  approval by the appropriate governmental agency for the
                  country in which the sale is to be made and, when governmental
                  approval is not required, the first sale in that country in
                  connection with the nationwide introduction of a PRODUCT in
                  that country.

         1.17     The term "NCI AGREEMENT" shall mean that certain Agreement by
                  and between the Division of Cancer Treatment at the National
                  Cancer Institute ("NCI") and ENTREMED, dated November 16,
                  1994, and executed on behalf of ENTREMED on November 23, 1994,
                  and on behalf of NCI on November 18, 1994, attached hereto as
                  Exhibit B.

         1.18     The term "NDA" shall mean a New Drug Application filed with
                  the United States Food and Drug Administration.



         1.19     The term "NET SALES" means the gross amount received by
                  CELGENE or its AFFILIATES or SUBLICENSEES for sale of PRODUCT
                  to THIRD PARTIES, less: (i) cost of freight, postage, and
                  freight insurance, (if paid by seller); (ii) sales taxes,
                  value added taxes, excise taxes, and customs duties; (iii)
                  cost of export licenses and any taxes, fees or other charges
                  associated with the exportation or importation of PRODUCTS;
                  (iv) rebates accrued, incurred or paid to Federal Medicaid and
                  State Medicare and any other price reductions required by a
                  governmental agency; (v) rejected shipments, returns, and
                  retroactive deductions; (vi) the amount received for sales
                  which become the subject of a subsequent temporary or partial
                  recall by a regulatory agency for safety or efficacy reasons
                  outside the control of CELGENE; and (vii) customary cash,
                  quantity, and trade discounts; provided, however, that a sale
                  or transfer to an AFFILIATE or SUBLICENSEE for re-sale by such
                  AFFILIATE or SUBLICENSEE shall not be considered a sale for
                  the purpose of this provision but the resale by such AFFILIATE
                  or SUBLICENSEE shall be a sale for such purposes. A "sale"
                  shall also include a transfer or other disposition for
                  consideration, but not such transfers or dispositions, without
                  consideration, for pre-clinical, clinical, regulatory or
                  governmental purposes prior to receiving marketing approval
                  for the specific indication for which such transfer is made.
                  In the event that consideration in addition to or in lieu of
                  money is received for PRODUCT, such consideration shall be
                  added to the NET SALES as valued on the day of receipt thereof
                  by CELGENE. To the extent that a PRODUCT is sold in other than
                  an arms length transaction, NET SALES shall be the fair market
                  value of such PRODUCT if sold in an arms length transaction,
                  less the costs identified in subsections (i)-(vi) of this
                  Section 1.19. PRODUCT shall be considered "sold" at the
                  earlier of (a) the transfer of title in such PRODUCT to a
                  person other than an AFFILIATE or SUBLICENSEE of CELGENE or
                  (b) the shipment of such PRODUCT from the manufacturing or
                  warehouse facilities of CELGENE or its AFFILIATE or
                  SUBLICENSEE to a THIRD PARTY.



         1.20     The term "PATENT RIGHT(s)" shall mean:

                  (a)          the United States patent applications and patents
                               listed in Appendix A;

                  (b)          the United States and foreign patents issued
                               from applications listed in Appendix A and from
                               divisionals and continuations of such
                               applications;

                  (c)          claims of United States continuation-in-part
                               applications and of equivalent foreign
                               applications, and of the resulting
                               patent(s), that are directed to subject
                               matter described in the United States and
                               foreign applications listed in Appendix A;

                  (d)          claims of all later-filed foreign patent
                               applications, and of the resulting patents,
                               that are directed to subject matter
                               described in the United States patents
                               and/or patent applications described in the
                               foregoing subsections of this Section 1.20;

                  (e)          any reissues, re-examinations or extension
                               of United States patents described in the
                               foregoing subsections of this Section 1.20; and

                  (f)          ENTREMED DEVELOPED PATENT RIGHTS, when
                               assigned to, licensed to or filed, solely or
                               jointly, by ENTREMED, or an AFFILIATE,
                               successor or assign thereof, pursuant to
                               Section 1.10 of this Agreement.


         1.21     The term "PRODUCT" shall mean any article of manufacture,
                  substance, material, chemical, formulation or composition for
                  use in the FIELD which is or includes THALIDOMIDE as an active
                  ingredient, including, without limitation, a composition that
                  comprises THALIDOMIDE and a non-steroidal anti-inflammatory
                  compound(s). PRODUCT expressly excludes THALIDOMIDE analogs.

         1.22     The term "SUBLICENSEE" shall mean any THIRD PARTY licensed by



                  CELGENE to make,  have made, use, offer to sell, sell
                  or import any PRODUCT.

         1.23     The term "TECHNOLOGY RIGHTS" shall mean any information
                  relating to PRODUCTS that is not covered by a patent or patent
                  application, including without limitation technical and
                  non-technical information, know-how, methods, processes,
                  procedures, compositions, devices, formulae, protocols,
                  techniques, software, designs, drawings, plans, diagrams,
                  specifications, data, the results of tests or assays, and all
                  other information relating to PRODUCTS.

         1.24     The term "TERRITORY" shall mean all countries of the world.

         1.25     The term "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.

         1.26     The term "THIRD  PARTY(IES)" shall mean a person or entity
                  who or which is neither a party hereto nor an AFFILIATE of
                  a party hereto.

         1.27     The term "VALID CLAIM" shall mean an issued claim of an
                  unexpired patent ("ISSUED VALID CLAIM") or a claim of a
                  pending patent application, which shall not have been
                  withdrawn, canceled or disclaimed, or held invalid or
                  unenforceable by a court of competent jurisdiction in an
                  unappealed or unappealable decision. Notwithstanding the
                  foregoing to the contrary, a claim of a pending patent
                  application, divisional application or continuation-in-part
                  shall cease to be a VALID CLAIM if no patent has issued on
                  such claim on or prior to the fifth (5th) anniversary of the
                  EFFECTIVE DATE of this Agreement, provided that such claim
                  shall once again become a VALID CLAIM on the issue date of a
                  patent that subsequently issues and covers such claim.



         1.28     The use herein of the plural shall include the singular, and
                  the use of the masculine shall include the feminine.

                                SECTION 2 - GRANT

         2.1      Grant of ENTREMED EXISTING PATENT RIGHTS and ENTREMED EXISTING
                  TECHNOLOGY RIGHTS. ENTREMED hereby grants to CELGENE and
                  CELGENE hereby accepts from ENTREMED an exclusive, royalty
                  bearing right and license or sublicense, as the case may be,
                  under the ENTREMED EXISTING PATENT RIGHTS and the ENTREMED
                  EXISTING TECHNOLOGY RIGHTS to make, have made, use, offer to
                  sell, sell, and import PRODUCTS in the TERRITORY.

         2.2      Grant of ENTREMED DEVELOPED PATENT RIGHTS and ENTREMED
                  DEVELOPED TECHNOLOGY RIGHTS. ENTREMED hereby grants to
                  CELGENE, to the extent not prohibited by the United States
                  Government or by prior contractual obligations to any THIRD
                  PARTY, and CELGENE hereby accepts from ENTREMED:

                  (a)      an exclusive, royalty bearing right and license
                           under the ENTREMED DEVELOPED PATENT RIGHTS and the
                           ENTREMED DEVELOPED TECHNOLOGY RIGHTS to make, have
                           made, use, offer to sell, sell, and import PRODUCTS
                           in the TERRITORY; and

                  (b)      to the extent an exclusive license is not available
                           to CELGENE in a country under a particular ENTREMED
                           DEVELOPED PATENT RIGHT or ENTREMED DEVELOPED
                           TECHNOLOGY RIGHT, but a non-exclusive license would
                           be available, ENTREMED hereby grants CELGENE a
                           nonexclusive, royalty bearing right and license under
                           such ENTREMED DEVELOPED PATENT RIGHT(s) and ENTREMED
                           DEVELOPED TECHNOLOGY RIGHT(s) to make, have made,
                           use, offer to sell, sell, and




                           import PRODUCTS in the TERRITORY.

         2.3      CELGENE'S Right To Sublicense.

                  (a)      In the United States. ENTREMED hereby grants to
                           CELGENE the right to sublicense ENTREMED INTELLECTUAL
                           PROPERTY in the United States with the consent of
                           ENTREMED, to be exercised in ENTREMED's sole
                           discretion.

                  (b)      Outside the United States. ENTREMED hereby grants to
                           CELGENE the right to sublicense ENTREMED INTELLECTUAL
                           PROPERTY outside the United States with the written
                           consent of ENTREMED, which consent shall not be
                           unreasonably withheld. Outside the United States,
                           CELGENE shall use reasonable efforts to negotiate
                           sublicensing agreements that are commercially
                           reasonable according to contemporaneous prevailing
                           standards within the pharmaceutical industry.

