LICENSE AGREEMENT

Exhibit 10.52

***Text Omitted and Filed Separately
Confidential Treatment Requested
Under 17 C.F.R. §§ 200.80(b)(4) and
240.24b-2(b)(1)

LICENSE AGREEMENT

     LICENSE AGREEMENT dated December 30, 2005 by and between IDM Pharma, Inc., a Delaware corporation (“ IDM ”), and Pharmexa, Inc., a Delaware corporation (hereinafter “ Pharmexa ”) (each, a “ Party ” and, collectively, the “ Parties ”).

WITNESSETH:

     WHEREAS, IDM and Pharmexa have entered into an Asset Purchase Agreement dated November 23, 2005 (the “ Asset Purchase Agreement ”);

     WHEREAS, it is a condition precedent to the consummation of the transactions contemplated by the Asset Purchase Agreement that the Parties enter into this Agreement;

     WHEREAS, pursuant to the Asset Purchase Agreement, Pharmexa has acquired IDM’s entire right and title to PADRE ^® ; and

     WHEREAS, IDM desires to obtain a license to PADRE ^® and the related Licensed Patents and Licensed Know-How, and Pharmexa is willing to grant such license and right to IDM, subject to the terms and conditions hereinafter set forth;

     NOW THEREFORE, in consideration of the mutual covenants and agreements contained herein, and intending to be bound, and it being understood that the above recitals shall have the same value as the stipulations that follow, the Parties hereby agree as follows:

      ARTICLE 1 . CERTAIN DEFINITIONS .

     As used in this Agreement, each term listed below has the meaning which is given after it:

     1.1 “ Affiliate ” means, with respect to each Party, any person, corporation or other business entity that controls, is controlled by or is under common control with such Party, but for only so long as such control exists. For the purpose of this definition, “control” means the ability, directly or indirectly, to vote or direct the vote of fifty percent (50%) or more of the outstanding voting stock of an entity (or other form of ownership interest with respect to an entity that is not a corporation), or to otherwise direct or cause the direction of the management and policies of an entity.

     1.2 “ Breach ” has the meaning set forth in Section 8.2(b).

     1.3 “ Cancer ” means any disease caused or characterized by an uncontrolled or abnormal cell division or growth within any part of the body, irrespective of cause or origin.

     1.4 “ Confidential Information ” of a Party means any confidential or proprietary information (including any technology, know-how, Patent application, test result, research study, business plan, budget, forecast or projection) relating directly or indirectly to the business of

such Party or any Affiliate, predecessor or successor of such Party (whether prepared by such Party or by any other person and whether or not in written form) that is or has been made available to the other Party or any of its Affiliates or representatives, including but not limited to information related to PADRE ^® .

     1.5 “ Effective Date ” means the date of this Agreement first written above.

     1.6 “ Field ” means all Cancer indications other than (i) indications covered by exclusive rights to use PADRE ^® for Cancer indications previously licensed by IDM (through its predecessor, Epimmune Inc.) to Pharmexa A/S described in Schedule A and (ii) other exclusive rights to use PADRE ^® for Cancer indications granted by IDM to Third Parties as described on Schedule A .

     1.7 “ IDM Cancer Product ” means a pharmaceutical product directed exclusively for the treatment of Cancer that was conceived by IDM and for which IDM makes substantive development efforts [. . . *** . . .] . For the purpose of clarification, an IDM Cancer Product shall not include (i) products conceived and/or developed [. . . *** . . .] and (ii) products conceived by IDM but for which no substantive efforts towards development are made by IDM.

     1.8 “ Indemnitee ” means a Person entitled to indemnification pursuant to Article 7.

     1.9 “ Indemnitor ” means a Person required to indemnify another Person pursuant to Article 7.

     1.10 “ Invention ” has the meaning set forth in Section 4.4.

