Exhibit 2.1








                        ---------------------------------

                            ASSET PURCHASE AGREEMENT

                        ---------------------------------




                                 BY AND BETWEEN


                ANTIGENICS INC., A MASSACHUSETTS CORPORATION AND
      A WHOLLY-OWNED SUBSIDIARY OF ANTIGENICS INC., A DELAWARE CORPORATION

                                       AND

            PP MANUFACTURING CORPORATION, A DELAWARE CORPORATION, AND
                        VIRBAC S.A., A FRENCH CORPORATION










                                DECEMBER 10, 2003





                                TABLE OF CONTENTS



                                                                                                               PAGE

                                                                                                        
     SECTION 1       -SALE AND PURCHASE OF ASSETS................................................................2

         1.1      Sale of Assets.................................................................................2

         1.2      Method of Conveyance...........................................................................2

         1.3      Assumption of Liabilities......................................................................2

         1.4      Price..........................................................................................3

         1.5      Allocation of Price............................................................................5

         1.6      Closing........................................................................................5

     SECTION 2       -REPRESENTATIONS AND WARRANTIES OF SELLER...................................................7

         2.1      Organization...................................................................................7

         2.2      Authority; Approval Enforceability.............................................................7

         2.3      No Violation...................................................................................7

         2.4      Title to Assets; Liens.........................................................................7

         2.5      Condition of Tangible Assets ..................................................................8

         2.6      reserved. .....................................................................................8

         2.7      Permits........................................................................................8

         2.8      Litigation.....................................................................................8

         2.9      Environmental Matters..........................................................................8

         2.10     Brokers' and Finders' Fees.....................................................................9

         2.11     Employment Agreements and Employee Plans.......................................................9

         2.12     No Other Representations and Warranties.......................................................10

      SECTION 3      -REPRESENTATIONS AND WARRANTIES OF BUYER ..................................................11

         3.1      Organization..................................................................................11

         3.2      Authority.....................................................................................11

         3.3      No Violation..................................................................................11

         3.4      Brokers' and Finders' Fees....................................................................11

         3.5      Guarantee.....................................................................................12

         3.6      Investigation.................................................................................12

     SECTION 4       -COVENANTS AND AGREEMENTS..................................................................12

         4.1      Corporate Examinations and Investigations.....................................................12


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                                TABLE OF CONTENTS

                                   (CONTINUED)



                                                                                                               PAGE

                                                                                                        
         4.2      Expenses......................................................................................12

         4.3      Authorization from Others.....................................................................12

         4.4      Related Agreements............................................................................13

         4.5      Purchase of Inventories, Raw Materials, and Other Office Assets...............................13

         4.6      Key Employees; Employment.....................................................................14

         4.7      Non-Transferable Permits......................................................................15

         4.8      Access to Records and Files...................................................................15

         4.9      Further Assurances............................................................................16

         4.10     Seller Assistance; Pre-Closing Access.........................................................16

         4.11     Reorganization of Equipment for the Benefit of Seller.........................................17

      SECTION 5      -CONDITIONS PRECEDENT TO THE OBLIGATION OF BUYER TO CLOSE..................................17

         5.1      Representations and Warranties True...........................................................17

         5.2      Litigation....................................................................................17

         5.3      Deliveries of Seller..........................................................................17

         5.4      Rights to be Secured With Respect to Third Parties............................................17

         5.5      Necessary Permits.............................................................................17

         5.6      Legal Opinion.................................................................................17

         5.7      Employees.....................................................................................18

         5.8      Phase I Site Assessment Report................................................................18

     SECTION 6       -CONDITIONS PRECEDENT TO THE OBLIGATION OF SELLER TO CLOSE.................................18

         6.1      Representations and Warranties True...........................................................18

         6.2      Litigation....................................................................................18

         6.3      Deliveries of Buyer...........................................................................18

         6.4      Employees.....................................................................................18

         6.5      Rights With Respect to Third Parties..........................................................18

         6.6      Purchase of Inventories, Raw Materials, and Other Office Assets ..............................19

     SECTION 7       -INDEMNIFICATION...........................................................................19



                                      -ii-


                                TABLE OF CONTENTS

                                   (CONTINUED)



                                                                                                               PAGE

                                                                                                        
         7.1      By Seller.....................................................................................19

         7.2      By Buyer......................................................................................19

         7.3      Threshold.....................................................................................19

         7.4      Minimum Claim.................................................................................20

         7.5      Maximum Liability; Limitation on Liability....................................................20

         7.6      Claims Period.................................................................................20

         7.7      Indemnification Procedures....................................................................20

         7.8      Third Party Recoveries........................................................................21

         7.9      Legislation...................................................................................21

         7.10     Contingent Liabilities........................................................................21

         7.11     No Third Party Beneficiaries..................................................................21

         7.12     Exclusive Remedy..............................................................................21

         7.13     Liabilities Under Prior Agreements............................................................21

      SECTION 8      -TERMINATION OF AGREEMENT..................................................................23

         8.1      Termination...................................................................................23

         8.2      Effect of Termination.........................................................................23

     SECTION 9       -MISCELLANEOUS.............................................................................23

         9.1      Confidentiality...............................................................................23

         9.2      Uniform Commercial Code And United Nations Convention Warranties..............................24

         9.3      Public Announcements..........................................................................24

         9.4      Notices.......................................................................................24

         9.5      Entire Agreement; Prior Agreements............................................................25

         9.6      Waivers and Amendments; Non-Contractual Remedies; Preservation of Remedies....................25

         9.7      Governing Law; Dispute Resolution.............................................................26

         9.8      Governing Language............................................................................26

         9.9      Enforceability in Jurisdictions; Consent......................................................26

         9.10     Survival......................................................................................26

         9.11     Binding Effect; No Assignment.................................................................27

         9.12     Variations in Pronouns........................................................................27



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                                TABLE OF CONTENTS

