(d)           Timing of Royalty Payments. Royalty obligations under Section 5.3(a) shall accrue at the time that a sale or use of a Product generates Net Sales, and royalty obligations that have accrued during a particular calendar quarter shall be paid, on a quarterly basis, within sixty (60) days after the end of the calendar quarter during which the obligation accrued.

(e)           Royalty Term. Celldex’s royalty obligations under this Section 5.3 as to a particular Product shall be payable, on a country-by-country and Product-by-Product basis, for the longer of (i) the period from the First Commercial Sale of such Product in such country until the date of expiration of the last to expire Valid Claim within the Assigned Patents or the Licensed Patent Rights that Covers the manufacture, use, sale, offer to sell, or import of such Product by Celldex, its Affiliate or Sublicensee in such country, or (ii) ten (10) years after the First Commercial Sale of the applicable Product in the applicable country (the “Royalty Term”). For the purpose of this Agreement, a Valid Claim “Covers” or is “Covering” a particular ac tivity if such activity would infringe, contribute to the infringement of, or induce the infringement of such Valid Claim, and the phrase “is Covered by” shall have a correlative meaning.  With respect to a patent application, a Valid Claim “Covers” a particular activity if such activity would infringe, contribute to the infringement of, or induce the infringement of such Valid Claim were such application to be an issued patent, and the phrase “is Covered by” shall have a correlative meaning.

(f)            Appropriate Measure of Value.  The Parties acknowledges that the value provided by the other hereunder is comprised of many related items, including intellectual property of various types, access to preclinical and clinical studies, data and regulatory filings, provision of Materials and other financial and non-financial consideration and that the royalties set forth in this Section 5.3 are intended to capture such value as an aggregate.  Therefore, the increase, decrease or lapse of any particular items or rights shall not affect the amount of such royalty, and the Parties agree that both the amount and duration of the royalties set forth in this Section 5.3 are reasonable.

5.4        Sublicense Revenues.  If Celldex licenses or sublicenses any of its rights under the Assigned Patent Rights, Licensed Patent Rights and/or Amgen Know-How for any Applicable Uses for any Molecule to a Third Party during the term of this Agreement, Celldex shall pay to Amgen (i) [*] of Gross Sublicense Revenues, if such license or sublicense is to a Third Party other than a Third Party set forth in Exhibit G; and (ii) [*] of the Gross Sublicense Revenues, if such sublicense is to a Third Party set forth in Exhibit G (or any such listed Third Party’s affiliates, successors and assigns) (any such payments to Amgen are collectively referred to as “Amgen Sublicense Payments”).  Amgen Sublicense Payments shall be calculated and payable on a calendar quarter basis. Such payments shall be paid within twenty (20) business days following the end of each applicable calendar quarter. The obligations set forth in this Section 5.4 are in addition to any other payment obligations under this Agreement.  For the avoidance of doubt, if Celldex licenses or sublicenses any of its rights under the Assigned Patent Rights, Licensed Patent Rights and/or Amgen Know-How for any uses other than Applicable Uses for any Molecule to a Third Party during the term of this Agreement, with respect to payments due Amgen, such

Sublicensee shall be subject to the payment provisions set forth in this Article 5 (but not Section 5.4 of this Agreement).

* Confidential

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5.5        Reports.  At the same time that Celldex makes a quarterly royalty payment required by Section 5.3, Celldex shall provide to Amgen a written report that sets forth a reasonably detailed and accurate record of all sales or dispositions by Celldex, its Affiliates and its Sublicensees of the Products in the Territory, showing the manufacturing, sales, use and other dispositions of the Products with respect to which royalty obligations have accrued during such calendar quarter, the gross amounts and allowed deductions forming the calculation of Net Sales, and a calculation of the royalties due for such calendar quarter pursuant to S ection 5.3.  Each such report shall include reasonably detailed and accurate calculations (together with applicable royalty rate percentages) of Third Party Royalties pursuant to Section 5.3(c).  At the same time that Celldex makes a quarterly payment required by Section 5.4, Celldex shall also provide to Amgen a written report that sets forth a reasonably detailed and accurate record of payments due Amgen under Section 5.4, including all Gross Sublicense Revenues and a calculation of the portion of Gross Sublicense Revenues due Amgen for such calendar quarter pursuant to Section 5.4.

5.6        Records and Audit.  During the term of this Agreement and for a period of three (3) years thereafter, Celldex shall keep and require its Affiliates and Sublicensees to keep and provide to Celldex complete and accurate records in accordance with GAAP (or the relevant accounting standards of such non-U.S. jurisdiction where such records are kept or to which they relate, as applicable) pertaining to the sale of the Products, in sufficient detail to permit Amgen to confirm the revenue, Net Sales, and Gross Sublicense Revenues attributable to such sales.  Amgen shall have the right, at its expense, to cause an independent, cert ified public accountant reasonably acceptable to Celldex to audit such records to confirm Celldex’s revenues and Net Sales attributable to sales of Products in the Field in the Territory and Gross Sublicense Revenues.  Such audits shall be conducted under conditions of confidentiality and during normal business hours.  A copy of the accountant’s report shall be provided to Celldex.  All amounts due (whether by Celldex or Amgen) as shown by the audit shall be paid within thirty (30) days following the receipt of the audit report.  Amgen shall bear the full cost of such audit unless such audit discloses an underpayment by Celldex of greater than seven percent (7%) of such amounts rightfully payable for the time period being audited.  In such case, Celldex shall bear the full cost of such audit.

5.7        Methods of Payments.  All payments due under this Agreement shall be paid in U.S. dollars by wire transfer to a bank designated in writing by the Party to which the payment is due.

5.8        Interest.  If Celldex fails to make any payment due to Amgen under this Agreement, then interest shall accrue on a daily basis at an interest rate equal to two percentage points (2%) above the then-applicable prime commercial lending rate of Citibank, N.A., San Francisco, California, or at the maximum rate permitted by applicable law, whichever is the lower.

5.9        Currency Conversion.  Net Sales amounts shall be translated from other currencies to U.S. Dollars by using the rate of exchange quoted under Foreign Exchange in the Eastern edition of the Wall Street Journal as of the last business day of the applicable calendar quarter.

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5.10      Blocked Currency.  If at any time legal restrictions prevent the prompt remittance of part or all of the royalties payable by Celldex with respect to any country where a Product is sold, Celldex shall have the right, at its option, to make such payments by depositing the amount thereof in local currency to Amgen’s account in a bank or other depository in such country.

5.11      Transaction Taxes.  Celldex is responsible for the payment of any state or local, sales or use, or similar fees or taxes arising as a result of the transfer of property by Amgen to Celldex pursuant to this Agreement, and Celldex shall promptly remit such fees or taxes to Amgen, as the collection agent, upon invoice.  Amgen shall, thereafter, timely report and submit the appropriate fees or taxes to the relevant taxing authority(ies).  Notwithstanding the foregoing, in the event that laws, rules or other regulations require Celldex to withhold taxes with respect to any payment to be made by Celldex pursuant to this Agreement, Celldex will notify Amgen of such withholding requirements prior to making the payment to Amgen and provide such assistance to Amgen, including the provision of such documentation as may be required by the applicable tax authority, as may be reasonably necessary in Amgen’s efforts to claim an exemption from or reduction of such taxes.  Celldex will, in accordance with such laws, rules or regulations, withhold taxes from the amount due, remit such taxes to the appropriate tax authority, and furnish Amgen with satisfactory proof of payment of such taxes within fifteen (15) business days following the payment.  If taxes are withheld and remitted to a tax authority, Celldex shall provide reasonable assistance to Amgen at Amgen’s expense to obtain a refund of such taxes or obtain a credit with respect to such taxes.

ARTICLE 6

PATENTS

6.1        Prosecution, Maintenance and Enforcement of Assigned Patents.  As of the Effective Date, Celldex, at its sole expense, shall be solely responsible for, and have complete discretion in controlling and making decisions with respect to, filing, prosecution, defense, maintenance and enforcement of the Assigned Patents before all patent authorities in the Territory, including but not limited to oppositions and interferences, and enforcement of the Assigned Patents, and shall be entitled to retain all recoveries related thereto.

6.2        Prosecution, Maintenance and Enforcement of Licensed Patent Rights.  Amgen shall be solely responsible for, and have complete discretion in controlling and making decisions with respect to, filing, prosecution, defense, maintenance and enforcement of the Licensed Patent Rights before all patent authorities in the Territory, including but not limited to oppositions and interferences, and enforcement of the Licensed Patent Rights.

6.3        Cooperation.  Amgen, at Celldex’s request and expense, agrees to reasonably cooperate with Celldex in the filing, prosecution and maintenance of Assigned Patents, including signing any necessary legal papers in support thereof.  Amgen further covenants and agrees that it shall not interfere with or otherwise seek to limit Celldex’s enforcement or defense of the

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Assigned Patents, or otherwise bring or join any action to challenge the validity or enforceability of any of the Assigned Patents.

ARTICLE 7

CONFIDENTIALITY

7.1         Confidentiality.  Except to the extent expressly authorized by this Agreement or otherwise agreed in writing by the Parties, each Party agrees that, for the term of this Agreement and for five (5) years thereafter, it shall keep confidential and shall not publish, otherwise disclose or use for any purpose other than as provided for in this Agreement (including, in each case, in connection with the exercise of license rights granted pursuant to this Agreement) any Confidential Information of the other Party unless the receiving Party can demonstrate by competent proof that such Confidential Information:

(a)           was already known to the receiving Party, other than under an obligation of confidentiality, at the time of disclosure by the other Party;

(b)           was generally available to the public or otherwise part of the public domain at the time of its disclosure to the receiving Party;

(c)           became generally available to the public or otherwise part of the public domain after its disclosure and other than through any act or omission of the receiving Party in breach of this Agreement;

(d)           was disclosed to the receiving Party, other than under an obligation of confidentiality, by a Third Party who, to the receiving Party’s knowledge, had no obligation to the disclosing Party not to disclose such information to others; or

(e)           was independently discovered or developed by the receiving Party without the use of Confidential Information belonging to the disclosing Party, as documented by the receiving Party’s written records.

7.2         Authorized Disclosure.  Notwithstanding the limitations in this Article 7, each Party may disclose Confidential Information belonging to the other Party to the extent such disclosure is reasonably necessary in the following instances:

(a)           prosecuting or defending litigation relating to this Agreement;

(b)           complying with applicable law, regulations, valid court orders, or rules of a securities exchange;

(c)           disclosure to licensees and collaborators, and potential licensees and collaborators, investors, potential investors, sources of finance, acquirers, or merger candidates who agree to be bound by confidentiality obligations at least equivalent in scope to those set forth in this Article 7, or in the case of financial institutions with respect to financial information and the terms of this Agreement only, equivalent in scope to those terms under which the disclosing

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Party is disclosing its own confidential information of similar type, provided that such disclosure is used solely for the purpose of evaluating such license, collaboration, investment, acquisition, or merger or providing required information under a financing (as the case may be);

(d)           disclosure of the terms of this Agreement, on a need-to-know basis in support of the development, manufacture or commercialization of Products, to members of its Board of Directors, Affiliates, licensees, collaborators, Sublicensees, employees, consultants, agents and subcontractors who agree to be bound by obligations of confidentiality and non-use at least equivalent in scope to those set forth in this Article 7;

(e)           in connection with making regulatory filings for Regulatory Approval; and

(f)            filing, prosecuting or maintaining the Assigned Patents (as to Celldex) or Licensed Patent Rights (as to Amgen) in accordance with Article 6.

Notwithstanding the foregoing, in the event a Party is required to make a disclosure of the other Party’s Confidential Information pursuant to Section 7.2(b), it will, except where not reasonably possible, give reasonable advance notice to the other Party of such disclosure and use commercially reasonable efforts to secure confidential treatment of such information.  In any event, the Parties agree to take all reasonable action to avoid disclosure of Confidential Information hereunder.

7.3         Authorized Disclosure by Amgen.  Notwithstanding the limitations set forth in this Article 7, and in addition to the authorized disclosures set forth in Section 7.2, Amgen shall be authorized to disclose the existence (but not the terms) of this Agreement to any Third Party requesting information on, or access to, the Products.

7.4         Employees; Agents.  Celldex shall ensure that each employee, consultant or other agent of Celldex or any of its Affiliates and Sublicensees who has access to Confidential Information of Amgen is bound to obligations of confidentiality and non-use at least equivalent in scope to those set forth in Sections 7.1 and 7.2.

7.5         Publicity.  The terms of this Agreement shall be Confidential Information of each Party and, as such, shall be subject to the provisions of this Article 7.  Neither Party shall issue any other news or press release, or make any public announcement relating to this Agreement or to the performance hereunder, without the other Party’s prior written consent. Notwithstanding the foregoing, the Parties agree that (i)  upon execution of this Agreement, the Parties shall negotiate in good faith a mutually agreed upon press release to be issued by Celldex; (ii) each Party may make statements that are not inconsistent with a previous press release issued by either Party in complianc e with this Section 7.5 and (iii) Amgen shall have the right to (a) make an announcement relating to this Agreement, with Celldex’s prior consent, not to be unreasonably withheld, to academic institutions and non-profit research organizations, as well as to any Third Parties with whom Amgen has had discussions prior to the Effective Date relating to the AMG 949 Program and AMG 950 Program, and to inform such Third Parties (including academic institutions and non-profit research organizations) that Celldex has (or will have) put in place a process for handling such requests for Products; and (b) direct any Third Parties requesting

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Products to Celldex, without the prior written consent of Celldex. The restriction set forth in this Section 7.5 shall not apply to disclosures required by law or regulation, including as may be required in connection with any filings made with the Securities and Exchange Commission or by the disclosure policies of a major stock exchange (including NASDAQ, NYSE and AMEX); provided, however, that the disclosing Party shall request, to the extent legally available, that the relevant legal or Regulatory Authority, or major stock exchange, treat as confidential any Confidential Information or other proprietary information of either Party included in any such disclosure and shall notify the other Party of the proposed disclosure in advance.