         2.4      Assignment Of Investigational New Drug and Orphan Drug Status
                  Applications. Within ten (10) days of the EFFECTIVE DATE,
                  ENTREMED and CELGENE shall notify the Food and Drug
                  Administration ("FDA") of the transfer of ENTREMED's rights in
                  PRODUCTS to CELGENE by submitting to the FDA letters
                  substantially in the form attached hereto as Exhibit C, and
                  ENTREMED shall notify CELGENE of its compliance with this
                  Section 0 by copies of such letters. ENTREMED shall take all
                  further steps necessary or helpful to assign to CELGENE all
                  Orphan Drug Status and Investigational New Drug applications
                  filed by ENTREMED as of the EFFECTIVE DATE, as set forth in
                  Appendix C. If the FDA declines to allow the assignment of any
                  of ENTREMED's Investigational New Drug and/or Orphan Drug
                  Status application(s) to CELGENE, for whatever reason, then
                  ENTREMED's rights under such application(s) will be included
                  in this Agreement as ENTREMED EXISTING TECHNOLOGY RIGHTS and
                  will be licensed to CELGENE in accordance with Section 2 of
                  this Agreement.



         2.5      Assignment Of Agreements. Within ten (10) days of the
                  EFFECTIVE DATE, ENTREMED shall notify CMCC and NCI of the
                  sublicense and transfer, respectively, of its rights in
                  PRODUCTS to CELGENE, and shall take all steps necessary or
                  helpful to assign to CELGENE the NCI AGREEMENT, including
                  without limitation requesting consent to assign ENTREMED's
                  obligations and entire right, title, and interest, under such
                  agreement to CELGENE, and upon receipt of the consent of NCI
                  to assign the NCI AGREEMENT, CELGENE will expressly assume all
                  of ENTREMED's duties and obligations thereunder. In the event
                  that ENTREMED is not permitted to assign its rights under the
                  NCI AGREEMENT to CELGENE, ENTREMED's rights in any PATENT
                  RIGHTS or TECHNOLOGY RIGHTS resulting from the NCI AGREEMENT
                  will be included in this Agreement as ENTREMED DEVELOPED
                  PATENT RIGHTS and ENTREMED DEVELOPED TECHNOLOGY RIGHTS,
                  respectively, and will be licensed to CELGENE in accordance
                  with Section 0 of this Agreement.

         2.6      Technology Transfer. As soon as reasonably possible following
                  the EFFECTIVE DATE, but in no event later than one (1) month
                  after such date, ENTREMED shall transfer to CELGENE all
                  ENTREMED EXISTING TECHNOLOGY RIGHTS and ENTREMED DEVELOPED
                  TECHNOLOGY RIGHTS not already in CELGENE's possession.
                  ENTREMED agrees to disclose and transfer all ENTREMED
                  DEVELOPED TECHNOLOGY RIGHTS to CELGENE promptly, as they are
                  obtained or developed. ENTREMED also agrees to provide, upon
                  reasonable notice from CELGENE, any technical, scientific,
                  statistical, and/or regulatory support necessary or useful to
                  CELGENE's understanding and/or use of ENTREMED EXISTING
                  TECHNOLOGY RIGHTS and ENTREMED DEVELOPED TECHNOLOGY RIGHTS.

         2.7      Understanding Regarding CMCC AGREEMENT. To the extent
                  TECHNOLOGY RIGHTS and/or PATENT RIGHTS licensed to CELGENE
                  under this Agreement



                  are rights which ENTREMED has licensed from CMCC under the
                  CMCC AGREEMENT, CELGENE and ENTREMED understand and agree as
                  follows:

                  (a)      The rights licensed to CELGENE by ENTREMED are
                           subject to the terms, limitations, restrictions and
                           obligations of the CMCC AGREEMENT.

                  (b)      CELGENE will comply with the terms, obligations,
                           limitations and restrictions of sublicensees under
                           Articles II, V, VII, VIII, IX, X, XII, XIII, and XV
                           of the CMCC AGREEMENT.

                  (c)      ENTREMED will, at its own expense, timely pay the
                           milestone payment of *******************************
                           due to CMCC upon completion of a Phase II clinical
                           trial for any indication, pursuant to Section 4.1.3
                           of the CMCC AGREEMENT. ENTREMED shall promptly
                           provide written notice to CELGENE of such payment.

                  (d)      CELGENE will, at its own expense, timely pay the
                           milestone payment of  *******************************
                           due to CMCC upon completion of a Product License
                           Application for any indication, pursuant to
                           Section 4.1.4 of the CMCC AGREEMENT, which payment
                           shall be made to ENTREMED and timely forwarded by
                           ENTREMED to CMCC; provided, however, that if (i)
                           such payment becomes due prior to January 1, 2000,
                           and (ii) CELGENE's annual sales in the year such
                           payment becomes due are less than
                           ********************, CELGENE may notify ENTREMED,
                           in writing, that it wishes ENTREMED to pay such
                           amount to CMCC directly, which ENTREMED hereby
                           agrees to do, and, by June 30, 2000 CELGENE shall
                           reimburse ENTREMED the amount paid to CMCC, plus
                           interest calculated at the annual rate of the sum
                           of ************ plus the prime interest rate quoted
                           by Citibank, N.A. on the date said payment is due.
                           ENTREMED shall promptly provide written notice to
                           CELGENE of all



                           payments under this Section 2.7(d).

                  (e)      ENTREMED will comply with the terms, obligations,
                           limitations and restrictions of the CMCC AGREEMENT,
                           including, without limitation, any provisions
                           relating to due diligence, notification with respect
                           to sublicenses, and milestone payments, subject to
                           Sections 2.7(c) and (d) of this Agreement.

                  (f)      The CMCC AGREEMENT and ENTREMED's rights thereunder
                           shall remain in full force and effect for the life of
                           the last to expire patent issued under the Patent
                           Rights, as defined therein, unless earlier terminated
                           pursuant to Article XIII of the CMCC AGREEMENT.

                            SECTION 3 - DUE DILIGENCE

         3.1      In the United States.

                  (a)      CELGENE shall initiate and diligently use reasonable
                           efforts to develop, or to file for regulatory
                           approval of or register, and to market and sell
                           PRODUCTS in the United States. Reasonable efforts
                           with respect to the development and/or pursuit of
                           regulatory approval or registration for PRODUCTS
                           in the United States shall be demonstrated by
                           CELGENE (i) developing and pursuing regulatory
                           approval for PRODUCTS for those uses CELGENE, in
                           good faith, determines to be commercially and
                           scientifically reasonable, including but not
                           limited to (a) one (1)**************, (b) one (1)
                           ****************, and (c) one (1)
                           ****************; and (ii) funding and conducting
                           clinical trials for PRODUCTS for other uses in
                           order to enhance scientific knowledge with regard
                           to such PRODUCTS, including for the publication of
                           data and results in scientific journals, whether
                           or not such clinical trials result in or
                           facilitate the pursuit of regulatory approval.



                  (b)      ENTREMED agrees that, subject to Section 3.6 of this
                           Agreement, (i) the decision regarding which uses to
                           pursue regulatory approval of PRODUCTS for, and/or to
                           fund and conduct clinical trials of PRODUCTS for,
                           pursuant to Section 3.1(a) of this Agreement, shall
                           be made by and in the sole discretion of CELGENE; and
                           (ii) with respect to the manner in which regulatory
                           approval is sought and/or clinical trials are funded
                           and conducted, CELGENE shall have sole discretion,
                           including, without limitation, complete control over
                           all regulatory submissions of PRODUCTS to the
                           appropriate regulatory agencies worldwide, including
                           whether, when, and how to file, maintain, withdraw,
                           or abandon an application for regulatory approval of
                           PRODUCTS.

                  (c)      Within 90 days after the EFFECTIVE DATE, CELGENE
                           shall draft a Development Plan outlining CELGENE'S
                           development objectives for PRODUCTS, in accordance
                           with Sections 3.1(a)(i) and (b) of this Agreement.
                           CELGENE shall consult with ENTREMED concerning the
                           Development Plan. The Development Plan shall include
                           suitable clinical milestones which are reasonably
                           intended to lead to regulatory approval of PRODUCTS,
                           in accordance with Sections 3.1(a)(i) and (b) of this
                           Agreement.

                  (d)      CELGENE shall provide a written summary report to
                           ENTREMED within thirty (30) days after June 30th and
                           December 31st of each calendar year concerning the
                           efforts being made in accordance with this Section
                           3.1 with respect to PRODUCTS. CELGENE shall provide
                           ENTREMED with any additional information reasonably
                           requested by ENTREMED in this respect.

                  (e)      At ENTREMED'S reasonable request, CELGENE shall
                           provide ENTREMED access to all clinical trial data
                           for PRODUCTS conducted by



                           CELGENE in accordance with the Development Plan
                           set forth in this Section 3.1. In the event that
                           rights are returned to ENTREMED under Section
                           3.1(f) of this Agreement, ENTREMED shall have the
                           right to review and use the clinical trial data in
                           its own clinical program.