     1.11 “ Licensed Know-How ” means all methods, procedures, trade secrets, formulas, techniques, assays, protocols, procedures, processes, systems, specifications, data, sequence information, algorithms, computer models, results of clinical trials and technical data owned or controlled by Pharmexa as of the Effective Date or during the term of this Agreement, including any Inventions, which are not included in the Licensed Patents, in each case which are necessary or useful for the commercial exploitation of the Licensed Patents and which are not generally publicly known, including, without limitation, any such methods, procedures, trade secrets, formulas, techniques, assays, protocols, procedures, processes, systems, specifications, data, sequence information, algorithms, computer models, results of clinical trials and technical data assigned to Pharmexa by IDM under the Asset Purchase Agreement that are necessary or useful for the commercial exploitation of the Licensed Patents.

     1.12 “ Licensed Patents ” means all Patents owned or controlled by Pharmexa that relate to PADRE ^® , including without limitation those listed on Schedule B, and any abandoned parent applications of any Patents listed therein.

     1.13 “ Licensed Technology ” means the Licensed Patents and Licensed Know-How.

     1.14 “ PADRE ^® ” or a pan-DR epitope or pan-DR peptide means a family of proprietary molecules that are universal helper T cell epitopes capable of binding antigen binding sites on major histocompatibility complex (MHC) molecules encoded by substantially all alleles of a DR locus, including, without limitation, peptides claimed or disclosed in United Sates Patent Application Serial No. 08/121,101 filed September 14, 1993 or any patent applications, such as continuing applications (including, without limitation, any continuations, continuations-in-part or divisional thereof) or patents issuing therefrom. Such peptides are also referred to as pan DR binding epitopes or peptides and include, without limitation, AKXVAAWTLKAAA (using the single letter designation for amino acids), wherein X is cyclohexylalanine or phenylalanine, and other peptides claimed and/or disclosed in the Patents described in this Section 1.13.

     1.15 “ Parties ” means Pharmexa and IDM, collectively.

     1.16 “ Party ” means either Pharmexa or IDM, as the context may require.

     1.17 “ Patents ” means all U.S. patents and patent applications, including, without limitation, certificates of invention and applications for certifications of invention, registered designs and registered design applications, industrial designs and industrial design applications and registrations, reissues, reexaminations, extensions, substitutions, confirmations, registrations, revalidations, renewals, term restorations, additions, provisionals, continuations, continuations-in-part, divisions, continued prosecution applications, and requests for continued examination thereof, and any foreign equivalents of any of the foregoing.

     1.18 “ Person ” means any individual, corporation, partnership, limited liability company, private or public institution, group, tribunal, government authority or other entity.

     1.19 “ Third Party ” means any Person other than IDM, Pharmexa, or their respective Affiliates.

      ARTICLE 2 . LICENSE GRANT .

     2.1 Grant of License .

          (a) Pharmexa hereby grants to IDM a non-exclusive, perpetual, royalty-free, fully paid up, worldwide license, with the right to grant sublicenses (subject to the limitations set forth in Schedule 2.1(b)), under the Licensed Technology to research, develop, make, have made, use, import, export, sell, offer for sale, promote, market, distribute, commercialize, and have sold, distributed and commercialized IDM Cancer Products in the Field (the “ License ”).

          (b) Notwithstanding anything to the contrary set forth in this Agreement, IDM may not grant sublicenses to, sell, or otherwise transfer its rights to the Licensed Technology set forth in Section 2.1(a) other than in connection with the sublicense, sale or transfer of an IDM Cancer Product and as permitted pursuant to Section 10.4. Each such sublicense granted by IDM will limit the sublicensee’s use of the Licensed Technology to the development and commercialization of the specific IDM Cancer Product that is the subject of the sublicense.

     2.2 Rights Retained by Pharmexa . Notwithstanding anything to the contrary herein, Pharmexa retains all rights under the Licensed Technology not explicitly granted to IDM under Section 2.1.

     2.3 Reasonable Access . Pharmexa will provide IDM with reasonable access to appropriate personnel of Pharmexa via telephone, facsimile or electronic mail during Pharmexa’s regular business hours in order to discuss questions relating to the use of the Licensed Technology, not to exceed a total of [. . . *** . . .] per month, up to a maximum of [. . . *** . . .] during the first year of this Agreement and a maximum of [. . . *** . . .] during each succeeding year.

      ARTICLE 3 . CONSIDERATION FOR LICENSE .