7.6         Attorney-Client Privilege.  Neither Party is waiving, nor shall be deemed to have waived or diminished, any of its attorney work product protections, attorney-client privileges or similar protections and privileges as a result of disclosing its Confidential Information (including Confidential Information related to pending or threatened litigation) to the receiving Party, regardless of whether the disclosing Party has asserted, or is or may be entitled to assert, such privileges and protections. The Parties (a) share a common legal and commercial interest in all of the disclosing Party’s Confidential Information that is subject to such privileges and protections; (b) are or may become joint defendants in proceedings to which the disclosing Party’s Confidential Information covered by such protections and privileges relates; (c) intend that such privileges and protections remain intact should either Party become subject to any actual or threatened proceeding to which the disclosing Party’s Confidential Information covered by such protections and privileges relates; and (d) intend that after the Effective Date the receiving Party shall have the right to assert such protections and privileges. No receiving Party shall admit, claim or contend, in proceedings involving either Party or otherwise, that the disclosing Party waived any of its attorney work-product protections, attorney-client privileges or similar protections and privileges with respect to any information, documents or other material due to the disclosing Party disclosing its Confidential Information (including Confidential Information related to pending or threatened litigation) to the receiving Party. Notwithstanding the foregoing, after the Effective Date, Celldex shall have t he right to waive its attorney-client privilege in its sole discretion, solely with respect to the Assigned Patents and the Products.

ARTICLE 8

REPRESENTATIONS, WARRANTIES AND COVENANTS

8.1         Representations and Warranties of Celldex.  Celldex hereby represents and warrants that, as of the Effective Date:

(a)           Corporate Power.  Celldex is duly organized and validly existing under the laws of Delaware and has full corporate power and authority to enter into this Agreement and to carry out the provisions hereof.

(b)           Due Authorization.  Celldex is duly authorized to execute and deliver this Agreement and to perform its obligations hereunder.  The person executing this Agreement on Celldex’s behalf has been duly authorized to do so by all requisite corporate action.

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(c)           Binding Agreement.  This Agreement is a legal and valid obligation binding upon Celldex and enforceable in accordance with its terms.  The execution, delivery and performance of this Agreement by Celldex does not conflict with any agreement, instrument or understanding, oral or written, to which it or any of its Affiliates is a party or by which it or any of its Affiliates may be bound.

(d)           Validity.  Neither Celldex nor any of its Affiliates is aware of any action, suit or inquiry or investigation instituted by any governmental agency which questions or threatens the validity of this Agreement.

(e)           Excluded Patents.  Amgen has provided to Celldex a list of Excluded Patents set forth in Exhibit L.  Celldex represents and warrants that Amgen has informed Celldex about the existence of the Excluded Patents, Celldex has elected not to obtain from Amgen a license or other rights in or to the Excluded Patents, and Celldex acknowledges and agrees that Excluded Patents shall not be included as Licensed Patent Rights under this Agreement.

8.2         Representations and Warranties of Amgen.  Amgen hereby represents and warrants that, as of the Effective Date:

(a)           Corporate Power.  Amgen is duly organized and validly existing under the laws of Delaware and has full corporate power and authority to enter into this Agreement and to carry out the provisions hereof.

(b)           Due Authorization.  Amgen is duly authorized to execute and deliver this Agreement and to perform its obligations hereunder.  The person executing this Agreement on Amgen’s behalf has been duly authorized to do so by all requisite corporate action.

(c)           Binding Agreement.  This Agreement is a legal and valid obligation binding upon Amgen and enforceable in accordance with its terms.  The execution, delivery and performance of this Agreement by Amgen do not conflict with any agreement, instrument or understanding, oral or written, to which it or any of its Affiliates is a party or by which it or any of its Affiliates may be bound.

(d)           Validity.  Neither Amgen nor its Affiliates are aware of any action, suit or inquiry or investigation instituted by any governmental agency which questions or threatens the validity of this Agreement.

(e)           Patent Rights.  (i) Amgen has the right to grant the licenses under the Licensed Patent Rights granted hereunder and has not assigned, transferred, conveyed or licensed its right, title and interest in the Licensed Patent Rights in a manner inconsistent with the terms of this Agreement; (ii) subject to the Third Party Royalty agreement and the rights licensed to Third Parties pursuant to the Excluded Contracts, Amgen and its Affiliates have the right to assign their entire right, title and interest in the Assigned Patents to Celldex as contemplated herein; (iii) there are no oppositions, cancellations, interferences or litigation proceedings pending, or, to the actual knowledge of the intellectual property law group of Amgen’s Law Department, expressly threatened in writing, within the twenty - -four (24) month period prior to the Effective Date,

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challenging the ownership, validity or enforceability of any of the Assigned Patents; and (iv) to the actual knowledge of the intellectual property law group of Amgen’s Law Department,  Exhibit C, Exhibit D and Exhibit E include all patent applications and patents owned or Controlled by Amgen and its Affiliates, including Immunex, as of the Effective Date, that specifically cover or specifically claim the composition of matter of, or methods specifically related to making or using, the Molecules, as made or intended to be used by Amgen and its Affiliates, including Immunex, in its development of the Molecules or Products conducted prior to the Effective Date, or any formulations specifically related to the Molecules or Products.  If, during the term of this Agreement, any patent application or patent other than Excluded Patents is identified that is owned or Controlled by Amgen or its Affiliates, including Immunex, and was owned or Controlled by Amgen or its Affiliates, including Immunex, as of the Effective Date, which patent application or patent should have been included in Assigned Patents or Licensed Patent Rights (i.e., it would have been encompassed within this Section 8.2(e)(iv) and included on Exhibit C, Exhibit D or Exhibit E), then Amgen or its Affiliates, including Immunex, shall promptly include such patent application or patent within Assigned Patents or Licensed Patent Rights, as may be applicable, and Exhibit C, Exhibit D or Exhibit E (as applicable) shall be updated to reflect such inclusion.  Celldex acknowledges and agrees that such inclusion shall be Celldex’s sole and exclusive remedy with respect to any breach of this Section 8.2(e)(iv).

(f)            Title to Transferred Assets.  Except as set forth on Schedule 8.2(f), Amgen and its Affiliates possess the exclusive right, title and interest in the Transferred Assets existing as of the Effective Date.  To the actual knowledge of Amgen, the Assigned Patents have not been pledged as collateral or security for any material financing transaction, and to the actual knowledge of Amgen, no Assigned Patents are subject to any funding agreement with any U.S. government or U.S. government agency.

(g)           Litigation.  There is no pending litigation, or, to the actual knowledge of the intellectual property law group of Amgen’s Law Department, any bona fide written claims received by Amgen within the twenty-four (24) month period prior to the Effective Date, expressly and specifically alleging that the research, development, manufacture, use or sale of Molecules or any formulation of Molecules infringes any Patent Right of a Third Party.

(h)           Third Party Agreements.  (1) to the actual knowledge of Amgen, the license agreements with Third Parties as to which Amgen or its Affiliates is a party relating to the Assigned Patents and which involve the license of Assigned Patents that claim the composition of matter of a Molecule or the formulation or method of manufacturing the Molecules as most recently formulated or manufactured by Amgen or its Affiliates, or the license to use the Molecules, are set forth on Exhibit K , (2) subject to the last sentence of Section 2.1(b)(ii) and except with respect to any Excluded Contract for which Amgen is unable to obtain the consent of the licensee under such Excluded Contract to disclose the terms and conditions of such Excluded Contract to Celldex, Amgen has provided Celldex with a true, co mplete and correct copy (or redacted copy, to the extent there is Third Party confidential information contained therein) of each such agreement listed on Exhibit K; and (3) except for agreement number 8 listed in Exhibit K (Excluded Contracts), to the actual knowledge of Amgen, the material transfer agreements for Ongoing Studies are listed in Exhibit F and such material transfer agreements for Ongoing Studies are in full force and effect.

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(i)            Safety Data.  To the actual knowledge of Amgen, Amgen has made available to Celldex all material safety data that is in Amgen’s safety database for the Molecules, and Amgen has not failed to make available to Celldex material safety data in Amgen’s possession that is related to the Molecules and is inconsistent with the safety data that has previously been made available to Celldex.

(j)            Molecules.  To the actual knowledge of Amgen, there are no special use, handling, storage, transportation, disposition and containment requirements for the Molecules.

(k)           Grant-Back License to Amgen.  In connection with the licenses granted to Amgen under Section 2.1(b)(ii) with respect to Excluded Contracts, in order to fulfill its obligations for item number 7 listed in Exhibit K (Excluded Contract), Amgen only requires rights and license pertaining to (i) the use of AMG 949 and AMG 950 in research to evaluate their utility as agents in the diagnosis of diseases, states or conditions); and (ii) the making, having made, using, selling or offering for sale, and development of reagents, derivatives and other products incorporating, using or derived from or based on AMG 949 and/or AMG 950, solely for in vitro laboratory research or in vivo animal research.

8.3 No Representations and Warranties; Exceptions. Except as expressly set forth in Section 8.2, Celldex understands and agrees that Amgen does not represent or warrant to Celldex in any way as to the Transferred Assets, or as to whether the Transferred Assets are sufficient, individually or collectively, to enable Celldex to conduct any business, or as to any consents or approvals required in connection with the consummation of the transactions contemplated by this Agreement, or as to any licenses or permits from any Regulatory Authority that may be necessary or desirable for the conduct of any business by Celldex, it being agreed and understood as between Celldex and Amgen that Celldex shall take all of the Transferred Assets “as is, where is” and that, except as expressly provided in this Article 8, C elldex shall bear the economic and legal risk that conveyances of the Transferred Assets shall prove to be insufficient or that the title of Celldex to any Transferred Assets shall be other than good and marketable and free from encumbrances.

8.4 Disclaimer.  EXCEPT AS EXPRESSLY SET FORTH IN THIS ARTICLE 8, ALL MATERIALS AND INFORMATION PROVIDED HEREUNDER ARE BEING PROVIDED “AS IS” AND WITHOUT ANY REPRESENTATIONS OR WARRANTIES.  EXCEPT AS EXPRESSLY SET FORTH IN THIS ARTICLE 8, NEITHER PARTY MAKES ANY REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, OF ANY KIND, INCLUDING AS TO MERCHANTABILITY, FITNESS FOR A PARTICULAR USE OR NON-INFRINGEMENT.  IN PARTICULAR, EXCEPT AS EXPRESSLY SET FORTH IN THIS ARTICLE 8, AMGEN DOES NOT WARRANT THE VALIDITY OR ENFORCEABILITY OF THE ASSIGNED PATENTS AND LICENSED PATENT RIGHTS, AND MAKES NO REPRESENTATIONS WHATSOEVER WITH REGARD TO THE SCOPE OF THE ASSIGNED PATENTS AND LICENSED PATENT RIGHTS, OR THAT THE ASSIGNED PATENTS, LICENSED PATENT RIGHTS AND AMGEN KNOW-HOW MAY BE EXPLOITED WITHOUT INFRINGING OTHER PATENTS OR OTHER INTELLECTUAL PROPERTY RIGHTS OF THIRD PARTIES.

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8.5         Limitation of Damages.  (I) IN NO EVENT SHALL ANY PARTY OR ANY OF ITS AFFILIATES BE LIABLE UNDER THIS AGREEMENT FOR SPECIAL, INDIRECT, INCIDENTAL, PUNITIVE, RELIANCE OR CONSEQUENTIAL DAMAGES (INCLUDING LOST PROFITS, LOST REVENUE OR LOST SAVINGS), WHETHER IN CONTRACT, WARRANTY, TORT, NEGLIGENCE, STRICT LIABILITY OR OTHERWISE, EVEN IF IT HAS NOTICE OF THE POSSIBILITY OF SUCH DAMAGES; PROVIDED, HOWEVER, THAT THE FOREGOING LIMITATION SHALL NOT APPLY TO DAMAGES WITH RESPECT TO (A) A PARTY’S WILLFUL MISCONDUCT, OR (B) A PARTY’S BREACH OF ITS CONFIDENTIALITY OBLIGATIONS UNDER ARTICLE 7.  NOTHING IN THIS SECTION 8.5 (I)  IS INTENDED TO LIMIT OR RESTRI CT THE INDEMNIFICATION RIGHTS OR OBLIGATIONS OF EITHER PARTY UNDER ARTICLE 9 (INDEMNIFICATION) WITH RESPECT TO ANY DAMAGES PAID BY THE OTHER PARTY TO A THIRD PARTY IN CONNECTION WITH A THIRD PARTY CLAIM.

(B) NOTWITHSTANDING ANYTHING HEREIN TO THE CONTRARY, IN NO EVENT SHALL THE TOTAL LIABILITY OF AMGEN ARISING OUT OF, BASED ON OR RELATED TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED HEREUNDER, INCLUDING WITHOUT LIMITATION ANY OBLIGATIONS UNDER THE INDEMNIFICATION PROVISIONS OF ARTICLE 9, EXCEED THE AGGREGATE AMOUNT IT SHALL HAVE RECEIVED FROM CELLDEX HEREUNDER; PROVIDED THAT THE FOREGOING LIMITATION SHALL NOT APPLY TO FRAUD OR INTENTIONAL MISCONDUCT.

The limitation of liability and exclusion of damages herein, shall apply even if a Party had or should have had knowledge, actual or constructive, of the possibility of such damages.  In addition, such limitations of liability and exclusion of damages and the sole and exclusive remedies provided herein:  (i) are a fundamental element of this Agreement, which would not be entered into without such limitations, exclusions and sole/exclusive remedies, (ii) shall apply whether a claim is based on breach of contract, breach of warranty, tort (excluding fraud or intentional misconduct) or otherwise, and (iii) shall apply even if the breach is a total and/or fundamental breach of this Agreement and regardless of whether the limited damages or remedies fail of their essential purpose and/or fail to provide relief to Celldex.

8.6         Covenants.

(a)           No Misappropriation or Infringement.  Celldex covenants to Amgen that Celldex shall not knowingly and willfully misappropriate any trade secret or knowingly and willfully infringe any claim of a patent of another party in its activities to develop, manufacture or commercialize Products.

(b)           No Debarment.  Celldex covenants to Amgen that, in the course of the development and commercialization of Products during the Term, Celldex shall not knowingly use any employee or consultant who is or has been debarred by any Regulatory Authority or is or has been the subject of debarment proceedings by any Regulatory Authority.