                  (f)      In the event that CELGENE fails to meet any of its
                           obligations under this Section 3.1 with respect to
                           PRODUCTS in the United States, and such failure is
                           not cured within sixty (60) days after written notice
                           thereof is received by CELGENE from ENTREMED, then
                           ENTREMED shall have the right and option to terminate
                           the license granted in this Agreement and this
                           Agreement by giving CELGENE sixty (60) days prior
                           written notice thereof.

         3.2      Outside the United States.

                  (a)      Diligence. CELGENE shall initiate and diligently use
                           reasonable efforts to develop, or to file for
                           regulatory approval of or register, and to market
                           and sell PRODUCTS in Europe, in Canada, and in the
                           Pacific Rim, Japan, and Australia (collectively,
                           the "PACIFIC RIM"). Reasonable efforts with
                           respect to the development and/or pursuit of
                           regulatory approval or registration for PRODUCTS
                           in Europe, Canada, and the PACIFIC RIM shall be
                           demonstrated by CELGENE, or a sublicensee thereof,
                           pursuing regulatory approval for PRODUCTS (i) in
                           Italy, France, the United Kingdom, and Germany (in
                           the case of Europe), and in Japan and one other
                           country of the PACIFIC RIM (in the case of the
                           PACIFIC RIM), within ************ from the date of
                           the first FDA approval of a PRODUCT for an
                           oncology indication or Crohn's disease, whichever
                           occurs earlier; and (ii) in Canada, within one (1)
                           year from the date of the first FDA approval of a
                           PRODUCT for an oncology indication or Crohn's
                           disease, whichever occurs earlier.



                  (b)      CELGENE's Discretion. ENTREMED agrees that, subject
                           to Section 3.6 of this Agreement, (i) the decision
                           regarding which uses to pursue regulatory approval
                           of PRODUCTS for, and/or to fund and conduct
                           clinical trials of PRODUCTS for, pursuant to
                           Section 3.2(a) of this Agreement, shall be made by
                           and in the sole discretion of CELGENE; and (ii)
                           with respect to the manner in which regulatory
                           approval is sought and/or clinical trials are
                           funded and conducted, CELGENE shall have sole
                           discretion, including, without limitation,
                           complete control over all regulatory submissions
                           of PRODUCTS to the appropriate regulatory agencies
                           worldwide, including whether, when, and how to
                           file, maintain, withdraw, or abandon an
                           application for regulatory approval of PRODUCTS.

                  (c)      Cooperation. If CELGENE fails to use reasonable
                           efforts in Europe, Canada, or the PACIFIC RIM, as set
                           forth in Section 3.2(a) of this Agreement, or to
                           sublicense its rights to a THIRD PARTY, then ENTREMED
                           shall have the right and option to either (i)
                           terminate the licenses granted in the region where
                           such failure has occurred, i.e., Europe, Canada, or
                           the PACIFIC RIM, respectively, by giving CELGENE
                           sixty (60) days prior written notice thereof, or (ii)
                           cooperate with CELGENE to find an appropriate
                           SUBLICENSEE for such rights.

         3.3      For PRODUCTS For Use In Animals.

                  (a)      Diligence. CELGENE shall initiate and diligently use
                           reasonable efforts to develop, or to file for
                           regulatory approval of or register, and to market and
                           sell PRODUCTS for use in animals. Such reasonable
                           efforts shall be demonstrated by CELGENE obtaining
                           regulatory approval for the sale of a PRODUCT for use
                           in animals within four (4) years of the EFFECTIVE
                           DATE in the United States and, outside the United
                           States, in one of the following countries: Italy,
                           France, the United Kingdom, or Germany.

                  (b)      Cooperation. If CELGENE fails to use reasonable
                           efforts either in the




                           United States or outside the United States, as set
                           forth in Section 3.3(a) of this Agreement, or to
                           sublicense its rights in such regions to a THIRD
                           PARTY, then ENTREMED shall have the right and
                           option to either (i) terminate CELGENE's rights in
                           the region where such failure has occurred, i.e.,
                           in the United States or outside the United States,
                           respectively, in and to such PRODUCTS for use in
                           animals by giving CELGENE sixty (60) days prior
                           written notice thereof, or (ii) cooperate with
                           CELGENE to find an appropriate SUBLICENSEE for
                           such rights.

         3.4      No Other ENTREMED Rights. Except as otherwise expressly
                  provided in this Agreement, ENTREMED agrees that it has not
                  retained any rights under ENTREMED INTELLECTUAL PROPERTY to
                  PRODUCTS, and that is shall not (i) make, use, offer to sell,
                  sell, or import PRODUCTS in the TERRITORY, or (ii)
                  collaborate, negotiate, or deal with THIRD PARTIES with
                  respect to PRODUCTS.

         3.5      Co-Promotion By CELGENE And ENTREMED.

                  (a)      With Regard To PRODUCTS. If CELGENE, in its sole
                           discretion, decides to co-promote any PRODUCT or to
                           seek sales assistance in promoting any PRODUCT,
                           including, but not limited to, sales assistance for
                           indications not then promoted by CELGENE sales
                           personnel, CELGENE shall, in good faith, consider
                           ENTREMED for the opportunity to co-promote such
                           PRODUCT(S) for such indications in the United States.
                           (i)      CELGENE will give ENTREMED due consideration
                                    for the opportunity to co-promote such
                                    PRODUCT(S) as set forth herein, provided
                                    that ENTREMED has a sales force capable of
                                    providing the required details to the
                                    targeted physician audience, or is capable
                                    of assembling such a sales force within six
                                    (6) months, and agrees to do so. If and only
                                    if ENTREMED either has a sales force capable
                                    of providing the required details to the
                                    targeted physician audience, or commits to
                                    assembling such a sales force within six (6)
                                    months, the



                                    decision to offer ENTREMED the opportunity
                                    to co-promote such PRODUCT(s) for such
                                    indications in the United States shall be
                                    made, in good faith, by CELGENE, and CELGENE
                                    shall notify ENTREMED of its decision in
                                    writing.
                           (ii)     If CELGENE offers ENTREMED the opportunity
                                    to co-promote, pursuant to Section 3.5(a)(i)
                                    of this Agreement, ENTREMED shall have
                                    thirty (30) days to accept such offer by
                                    written notice to CELGENE. If ENTREMED
                                    accepts such offer to co-promote PRODUCTS,
                                    then the parties will negotiate, in good
                                    faith, a co-promotion agreement setting
                                    forth the substance of this Section 3.5 and
                                    other normal and customary conditions within
                                    six (6) months of CELGENE's receipt of
                                    ENTREMED's acceptance pursuant to this
                                    Section 3.5(a)(ii).
                           (iii)    ENTREMED's co-promotion efforts will focus
                                    on detailing (product presentations) the
                                    PRODUCT to the targeted physician audience.
                                    In such case, ENTREMED's sales
                                    representatives will also have the
                                    opportunity, from time to time, to
                                    participate in seminars, in-service
                                    training, group presentations, and other
                                    educational and promotional activities
                                    initiated by CELGENE in consultations with
                                    ENTREMED. In addition, ENTREMED will assign
                                    a product manager to participate with the
                                    CELGENE marketing team to provide input as
                                    appropriate and to be the operational
                                    liaison between CELGENE and ENTREMED's sales
                                    force.

                  (b)      With Regard To Anti-angiogenic Compounds. If
                           ENTREMED,  in its sole discretion, decides to 
                           co-promote an anti-angiogenic compound or a
                           composition containing, as an active ingredient,
                           such a compound, or to seek sales assistance in
                           promoting any such anti-angiogenic compound or
                           composition, including, but not limited to, sales
                           assistance for indications not then promoted by
                           ENTREMED sales personnel, ENTREMED shall, in good
                           faith, consider CELGENE for the opportunity to
                           co-promote such anti-




                           angiogenic compounds and/or compositions. The
                           decision to offer CELGENE the opportunity to
                           co-promote such anti-angiogenic compounds and/or
                           compositions shall be made in the sole discretion of
                           ENTREMED, and be subject, mutatis mutandis, to the
                           terms and conditions set forth in Sections
                           3.5(a)(ii) and (iii) of this Agreement.

         3.6      Establishment Of A Scientific Committee. CELGENE agrees to
                  conduct and fund a development program designed to obtain
                  approval to market PRODUCTS, in accordance with its
                  obligations under Section 3.1(a)(i) and 3.1(b) of this
                  Agreement (the "PROGRAM"). To ensure the continued
                  participation of ENTREMED in these development activities, the
                  PROGRAM will be monitored by a Scientific Committee as
                  described herein (the "COMMITTEE").