     3.1 Consideration . Pharmexa acknowledges and agrees that the sole consideration for the grant of the License is the consummation by IDM of the transactions contemplated by the Asset Purchase Agreement. No other license fees, milestones, royalties or other consideration shall be paid or given to Pharmexa by IDM for the rights granted under this Agreement.

      ARTICLE 4 . PATENTS .

     4.1 No Assignment . The License shall not constitute an assignment of the Licensed Technology, nor a grant to IDM of any ownership right or title therein or any other right, other than the use of PADRE ^® and practice of the Licensed Technology in accordance with the terms of this Agreement. Nothing contained in this Agreement shall be construed as conferring upon IDM by implication, estoppel or otherwise any license or other rights under any patent or unpatented technology belonging to Pharmexa, except rights expressly granted hereunder to IDM.

     4.2 Patent Filing, Prosecution and Maintenance .

          (a) Pharmexa shall be responsible for and have complete discretion in connection with the preparation, filing, prosecution, defense and maintenance of the Licensed Patents. Pharmexa shall keep IDM informed of all material developments pertaining to the Licensed Patents and give consideration to IDM’s recommendations and concerns regarding the prosecution and maintenance of the Licensed Patents.

          (b) Pharmexa will pay all costs associated with the prosecution and maintenance of the Licensed Patents.

          (c) Pharmexa shall not allow an issued Patent included in the Licensed Patents to lapse without providing prior written notice to IDM. In the event that Pharmexa decides to abandon or discontinue the prosecution or maintenance of any of the Licensed Patents, IDM shall have the right to undertake such prosecution or maintenance in its own name at its expense through counsel of its own choosing. If IDM exercise such right, (i) Pharmexa shall provide such cooperation as IDM may request, at IDM’s expense, including but not limited to

delivering to IDM all records pertaining to such Patent executing any and all documents as may be needed to assign such Licensed Patent to IDM, without additional consideration being payable by IDM for such assignment other than actual costs associated with such transfer, and (ii) upon assignment, such Patent shall cease to be a Licensed Patent. In such event, IDM will grant to Pharmexa a non-exclusive, perpetual, royalty-free, fully paid up license under such Patent, with the right to grant sublicenses to research, develop, make, have made, use, import, sell, offer for sale, promote, market, distribute, commercialize and have sold pharmaceutical products in the country in which the Patent is granted.

     4.3 Infringement Actions .

          (a) In the event that a Party becomes aware of actual or threatened infringement by a Third Party of any of the Licensed Patents anywhere in the world, such Party shall (i) promptly notify the other Party in writing of the occurrence such infringement and (ii) provide the other Party with the full details of any such infringement to the best of its knowledge.

          (b) Pharmexa shall have the exclusive right to commence a lawsuit to enjoin the infringing activity or take such other action against the Third Party as it determines is appropriate, at Pharmexa’s expense. IDM will cooperate with Pharmexa at Pharmexa’s request in connection with any such action. IDM will have the right to participate in any legal action commenced by Pharmexa against the Third Party through counsel of its own choosing at its expense, provided that Pharmexa will control all elements of the prosecution of the legal action against the Third Party, including all decisions to enter into settlements, judgments or other arrangements. In such case, the amount, if any, recovered in an action against a Third Party found liable for infringing the Licensed Patents, whether by judgment, award, decree or settlement, shall be applied as follows: (i) first, to reimburse Pharmexa for its legal fees and other litigation expenses incurred in connection with the prosecution of such action; (ii) second, to reimburse IDM for its legal fees and other litigation expenses incurred in connection with the prosecution of such action; and (iii) the balance shall be allocated among the Parties as they shall [. . . *** . . .].