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(c)           Compliance with Applicable Law.  Celldex covenants to comply with all statutes and regulations (including statutes, regulations and guidance of Regulatory Authorities) applicable to its activities under this Agreement.

ARTICLE 9

INDEMNIFICATION

9.1         Indemnification by Amgen.  Unless otherwise provided herein, Amgen agrees to indemnify, hold harmless, and defend Celldex, its Affiliates, and their respective directors, officers, employees, and agents (the “Celldex Indemnitees”) from and against any and all Losses resulting from any Third Party suits, claims, actions or demands (collectively, “Third Party Claims”), to the extent arising out of any of the following:

(a)           the internal research use of the Molecules and Materials by or on the behalf of Amgen or its Affiliates pursuant to Section 2.1(b)(i)(A); or

(b)           the Excluded Contracts; or

(c)           a breach by Amgen of a representation, warranty, or covenant in this Agreement; or

(d)           the negligence, recklessness or willful misconduct of Amgen, any of its Affiliates, or any of their respective employees or agents in performing Amgen’s obligations hereunder.

Such indemnity shall not apply to the extent Celldex’s failure to comply with the indemnification procedures set forth in Section 9.3 has materially prejudiced Amgen’s ability to defend against such Third Party Claims or to the extent that it is shown that the Third Party Claim was the result of (i) a breach by Celldex of a representation, warranty, or covenant in this Agreement; or (ii) the negligence, recklessness or willful misconduct of Celldex, any of its Affiliates, or any of their respective employees or agents.

9.2         Indemnification by Celldex.  Unless otherwise provided herein, Celldex agrees to indemnify, hold harmless, and defend Amgen, its Affiliates, and their respective directors, officers, employees, and agents (the “Amgen Indemnitees”) from and against any and all Losses resulting from any Third Party Claims, including claims of infringement of the Excluded Patents, to the extent arising out of any of the following:

(a)           the Transferred Assets, and the research, development, manufacture, possession, storage, transport, importation, use, sale, marketing, or distribution of the Molecules and Products by or on the behalf of Celldex or its Affiliates or Sublicensees; or

(b)           the Third Party Royalty agreement set forth in Exhibit H, with respect to any royalties due and payable on or after the Effective Date; or

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(c)           a breach by Celldex of a representation, warranty, or covenant in this Agreement; or

(d)           the negligence, recklessness or willful misconduct of Celldex, any of its Affiliates, or any of their respective employees or agents in performing Celldex’s obligations hereunder.

Such indemnity shall not apply to the extent Amgen’s failure to comply with the indemnification procedures set forth in Section 9.3 has materially prejudiced Celldex’s ability to defend against such Third Party Claims or to the extent that it is shown that the Third Party Claim was the result of (i) a breach by Amgen of a representation, warranty, or covenant in this Agreement; or (ii) the negligence, recklessness or willful misconduct of Amgen, any of its Affiliates, or any of their respective employees or agents.

9.3         Control of Defense.  Any entity entitled to indemnification under this Article 9 shall give written notice to the indemnifying Party of any Third Party Claims that may be subject to indemnification, promptly after learning of such Third Party Claim. Within a reasonable time after receiving such notice, the indemnifying Party shall assume the defense of such Third Party Claims with counsel reasonably satisfactory to the indemnified Party.  The indemnified Party shall cooperate with the indemnifying Party in such defense. The indemnified Party may, at its option and expense, be represented by counsel of its choice in any action or proceeding with respect to such Third Party Claim.  The indemnifying Party shall not be liable for any litigation costs or exp enses incurred by the indemnified Party without the indemnifying Party’s written consent, such consent not to be unreasonably withheld. The indemnifying Party shall not settle any such Third Party Claim if such settlement (a) does not fully and unconditionally release the indemnified Party from all liability relating thereto or (b) adversely impacts the rights granted to the indemnified Party under this Agreement in a material way, unless the indemnified Party otherwise agrees in writing.  The indemnified Party shall not settle any Third Party Claim for which indemnification is sought hereunder without the prior written consent of the indemnifying Party.

9.4         Insurance.  Celldex shall at its own expense procure and maintain during the term of this Agreement, insurance policy/policies, including product liability insurance, adequate to cover its obligations hereunder and which are consistent with normal business practices of prudent companies similarly situated.  Any insurance shall not be construed to create a limit of Celldex’s liability with respect to its indemnification obligations under Section 9.2. Celldex’s insurance hereunder shall be primary with respect to the obligations for which Celldex is liable hereunder.

9.5         Pre-Effective Date Losses.  In connection with this Agreement and subject to Section 3.1(c)(ii) (Assumption of Risk), Celldex is not assuming any liability for any Losses to the extent resulting from or arising in connection with the research, development, manufacture, possession, storage, transport, importation, use, sale, offer for sale, marketing, importation, or distribution of the Transferred Assets, or the Third Party Royalty agreement set forth on Exhibit H, prior to the Effective Date.

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ARTICLE 10

TERM; TERMINATION

10.1      Term.  This Agreement shall commence on the Effective Date, and shall continue until terminated pursuant to Section 10.2, 10.3, 10.4 or 10.5, or until expiration, on a Product by Product and country by country basis, upon the expiration of the applicable Royalty Term. Upon expiration of the Royalty Term with respect to a Product in any country in the Territory, and payment in full of all amounts owed to Amgen hereunder with respect to such Product in such country, the licenses granted to Celldex under Section 2.1(a) with respect to such Product in such country shall become non-exclusive, fully paid-up and irrevocable, and shall survive any expiration (but not early termination) of this Agreement.

10.2      Termination for Material Breach.  If either Party believes that the other Party is in material breach of this Agreement, then the non-breaching Party shall deliver written notice of such material breach to the breaching Party, specifying the alleged breach.  If the breaching Party fails to cure such material breach within ninety (90) days (thirty (30) days in case of a monetary default) after the receipt of such notice, then the non-breaching Party shall be permitted to terminate this Agreement, effective at the end of such ninety (90) day period (thirty (30) day period in the case of a monetary default).

10.3      Termination for Insolvency.  A Party may terminate this Agreement upon written notice in the event any of the following occurs with respect to the other Party: (i) such other Party becomes bankrupt or insolvent, or files a petition in bankruptcy or makes a general assignment for the benefit of creditors or otherwise acknowledges in writing insolvency, or is adjudged bankrupt, and such other Party (A) fails to assume this Agreement in any such bankruptcy proceeding within thirty (30) days after filing or (B) assumes and assigns this Agreement to a Third Party; (ii) such other Party goes into or is placed in a process of comp lete liquidation; (iii) a trustee or receiver is appointed for any substantial portion of such other Party’s business and such trustee or receiver is not discharged within sixty (60) days after appointment; (iv) any case or proceeding shall have been commenced or other action taken against such other Party in bankruptcy or seeking liquidation, reorganization, dissolution, a winding-up arrangement, composition or readjustment of its debts or any other relief under any applicable bankruptcy, insolvency, reorganization or similar law now or hereafter in effect and is not dismissed or converted into a voluntary proceeding governed by clause (i) above within sixty (60) days after filing; or (v) there shall have been issued a warrant of attachment, execution, distraint or similar process against any substantial part of the property of such other Party and such event shall have continued for a period of sixty (60) days and none of the following has occurred: (A) it is dismissed, (B)&nb sp;it is bonded in a manner reasonably satisfactory to the terminating Party, or (C) it is discharged.

10.4      Termination by Celldex.  Celldex may terminate this Agreement (i) upon one hundred and twenty (120) days prior written notice to Amgen (which written notice shall be dated no earlier than the first anniversary of the Effective Date), or (ii) upon ninety (90) days prior written notice to Amgen, due to a Safety Concern.  If Celldex elects to terminate this

30

Agreement pursuant to Section 10.4 (ii), Celldex shall promptly provide Amgen written details of such Safety Concern.

10.5                  Other Termination.  Except to the extent necessary to defend against a claim of infringement under Licensed Patent Rights, if Celldex, its Affiliates or Sublicensee(s) brings or joins any challenge to the validity of any of the Licensed Patent Rights, then Amgen shall have the right, upon ten (10) days written notice, to terminate this Agreement.

10.6                  Effect of Termination.

(a)                                 Termination by Amgen Pursuant to Sections 10.2, 10.3 or 10.5.  Upon termination of this Agreement by Amgen pursuant to Sections 10.2 or 10.3, Amgen shall have the right within ten (10) days after the effective date of such termination to request Celldex to either:

(i)                                     Use commercially reasonable efforts to promptly transfer and assign the Transferred Assets received from Amgen under this Agreement, together with all of Celldex’s rights and obligations (including but not limited to Celldex’s payment obligations under Article 5) under this Agreement, to a Third Party, at Celldex’s sole cost and expense; or

(ii)                                  Use commercially reasonable efforts to promptly transfer and assign all of Celldex’s rights and obligations under this Agreement with respect to the manufacturing and supply of Products (but expressly excluding the right to commercialize Products), to a Governmental Entity.  In order to enable such Governmental Entity to manufacture and supply Products in accordance with the terms and conditions set forth in this Agreement, Celldex shall use commercially reasonable efforts to:

(a)                                 promptly transfer and assign to such Governmental Entity all of Celldex’s rights and obligations with respect to the manufacture and supply of Products under this Agreement; provided, however, that at the reasonable request of Celldex, Amgen shall have the right but not the obligation, in its sole discretion and election, to delete, waive or modify the payment obligations set forth in Article 5, and any other obligations as may be reasonably requested by Celldex;

(b)                                 promptly assign, transfer, or license, at Celldex’s sole discretion, Assigned Patents claiming the manufacture of Molecules to such Governmental Entity (including prompt transition to such Governmental Entity, appropriate rights for the filing, prosecution, defense, maintenance and enforcement in the Territory of such Assigned Patents);

(c)                                  promptly provide access to such Governmental Entity to all regulatory documents related to the manufacture of the Molecules (including all regulatory filings covering the manufacture of Products);

(d)                                 promptly provide access to such Governmental Entity to all clinical data with respect to Products generated by Celldex prior to the date of such termination;

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(e)                                  promptly transfer to such Governmental Entity reasonable quantities of clinical material, API and/or intermediates of the Molecules, and Products, held by or on behalf of Celldex or its Affiliates at the time of termination of this Agreement, at a reasonable cost to be mutually agreed upon by Celldex and such Governmental Entity;

(f)                                   promptly transfer to such Governmental Entity any remaining Materials held by or on behalf of Celldex or its Affiliates at the time of termination of this Agreement;  and

(g)                                 promptly and smoothly transition the manufacturing of Products from Celldex, its Affiliate or Third Party manufacturer to such Governmental Entity (including the manufacturing processes for bulk and filling and finishing), and further including assigning any contract related to supply or Third Party contract manufacturing to such Governmental Entity (to the extent permissible under such contracts and, if not permissible, Celldex shall use its reasonable efforts to seek the right to so assign such contracts).

(h)                                 Other Transfers and Assignments to Amgen.  To the extent not transferred to a Governmental Entity pursuant to Section 10.6 (a)(ii) (a) through (g), Amgen shall have the right (but not the obligation) to request (within ten (10) days of Amgen’s receipt of Celldex’s written notification of the transfers made to a Governmental Entity, together with specific items transferred to such Governmental Entity, or in the event Celldex has not completed a transfer to a Governmental Entity, then within ten (10) days after Amgen delivers a written request therefor to Celldex) that Celldex shall, at no cost to Amgen:

(1)                                 promptly assign and transfer the remaining Assigned Patents to Amgen or its designee (including cooperating with Amgen to promptly transition to Amgen or its designee sole responsibility for the filing, prosecution, defense, maintenance and enforcement in the Territory of such Assigned Patents);

(2)                                 promptly transfer and assign to Amgen or its designee all regulatory documents related to AMG 949 and AMG 950 and all regulatory filings covering Products, including all Regulatory Documents;

(3)                                 grant to Amgen an exclusive, perpetual and royalty-free license, with the right to sublicense through multiple tiers, under any and all data, information, patents and other intellectual property relating to the Assigned Patents, Licensed Patent Rights, Transferred Assets, and/or Products Controlled by Celldex or its Affiliates to research, develop, make, use, import, offer to sell, or sell Products (which grant shall take effect automatically and does not require further action of either Party);

(4)                                 promptly transition responsibility for commercial development and commercialization of the Products to Amgen or its designee in a manner requested by Amgen and Celldex shall seek to minimize disruption to the development and commercialization of the Products, including upon Amgen’s request assigning any contracts related to the development or commercialization from Celldex or its Affiliates to Amgen or its

32

designee (to the extent permissible under such contracts and, if not permissible, Celldex shall use its reasonable efforts to seek the right to so assign such contracts); and

(5) promptly transfer and assign to Amgen any trademarks adopted for or used in the development or commercialization of Products.

(b)                                 Termination Pursuant to Section 10.4(i).  Upon termination of this Agreement pursuant to Section 10.4(i), Celldex shall promptly comply, at Celldex’s sole cost and expense, with either: (i) Section 10.6(a)(i) above (transfer to a Third Party); or (ii) Section 10.6(a)(ii)(a)-(h) above (transfer to a Governmental Entity).

(c)                                  Termination Pursuant to Section 10.4(ii).  Upon termination of this Agreement pursuant to Section 10.4(ii), Celldex shall promptly transfer and return all Transferred Assets to Amgen, except to the extent Celldex is required by law to retain any of the Transferred Assets.

(d)                                 Consent of Amgen.  Any transfer or assignment to a Third Party or Governmental Entity in accordance with this Section 10.6 shall require the prior written consent of Amgen (such consent not to be unreasonably withheld).

(e)                                  Return of Amgen Know-How and Confidential Information.  In the event of any early termination (but not expiration) of this Agreement Celldex shall return to Amgen within sixty (60) days of such termination all other tangible Amgen Know-How (to the extent not already transferred to a Third Party under Section 10.6(a)(i) or returned to Amgen under Section 10.6(a)(ii)(h) above) and Confidential Information provided to Celldex by Amgen pursuant to this Agreement, and shall use reasonable efforts to delete from its systems all other Confidential Information of Amgen, provided, however, that Celldex may retain a copy of clinical Information and records, and any other Information otherwise required to be retained by Celldex under law.