                  (a)      Members. Within ten (10) days of the date hereof,
                           ENTREMED and CELGENE shall each appoint two (2)
                           persons to serve on the COMMITTEE. Each party will
                           have the right to change its representation on the
                           COMMITTEE upon written notice to the other.

                  (b)      Chairperson. The COMMITTEE will be chaired by one
                           representative of CELGENE, who shall be chosen in the
                           sole discretion of CELGENE.

                  (c)      Responsibilities. The COMMITTEE will have authority
                           to:
                           (i)      act in an advisory role and provide
                                    information, including without limitation
                                    technical and regulatory information and
                                    marketing and sales information, helpful in
                                    connection with the PROGRAM;
                           (ii)     make recommendations regarding the
                                    performance of the PROGRAM and the conduct
                                    of the work pursuant thereto, and monitor
                                    performance thereunder;
                           (iii)    propose modifications to the PROGRAM;
                           (iv)     review any and all proposed publication(s)
                                    relating to the PROGRAM and the results
                                    therefrom; and
                           (v)      review all information and data resulting
                           from the PROGRAM.

                  (d)      Meetings. The COMMITTEE will meet not less than four
                           (4) times a year



                           during the term of the PROGRAM, at such dates and
                           times as agreed to by the parties. The COMMITTEE
                           will prepare written minutes of each meeting and a
                           written record of all decisions whether made at a
                           formal meeting or not. All decisions made and
                           actions taken by the COMMITTEE will be made or taken
                           in the sole discretion of CELGENE after good faith
                           consideration of the position or opinion of the
                           ENTREMED members.

                  (e)      Term and Termination. The PROGRAM will continue until
                           there are no longer any ongoing activities in
                           pursuit of regulatory approval, or any pending
                           applications for regulatory approval, for PRODUCTS,
                           pursuant to Sections 3.1(a)(i) and (b) of this
                           Agreement. Once all such activities have been
                           completed and all such regulatory approvals have
                           been obtained, CELGENE may, in its sole discretion,
                           extend the term of the PROGRAM to include PRODUCTS
                           in clinical trials for other uses, as set forth in
                           Sections 3.1(a)(ii) and (b) of this Agreement, in
                           which case the PROGRAM will continue until such
                           clinical trials have been completed or otherwise
                           terminated or, if applicable, until regulatory
                           approval has been obtained, unless the PROGRAM is
                           sooner terminated by CELGENE.

                              SECTION 4 - ROYALTIES

         4.1      Royalty Payments.

         (a)      First Twelve Years. CELGENE shall pay to ENTREMED the
                  following royalties on the NET SALES of PRODUCTS sold by
                  CELGENE or its AFFILIATES in each country of the TERRITORY (i)
                  for the first consecutive twelve (12) years from the date of
                  the FIRST COMMERCIAL SALE of a PRODUCT in each country of the
                  TERRITORY, and, separately and independently, (ii) for the
                  first consecutive twelve (12) years from the date of the FIRST
                  COMMERCIAL SALE of each PRODUCT that contains, as a second
                  active ingredient, a compound other than THALIDOMIDE, in each
                  country of the TERRITORY:



                    (i) **************of NET SALES up to ************* of such
                        sales;

                   (ii) ************** of NET SALES between **********
                        and ************ of such sales;

                  (iii) *************of NET SALES between **************and
                        **************dollars of such sales; and

                   (iv) ***************of NET SALES over **************** of
                        such sales.

         (b)      After Twelve Years. For each PRODUCT in each country in the
                  TERRITORY in which the twelve (12) year period provided for in
                  Section 4.1(a) of this Agreement shall have terminated,
                  CELGENE shall pay to ENTREMED the following royalties on the
                  NET SALES of such PRODUCT covered by an ISSUED VALID CLAIM of
                  the PATENT RIGHTS that are sold by CELGENE or its AFFILIATES
                  in such country:

                    (i) ************of NET SALES up to **************of such
                        sales;

                   (ii) ************of NET SALES between *************and
                        ********************of such sales;

                  (iii) *************of NET SALES between **************and
                        ******************dollars of such sales; and

                   (iv) **************of NET SALES over ************* of such
                        sales;



                  and such royalties under this Section 4.1(b) shall be payable
                  until the last to expire PATENT RIGHT containing an ISSUED
                  VALID CLAIM covering such PRODUCT sold by CELGENE or its
                  AFFILIATES in such country.

         4.2      Sublicensing Payments and Royalties.

                  (a)      Under CELGENE's Rights. If CELGENE grants a
                           sublicense of its exclusive rights under this
                           Agreement, pursuant to Section 2.3 of this Agreement,
                           in any country(ies) of the TERRITORY, CELGENE shall
                           pay to ENTREMED (i) ***************of any non-royalty
                           consideration, including but not limited to any
                           sublicensing and/or milestone payments received by
                           CELGENE pursuant to such sublicense and (ii)
                           *************of the royalty income paid by
                           SUBLICENSEES to CELGENE on NET SALES of PRODUCTS.

                  (b)      CELGENE-ENTREMED  Cooperation.  If CELGENE  grants
                           a sublicense of any of its rights under this
                           Agreement in any area of the FIELD or any country of
                           the TERRITORY with respect to which ENTREMED and
                           CELGENE are cooperating pursuant to Sections 3.2 or
                           3.3 of this Agreement, CELGENE shall pay to ENTREMED
                           ************** of any non-royalty consideration,
                           including but not limited to any sublicensing and/or
                           milestone payments received by CELGENE pursuant to
                           such sublicense. CELGENE shall also pay to ENTREMED,
                           as applicable, the following: (i) if CELGENE and
                           ENTREMED are cooperating in any country(ies)
                           pursuant to Section 3.2 of this Agreement,
                           *************of the royalty income paid by
                           SUBLICENSEES to CELGENE on NET SALES, in such
                           country(ies), of PRODUCTS; and (ii) if CELGENE and
                           ENTREMED are cooperating in any country(ies) with
                           regard to PRODUCTS for use in animals pursuant to
                           Section 3.3 of this Agreement, **************of the
                           royalty income paid by SUBLICENSEES to CELGENE on
                           NET SALES in such country(ies) of such PRODUCTS.



         4.3      Later-Issued VALID CLAIM. In the event that there is no ISSUED
                  VALID CLAIM of a PATENT RIGHT in a country within the
                  TERRITORY on the date the twelve (12) year period provided for
                  in Section 4.1(a) of this Agreement expires, no royalties
                  shall be owed by CELGENE to ENTREMED under Sections 4.1(b) and
                  4.2 of this Agreement on PRODUCTS sold by CELGENE or its
                  AFFILIATES in such country, provided, however, that if a VALID
                  CLAIM of a PATENT RIGHT thereafter issues in such country,
                  CELGENE shall pay ENTREMED royalties on the NET SALES in such
                  country of PRODUCTS covered by an ISSUED VALID CLAIM of the
                  PATENT RIGHTS that are sold by CELGENE or its AFFILIATES,
                  according to the royalty rates set forth in Sections 4.1(b)
                  and 4.2 of this Agreement, and such royalties under this
                  Section 4.3 shall be payable until the last to expire PATENT
                  RIGHT containing an ISSUED VALID CLAIM covering the PRODUCTS
                  sold by CELGENE, its AFFILIATES or SUBLICENSEE in such
                  country.

         4.4      No Multiple Royalties. No multiple royalties shall be payable
                  because any PRODUCT, its manufacture, use, importation, lease,
                  or sale is or shall be covered by more than one PATENT RIGHT.

         4.5      THIRD PARTY Sales. In any country where sales by a THIRD PARTY
                  of a PRODUCT(s) for a similar dosage form and/or route of
                  administration: 

                  (a)      are equal to or greater than ************of the
                           dollar market share for such PRODUCT in such country
                           ("MARKET SHARE"), but less than ************of the
                           MARKET SHARE, then the royalty payable to ENTREMED
                           pursuant to Sections 4.1 and 4.3 of this Agreement
                           shall be reduced by ***********;

                  (b)      are equal to or greater than **************of the
                           MARKET SHARE, but less than ************of the MARKET
                           SHARE, then the royalty payable to ENTREMED pursuant
                           to Sections 4.1 and 4.3 of this Agreement shall be
                           reduced by**************;



                  (c)      are equal to or greater than ************of the
                           MARKET SHARE, but less than ***************of the
                           MARKET SHARE, then the royalty payable to ENTREMED
                           pursuant to set Sections 4.1 and 4.3 of this
                           Agreement shall be reduced by***********; and

                  (d)      are equal to or greater than *************of the
                           MARKET SHARE, then the royalty payable to ENTREMED
                           pursuant to Sections 4.1 and 4.3 of this Agreement
                           shall be reduced by************;

                  provided that royalties payable to ENTREMED shall never be
                  reduced below ************of NET SALES in each royalty
                  bracket. For purposes of this Section 4.5, oral dosage forms
                  shall include, without limitation, all capsule, caplet,
                  tablet, and liquid formulations for oral administration.