     4.4 Inventions . Each Party shall promptly notify the other Party in writing of any and all discoveries, inventions or improvements that specifically pertain to PADRE ^® ( or any part thereof) or methods of its use conceived or reduced to practice by any employee or contractor of such Party during the term of this Agreement (“ Inventions ”). Inventorship of Inventions shall be determined in accordance with the rules of inventorship under United States patent laws. All right, title and interest to any Inventions made by IDM will be assigned to Pharmexa and Pharmexa shall have the first right to file, prosecute and maintain Patents on Inventions at its expense through counsel of its own choosing. Any Patents on Inventions become Licensed Patents upon filing. With respect to any Invention, if Pharmexa does not take steps to prepare and file a patent application within [. . . *** . . .] after disclosure of such Invention by either Party, or if it files an application but subsequently elects to abandon such application, IDM

shall have the option to undertake such filing and/or prosecution and Pharmexa shall provide such cooperation as IDM may request, at IDM’s expense, including but not limited to delivering to the IDM all records reasonably necessary for the filing and prosecution of the patent application claiming or disclosing such Invention and executing any and all documents as may be needed to assign such Invention and patent application to the IDM, without additional consideration being payable for such assignment, and upon assignment such Patent shall cease to be a Licensed Patent.

     4.5 Infringement of Third Party Rights . If the sale of any product by a Party is determined or alleged to infringe, or if a party receives notice of or is sued for infringement of, a Patent owned or licensed by a Third Party, the Parties shall meet to discuss what action should be taken if such infringement claim is based on the use of PADRE ^® in the development, manufacture, sale or use of the product. Each Party shall have the first right in its sole discretion to control at its own expense the defense of all charges of infringement by any Third Party arising as a result of its development, manufacture, use, sale or commercialization of its products. The other Party shall have the right to be represented by counsel of its own selection, at such other Party’s own expense, in any such action that may impact its rights to PADRE ^® , and shall cooperate fully in the defense of such suit, including furnishing to the other Party all relevant evidence and assistance in its control. The Party controlling the defense of any such infringement action may not settle the action or otherwise consent to an adverse judgment in such action if such settlement or judgment would diminish the rights or interest of the other Party without the prior written consent of the other Party, which consent shall not be unreasonably withheld or delayed.

      ARTICLE 5 . CONFIDENTIALITY .

     5.1 Confidentiality . The Parties acknowledge that in connection with the license and rights granted under this Agreement, the Parties may exchange Confidential Information. At all times during the term of this Agreement and for a period of [. . . *** . . .] thereafter, each Party shall keep the other Party’s Confidential Information secret and confidential and not use the other Party’s Confidential Information for any purpose other than the exercise of the rights granted under this Agreement. Notwithstanding the foregoing, each Party may disclose Confidential Information to its employees, agents, consultants and sublicensees in connection with its exercise of its rights under this Agreement, provided that the recipient Party must obtain the prior written agreement of all such employees, agents, consultants and sublicensees to whom it may disclose the other Party’s Confidential Information not to use or disclose such Confidential Information for any purpose other than those purposes permitted by this Agreement. Each Party agrees that it will take the same measures to protect the confidentiality of the other Party’s Confidential Information which it takes with respect to its own confidential and proprietary information, but not less than reasonable care. Each Party will promptly notify the other upon discovery of any unauthorized use or disclosure of Confidential Information. For the purpose of clarification, all confidential and proprietary information regarding PADRE ^® in IDM’s possession or control on or prior to the Effective Date (excluding information specific to any IDM Cancer Product derived through the use of PADRE ^® , and which is not generally applicable to PADRE ^® itself) will be deemed by virtue of the transactions consummated pursuant to the Asset Purchase Agreement to be Confidential Information of Pharmexa.

     5.2 Exceptions . The obligations of a Party receiving Confidential Information from the other Party shall not apply to any information to the extent it can be established by the receiving Party by competent written proof that such information (a) was in the public domain as of the Effective Date; (b) becomes part of the public domain subsequent to the Effective Date by publication or otherwise, except by breach of Section 5.1 by the receiving Party or its employees, agents, consultants or sublicensees; (c) is received by the receiving Party from a Third Party that has the legal right to disclose such information without restriction or (d) was independently developed by employees of the receiving Party that did not have access to or knowledge of the information disclosed by the disclosing Party. Notwithstanding the foregoing, information in IDM’s possession as of the Effective Date that is being transferred to Pharmexa pursuant to the Asset Purchase Agreement will not fall within the exceptions provided by clauses (a) and (d). In addition, each Party may disclose Confidential Information belonging to the other Par