(f)                                                     Except as expressly set forth herein (including the perpetual licenses granted to Amgen under Section 2.1(b), which will survive), all licenses, rights and obligations under this Agreement shall immediately end upon termination (but not expiration) of this Agreement for any reason.

10.7                  Accrued Rights; Surviving Obligations.  Termination or expiration of this Agreement shall not affect any rights of either Party arising out of any event or occurrence prior to such termination or expiration.  The following provisions shall survive any expiration or termination of this Agreement: Articles 4 (Celldex’s Manufacture and Supply Obligations) (subject to Section 4.4 (Survival of Manufacture and Supply Obligations)); 7 (Confidentiality); 9 (Indemnification); 11 (General Provisions), and Sections 2.1(a) (but solely to the extent such licenses sur vive expiration (but not termination) of this Agreement pursuant to Section 10.1); 2.1(b) (perpetual licenses granted to Amgen); 5.3(f) (Appropriate Measure of Value); 5.6 (Records and Audit); 8.3 (No Representations and Warranties; Exceptions); 8.4 (Disclaimer); 8.5 (Limitation of Damages); 10.6 (Effects of Termination); and 10.7 (Accrued Rights; Surviving Obligations).

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ARTICLE 11

GENERAL PROVISIONS

11.1                  Governing Law.  This Agreement shall be governed by the laws of the State of Delaware, without regard to any conflicts of law principles that would provide for application of the law of a jurisdiction other than Delaware. Each Party hereby irrevocably submits to the exclusive jurisdiction of the courts of the State of Delaware and the courts of the United States of America located in the State of Delaware, for the purposes of any suit, action or other proceeding arising out of or relating to this Agreement or out of any transaction contemplated hereby.

11.2                  Notices.  All notices required or permitted to be given under this Agreement shall be in writing and shall be deemed to have been given (a) upon personal delivery to the Party to be notified at the address set forth below, (b) upon confirmation of receipt if sent by registered or certified mail, return receipt requested, postage prepaid, to the address set forth below, (c) upon delivery if sent via a nationally recognized overnight courier to the address set forth below, with written verification of receipt, or (d) upon confirmation of receipt if sent by facsimile to the number set forth below.

To Amgen:

Amgen Inc.
One Amgen Center Drive

Thousand Oaks, CA  91320-1799

Attention:  Corporate Secretary

Telephone:  (805) 447-1000

Facsimile:  (805) 499-6751

To Celldex:

222 Cameron Drive, Suite 400,

Phillipsburg, NJ 08865

Attn: Chief Executive Officer

Telephone: (908) 454-7120

Facsimile: (908) 454-1911

Any Party may, by written notice to the other, designate a new address or fax number to which notices to the Party giving the notice shall thereafter be mailed or faxed.

11.3                  Force Majeure.  No Party shall be liable for any delay or failure of performance to the extent such delay or failure is caused by circumstances beyond its reasonable control and that by the exercise of due diligence it is unable to prevent, provided that the Party claiming excuse

34

uses its reasonable efforts to overcome the same.  This Section 11.3 shall not excuse any delay or failure by Celldex to pay any amounts owed to Amgen hereunder.

11.4                  Entirety of Agreement.  This Agreement sets forth the entire agreement and understanding of the Parties relating to the subject matter contained herein and merges all prior discussions and agreements between them, and no Party shall be bound by any representation other than as expressly stated in this Agreement, or a written amendment to this Agreement signed by authorized representatives of each of the Parties.

11.5                  Non-Waiver.  The failure of any Party to insist on the performance of any obligation hereunder shall not be deemed to be a waiver of such obligation.  Waiver of any breach of any provision hereof shall not be deemed to be a waiver of any other breach of such provision or any other provision on such occasion or any other occasion.  No waiver, modification, release or amendment of any right or obligation under or provision of this Agreement shall be valid or effective unless in writing and signed by all Parties hereto.

11.6                  Independent Contractors.  Each Party shall act solely as an independent contractor, and nothing in this Agreement shall be construed to give either Party the power or authority to act for, bind or commit the other Party in any way. Nothing herein shall be construed to create the relationship of partnership, principal and agent, joint venture or any other fiduciary relationship between the Parties.

11.7                  Severance.  If any one or more of the provisions of this Agreement is held to be invalid or unenforceable, the provision shall be considered severed from this Agreement and shall not serve to invalidate any remaining provisions hereof.  The Parties shall negotiate in good faith to replace any invalid or unenforceable provision with a valid and enforceable one such that the objectives contemplated by the Parties when entering this Agreement may be realized

11.8                  Assignment.  Neither Party may assign or transfer this Agreement or any rights or obligations hereunder, by operation of law or otherwise, without the prior written consent of the other Party, provided, however that a Party may make such an assignment or transfer, by operation of law or otherwise, without the other Party’s consent to Affiliates or to an entity that acquires all or substantially all of the business of Amgen and its Affiliates or Celldex and/or its Affiliates, respectively, whether in a merger, consolidation, reorganization, acquisition, sale or otherwis e.  To the extent any rights and/or obligations of a Party are held by an Affiliate of such Party then any business transaction or other event that, in each case, causes such Affiliate to cease to be an Affiliate of the Party, shall be deemed an assignment of the rights and/or obligations held by such former Affiliate and require prior written consent of the other Party.  Notwithstanding the foregoing, Amgen shall have the right to assign its rights to payment pursuant to Article 5 without Celldex’s consent. This Agreement shall be binding on the successors and permitted assigns of the assigning Party, and the name of a Party appearing herein shall be deemed to include the name(s) of such Party’s successors and permitted assigns to the extent necessary to carry out the intent of this Agreement.  Any assignment or attempted assignment by either Party in violation of the terms of this Section 11.8 shall be null and void and of no legal effect.

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11.9                  Bankruptcy.  All rights and licenses granted under this Agreement are, and shall otherwise be deemed to be, for purposes of Section 365(n) of Title 11, U.S. Code (the “Bankruptcy Code”), licenses of rights to “intellectual property” as defined under Section 101 of the Bankruptcy Code.  Celldex, as a licensee of such rights under this Agreement, shall retain and may fully exercise any or all of its rights and elections under the Bankruptcy Code.

11.10           Headings; Interpretation.  The headings contained in this Agreement have been added for convenience only and shall not be construed as limiting.  The language used in this Agreement shall be deemed to be the language chosen by the Parties hereto to express their mutual intent and no rule of strict construction shall be applied against any Party.  The words “include,” “includes,” or “including” shall be deemed followed by the words “without limitation.”  The words “herein,” “hereof,” “hereunder,” and other words of similar imp ort in this Agreement refer to this Agreement as a whole, including the exhibits, and not to any particular section, paragraph or clause contained in this Agreement.

11.11           Counterparts.  This Agreement may be executed in one or more counterparts, each of which shall be an original and all of which shall constitute together the same document.

11.12           Performance by Affiliates.  Either Party may perform its obligations and exercise its rights hereunder by or through one or more of its Affiliates, provided that such Party shall be responsible for the acts and/or omissions of any of its Affiliates. To the extent any of the obligations set forth herein are the obligations of Immunex, Amgen hereby undertakes to cause Immunex to perform such obligations.

11.13           Legal Compliance.  The Parties shall review in good faith and cooperate in taking such actions to ensure compliance of this Agreement with all applicable laws.

11.14           Construction.  The Parties mutually acknowledge that they and their attorneys have participated in the negotiation and preparation of this Agreement.  Ambiguities, if any, in this Agreement shall not be construed against any Party, irrespective of which Party may be deemed to have drafted the Agreement or authorized the ambiguous provision.

11.15           Further Acts.  Each Party agrees to execute, acknowledge and deliver such further instruments, and to do all such other acts, as may be necessary or appropriate in order to carry out the purposes and intent of this Agreement.

11.16                 Fees and Expenses. Regardless of whether or not the transactions contemplated by this Agreement are consummated, each Party shall bear its own fees and expenses incurred in connection with the negotiation and execution of this Agreement.

[SIGNATURES ON FOLLOWING PAGE]

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IN WITNESS WHEREOF, the Parties hereto have duly executed this License and Assignment Agreement.

37

EXHIBIT A

AMG 949 Sequence

[*]

* Confidential

EXHIBIT B

AMG 950 Sequence

[*]

* Confidential

2

Exhibit C

Assigned AMG 949/AMG950 Patent Rights

[*]

* Confidential

[*]

* Confidential

2

[*]

* Confidential

3

[*]

* Confidential

4

[*]

* Confidential

5

[*]

* Confidential

6

[*]

* Confidential

7

[*]

* Confidential

8

[*]

* Confidential

9

[*]

* Confidential

10

[*]

* Confidential

11

[*]

* Confidential

12

EXHIBIT D

OTHER ASSIGNED AMG 950 PATENTS

[*]

* Confidential

[*]

* Confidential

2

[*]

* Confidential

3

Exhibit E-1

AMG 949/AMG 950 Licensed Patent Rights

[*]

* Confidential

[*]

* Confidential

2

Exhibit E-2

EASE LICENSED PATENT RIGHTS

[*]

* Confidential

EXHIBIT E-3

NUCLEOTIDE SEQUENCE OF PG5.7 EASE

[*]

* Confidential

[*]

* Confidential

2

[*]

* Confidential

3

[*]

* Confidential

4

Exhibit F

Ongoing Studies

[updated list to be provided]

Exhibit G

Third Party Sublicensees

[*]

* Confidential

Exhibit H

Third Party Royalty Agreement

·                  Royalty agreement effective as of July 1, 1998 by and between American Home Products Corporation, American Cynamid Company and Immunex Corporation.

Exhibit I-1

Form of Assignment for Assigned AMG 949/AMG 950 Patent Rights

ASSIGNMENT

WHEREAS IMMUNEX CORPORATION, (hereinafter, “ASSIGNOR”), a wholly-owned subsidiary of Amgen Inc. and a corporation organized and existing under the laws of the State of Washington, and having a place of business at 51 University Street, Seattle, Washington 98101, is the assignee of interest in inventions set forth in U.S. and foreign patents and U.S. and foreign patent applications and any continuation, continuation-in-part, divisional, substitute, reissues, re-examinations, and extensions thereof (collectively, “Patent Documents”), listed in Appendix A hereto; and

WHEREAS Celldex Therapeutics, Inc., (hereinafter, “ASSIGNEE”), a corporation organized and existing under the laws of the State of Delaware, and having a place of business at 222 Cameron Drive, Suite 400, Phillipsburg, NJ 08865, is desirous of acquiring all interest in and to said inventions and to the Patent Documents listed in Appendix A.

NOW, THEREFORE, be it known to all whom it may concern:

NOW, THEREFORE, for good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, Assignor has sold, assigned, transferred and set over, and by these presents does hereby irrevocably sell, assign, transfer and set over, unto Assignee, its successors, legal representatives and assigns, all of Assignor’s right, title and interest, as of the Effective Date, in, to and under the issued patents set forth on Appendix A and any reissues, reexaminations, and extensions thereof, and the patent applications set forth on Appendix A and all patents of the United States which may be granted thereon, and all divisions, renewals, continuations, and substitute applications thereof, and all patents worldwide that may be granted thereon, and all reissues, reexaminations, and extensions thereo f, together with the right to file such applications and the right to claim for the same the priority rights derived from such patent application under the patent laws of the United States, the International Convention for the Protection of Industrial Property, or any other international agreement or the domestic laws of the country in which any such application is filed, as may be applicable, to be held and enjoyed by ASSIGNEE for its own use and enjoyment, and for the use and enjoyment of its successors and assigns, to the end of the term or terms for which such letters patent may be granted or reissued, as fully and entirely as the same would have been held and enjoyed by ASSIGNOR if this assignment and sale had not been made, each of the foregoing including, to the extent applicable, the right to seek damages and/or injunctive relief in the event of infringement of any such issued patent, with the right to sue for and receive the same for Assignee’s own account and use, solely to the extent such inf ringement occurs from and after the

Effective Date, and, to the extent set forth above, for the use and on behalf of its successors and assigns.

ASSIGNOR HEREBY authorizes and requests the Commissioner of Patents and Trademarks of the United States, and any official of any country or countries foreign to the United States, whose duty it is to issue patents or other evidence or forms of industrial property protection on applications as aforesaid, to issue the same to Assignee, its successors, legal representatives and assigns, in accordance with the terms of this Assignment, and hereby grants the attorney of record the power to insert on this Assignment any further identification of the issued patents and the patent applications set forth on Appendix A that is necessary under the rules of the United States Patent and Trademark Office, and the patent office of any country or countries foreign to the United States, for recordation of this Assignment, and ag rees, without further consideration, at Assignee’s expense, to execute and deliver such other documents that Assignee, its successors and/or assigns may reasonably request that are necessary under the rules of the United States Patent and Trademark Office, and the patent office of any country or countries foreign to the United States, for recordation of this Assignment; provided that Assignee shall be solely responsible for performing all activities in connection with recordation of this Assignment with the United States Patent and Trademark Office, and the patent office of any country or countries foreign to the United States.

ASSIGNOR HEREBY covenants and agrees that it has the full right to convey the interest herein assigned, and ASSIGNOR has not executed, and will not execute, any agreement in conflict herewith.

 [Signatures Appear on the Following Page]

2

IN WITNESS WHEREOF, Assignor has caused this Assignment to be to be executed by its duly authorized representatives effective as of the Effective Date.

STATE OF WASHINGTON

COUNTY OF [                          ]

On [                              ], before me,                                                                 , personally appeared                                                       ;                              ,personally known to me (or proved to me on the basis of satisfactory evidence) to be the person(s) whose name(s) is/are subscribed to the within instrument and acknowledged to me that he/she/they executed the same in his/her/their authorized capacity(ies), and that by his/her/their signature(s) on the instrument the person(s), or the entity upon behalf of which the person(s) acted, executed the instrument.

WITNESS my hand and official seal.

My Commission Expires:

3

Appendix A

Exhibit I-2

Form of Assignment for Other Assigned AMG 950 Patents

ASSIGNMENT

WHEREAS IMMUNEX CORPORATION, (hereinafter, “ASSIGNOR”), a wholly-owned subsidiary of Amgen Inc. and a corporation organized and existing under the laws of the State of Washington, and having a place of business at 51 University Street, Seattle, Washington 98101, is the assignee of interest in inventions set forth in certain U.S. and foreign patents (collectively, “Patent Documents”), listed in Appendix A hereto; and

WHEREAS Celldex Therapeutics, Inc., (hereinafter, “ASSIGNEE”), a corporation organized and existing under the laws of the State of Delaware, and having a place of business at 222 Cameron Drive, Suite 400, Phillipsburg, NJ 08865, is desirous of acquiring all interest in and to said inventions and to the Patent Documents listed in Appendix A.