         4.6      Recordkeeping. CELGENE shall keep, and shall cause each of its
                  AFFILIATES and SUBLICENSEES to keep, full and accurate books
                  of account containing all particulars relevant to its sales of
                  PRODUCTS that may be necessary for the purpose of calculating
                  all royalties payable to ENTREMED. Such books of account shall
                  be kept at their principal place of business and, with all
                  necessary supporting data shall, for the three (3) years next
                  following the end of the calendar year to which each shall
                  pertain, be open for inspection by an independent certified
                  public accountant reasonably acceptable to CELGENE, upon
                  reasonable notice during normal business hours at ENTREMED'S
                  expense for the sole purpose of verifying royalty statements
                  or compliance with this Agreement. In the event the inspection
                  determines that royalties due ENTREMED for any period have
                  been underpaid by ***********or more, then CELGENE shall pay
                  for all costs of the inspection. In all cases, CELGENE shall
                  pay to ENTREMED any underpaid royalties promptly and with
                  interest at the prime rate available to ENTREMED from its bank
                  plus**********. All information and data reviewed in the
                  inspection shall be used only for the purpose of verifying
                  royalties and shall be treated as CELGENE CONFIDENTIAL
                  INFORMATION subject to the obligations of this Agreement. No
                  audit by an agent of ENTREMED shall occur more frequently than
                  once during




                  any twelve (12) month period.

         4.7      Quarterly Payments and Reports. In each year the amount of
                  royalty due shall be calculated quarterly as of the end of
                  each CALENDAR QUARTER and shall be paid quarterly within the
                  forty-five (45) days next following such date. Every such
                  payment shall be supported by the accounting described in
                  Section 4.8 of this Agreement. All royalties due ENTREMED are
                  payable in United States dollars. When PRODUCTS are sold for
                  currency other than United States dollars, the earned
                  royalties will first be determined in the foreign currency of
                  the country in which such PRODUCTS were sold and then
                  converted into equivalent United States funds. The exchange
                  rate will be that rate quoted in the Wall Street Journal on
                  the last business day of the CALENDAR QUARTER in which such
                  sales were made.

         4.8      Accounting Reports. With each quarterly payment, CELGENE shall
                  deliver to ENTREMED a full and accurate accounting to include
                  at least the following information:

                  (a)      Quantity of PRODUCT subject to royalty sold, by
                           country, by CELGENE, its AFFILIATES or SUBLICENSEES;

                  (b)      Total receipts for each PRODUCT subject to royalty,
                           by country and, to the extent used in any royalty
                           calculations during such quarter, the exchange rate
                           set forth in Section 4.7 of this Agreement;

                  (c)      Compensation on PRODUCTS received from SUBLICENSEES
                           pursuant to a sublicense of CELGENE's rights under
                           this Agreement; and

                  (c)      Total royalties and/or compensation payable to
                           ENTREMED.

                           SECTION 5 - CONFIDENTIALITY



         5.1      Confidential Information. During the term of this Agreement,
                  it is contemplated that each party may disclose to the other,
                  proprietary and confidential technology, inventions, technical
                  information, material, reagents, biological materials and the
                  like which are owned or controlled by the party providing such
                  information or which that party is obligated to maintain in
                  confidence and which is designated by the party providing such
                  information as confidential ("CONFIDENTIAL INFORMATION"). Each
                  party agrees not to disclose the CONFIDENTIAL INFORMATION and
                  to maintain the CONFIDENTIAL INFORMATION in strict confidence,
                  to cause all of its agents, representatives and employees to
                  maintain the disclosing party's CONFIDENTIAL INFORMATION in
                  confidence and not to disclose any such CONFIDENTIAL
                  INFORMATION to a THIRD PARTY without the prior written consent
                  of the disclosing party, and not to use such CONFIDENTIAL
                  INFORMATION for any purpose other than as provided under this
                  Agreement. The secrecy obligations of the parties with respect
                  to CONFIDENTIAL INFORMATION shall continue for a period ending
                  ten (10) years from the termination of this Agreement.

         5.2      Non-Confidential Information. The obligations of 
                  confidentiality will not apply to information that:

                  (a)      was known to the receiving party or generally known
                           to the public prior to its disclosure hereunder
                           through no fault of the disclosing party or any
                           agent, representative or employee thereof; or

                  (b)      subsequently becomes known to the public by some
                           means other than a breach of this Agreement,
                           including publication and/or laying open to
                           inspection of any patent applications or patents;

                  (c)      is subsequently disclosed to the receiving party by a
                           THIRD PARTY having




                           a lawful right to make such disclosure and who is
                           not under an obligation of confidentiality to the
                           disclosing party;

                  (d)      is required by law, rule, regulation or bona fide
                           legal process to be disclosed, provided that the
                           disclosing party takes all reasonable stem to
                           restrict and maintain confidentiality of such
                           disclosure and provides reasonable notice to the
                           non-disclosing party; or

                  (e)      is approved for release by the parties.

         5.3      Disclosure To THIRD PARTIES. The obligations of Section 5.1
                  notwithstanding, CELGENE or ENTREMED, as the case may be, may
                  disclose the CONFIDENTIAL INFORMATION licensed hereunder to
                  THIRD PARTIES

                  (a)      who need to know the same in order to obtain
                           regulatory approval for a PRODUCT under this
                           Agreement, provided that the actions of such THIRD
                           PARTY are not in conflict with CELGENE's rights under
                           this Agreement,

                  (b)      who need to know the same in order to work towards
                           the commercial development of PRODUCT on behalf of
                           CELGENE, or

                  (c)      for whom the non-disclosing party, ENTREMED or
                           CELGENE, as the case may be, has given prior written
                           approval 

                  provided that such THIRD PARTIES are bound by obligations of 
                  confidentiality and non-use at least as stringent as those set
                  forth herein.

         5.4      Disclosure To Sublicensees. CELGENE may disclose ENTREMED's
                  CONFIDENTIAL INFORMATION to a SUBLICENSEE without ENTREMED's
                  approval, provided that such SUBLICENSEES are bound by
                  obligations of confidentiality and non-use at least as
                  stringent as those set forth herein.



         5.5      Public Statements. Neither CELGENE nor ENTREMED may issue a
                  public statement, including without limitation a press
                  release, with regard to this Agreement without the prior
                  written consent of the other party, which consent shall not be
                  unreasonably withheld. In accordance with the rules and
                  regulations promulgated by the Securities and Exchange
                  Commission, the parties will request that this Agreement be
                  treated as confidential.

                     SECTION 6 - ADVERSE MEDICAL EXPERIENCES

         6.1      Adverse Medical Experience Reporting. CELGENE shall comply
                  fully with all applicable medical/adverse experience reporting
                  requirements in all countries where CELGENE intends to carry
                  out clinical trials and/or market PRODUCT.

                               SECTION 7 - PATENTS

         7.1      Patent Prosecution.

                  (a)      ENTREMED shall use reasonable efforts to prepare,
                           file, prosecute and maintain patent applications and
                           patents directed to PATENT RIGHTS and PRODUCTS
                           through patent counsel selected by ENTREMED and
                           reasonably acceptable to CELGENE, who shall consult
                           with and keep CELGENE advised with respect thereto.

                  (b)      CELGENE shall reimburse ENTREMED for all reasonable
                           costs and expenses incurred after the EFFECTIVE DATE
                           for the filing, prosecution and maintenance of PATENT
                           RIGHTS.

         7.2      Cooperation In Prosecution.

                  (a)      With respect to any PATENT RIGHTS, each patent
                           application, office



                           action, response to office action, request for
                           terminal disclaimer, petition, and request for
                           reissue or reexamination of any patent issuing from
                           such application shall be provided to CELGENE
                           sufficiently prior to the filing of such
                           application, response, petition, or request to allow
                           for review and comment by CELGENE. ENTREMED shall
                           have the right to take any action that, in its
                           judgement, is necessary to preserve such PATENT
                           RIGHTS.

                  (b)      Within a reasonable time from the EFFECTIVE DATE,
                           CELGENE and ENTREMED will discuss each party's patent
                           portfolio with regard to PRODUCTS, in accordance with
                           prior obligations of confidentiality owed by each
                           party to any THIRD PARTY, and will use reasonable
                           efforts to coordinate their respective patent
                           portfolio, to the extent possible, so as to maximize
                           the patent protection for PRODUCTS.