NOW, THEREFORE, be it known to all whom it may concern:

NOW, THEREFORE, for good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, Assignor has sold, assigned, transferred and set over, and by these presents does hereby irrevocably sell, assign, transfer and set over, unto Assignee, its successors, legal representatives and assigns, all of Assignor’s right, title and interest, as of the Effective Date, in, to and under the issued patents set forth on Appendix A, to be held and enjoyed by ASSIGNEE for its own use and enjoyment, and for the use and enjoyment of its successors and assigns, to the end of the term or terms for which such letters patent may be granted, as fully and entirely as the same would have been held and enjoyed by ASSIGNOR if this assignment and sale had not been made, each of the foregoing including, to the ext ent applicable, the right to seek damages and/or injunctive relief in the event of infringement of any such issued patent, with the right to sue for and receive the same for Assignee’s own account and use, solely to the extent such infringement occurs from and after the Effective Date, and, to the extent set forth above, for the use and on behalf of its successors and assigns.

ASSIGNOR HEREBY authorizes and requests the Commissioner of Patents and Trademarks of the United States, and any official of any country or countries foreign to the United States, whose duty it is to issue patents or other evidence or forms of industrial property protection on applications as aforesaid, to issue the same to Assignee, its successors, legal representatives and assigns, in accordance with the terms of this Assignment, and hereby grants the attorney of record the power to insert on this Assignment any further identification of the issued patents set forth on Appendix A that is necessary under the rules of the United States Patent and Trademark Office, and the patent office of any country or countries foreign to the United States, for recordation of this Assignment, and agrees, without further consid eration, at Assignee’s expense, to execute and deliver such other documents that Assignee, its successors

and/or assigns may reasonably request that are necessary under the rules of the United States Patent and Trademark Office, and the patent office of any country or countries foreign to the United States, for recordation of this Assignment; provided that Assignee shall be solely responsible for performing all activities in connection with recordation of this Assignment with the United States Patent and Trademark Office, and the patent office of any country or countries foreign to the United States.

ASSIGNOR HEREBY covenants and agrees that it has the full right to convey the interest herein assigned, and ASSIGNOR has not executed, and will not execute, any agreement in conflict herewith.

 [Signatures Appear on the Following Page]

2

IN WITNESS WHEREOF, Assignor has caused this Assignment to be to be executed by its duly authorized representatives effective as of the Effective Date.

STATE OF WASHINGTON

COUNTY OF [                          ]

On [                              ], before me,                                                                 , personally appeared                                                       ;                                           ,personally known to me (or proved to me on the basis of satisfactory evidence) to be the person(s) whose name(s) is/are subscribed to the within instrument and acknowledged to me that he/she/they executed the same in his/her/their authorized capacity(ies), and that by his/her/their signature(s) on the instrument the person(s), or the entity upon behalf of which the person(s) acted, executed the instrument.

WITNESS my hand and official seal.

My Commission Expires:

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Appendix A

Exhibit J

Form of Assignment and Assumption Agreement

INSTRUMENT OF ASSIGNMENT AND ASSUMPTION

This Instrument of Assignment and Assumption (this “Agreement”) is made and effective as of this        day of         , 2009 (the “Assignment Effective Date”), by and between Amgen Inc., a Delaware corporation (“Amgen”) and Celldex Therapeutics, Inc.,  a Delaware corporation (“Celldex”). Capitalized terms used but not defined herein shall have the meanings ascribed to such terms in the License and Assignment Agreement (as defined below).

W I T N E S S E T H

WHEREAS, Amgen or one of its Affiliates is a party to each of the contracts set forth on Attachment A hereto (“Assumed Agreements”);

WHEREAS, Amgen and Celldex have entered into a License and Assignment Agreement, dated as of                                             , 2009 (the “License and Assignment Agreement”), pursuant to which, among other things, Amgen has agreed to assign to Celldex, and Celldex has agreed to assume from Amgen, the Assumed Agreements, all on the terms and subject to the conditions set forth in the License and Assignment Agreement;

NOW, THEREFORE, in consideration of the representations, warranties, covenants and agreements contained in the License and Assignment Agreement, the parties hereto, intending to be legally bound hereby, agree as follows:

1.     Assignment of Assumed Agreements.  Amgen hereby irrevocably assigns, transfers and delivers unto Celldex all right, title and interest of Amgen in, to and under the Assumed Agreements solely to the extent they relate to the Molecules as defined in the License and Assignment Agreement (the “Molecules”), and except to the extent such rights relate to liabilities or obligations of Amgen which became due and payable, or were required to be performed, or arise as a result of Amgen’s performance, actions or failure to act on or prior to the Assignment Effective Date of this Agreement, and Celldex hereby accepts such assignment, transfer and delivery, all on the terms and subject to the conditions set forth in the License and Assignment Agreement.

2.     Assumption of Assumed Agreements.  Celldex hereby accepts and assumes all liabilities and obligations of Amgen under the Assumed Agreements solely to the extent they relate to the Molecules, and except to the extent such liabilities and obligations became due and payable, or were required to be performed, or arise as a result of Amgen’s performance, actions or failure to act on or prior to the Assignment Effective Date of this Agreement, all on the terms and subject to the conditions set forth in the License and Assignment Agreement.  To the extent any of the Assumed Agreements relate to molecules or compounds other than the Molecules,

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Amgen expressly retains the rights and obligations of Amgen under such Assumed Agreements with respect to any molecules or compounds other than the Molecules.

3.     Governing Law.  This Agreement shall be governed and construed in accordance with the laws of the State of Delaware, as applied to agreements executed and performed entirely within the State of Delaware, without regard to any applicable principles of conflicts of law.

4.     Counterparts.  This Agreement may be executed in two (2) or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

5.     Successors.  This Agreement shall be binding upon and inure solely to the benefit of each party hereto and their respective successors under the License and Assignment Agreement, and nothing in this Agreement, express or implied, is intended to or shall confer upon any other person or entity any rights, interests, benefits or remedies of any nature whatsoever under or by reason of this Agreement.

6.     Descriptive Headings.  The descriptive headings herein are inserted for convenience of reference only and are not intended to limit or expand on the meaning of the language contained herein.

7.     Severability.  In the event that any one or more of the provision contained herein, or the application thereof in any circumstances, is held invalid, illegal or unenforceable in any respect for any reason, the parties shall negotiate in good faith with a view to the substitution therefor of a suitable and equitable provision in order to carry out, so far as may be valid and enforceable, the intent and purpose of such invalid provision; provided, however, that the validity, legality and enforceability of any such provision in every other respect and of the remaining provisions contained herein shall not be in any way impaired thereby, it being intended that all of the rights and privileges of the parties hereto shall be enforceable to the fullest extent permitted by law.

8.     Entire Agreement.  This Agreement is subject to all of the terms, conditions and limitations set forth in the License and Assignment Agreement, and together with the License and Assignment Agreement constitutes the entire agreement of the parties hereto, and supersedes all prior agreements and understandings, both written and oral, between the parties with respect to the subject matter hereof.  EXCEPT AS EXPRESSLY SET FORTH IN THE LICENSE AND ASSIGNMENT AGREEMENT, AMGEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, AS TO THE ASSUMED AGREEMENTS.

9.     Conflicts.  Notwithstanding anything to the contrary contained in this Agreement, in the event of any conflict between the terms of this Agreement and the terms of the License and Assignment Agreement, the terms of the License and Assignment Agreement shall control.

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(signature page immediately follows)

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

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ATTACHMENT A

Exhibit K

Excluded Contracts

1.               FLT3 Ligand Product License and Supply Agreement effective as of December 15, 1996 by and between ImClone Systems Incorporated and Immunex Corporation.

2.               License Agreement effective as of July 11, 2008 by and between Amgen Inc. and Gamida-Cell Ltd.

3.               Collaboration Agreement effective as of December 23, 2003, as amended, by and between Amgen Inc. and ViaCell, Inc.

4.               Flt3 Receptor Patents License Agreement and License and Supply Agreement effective as of December 16, 1996 by and between ImClone Systems Incorporated and Immunex Corporation.

5.               FLT3 Ligand Agreement effective as of June 29, 1998 by and between Schering Corporation and Schering-Plough, Ltd, and Immunex Corporation.

6.     Gene Transfer Technology License Agreement dated as of February 18, 1992 by and between Immunex Corporation and Targeted Genetics Corporation.

7.               Any Third Party license agreement for which Amgen requires the rights and license pertaining to (i) the use of AMG 949 and AMG 950 in research to evaluate their utility as agents in the diagnosis of diseases, states or conditions); and (ii) the making, having made, using, selling or offering for sale, and development of reagents, derivatives and other products incorporating, using or derived from or based on AMG 949 and/or AMG 950, solely for in vitro laboratory research or in vivo animal research.

8.               Clinical Research Grant Agreement effective as of the June 11, 2006 by and between The University of Texas M.D. Anderson Cancer Center and Amgen Inc.

EXHIBIT L

EXCLUDED PATENTS

Excluded Patents consist of the following Patent Rights:

[*]

* Confidential

[*]

* Confidential

2

[*]

* Confidential

3

SCHEDULE 8.2(f)

[*]

* Confidential

EXHIBIT M

[*]

* Confidential

[*]

* Confidential

2

[*]

* Confidential

3

[*]

* Confidential

4

[*]

* Confidential

5

[*]

* Confidential

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Exhibit 10.2

AMENDMENT TO LOAN DOCUMENTS

This Amendment to Loan Documents is made as of January 1, 2009, by and between Celldex Therapeutics, Inc. successor in interest to Avant Immunotherapeutics, Inc. (“Borrower”) and MASSACHUSETTS DEVELOPMENT FINANCE AGENCY, a body politic and corporate created under Massachusetts General Laws Chapter 23G (“Lender”).

Recitals

A.                                   Borrower made a Promissory Note payable to Lender dated December 22, 2003, in the original principal amount of $1,104,000.00 as decreased in November 2004 to $904,000.00 (the “Note”).

B.                                     To further evidence and to secure the Note, the Borrower entered into certain loan documents also dated December 22, 2003, including, without limitation, a Security Agreement: Equipment (the “Security Agreement”), and certain other documents evidencing and securing the Note (collectively, the “Loan Documents”).

C.                                     Whereas, on October      , 2008, Avant Immunotherapeutics, Inc. changed its name to Celldex Therapeutics, Inc.

D.                                    Lender and Borrower have agreed to amend the Note by an amendment of even date herewith to reflect the name change of the Borrower (the “Note Amendment”).

E.                                      Borrower and Lender have agreed to amend the Loan Documents to reflect the amendment of the Note as set forth in the Note Amendment.

Now, therefore, in consideration of the making of the loan evidenced by the Note and the amendment of the terms thereof and other valuable consideration, Lender and Borrower hereby agree as follows:

1.                                       All references in the Loan Documents to the “Borrower” shall mean Celldex Therapeutics, Inc.

2.                                       All references to the Note or any similar term shall mean the Note as amended by the Note Amendment.

Borrower further ratifies, affirms, represents and acknowledges for the benefit of Lender, as follows:

All terms, provisions, agreements, covenants, and assignments in the Loan Documents, as amended hereby, are ratified and affirmed by Borrower.

All representations and warranties contained in the Loan Documents remain true as of the date hereof.

The Borrower acknowledges that its obligations under the Loan Documents, as amended hereby, remain in full force and effect and that the collateral described therein continues to secure the Loan and the Note as amended by the Note Amendment. This amendment does not in any manner release the Borrower from its obligations under the Loan Documents nor does this amendment in any manner cancel, terminate, or impair the status or priority of any of the terms of the Loan Documents or the liens or security interests granted to the Lender thereunder.

Executed as a sealed instrument as of the date first set forth above.

Exhibit 10.3

ALLONGE TO PROMISSORY NOTE

This Allonge to Promissory Note is made as of January 1, 2009, by and between Celldex Therapeutics, Inc., successor in interest to Avant Immunotherapeutics, Inc., a Delaware corporation, (“Borrower”) and MASSACHUSETTS DEVELOPMENT FINANCE AGENCY, a body corporate and politic created under Massachusetts General Laws chapter 23G, (“Lender”).

Recitals

A.                                   Avant Immunotherapeutics, Inc. made a Promissory Note (the “Note”) payable to Lender dated December 22, 2003 in the original principal amount of $1,104,000.00 as reduced in November, 2004 to $904,000.00 (the “Loan”), secured by a Security Agreement: Equipment also dated December 22,2003 and all other instruments evidencing, securing or given in relation to the loan, (the “Loan Documents”).

B.                                     Lender and Borrower have agreed to amend the Note to reflect the name change of Avant Immunotherapeutics, Inc. to Celldex Therapeutics, Inc.

C.                                     Now, therefore, in consideration of the making of the Loan and the agreement to amend the terms thereof and other valuable consideration, Borrower and Lender hereby agree that the Note is amended as follows:

The Maker of the Note, as defined on page 1 of the Note shall be Celldex Therapeutics, Inc.

This Allonge shall be affixed to the Note and together they shall constitute one instrument.

All terms, provisions, agreements, and covenants in the Note, as amended hereby, are ratified and affirmed by Borrower and the guarantors of the Loan as evidenced by their signatures hereon.

All representations and warranties contained in the Note and Loan Documents remain true as of the date hereof.

Borrower and Lender agree that the Loan Documents are hereby amended so that all references therein to the Note shall mean the Note as amended hereby.

Borrower acknowledges that its obligations under the Note and Loan Documents, as amended hereby, remain in full force and effect. This amendment does not in any manner release the Borrower from its obligations under the Note or the Loan Documents nor does this amendment in any manner cancel, terminate, or impair the status or priority of any of the terms of the Note or the Loan Documents or the liens or security interests granted to the Lender thereunder.

Executed as a sealed instrument as of the date first set forth above.