         7.3      Infringement and Declaratory Judgment Actions.

                  (a)      Notification. In the event that either party learns
                           of the infringement of any PATENT RIGHT, or the
                           filing of a Declaratory Judgement action alleging the
                           invalidity, unenforceability, or noninfringement of
                           any PATENT RIGHT ("DJ ACTION"), that party must
                           promptly notify the other party of the infringement
                           or DJ ACTION, as the case may be, in writing, and
                           must provide reasonable evidence of the infringement.
                           Neither party will notify a THIRD PARTY of the
                           infringement of any PATENT RIGHT or of the filing of
                           a DJ ACTION directed to any PATENT RIGHT without
                           first obtaining consent of the other party, which
                           consent shall not be unreasonably withheld.

                  (b)      CELGENE's Right To File Infringement Actions. To the
                           extent ENTREMED has the right to bring a suit or
                           action to compel the termination



                           of infringement of the PATENT RIGHTS, including to
                           the extent provided in Article 7 of the CMCC
                           AGREEMENT, ENTREMED hereby grants CELGENE the right
                           and option, but not the obligation, to bring an
                           action for infringement or to defend against a DJ
                           action, at its sole expense, in the name of ENTREMED
                           and/or in the name of CELGENE, and to join ENTREMED
                           as a party plaintiff if required. No settlement,
                           consent judgment or other voluntary final
                           disposition of a suit that adversely affects PATENT
                           RIGHTS may be entered into without the consent of
                           ENTREMED, which consent shall not be unreasonably
                           withheld.

                  (c)      CELGENE's Right To Defend DJ ACTIONS. In the event
                           that a DJ ACTION is brought naming CELGENE as a
                           defendant, CELGENE shall have the right to proceed
                           with the litigation or settle such action provided,
                           however, that no settlement, consent judgment or
                           other voluntary final disposition of a suit that
                           adversely affects PATENT RIGHTS may be entered into
                           without the consent of ENTREMED, which consent shall
                           not be unreasonably withheld.

                  (d)      CELGENE's Recovery. In the event that CELGENE shall
                           undertake the enforcement and/or defense of the
                           PATENT RIGHTS by litigation, any recovery of damages
                           by CELGENE for any such litigation shall be applied
                           first in satisfaction of any unreimbursed expenses
                           and legal fees of CELGENE relating to the suit. The
                           balance remaining from any such recovery shall, after
                           ENTREMED receives its royalties from lost sales,
                           belong to CELGENE.

                  (e)      ENTREMED's Right To Litigate. In the event that
                           CELGENE elects not to pursue an action for
                           infringement or to defend against a DJ action, as the
                           case may be, CELGENE shall notify ENTREMED in writing
                           of such election and ENTREMED shall have the right
                           and option, but not the



                           obligation, at its cost and expense, to initiate
                           infringement litigation and to retain any recovered
                           damages.

                  (f)      Cooperation. In any infringement suit either party
                           may institute to enforce or defend the PATENT RIGHTS
                           pursuant to this Agreement, the other party hereto
                           shall, at the request of the party initiating such
                           suit, cooperate in all respects and, to the extent
                           possible, have its employees testify when requested
                           and make available relevant records, papers,
                           information, samples, specimens, and the like. All
                           reasonable out-of-pocket costs incurred in connection
                           with rendering cooperation requested hereunder shall
                           be paid by the party requesting cooperation.

                  (g)      THIRD PARTY Royalty Reduction. In the event that an
                           infringement action is brought by a THIRD PARTY
                           against CELGENE alleging that CELGENE's making,
                           using, offering to sell, selling, or importing of
                           PRODUCTS under the PATENT RIGHTS infringes a THIRD
                           PARTY patent, and results in a judgment or
                           settlement requiring royalties to be paid by CELGENE
                           to such THIRD PARTY, the royalties owed by CELGENE
                           to ENTREMED under Section 4 of this Agreement shall
                           be reduced by an amount equal to ****************of
                           the royalties owed to such THIRD PARTY, provided
                           that the royalties owed to ENTREMED shall not be
                           reduced under this Section 7.3(f) to less than
                           ************of NET SALES, nor shall any specific
                           royalty payment be reduced under this Section 7.3(g)
                           by more than**********.

                   SECTION 8 - REPRESENTATIONS AND WARRANTIES.

         8.1      By Both Parties. Each party hereby represents and warrants
                  that each has the full right and authority to enter into this
                  Agreement and that the entry into this Agreement does not
                  require the consent of a THIRD PARTY whose consent has not



                  been obtained.

         8.2      By ENTREMED.  ENTREMED represents and warrants as follows:

                  (a)      that ENTREMED has not received any notice of
                           infringement of THIRD PARTY patents or notice of
                           interfering subject matter; that, without having made
                           any special investigation, ENTREMED is not aware of
                           any THIRD PARTY patents or patent applications that
                           contain any interfering subject matter, or 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, or by the exercise by CELGENE of any right
                           granted to it under this Agreement, aside from those
                           set forth in Appendix D;

                  (b)      that the PATENT RIGHTS set forth in Appendix A and
                           the TECHNOLOGY RIGHTS transferred to CELGENE under
                           this Agreement, constitute the entirety of ENTREMED
                           EXISTING PATENT RIGHTS and ENTREMED EXISTING
                           TECHNOLOGY RIGHTS;

                  (c)      that ENTREMED presently has no rights in PRODUCTS,
                           nor any option in or expectation of any rights in
                           PRODUCTS, apart from those identified in this
                           Agreement and set forth in the agreements listed in
                           Appendix B, and that ENTREMED is not in material
                           breach or default of any of the agreements set forth
                           in Appendix B, and that if ENTREMED acquires any such
                           rights after the EFFECTIVE DATE, the agreements
                           setting forth those rights, including all licenses
                           and assignments for ENTREMED DEVELOPED PATENT RIGHTS
                           and ENTREMED DEVELOPED TECHNOLOGY RIGHTS, shall be
                           redacted to the extent they do not relate to
                           CELGENE's rights under this Agreement, and attached
                           hereto as independent Exhibits and incorporated
                           herein;

                  (d)      that, with regard to PRODUCTS, ENTREMED has no
                           applications filed or pending with the FDA as of the
                           EFFECTIVE DATE, including without



                           limitation any Investigational New Drug or Orphan
                           Drug Status applications, apart from those set forth
                           in Appendix C;

                  (e)      that ENTREMED will comply with all obligations and
                           duties with regard to PRODUCTS under the CMCC
                           AGREEMENT and, unless and until it is assigned to
                           CELGENE pursuant to Section 2.5 of this Agreement,
                           the NCI AGREEMENT, including, without limitation, any
                           notification provisions necessary to maintain in
                           effect this Agreement or preserve CELGENE's exclusive
                           or non-exclusive rights under this Agreement,
                           including without limitation the preservation of
                           CELGENE's rights hereunder in the event that ENTREMED
                           shall breach or default on its obligations under the
                           CMCC AGREEMENT or the NCI AGREEMENT;

                  (f)      that ENTREMED understands and agrees that it has not
                           retained any rights under the ENTREMED INTELLECTUAL
                           PROPERTY to PRODUCTS in the TERRITORY, and that the
                           licenses and assignments granted in Sections 0, 0, 0,
                           and 0 of this Agreement are exclusive of any
                           continuing right of ENTREMED, except as otherwise
                           provided herein; and

                  (g)      that ENTREMED will not collaborate, negotiate, or
                           deal with THIRD PARTIES with respect to PRODUCTS,
                           except as expressly provided herein.

         8.3      EXCEPT AS OTHERWISE EXPRESSLY SET FORTH HEREIN, ENTREMED MAKES
                  NO REPRESENTATIONS OR EXTENDS ANY WARRANTIES OF ANY KIND
                  EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
                  WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
                  PURPOSE, NON-INFRINGEMENT OR VALIDITY OF ANY ENTREMED PATENT
                  OR OTHER INTELLECTUAL PROPERTY RIGHTS.

                    SECTION 9 - INDEMNIFICATION AND INSURANCE

         9.1      By CELGENE. CELGENE will defend, indemnify and hold harmless
                  ENTREMED, its successors, AFFILIATES and licensors and their
                  employees,



                  agents, officers, trustees, shareholders and directors and
                  each of them (the "ENTREMED Indemnified Parties") from and
                  against any and all THIRD PARTY claims, causes of action and
                  costs (including reasonable attorney's fees) of any nature
                  made or lawsuits or other proceedings filed or otherwise
                  instituted against the ENTREMED Indemnified Parties in
                  connection with any claims, suits or judgments arising out of
                  any theory of product liability concerning the development,
                  testing, manufacture, sale or use of any PRODUCT by CELGENE,
                  its AFFILIATES or its SUBLICENSEES.

                  9.1.1             CELGENE's indemnification under this Section
                                    9.1 shall not apply to any liability,
                                    damage, loss or expense to the extent that
                                    it is directly attributable to the negligent
                                    activity, reckless misconduct or intentional
                                    misconduct of ENTREMED.

                  9.1.2             Commencing not later than the date of FIRST
                                    COMMERCIAL SALE of a PRODUCT, CELGENE shall
                                    obtain and carry in full force and effect
                                    product liability insurance against any
                                    claims, judgments, liabilities and expenses
                                    for which it is obligated to indemnify
                                    ENTREMED and others under Section 9.1 of
                                    this Agreement, in such amounts and with
                                    such deductibles as are customary at the
                                    time for companies engaged in a similar
                                    business, and shall provide ENTREMED with
                                    written evidence of such insurance upon
                                    request.

         9.2      By ENTREMED. ENTREMED will defend, indemnify and hold harmless
                  CELGENE, its successors, AFFILIATES and licensors and their
                  employees, agents, officers, trustees, shareholders and
                  directors and each of them (the "CELGENE Indemnified Parties")
                  from and against any and all THIRD PARTY claims, causes of
                  action and costs (including reasonable attorney's fees) of any
                  nature made or lawsuits or other proceedings filed or
                  otherwise instituted against the CELGENE




                  Indemnified Parties in connection with any claims, suits or
                  judgments arising out of any theory of product liability
                  concerning the development, testing, manufacture, sale or use
                  of any PRODUCT by ENTREMED, its AFFILIATES or its SUBLICENSEES
                  prior to the EFFECTIVE DATE.

                  9.2.1             ENTREMED's represents and warrants that it
                                    presently carries, in full force and effect,
                                    and will continue to carry, product
                                    liability insurance against any claims,
                                    judgments, liabilities and expenses incurred
                                    in connection with the use of THALIDOMIDE in
                                    clinical trials by or on behalf of ENTREMED,
                                    and shall provide CELGENE with written
                                    evidence of such insurance upon request.

         9.3      Conditions to Indemnification. A person or entity that intends
                  to claim indemnification under this Section 9 (the
                  "Indemnitee") shall promptly notify the party from whom
                  indemnification is sought (the "Indemnitor"), of any loss,
                  claim, damage, liability or action in respect of which the
                  Indemnitee intends to claim such indemnification, and the
                  Indemnitor shall assume the defense thereof with counsel
                  mutually satisfactory to the Indemnitee whether or not such
                  claim is rightfully brought; provided, however, that an
                  Indemnitee shall have the right to retain its own counsel,
                  with the fees and expenses to be paid by the Indemnitor if
                  Indemnitor does not assume the defense, or if representation
                  of such Indemnitee by the counsel retained by the Indemnitor
                  would be inappropriate due to actual or potential differing
                  interests between such Indemnitee and any other person
                  represented by such counsel in such proceedings. The failure
                  to deliver notice to the Indemnitor within a reasonable time
                  after the commencement of any such action, only if prejudicial
                  to its ability to defend such action, shall relieve such
                  Indemnitor of any liability to the Indemnitee under this
                  Section 9, but the omission so to deliver notice to the
                  Indemnitor will not relieve it of any liability that it may
                  have to any Indemnitee otherwise than under this Section 9.
                  The Indemnitee under this Section 9, its employees and agents,
                  shall cooperate fully with the Indemnitor and its legal
                  representatives in the investigations of any action, claim or
                  liability covered by this



                  indemnification.

                     SECTION 10 - ASSIGNMENT AND SUCCESSORS

         10.1     By Either Party. This Agreement shall not be assignable by
                  either party without the written consent of the other party,
                  except that either party may assign this Agreement to an
                  AFFILIATE, successor in interest or transferee of all or
                  substantially all of the portion of the business to which this
                  Agreement relates without the consent of the other party.

         10.2     By CELGENE. If CELGENE assigns or licenses its rights under
                  this Agreement to a SUBLICENSEE or an AFFILIATE, such
                  SUBLICENSEE or AFFILIATE shall be bound by the terms and
                  conditions of this Agreement. CELGENE shall advise ENTREMED of
                  any such assignment or license and provide ENTREMED with a
                  copy of any sublicense within thirty (30) days of execution of
                  such sublicense.

         10.3     CELGENE As Guarantor. CELGENE shall guarantee and be
                  responsible for the payment of all royalties due and the
                  making of reports under this Agreement by reason of the
                  development and sales of any PRODUCTS by CELGENE, its
                  AFFILIATES and SUBLICENSEES and their compliance with all
                  applicable terms of this Agreement. Performance or
                  satisfaction of any obligations of CELGENE under this
                  Agreement by any of its AFFILIATES or SUBLICENSEES shall be
                  deemed performance or satisfaction of such obligation by
                  CELGENE.

         10.4     Binding Effect. This agreement shall be binding upon and inure
                  to the benefit of said successors in interest and assignees to
                  the parties. Any such successor or assignee of a party's
                  interest shall expressly assume in writing the performance of
                  all the terms and conditions of this Agreement to be performed
                  by said party and such Assignment shall not relieve the
                  Assignor of any of its obligations under this Agreement.



                           SECTION 11 - FORCE MAJEURE

         11.1     Neither party shall be liable to the other party for damages
                  or loss occasioned by failure of performance by the defaulting
                  party if the failure is occasioned by war, fire, explosion,
                  flood, strike or lockout, embargo, or any similar cause beyond
                  the control of the defaulting party, provided that the party
                  claiming this exception has exerted all reasonable efforts to
                  avoid or remedy such event and provided such event does not
                  extend for more than six (6) months.

                            SECTION 12 - TERMINATION

         12.1     Term. Unless earlier terminated as hereinafter provided, this
                  Agreement shall remain in full force and effect until
                  CELGENE's obligations to pay royalties or other compensation
                  under Section 4 of this Agreement, either directly or pursuant
                  to a sublicense, terminate.

         12.2     By Reason Of FDA Action. If the FDA withdraws or recalls
                  THALIDOMIDE from the market permanently, or in any other way
                  revokes or terminates CELGENE's regulatory approval to market
                  and sell THALIDOMIDE and/or PRODUCTS, CELGENE shall promptly
                  notify ENTREMED in writing, and this Agreement and all of
                  CELGENE's and ENTREMED's rights and obligations hereunder
                  shall terminate upon receipt by ENTREMED of such notice.

         12.3     Termination Of Royalty Obligations. Upon termination of
                  CELGENE's obligation to pay royalties and other compensation
                  hereunder with respect to a specific country and specific
                  PRODUCT as to which CELGENE's license is then in effect, the
                  license granted to CELGENE with respect to such country and
                  such PRODUCT pursuant to Section 2 shall be deemed to be fully
                  paid and CELGENE shall thereafter have a royalty free,
                  exclusive right to use the PATENT RIGHTS to make,



                  have made, use, offer to sell, sell and import such PRODUCT
                  in such country.

         12.4     Breach.

                  (a)      By Either Party. This Agreement shall be terminable
                           upon the material breach or default of either party.
                           In the event of a material breach or default by a
                           party ("Defaulting Party"), the other party
                           ("Non-Defaulting Party") shall give the Defaulting
                           Party written notice of the default. The Defaulting
                           Party will then have sixty (60) days to cure the
                           breach. If cure has not been affected within said
                           sixty (60) days, the Non-Defaulting Party shall have
                           the right to terminate this Agreement.

                  (b)      
                           By CELGENE.
                           (i)      Payments. If and only if CELGENE materially
                                    breaches this Agreement by failure to pay
                                    royalties and/or sublicensing or milestone
                                    payments due under Section 4 of this
                                    Agreement, and fails to cure such material
                                    breach within sixty (60) days of receiving
                                    written notice thereof pursuant to Section
                                    12.4(a) of this Agreement then: 
                                    a)      CELGENE's rights under this
                                            Agreement to ENTREMED INTELLECTUAL
                                            PROPERTY shall terminate; and
                                    b)      CELGENE shall grant to ENTREMED, to
                                            the extent not prohibited by the
                                            United States Government or by prior
                                            contractual obligations to any THIRD
                                            PARTY, an exclusive, worldwide,
                                            royalty-free license, with the right
                                            to sublicense, under CELGENE
                                            DEVELOPED INTELLECTUAL PROPERTY to
                                            make, use, offer to sell, sell, and
                                            import PRODUCTS in the TERRITORY.
                           (ii)     Diligence. If and only if ENTREMED exercises
                                    its right and option to terminate the
                                    license granted to CELGENE in the entire
                                    TERRITORY, pursuant to Section 3.1(f) of
                                    this Agreement, or



                                    ENTREMED exercises its right and option to
                                    terminate the license granted to CELGENE in
                                    Europe, Canada, or the PACIFIC RIM, pursuant
                                    to Section 3.2(c)(i) of this Agreement,
                                    then, either in the entire TERRITORY or in
                                    the region in which such termination has
                                    occurred, i.e., Europe, Canada, or the
                                    PACIFIC RIM, as applicable: 
                                    a)      CELGENE's rights under this
                                            Agreement to ENTREMED INTELLECTUAL
                                            PROPERTY shall terminate; and
                                    b)      CELGENE shall grant to ENTREMED, to
                                            the extent not prohibited by the
                                            United States Government or by prior
                                            contractual obligations to any THIRD
                                            PARTY, an exclusive, worldwide,
                                            royalty-free license, with the right
                                            to sublicense, under CELGENE
                                            DEVELOPED INTELLECTUAL PROPERTY to
                                            make, use, offer to sell, sell, and
                                            import PRODUCTS.
                           The grant of rights by CELGENE to ENTREMED under this
                           Section 12.4 expressly excludes rights in any CELGENE
                           EXISTING INTELLECTUAL PROPERTY.