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Exhibit 10.4

Amendment to Security Agreement

This Amendment to Security Agreement is made as of January 1, 2009, by and between Celldex Therapeutics, Inc. successor in interest to Avant Immunotherapeutics, Inc. (“Borrower”) and MASSACHUSETTS DEVELOPMENT FINANCE AGENCY, a body politic and corporate created under Massachusetts General Laws Chapter 23G (“Lender”).

Recitals

Reference is made to the loan in the original principal amount of $1,104,000.00 as decreased in November 2004 to $904,000.00 (the “Loan”) made by the Lender to Borrower. The Loan is evidenced by that certain Promissory Note (the “Note”) and secured by that certain Security Agreement: Equipment (“Security Agreement”) both dated December 22, 2003. The Security Agreement and the Note, together with all other documents evidencing, securing, or otherwise delivered to the undersigned in connection with the Loan, are referred to, collectively, as the “Loan Documents.”

Borrower is requesting Lender’s consent to the sale of the portion of the Collateral (as defined in the Security Agreement) listed on Exhibit A hereto and its replacement with the equipment listed on Exhibit B hereto (the “Replacement Equipment”). Section 4(e)(iii) of the Security Agreement requires (i) that Lender determine that the replacement equipment has an aggregate market value equal or greater to the Collateral to be sold and (ii) that Borrower grant Lender a first priority security interest in the Replacement Equipment.

Now therefore Borrower and Lender agree as follows:

Pursuant to Section 4(e)(iii) of the Security Agreement, Lender consents to the sale of the portion of the Collateral listed on Exhibit A hereto and the substitution of the Replacement Equipment.

Borrower grants Lender a first priority security interest in the Replacement Equipment.

Borrower further ratifies, affirms, represents and acknowledges for the benefit of Lender, as follows:

All terms, provisions, agreements, covenants, and assignments in the Security Agreement, as amended hereby, are ratified and affirmed by Borrower.

All representations and warranties contained in the Security Agreement remain true as of the date hereof.

The Borrower acknowledges that its obligations under the Security Agreement, as amended hereby, remain in full force and effect and that the collateral described therein continues to secure the Loan and the Note as amended by the Note Amendment.

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Executed under seal this      day of January, 2009.

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Exhibit 10.5

Dr. Rose Ritts

Office of Licensing and Ventures

Duke University

2812 Erwin Rd, Suite 306

P.O. Box 90083

Durham, NC    27705

Re:          Amended and Restated License Agreement between Duke University (“Duke”) and Celldex Therapeutics, Inc. (“Celldex”), dated September 1, 2006 (the “Duke Agreement”)

Ladies and Gentlemen:

As you are aware, pursuant to the Duke Agreement, Duke has licensed to Celldex certain rights owned by Duke.  Celldex proposes to enter into an agreement (the “Pfizer Agreement”) with Pfizer Vaccines LLC (“Pfizer”) pursuant to which Celldex will sublicense to Pfizer the rights licensed to Celldex by Duke under the Duke Agreement.

1.             No Breach.  Duke confirms that, as of the date of this letter agreement (this “Letter Agreement”): (i) the Duke Agreement remains in full force and effect; and (ii) it has not given any notice to Celldex of any breach by Celldex under the Duke Agreement.

2.             Effective Date.  Duke acknowledges that the Pfizer Agreement will not become effective until Celldex and Pfizer have received any clearance that may be required under the Hart-Scott-Rodino Antitrust Improvements Act of 1976.  Celldex agrees to notify Duke promptly as to the effective date of the Pfizer Agreement once it has occurred (the “Effective Date”).  Paragraphs 3, 4, and 5 of this Letter Agreement shall become effective as of the Effective Date.  Except as otherwise expressly provided herein, the provisions of this Letter Agreement shall be effective from the date of this Letter Agreement written above. If Celldex notifies Duke that Celldex and Pf izer have decided not to enter into the Pfizer Agreement or that the Pfizer Agreement has been terminated prior to the Effective Date, this Letter Agreement shall become null and void.  Duke confirms that this Letter Agreement satisfies Celldex’s notice obligation under Section 2.4 of the Duke Agreement with respect to the Pfizer Agreement.

3.             Breach under Duke Agreement.  In the event of any breach by Celldex of the Duke Agreement, Duke shall promptly notify Pfizer in writing of such breach, and Pfizer shall have the right, but no obligation, to cure such breach on behalf of Celldex within sixty (60) days after Pfizer’s receipt from Duke of written notification of such breach.  During such sixty (60) day cure period Duke shall not terminate the Duke Agreement.

4.             Option to Obtain a License Directly from Duke Upon Termination of the Duke Agreement.  In the event Duke has the right to terminate the Duke Agreement for any reason (the “Breached

License”), and the Pfizer Agreement is in force and effect as of the proposed date of termination of the Duke Agreement, Duke shall promptly notify Pfizer, and Pfizer shall have the right to obtain directly from Duke a license agreement on substantially the same terms and conditions set forth in the Breached License (such right, the “License Option”).  Pfizer may exercise the License Option by providing a written notice to Duke within sixty (60) days from the date that Duke notifies Pfizer that Duke has the right to terminate the Breached License.  If Pfizer exercises the License Option, Duke shall enter into a license agreement directly with Pfizer (the “New License Agreement”) on substantially the same terms and conditions as those set forth in the Breached License, including but not limite d to license scope, territory, and duration of license grant; provided however, (i) that Pfizer shall agree in the New License Agreement to terms providing that in no event shall Duke be liable to Pfizer for any actual or alleged breach by Celldex of the Breached License; (ii) that the financial terms of any New License Agreement, including without limitation the running royalty rate, shall in no event be greater than the corresponding financial terms set forth in the Breached License; and (iii) that in no event shall Duke be obliged to accept provisions in any New License Agreement (a) unless such provisions correspond to rights granted by Celldex to Pfizer in the Pfizer Agreement, and such provisions are not in conflict with the material rights, duties and obligations accruing to Celldex under the Breached License; or (b) where such provisions are inconsistent with Duke’s legal obligations under any applicable law.  Duke agrees that it will not terminate th e Breached License until the New License Agreement is fully executed and is in full force and effect.

5.             Assignments.  Duke agrees that if it assigns its rights under the Duke Agreement, or any of the intellectual property licensed to Celldex thereunder, Duke shall cause such assignee to be bound by the terms of this Letter Agreement applicable to Duke.

6.             Confidentiality.  Any information disclosed to or received by Duke relating to the subject matter of the Pfizer Agreement or this Letter Agreement, whether provided to Duke by Pfizer or Celldex, shall be subject to the provisions of Section 6 of the Duke Agreement as Confidential Information of Celldex.

7.             Third Party Beneficiary. The parties hereby agree that Pfizer Vaccines LLC and Pfizer Inc. shall be third party beneficiaries of this Letter Agreement while the Pfizer Agreement is in full force and effect.

8.             Notices.  Any notices required hereunder shall be sent by registered or certified mail or by an equivalent service capable of verification at the address stated below or such other address as to which the parties may provide in the future.

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9.             Miscellaneous.

(a)      Counterparts. This Letter Agreement may be executed (including by facsimile) in any number of counterparts each of which shall be original and all originals of which shall be deemed a single instrument.

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(b)      Full Understanding. This Letter Agreement represents the full understanding among the parties with respect to the subject matter hereof.

(c)      Modification/Waiver. No modification or waiver of this Letter Agreement shall be effective except in a written document signed by the party against whom such waiver or modification is to be enforced.

(d)      No Assignment. This Letter Agreement may not be assigned without the prior written consent of each party hereto except in connection with the sale or transfer of the entire business and assets of the assigning party, or in connection with a permitted assignment by Duke as provided in Section 7.6 of the Duke Agreement. Any other attempt to transfer or assign this Letter Agreement without such consent shall be null and void.

(e)      Independent Contractors. This Letter Agreement shall not constitute any party as the joint venturer, legal representative or agent of any other party hereto, and no party hereto shall have the right or authority to assume or create any obligation on the part of any other party hereto.

(f)       Governing Law. This Letter Agreement shall be governed by and construed in accordance with the laws of the State of Delaware.

[Remainder of Page Intentionally Left Blank]

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Please sign and return a copy of this Letter Agreement to us to acknowledge our mutual agreement on this matter. Thank you, again, for all of your assistance.

Exhibit 10.6

FIRST AMENDMENT TO LEASE

This FIRST AMENDMENT TO LEASE (this “Amendment”) is made as of the 17th day of March, 2005, (the “Effective Date”) by and between MASSACHUSETTS DEVELOPMENT FINANCE AGENCY, a body politic and corporate and a public instrumentality of the Commonwealth of Massachusetts pursuant to Massachusetts General Laws, Chapter 23G, with an address of 160 Federal Street, Boston, Massachusetts 02110 (“Landlord”) and AVANT IMMUNOTHERAPEUTICS, INC., a Delaware corporation, with an address of 119 Fourth Avenue, Needham, Massachusetts (“Tenant”).

RECITALS

WHEREAS, Landlord and Tenant entered into a certain lease dated effective December 22, 2003 (the “Lease”) of certain premises consisting of 11,756 rentable square feet of space (the “Premises”) in the building (the “Building”) located at 151 Martine Street, Fall River, Massachusetts (the “Property”) in the South Coast Research & Technology Park (the “Park”);

WHEREAS, Landlord and Tenant wish to amend the Lease to add to the Premises additional space in which Tenant will install a pH neutralization system for Tenant’s sole use (“Tenant’s pH System”); to grant to Tenant rights to use certain common areas of the Building to install pipes, lines and other necessary conduits from the Premises to Tenant’s pH System and from Tenant’s pH System to Landlord’s main sewer line connecting the entire Building and other parties to the City sewer line (the “Main Sewer Line”); and a right to connect such pipes, lines and other conduits to the Main Sewer Line, subject to the terms set forth herein;

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which is hereby mutually acknowledged, Landlord and Tenant agree as follows:

1.             Capitalized Terms. Unless otherwise defined herein, all capitalized terms used in this Amendment shall have the meanings ascribed to them in the Lease, and all references in the Lease to the “Lease” or “this Lease” or “herein” or “hereunder” or similar terms or to any section thereof shall mean the Lease, or such section thereof, as amended by this Amendment.

2.             Addition to the Premises. The Premises as defined in Section 1 of the Lease and shown on Exhibit A thereto shall, as of the Effective Date, also include the approximately 60 rentable square feet of space in the west wing of the Building on the first floor thereof described on Exhibit A-1 hereto (the “Additional Space”), which is hereby incorporated into and made a part of the Lease. As of the Effective Date, the Premises Square Footage shall be approximately 11,816 rentable square feet. After the build out of the Additional Space pursuant to the Tenant’s System Plans (as hereafter defined), Landlord and Tenant agree to complete and execute the letter attached hereto as Exhibit C to set forth th e exact square footage of the Additional Space and Premises Square Footage.

3.             Fixed Rate; Tenant’s Proportionate Fraction: Neither the amount of the Fixed Rent nor the Annual Fixed Rental Rate shall increase due to the addition of the Additional Space to the Premises. Notwithstanding that the size of the Premises is increased hereby, Landlord and

Tenant agree that the Building Square Footage and Tenant’s Proportionate Fraction set forth in the Lease are not amended hereby.

4.             Terms of the Lease. All terms of the Lease, as modified hereby, apply to the Premises with the same force and effect as they applied to the Premises on the Date of the Lease.

5.             Utilities; Common Area Maintenance Expenses:

5.1           The following is added to Exhibit H of the Lease, the list of items excluded from Common Area Maintenance expenses: all expenses incurred by Landlord in the operation, maintenance, repair, and/or replacement, if necessary, of the Existing pH System (as defined in Section 6.7) in the Building servicing other Building tenants and licensees and any expenses related to any current or additional permits for that existing system.

5.2           As provided in the Lease, Tenant will pay for any electricity required for Tenant’s pH System, which will be metered either by Tenant’s existing electric meter in the Premises or, if necessary, by an additional meter installed by Tenant at its expense.

6.             Tenant’s pH System.

6.1           Tenant may install, operate, maintain and, if necessary, replace Tenant’s pH System and any wastewater pipes and other pipes, lines and conduits associated therewith running from Tenant’s pH System to the Premises on the second floor of the Building and any wastewater pipe, lines and conduits associated therewith running from Tenant’s pH System to the Main Sewer Line (such pipes, lines and conduits and all equipment accessory thereto, collectively, the “Pipes”) and any electric or telephone lines necessary thereto from the Premises on the second floor to Tenant’s pH System (the “Utility Lines”). Tenant shall operate, maintain and, if necessary, replace Tenant’s pH System, Pipes and Utility Lines in good working order throughout the Term of the Lease, at its sole cost and e xpense and at its sole risk, and shall perform the foregoing and shall connect to the Main Sewer Line and discharge all industrial wastewater in compliance with all applicable laws, rules, regulations, permits, and licenses.

6.2           Landlord hereby grants to Tenant, as of the Effective Date, as rights appurtenant to Tenant’s occupancy of the Premises, (i) the right to install, operate, maintain, and, if necessary, replace the Pipes and Utility Lines in those common areas of the Building shown on the plan attached hereto as Exhibit B-1 (collectively, the “System Areas”) and Tenant shall have the right to access such System Areas so as to permit Tenant to operate, maintain and replace the Pipes and Utility Lines, which right of access to the System Areas shall not be exclusive and shall be used concurrently with Landlord, its agents, contractors, tenants, and licensees for purposes of operating and maintaining the Building and systems thereof, (ii) the right to install Tenant’s su bsurface Pipe to the Main Sewer Line in the approximate area shown on Exhibit B-2 labeled “4”-S” and the right to connect such Pipe to the Main Sewer Line, which connection shall be exclusive; and (iii) the right to discharge the product from Tenant’s pH System through such connection into the Main Sewer Line. Tenant acknowledges that while the connection is exclusive the use of the Main Sewer Line is not exclusive and shall be used concurrently by other parties with connections separate from that of Tenant.