                  (c)      Termination under this Section 12.4 will be effective
                           upon the date specified in the written notice. All
                           termination rights shall be in addition to and not in
                           substitution for any other remedies that may be
                           available to the Non-Defaulting Party. Termination
                           pursuant to this Section 12.4 shall not relieve the
                           Defaulting Party from liability and damages to the
                           Non-Defaulting Party for default. Waiver by either
                           party of a single default or a succession of defaults
                           shall not deprive such party of any right to
                           terminate or convert this Agreement arising by reason
                           of any subsequent default.

         12.5     Insolvency. Either party to this Agreement may terminate this
                  Agreement upon receipt of notice that the other party has
                  become insolvent or has suspended business in all material
                  respects hereof, or has consented to an involuntary petition
                  purporting



                  to be pursuant to any reorganization or insolvency law of any
                  jurisdiction, or has made an assignment for the benefit of
                  creditors or has applied for or consented to the appointment
                  of a receiver or trustee for a substantial part of its
                  property, by giving written notice to the other party, and
                  termination of this Agreement will be effective upon receipt
                  of such notice.

         12.6     Work-In-Progress. Upon termination of this Agreement, CELGENE
                  shall be entitled to, but shall not be obligated to finish any
                  work-in-progress at the time of termination and sell the same
                  as well as all completed inventory of PRODUCTS which remains
                  on hand as of the date of the termination, so long as CELGENE
                  pays to ENTREMED the royalties applicable to said subsequent
                  sales in accordance with the same terms and conditions as set
                  forth in this Agreement.

         12.7     Survival. The obligations of Sections 5 and 9, as well as
                  Sections 12.6, 12.7, 12.8, and 13.3, shall survive any
                  termination of this Agreement.

         12.8     Reversion of Rights. Upon termination of this Agreement or of
                  the rights and licenses granted to CELGENE in any country of
                  the TERRITORY, CELGENE agrees not to use the TECHNOLOGY RIGHTS
                  or PATENT RIGHTS or information or technology derived
                  therefrom for the manufacture, use or sale of PRODUCTS in any
                  country other than those countries in which CELGENE retains a
                  license under this Agreement. In addition, all rights to the
                  TECHNOLOGY RIGHTS and PATENT RIGHTS in such country shall
                  revert to ENTREMED and may be used by ENTREMED without
                  restriction in any country other than those countries in which
                  CELGENE retains a license under this Agreement.



                         SECTION 13 - GENERAL PROVISIONS

         13.1     Relationship of Parties. The relationship between ENTREMED and
                  CELGENE is that of independent contractors. ENTREMED and
                  CELGENE are not joint venturers, partners, principal and
                  agent, master and servant, employer or employee, and have no
                  relationship other than as independent contracting parties.
                  ENTREMED shall have no power to bind or obligate CELGENE in
                  any manner. Likewise, CELGENE shall have no power to bind or
                  obligate ENTREMED in any manner.

         13.2     Entire Understanding. This Agreement sets forth the entire
                  agreement and understanding between the parties as to the
                  subject matter thereof and supersedes all prior agreements in
                  this respect. There shall be no amendments or modifications to
                  these Agreements, except by a written document which is signed
                  by both parties.

         13.3     Governing Law. This Agreement shall be construed and enforced
                  in accordance  with the laws of the State of Delaware,
                  U.S.A. without reference to its choice of law principles.

         13.4     Headings. The headings in this Agreement have been inserted
                  for the convenience of reference only and are not intended to
                  limit or expand on the meaning of the language contained in
                  the particular or section or paragraph.

         13.5     No Waiver. Any delay in enforcing a party's rights under this
                  Agreement or any waiver as to a particular default or other
                  matter shall not constitute a waiver of a party's right to the
                  future enforcement of its rights under this Agreement,
                  excepting only as to an expressed written and signed waiver as
                  to a particular matter for a particular period of time.

         13.6     Export Controls. In conducting any activities under this
                  Agreement or in connection with the manufacture use or sale of
                  PRODUCT, CELGENE shall comply with all



                  applicable laws and regulations including, but not limited to,
                  all Export Administration Regulations of the United States
                  Department of Commerce.

         13.7     Notices. Any notices given pursuant to this Agreement shall be
                  in writing and shall be deemed delivered upon the earlier of
                  (i) when received at the address set forth below, or (ii)
                  three (3) business days after mailed by certified or
                  registered mail postage prepaid and properly addressed, with
                  return receipt requested, or (iii) when sent, if sent by
                  facsimile, as confirmed by certified or registered mail.
                  Notices shall be delivered to the respective parties as
                  indicated below:

                  If To ENTREMED                     EntreMed, Inc.
                                                     9610 Medical Center Drive
                                                     Rockville, MD 20850
                                                     Attn: CEO
                                                     Fax: (301) 217-9594

                  If To CELGENE:                     Celgene Corporation
                                                     6 Powder Horn Drive
                                                     Warren, NJ 07059
                                                     Attn: President
                                                     Fax: (732) 805-3931


         13.8     Original Counterparts. This Agreement may be executed in any
                  number of separate counterpart, each of which shall be deemed
                  to be an original, but which together shall constitute one and
                  the same instrument.



                  IN WITNESS WHEREOF, the parties have executed this Agreement
as of the date set forth above.


ENTREMED, INC.                                 CELGENE CORPORATION




By:____________________________                By:____________________________
                                                                              
                                                                              
                                                                              
Name:__________________________                Name:__________________________
                                                                              
                                                                              
                                                                              
Title:_________________________                Title:_________________________



         IN WITNESS WHEREOF, the parties have executed this Agreement as of the
date set forth above.

ENTREMED, INC.                               CELGENE CORPORATION


By:    /s/  Edward R. Gubish                 By:      /s/  John W. Jackson
  -------------------------------               -------------------------------
Name:       Edward R. Gubish                 Name:         John W. Jackson
     ----------------------------                  ----------------------------

Title:      Sr. V.P. R & D                   Title:        Chairman & CEO
      ---------------------------                  ----------------------------



                                   APPENDIX A


United States Patent No. 5,629,327
United States Patent No. 5,593,990
United States Patent Application Serial No. 08/025,046
United States Patent Application Serial No. 08/168,817
United States Patent Application Serial No. 08/371,987
United States Patent Application Serial No. 08/468,792
United States Patent Application Serial No. 08/918,610
United States Patent Application Serial No. 08/955,638
United States Patent Provisional Application Serial No. 60/028,708
United States Patent Application Serial No. 08/963,058
United States Patent Application Serial No. 09/107,578
United States Patent Application Serial No. 09/126,542



                                   APPENDIX B


1.       That certain License Agreement entered into by and between ENTREMED and
         Children's Medical Center Corporation ("CMCC"), dated May 26, 1994, as
         amended to the date hereof, attached as Exhibit A to this Agreement.

2.       That certain Agreement by and between the Division of Cancer Treatment
         at the National Cancer Institute ("NCI") and ENTREMED, dated November
         16, 1994, and executed on behalf of ENTREMED on November 23, 1994, and
         on behalf of NCI on November 18, 1994, attached as Exhibit C to this
         Agreement.



                                   APPENDIX C


Orphan Drug Designation Application (ODA) 97-1011    Primary Brain Malignancies
Orphan Drug Designation Application (ODA) 98-1149    Kaposis Sarcoma
Orphan Drug Designation Application (ODA) 98-1143    Prostate Cancer

Investigational New Drug Application 46,591          Ophthalmology
Investigational New Drug Application 55,966          Oncology



                                   APPENDIX D


United States Patent No. 5,605,684 to Piacquadio
United States Patent No. 5,443,824 to Piacquadio
United States Patent No. 5,731,325 to Andrulis, Jr. et al.
United States Patent No. 5,654,312 to Andrulis, Jr. et al.
United States Patent No. 5,643,915 to Andrulis, Jr. et al.
United States Patent No. 5,434,170 to Andrulis, Jr.



                                    EXHIBIT A

                                 CMCC AGREEMENT





                                    EXHIBIT B

                                  NCI AGREEMENT



                                    EXHIBIT C

                      LETTER TO FDA INDICATING TRANSFER OF
                       RIGHTS IN INVESTIGATIONAL NEW DRUG
                     AND ORPHAN DRUG APPLICATIONS TO CELGENE