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6.3           The plans prepared by Tenant’s engineer for Tenant’s pH System, Pipes, Utility Lines and the connection of the Pipes to the Main Sewer Line are attached hereto as Exhibit B-2 (“Tenant’s System Plans”) and Landlord hereby approves Tenant’s System Plans for all purposes of the Lease, including, without limitation Section 10.4 of the Lease. Tenant covenants to install Tenant’s pH System, Pipes and Utility Lines in substantial compliance with Tenant’s System Plans. Landlord agrees that Tenant may use SPEC Process Engineering & Construction, Inc. as its contractor to perform the installations contemplated by this Amendment and that Landlord waives any requirement that Tenant post a bond or other security for the construction work contemplated by this Amendmen t.

6.4           Upon the expiration or earlier termination of the Lease, as the same may be extended, (the applicable date of the foregoing, the “Lease Termination Date”), all of Tenant’s rights, title and interests in Tenant’s pH System, Pipes, and Utility Lines, and in the System Areas shall automatically terminate and vest in Landlord, and Tenant shall leave Tenant’s pH System, Pipes, and Utility Lines in good working order, repair, and condition, except for reasonable wear and tear and damage for which Landlord or another party not controlled by Tenant is responsible and in compliance with all applicable laws and permits.

6.5           Landlord agrees that it will not (i) connect any other lines, pipes or conduits in the Building to Tenant’s pH System, the Pipes, or the Utility Lines, (ii) discharge any wastewater into Tenant’s pH System, (iii) knowingly take any action that will adversely affect Tenant’s permits or licenses, or (iv) interfere with Tenant’s use of Tenant’s pH System during the Term of the Lease; except that in the event of an emergency, if necessary, Landlord may take action required to protect public safety.

6.6           Tenant shall amend Tenant’s insurance policy required under Section 6.1 (a) of the Lease to extend to and cover Tenant’s pH System, Pipes and Utility Lines, including any property damage thereto.

6.7           Tenant shall be solely responsible at its own cost for obtaining all permits for the installation, use, and operation of Tenant’s pH System, Pipes and Utility Lines and for maintaining such permits, complying with them, filing any reports required by them, and correcting any violations of them. Tenant agrees (i) to provide Landlord with a copy of its permit(s) obtained for Tenant’s pH System promptly after Tenant receives the same, and (ii) to provide Landlord with at least thirty (30) days prior written notice of any proposed material modifications to such permit(s) which Tenant plans to pursue. Landlord shall be solely responsible at its own cost for obtaining all permits for the installation, use, and operation of the existing pH system in the Building (“Existing pH System”) consisting of the existing pH tank and system in the Building, any wastewater pipes, lines and conduits from tenants’ spaces, other than from the Premises, to that system, and any wastewater pipe, lines, and conduits associated therewith running from that system to the Main Sewer Line, and for maintaining such permits, complying with them, filing any reports required by them, and correcting any violations of them.

6.8           During the Lease Term and prior to the Lease Termination Date, Tenant shall clean any debris and repair any damage to and as reasonably necessary replace any components of the System Areas or any other part of the Building, its systems, the Property, or the Park caused by Tenant’s use of Tenant’s pH System, Pipes, Utility Lines and/or the System

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Areas. Tenant acknowledges that the provisions of Section 3.1 concerning the “as is” condition of the Premises apply to the Additional Space and the System Areas.

6.9           Throughout the Term of the Lease, Tenant shall operate, maintain and if necessary replace Tenant’s pH System, the Pipes and Utility Lines and use the Additional Space and the System Areas in a manner that shall not unreasonably disturb Landlord or other Building occupants and guests, including without limitation, users of the Conference Center. To the extent reasonably necessary to comply with the foregoing, Tenant shall insulate the Additional Space and Pipes as noted on the Tenant’s System Plans.

6.10         Tenant has the right under Section 6.2 hereof to connect to and discharge from Tenant’s pH System into the Main Sewer Line. Tenant agrees that it will not (i) connect any other lines, pipes or conduits to the Existing pH System except as provided below, (ii) discharge any wastewater into the Existing pH System except as provided below, (iii) knowingly take any action that will adversely affect Landlord’s permits or licenses, or (iv) interfere with others’ use of the Existing pH System during the Term of the Lease, except that in the event of an emergency, if necessary, Tenant may take action required to protect public safety. Nothing herein shall modify or change any provision of or obligation under Section 7.5 of the Lease. Tenant has the continued right to use the sanitary sewer lines in the Bui lding as provided in the Lease and furthermore shall have the right to continue to use the existing line in the Building from the Premises to the Existing pH System to discharge pH neutral wastewater from the Premises pursuant to its letter agreement/permit dated February 18, 2005, executed by the Fall River Sewer Commission on February 22, 2005, (the “Temporary Permit”) until the Tenant’s pH System is installed and operational and permits for its use have been obtained by Tenant, provided such discharge must be in compliance with all laws and with the Temporary Permit and Tenant shall not knowingly take any action that will adversely affect Landlord’s permits or licenses or interfere with others’ use of the Existing pH System.

6.11         The indemnity provisions of Section 10.5 of the Lease shall apply hereto, including, without limitation, to the installation, use, maintenance, and operation of Tenant’s pH System, Pipes and Utility Lines, all discharges of Tenant’s wastewater, and all actions under permits or licenses related thereto and/or Tenant’s use of the System Areas, and Tenant’s temporary use of the Existing pH System described in Section 6.10 above, and this provision for indemnification shall survive the Lease Termination Date.

7.             Specialized Tenant Improvements. The parties agree that Tenant’s pH System, Pipes, and Utility Lines are not part of the Approved Specialized Tenant Improvements.

8.             Landlord Address: The Landlord Address is hereby amended to be 160 Federal Street, Boston, Massachusetts 02110, Attn: General Counsel.

9.             Ratification. Except as expressly modified by this Amendment, the Lease shall remain in full force and effect, and as further modified by this Amendment, is expressly ratified and confirmed by the parties hereto. This Amendment shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns, subject to the provisions of the Lease regarding assignment and subletting.

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10.           Governing Law; Interpretation; and Partial Invalidity. This Amendment shall be governed and construed in accordance with the laws of the Commonwealth of Massachusetts. If any term of this Amendment, or the application thereof to any person or circumstances, shall to any extent be invalid or unenforceable, the remainder of this Amendment, or the application of such term to persons or circumstances other than those as to which it is invalid or unenforceable, shall not be affected thereby, and each term of this Amendment shall be valid and enforceable to the fullest extent permitted by law. The titles for the paragraphs are for convenience only and not to be considered in construing this Amendment. This Amendment contains all of the agreements of the parties with respect to the subject matter hereof, and supersedes all prior de alings between them with respect to such subject matter. No delay or omission on the part of either party to this Amendment in requiring performance by the other party or exercising any right hereunder shall operate as a waiver of any provision hereof or any rights hereunder, and no waiver, omission or delay in requiring performance or exercising any right hereunder on any one occasion shall be construed as a bar to or waiver of such performance or right on any future occasion.

11.           Counterparts and Authority. This Amendment may be executed in multiple counterparts, each of which shall be deemed an original and all of which together shall constitute one and the same document. Landlord and Tenant each warrant to the other that the person or persons executing this Amendment on its behalf has or have authority to do so and that such execution has fully obligated and bound such party to all terms and provisions of this Amendment.

IN WITNESS WHEREOF, the undersigned executed this Amendment as of the date and year first written above.

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Exhibit 10.7

THIRD AMENDMENT TO LEASE

This THIRD AMENDMENT TO LEASE (this “Amendment”) is made as of the 20th day of December, 2006, (the “Effective Date”) by and between MASSACHUSETTS DEVELOPMENT FINANCE AGENCY, a body politic and corporate and a public instrumentality of the Commonwealth of Massachusetts pursuant to Massachusetts General Laws, Chapter 23G, with an address of 160 Federal Street, Boston, Massachusetts 02110 (“Landlord”) and AVANT IMMUNOTHERAPEUTICS, INC., a Delaware corporation, with an address of 119 Fourth Avenue, Needham, Massachusetts (“Tenant”).

R E C I T A L S

WHEREAS, Landlord and Tenant entered into a certain Lease dated effective December 22, 2003, as amended by that certain First Amendment to Lease dated March 17, 2005 (the “First Amendment”) and that certain Second Amendment to Lease dated as of November 4, 2005 (the “Second Amendment”) (as so amended, collectively, the “Lease”) of certain premises consisting of approximately 14,314 rentable square feet of space (the “Existing Premises”) in the building (the “Building”) located at 151 Martine Street, Fall River, Massachusetts (the “Property”) in the South Coast Research & Technology Park (the “Park”);

WHEREAS, (i) the original premises demised by the Lease consists of 11,756 rentable square feet in the Building, (ii) the Additional Space (as defined in the First Amendment) demised by the First Amendment consists of 71 rentable square feet and (iii) the Expansion Premises (as defined in the Second Amendment) consists of 2,487 rentable square feet on the second (2nd) floor of the Building;

WHEREAS, Landlord and Tenant wish to amend the Lease to (i) provide for the addition of approximately 1,853 rentable square feet on the second (2nd) floor in the Building, being known as Suite 219, as shown on the floor plan attached hereto as Exhibit A-3 (the “Second Expansion Premises”); and (ii) amend certain other terms of the Lease.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which is hereby mutually acknowledged, Landlord and Tenant agree as follows:

1.             Capitalized Terms.  Unless otherwise defined herein, all capitalized terms used in this Amendment shall have the meanings ascribed to them in the Lease, and all references in the Lease to the “Lease” or “this Lease” or “herein” or “hereunder” or similar terms or to any section thereof shall, after the Effective Date, mean the Lease, or such section thereof, as amended by this Amendment.

2.             Demise of Expansion Premises.  Commencing on December 18, 2006 (the “Second Expansion Premises Commencement Date”), Landlord does hereby lease to Tenant and Tenant does lease from Landlord the Second Expansion Premises to have and to hold for the remainder of the Lease Term as set forth in the Lease.  Except as otherwise expressly provided herein, Tenant’s lease of the Second Expansion Premises shall be on all of the terms and conditions of the Lease (including, without limitation, extension rights of Tenant for Extension Terms) and the term of the Lease with respect to the Second Expansion Premises shall be

coterminous with the Original Term (and, if exercised, Extension Terms) of the Lease for the Existing Premises.  As of the Second Expansion Premises Commencement Date, all references in the Lease to (i) the “Premises” and/or the premises demised by the Lease shall mean the Existing Premises and the Second Expansion Premises collectively as shown on the Exhibit A to the Lease,  Exhibit A-1 attached to the First Amendment, Exhibit A-2 attached to the Second Amendment and Exhibit A-3 attached to the Third Amendment; (ii) the “Tenant’s Proportionate Fraction” shall mean 28% which is calculated based upon the rentable square footage of the Premises less the 71 rentable square feet of the Additional Space described in the First Amendment; and (iii) the “Premises Square Footage” shall mean 16 ,167 rentable square feet.

3.             Fixed Rent.  Tenant shall pay to Landlord Fixed Rent with respect to the Expansion Premises in the manner and at the times set forth in the Lease, in the amounts set forth below:

4.             Condition of Second Expansion Premises.  The Second Expansion Premises is being leased in their AS IS condition as of the date of this Lease.  Landlord shall, at Landlord’s sole cost and expense, deliver the Second Expansion Premises to Tenant on the Second Expansion Premises Commencement Date therefor vacant, broom-clean, and with all debris and personal property removed therefrom.

5.             Utility Payments.  From and after the Second Expansion Premises Commencement Date, Tenant shall be responsible for the payment of all utilities used and consumed in the Second Expansion Premises directly to the utility companies if the Second Expansion Premises are separately metered or to Landlord if the Second Expansion Premises is sub-metered for such utility usage; provided, however, that (i) costs for electricity for electrical plugs in the Second Expansion Premises shall be paid to Landlord by Tenant on the basis of a sub-meter and (ii) Tenant shall pay for electricity for lights in the Second Expansion Premises based upon Tenant’s pro rata share of the costs supplied to the leaseable areas of the Building which are not separately metered or submetered for determinatio n of electrical usage.  Tenant’s pro rata share under clause (ii) of the prior sentence shall be determined by a fraction (expressed as a percentage), the numerator of which is 1,853 rsf and the denominator of which is the total

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rentable square footage of all leaseable areas of the Building (exclusive of common areas for which Tenant pays Tenant’s Proportionate Fraction of electrical costs pursuant to Section 7.3 of the Lease) which are served by the same electrical meter as the Second Expansion Premises (i.e., such denominator is 5,491 rsf; accordingly, expressed as a percentage, Tenant’s pro rata share under clause (ii) of the prior sentence is 33.75%) .  Tenant shall pay the utility company directly for all telephone and telecommunications service to the Second Expansion Premises.

6.             Use of Second Expansion Premises.  Notwithstanding any terms or provisions of the Lease to the contrary, including without limitation, the provisions of the first sentence of Section 10.1 of the Lease, Tenant shall use the Second Expansion Premises for general office purposes only and for no other uses whatsoever.

7.             Inapplicable Provisions.  Sections 4.2 and 4.3 of the Lease shall not be applicable to the Second Expansion Premises or any work therein performed by Tenant.

8.             Ratification.  Except as expressly modified by this Amendment, the Lease shall remain in full force and effect, and as further modified by this Amendment, is expressly ratified and confirmed by the parties hereto.  This Amendment shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns, subject to the provisions of the Lease regarding assignment and subletting.

9.             Brokerage.  Landlord and Tenant each represent and warrant to the other that neither of them has employed or dealt with any broker, agent or finder carrying on the negotiations relating to this Amendment to the Lease.  Tenant shall indemnify and hold Landlord harmless from and against any claim or claims for brokerage or other commissions asserted by any broker, agent or finder engaged by Tenant or with whom Tenant has dealt.  Similarly, Landlord shall indemnify and hold Tenant harmless from and against any claims asserted by any broker, agent or finder engaged by Landlord or with whom Landlord has dealt.  The representations and warranties contained in this Section 9 shall survive any termination of the Lease.

10.           Governing Law; Interpretation; and Partial Invalidity.  This Amendment shall be governed and construed in accordance with the laws of the Commonwealth of Massachusetts.   If any term of this Amendment, or the application thereof to any person or circumstances, shall to any extent be invalid or unenforceable, the remainder of this Amendment, or the application of such term to persons or circumstances other than those as to which it is invalid or unenforceable, shall not be affected thereby, and each term of this Amendment shall be valid and enforceable to the fullest extent permitted by law.  The titles for the paragraphs are for convenience only and not to be considered in construing this Amendment.  This Amendment contains all of the agreements of the parties with respect to the subject matter hereof, and supersedes all prior dealings between them with respect to such subject matter.  No delay or omission on the part of either party to this Amendment in requiring performance by the other party or exercising any right hereunder shall operate as a waiver of any provision hereof or any rights hereunder, and no waiver, omission or delay in requiring performance or exercising any right hereunder on any one occasion shall be construed as a bar to or waiver of such performance or right on any future occasion.

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11.           Counterparts and Authority.  This Amendment may be executed in multiple counterparts, each of which shall be deemed an original and all of which together shall constitute one and the same document. Landlord and Tenant each warrant to the other that the person or persons executing this Amendment on its behalf has or have authority to do so and that such execution has fully obligated and bound such party to all terms and provisions of this Amendment.

[Signatures Commence on Following Page]

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IN WITNESS WHEREOF, the undersigned executed this Amendment as of the date and year first written above.

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Exhibit A-3 — Plan of Second Expansion Premises

Exhibit 10.8

FIFTH AMENDMENT TO LEASE

This FIFTH AMENDMENT TO LEASE (this “Amendment”) is made as of the 3rd day of October, 2008, (the “Effective Date”) by and between MASSACHUSETTS DEVELOPMENT FINANCE AGENCY, a body politic and corporate and a public instrumentality of the Commonwealth of Massachusetts pursuant to Massachusetts General Laws, Chapter 23G, with an address of 160 Federal Street, Boston, Massachusetts 02110 (“Landlord”) and CELLDEX THERAPEUTICS, INC. (formerly AVANT Immunotherapeutics, Inc.), a Delaware corporation, with an address of 119 Fourth Avenue, Needham, Massachusetts (“Tenant”).

R E C I T A L S

WHEREAS, Landlord and Tenant entered into a certain Lease dated effective December 22, 2003, as amended by that certain First Amendment to Lease dated March 17, 2005 (the “First Amendment”), that certain Second Amendment to Lease dated as of November 4, 2005 (the “Second Amendment”), and by that certain Third Amendment To Lease dated as of December 20, 2006 (the “Third Amendment”) of certain premises consisting of approximately 16,167 rentable square feet of space (the “Existing Premises”) in the building (the “Building”) located at 151 Martine Street, Fall River, Massachusetts (the “Property”) in the South Coast Research & Technology Park (the “Park”);

WHEREAS, the Existing Premises is comprised of: (i) the original premises demised by the Lease, as amended through the Third Amendment, being 11,756 rentable square feet in the Building on the second (2nd) floor, (ii) the Additional Space (as defined in the First Amendment) demised by the First Amendment, being 71 rentable square feet on the first (1st) floor, (iii) the Expansion Premises (as defined in the Second Amendment), being 2,487 rentable square feet on

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the second (2nd) floor of the Building, and (iv) the Second Expansion Premises (as defined in the Third Amendment), being 1,853 rentable square feet on the second (2nd) floor of the Building;

WHEREAS, Landlord and Tenant entered into a certain Fourth Amendment to Lease dated as of July 18, 2008 (the “Fourth Amendment”), which provided for an additional 2,382 rentable square feet of space (referred to therein as the “Third Expansion Premises”) to be added to the Existing Premises.

WHEREAS, Landlord and Tenant have agreed to add, in lieu of the Third Expansion Premises, different premises in the Building to the Existing Premises under the Lease, and to void in its entirety the Fourth Amendment.

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which is hereby mutually acknowledged, Landlord and Tenant agree as follows:

1.             Capitalized Terms.  Unless otherwise defined herein, all capitalized terms used in this Amendment shall have the meanings ascribed to them in the Lease, and all references in the Lease to the “Lease” or “this Lease” or “herein” or “hereunder” or similar terms or to any section thereof shall, after the Effective Date, mean the Lease, or such section thereof, as amended by this Amendment.

2.             Nullity of Fourth Amendment.  The parties agree that the Fourth Amendment and all of its terms and provisions are hereby null and void and of no force or effect.

3.             Demise of Substitute Third Expansion Premises.  Commencing on November 1, 2008 (the “Substitute Third Expansion Premises Commencement Date”), Landlord does hereby lease to Tenant and Tenant does lease from Landlord the approximately 4,864 rentable square feet on the second (2nd) floor of the Building, being known as Suites 223, 224, 225, 226, 227, 228, 229 and 230, as shown on the floor plan attached hereto as Exhibit A-5 (the “Substitute

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Third Expansion Premises”) to have and to hold for the remainder of the Lease Term as set forth in the Lease.  Except as otherwise expressly provided herein, Tenant’s lease of the Substitute Third Expansion Premises shall be on all of the terms and conditions of the Lease (including, without limitation, extension rights of Tenant for Extension Terms) and the term of the Lease with respect to the Substitute Third Expansion Premises shall be coterminous with the Original Term (and, if exercised, Extension Terms) of the Lease for the Existing Premises.  As of the Substitute Third Expansion Premises Commencement Date, all references in the Lease to (i) the “Premises” and/or the premises demised by the Lease shall mean the Existing Premises and the Substitute Third Expansion Premises collectively as shown on the Exhibit A to the Lease,  Exhibit A-1 atta ched to the First Amendment, Exhibit A-2 attached to the Second Amendment, Exhibit A-3 attached to the Third Amendment and on Exhibit A-5 attached to this Amendment; (ii) the “Tenant’s Proportionate Fraction” shall mean 36.47% which is calculated based upon the rentable square footage of the Premises less the 71 rentable square feet of the Additional Space described in the First Amendment; and (iii) the “Premises Square Footage” shall mean 21,031 rentable square feet.

4.             Fixed Rent. Commencing on the Substitute Third Expansion Premises Commencement Date, Tenant shall pay to Landlord Fixed Rent with respect to the Substitute Third Expansion Premises in the manner and at the times set forth in the Lease, in the amounts set forth below:

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5.             Condition of Substitute Third Expansion Premises.  Except for the installation of two (2) Building standard HVAC VAV boxes in the Substitute Third Expansion Premises (the “Landlord’s Substitute Third Expansion Premises Work”), which installation Landlord shall perform on or before the Substitute Third Expansion Premises Commencement Date, the Substitute Third Expansion Premises is being leased in their AS IS condition as of the date of this Lease.  Landlord shall perform Landlord’s Substitute Third Expansion Premises Work in a good and workmanlike manner and in compliance with all applicable building, fire, health and other codes, regulations, ordinances and laws and with all applicable insurance requirements.

6.             Utility Payments. From and after the Substitute Third Expansion Premises Commencement Date, Tenant shall be responsible for the payment of all utilities used and consumed in the Substitute Third Expansion Premises directly to the utility companies if the Substitute Third Expansion Premises is separately metered or to Landlord if the Substitute Third Expansion Premises is sub-metered for such utility usage; provided, however, that (i) costs for electricity for electrical plugs in the Substitute Third Expansion Premises shall be paid to Landlord by Tenant on the basis of a sub-meter and (ii) Tenant shall pay for electricity for lights in the Substitute Third Expansion Premises based upon Tenant’s pro rata share of the costs supplied to the leaseable areas of the Building which are not separately metered or subm etered for determination of electrical usage.  Tenant’s pro rata share under clause (ii) of the prior

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sentence shall be 8.46%.  Tenant shall pay the utility company directly for all telephone and telecommunications service to the Substitute Third Expansion Premises.

7.             Inapplicable Provisions.  Sections 4.2 and 4.3 of the Lease shall not be applicable to the Substitute Third Expansion Premises or any work therein performed by Tenant.

8.             Exhibit H of the Lease shall be amended by deleting paragraph 27 thereof and by substituting therefor the following:

“27.  Costs to supply compressed air to the leasable areas of the Building, provided, however, that in the event Tenant utilizes the Building’s compressed air unit(s) (the “Building CA System”) for the supply of compressed air to the Premises, then the cost of such service shall be included in the common area maintenance expenses.  Notwithstanding the foregoing, if only the Existing Premises (as such term is defined in the Second Amendment to Lease) utilizes the Building CA System, then Tenant will only be responsible to pay 20.45% of the common area maintenance expenses associated with the Building CA Systems and if only the Expansion Premises (as such term is defined in the Second Amendment to Lease) utilizes the Building CA System, then Tenant will only be responsible to pay 4.33% of such costs, and if only the Substitute Third Expansion Premises (as such term is de fined in the Fifth Amendment to Lease) utilizes the Building CA System, then Tenant will only be responsible to pay 8.46% of such costs.”

9.             Replacement Signage To Reflect Change In Tenant’s Name.  Tenant shall obtain Landlord’s prior written consent prior to replacing its existing signage at the Building to reflect Tenant’s change in name, including the exterior sign located on the Building, it being agreed that

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Landlord shall have the right to approve the color, size, design and installation methods of such replacement signage.  Tenant shall be responsible for paying all costs associated with replacing such signage and shall be responsible for the costs of all repairs and replacements to the Building in connection with the removal of any existing signs and the installation of any replacement signs.  Without limiting the foregoing, Tenant shall be responsible for any repairs or replacements required to be made to the Alucobon panels on the exterior of the Building that are caused by the removal of the existing Building exterior sign and the installation of a replacement sign.  Any repairs or replacements to such Alucobon panels shall be made by a contractor approved by Landlord, which contractor shall also be an Alucobon-approved contractor.

Landlord’s property manager shall change the identification of Tenant in the outside tenant directory for the Building to reflect Tenant’s change in name, and Tenant shall reimburse Landlord for such costs within fifteen (15) days of Landlord’s billing therefor.

10.           Ratification. Except as expressly modified by this Amendment, the Lease shall remain in full force and effect, and as further modified by this Amendment, is expressly ratified and confirmed by the parties hereto.  This Amendment shall be binding upon and inure to the benefit of the parties hereto and their respective successors and assigns, subject to the provisions of the Lease regarding assignment and subletting.

11.           Brokerage. Landlord and Tenant each represent and warrant to the other that neither of them has employed or dealt with any broker, agent or finder carrying on the negotiations relating to this Amendment. Tenant shall indemnify and hold Landlord harmless from and against any claim or claims for brokerage or other commissions asserted by any broker, agent or finder engaged by Tenant or with whom Tenant has dealt.  Similarly, Landlord shall indemnify and hold Tenant harmless from and against any claims asserted by any broker, agent

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or finder engaged by Landlord or with whom Landlord has dealt.  The representations and warranties contained in this Section 11 shall survive any termination of the Lease.

12.           Governing Law; Interpretation; and Partial Invalidity.  This Amendment shall be governed and construed in accordance with the laws of the Commonwealth of Massachusetts.   If any term of this Amendment, or the application thereof to any person or circumstances, shall to any extent be invalid or unenforceable, the remainder of this Amendment, or the application of such term to persons or circumstances other than those as to which it is invalid or unenforceable, shall not be affected thereby, and each term of this Amendment shall be valid and enforceable to the fullest extent permitted by law.  The titles for the paragraphs are for convenience only and not to be considered in construing this Amendment.  This Amendment contains all of the agreements of the parties with respect to the subject matter hereo f, and supersedes all prior dealings between them with respect to such subject matter.  No delay or omission on the part of either party to this Amendment in requiring performance by the other party or exercising any right hereunder shall operate as a waiver of any provision hereof or any rights hereunder, and no waiver, omission or delay in requiring performance or exercising any right hereunder on any one occasion shall be construed as a bar to or waiver of such performance or right on any future occasion.

13.           Counterparts and Authority.  This Amendment may be executed in multiple counterparts, each of which shall be deemed an original and all of which together shall constitute one and the same document. Landlord and Tenant each warrant to the other that the person or persons executing this Amendment on its behalf has or have authority to do so and that such execution has fully obligated and bound such party to all terms and provisions of this Amendment.

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IN WITNESS WHEREOF, the undersigned executed this Amendment as of the date and year first written above.

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Exhibit A-5 — Plan of Substitute Third Expansion Premises

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Exhibit 10.9

SIXTH AMENDMENT TO NOTICE OF LEASE

Reference is hereby made to that certain Notice of Lease dated December 22, 2003 and recorded with the Bristol County (Fall River District) Registry of Deeds (“Registry”) in Book 5268, Page 285, as amended by that certain Amended Notice of Lease dated March 16, 2005 and recorded with the Registry in Book 6116, Page 308; that certain Second Amendment to Notice of Lease dated August 22, 2005, and recorded with the Registry in Book 6348, Page 24; that certain Third Amendment to Notice of Lease dated December 19, 2006, and recorded with the Registry in Book 6562, Page 346; that certain Fourth Amendment to Notice of Lease dated July 18, 2008 and recorded with the Registry in Book      , Page                ; and that certain Fifth Amendment to Notice of Lease dated as of October 3, 2008, and recorded in the Registry in Book                , Page                 (the foregoing collectively referred to as the “Notice of Lease”) with respect to a certain lease agreement by and between Massachusetts Development Finance Agency, a body politic and corporate and a public instrumentality of the Commonwealth of Massachusetts pursuant to Massachusetts General Laws, Chapter 23G (the “Landlord”), and Celldex Therapeutics, Inc. (formerly AVANT Immunotherapeutics, Inc.) a Delaware corporation (the “Tenant”) dated December 22, 2003, as affected by that certain First Amendment to Leas e (the “First Amendment”) dated March 17, 2005; that certain Second Amendment to Lease dated as of November 4, 2005 (the “Second Amendment”); that certain Third Amendment to Lease dated December 20, 2006 (the “Third Amendment”); that certain Fourth Amendment to Lease dated July 18, 2008 (the “Fourth Amendment”); and that certain Fifth Amendment to Lease dated as of October 3, 2008 (the “Fifth Amendment”) (as so amended, the “Original Lease”).

The Original Lease continues to be effective and has been amended by that certain Sixth Amendment to Lease dated as of August 20, 2009 (the “Sixth Amendment”) to (i) add to the original Premises (as described in the Third Amendment) an additional 2,382 rentable square feet as more particularly described in the Sixth Amendment (the “Fourth Expansion Premises”) and (ii) to amend certain other terms of the Original Lease. The Original Lease as amended by the Sixth Amendment is referred to herein as the “Lease”.