                                   (CONTINUED)



                                                                                                               PAGE

                                                                                                        
         9.13     Counterparts..................................................................................27

         9.14     Severability..................................................................................27

         9.15     Knowledge.....................................................................................27

         9.16     Appendices; Schedules.........................................................................28*

         9.17     Headings......................................................................................28



*APPENDICES AND SCHEDULES HAVE BEEN OMITTED. THE REGISTRANT WILL FURNISH
 SUPPLEMENTALLY TO THE COMMISSION UPON REQUEST.














                                      -iv-



                            ASSET PURCHASE AGREEMENT

         This ASSET PURCHASE AGREEMENT (this "Agreement") is dated as of
December 10, 2003 (the "Effective Date"), by and between ANTIGENICS INC., a
Massachusetts corporation and a wholly-owned subsidiary of ANTIGENICS INC., a
Delaware corporation, having its offices at 3 Forbes Road, Lexington, MA 02421
U.S.A. ("SELLER") and PP MANUFACTURING CORPORATION, a Delaware corporation that
will have offices located on or after the Closing at 175 Crossing Boulevard,
Framingham, Massachusetts, 01702-5404 ("SUB") and VIRBAC S.A., a French
corporation having its offices at 1 ere Avenue-2065 m L.I.D.-06516 CARROS FRANCE
("PARENT," and together with SUB, "BUYER").

                                   WITNESSETH

         WHEREAS, SELLER and PARENT are parties to (i) that certain Agreement
dated June 13, 1983 by and between Virbac Laboratories S.A. and Cambridge
Bioscience Corporation (as amended by Amendment dated December 20, 1988, by
Amendment Agreement dated May 23, 1989, by Agreement and Amendment dated
December 3, 1990, by Amendment Agreement dated April 21, 1993, and by Option
Agreement dated September 30, 1993), pursuant to which PARENT obtained a
perpetual, royalty-free, fully paid-up, exclusive license to market and have
customers use a vaccine protective against feline leukemia virus ("FeLV")
developed by the parties thereunder (the "Vaccine"), (ii) that certain Supply
Agreement dated May 24, 1989 by and between Cambridge Bioscience Corporation and
Virbac, Inc. (as amended by Amendment No. 1 dated December 21, 1990 and by
Amendment No. 2 dated April 21, 1993) relating to the supply of the Vaccine for
the North American market, and (iii) that certain Letter Agreement dated
November 4, 2003 (and any successor agreement) by and between PARENT and SELLER
relating to the supply of P45 (as hereinafter defined) for the ex-North American
market (collectively, the "Prior Agreements");

         WHEREAS, SELLER and PARENT have agreed to terminate the Prior
Agreements and the agreements set forth on Appendix A (the "Other Prior
Agreements") pursuant to this Agreement upon the Closing (as hereinafter
defined);

         WHEREAS, SELLER desires to sell to SUB, and SUB desires to purchase
from SELLER, certain equipment and other tangible assets listed on Schedule
1.1.1 hereto and utilized in the manufacture of (i) the antigen described in
Appendix B to this Agreement ("P45") and (ii) a veterinary grade extract of
Quillaja Saponaria bark as more specifically described on Appendix C to this
Agreement ("QA-21 Adjuvant");

         WHEREAS, pursuant to that certain Patent Purchase Agreement (as defined
in Section 1.6.1(f)), SELLER desires to sell to PARENT, and PARENT desires to
purchase from SELLER, the intangible assets set forth on Schedule 1.1.2 hereto;

         WHEREAS, SELLER desires to license to SUB and SUB desires to obtain a
license from SELLER under certain intellectual property rights owned by or
licensed to SELLER for the manufacture, use, sale, offer for sale or importation
world-wide of the P45, and QA-21 Adjuvant for use in its own animal healthcare
vaccines formulated to contain or comprise P45 (and/or



other antigens) as one component and QA-21 Adjuvant as another component (the
"Licensed Assets"); and

         WHEREAS, SELLER desires to grant SUB and SUB desires to obtain, a
sublease to that portion of approximately 20,432 rentable square feet located in
part on the first and second floors of SELLER's Framingham authorized
manufacturing site (Establishment License no. 317) located at 175 Crossing
Boulevard, Framingham, Massachusetts, 01702-5404 which is currently being
occupied and utilized by SELLER for the manufacture of P45 and QA-21 Adjuvant
(the "Manufacturing Site").

NOW THEREFORE, in consideration of the foregoing and of the mutual covenants set
forth below, the parties hereby agree as follows:



                     SECTION 1 -SALE AND PURCHASE OF ASSETS

         1.1      Sale of Assets. On the terms and subject to the conditions of
this Agreement, at the Closing (as defined in Section 1.6 hereof):

                  1.1.1    SELLER shall sell, convey, assign, transfer and
deliver to SUB, and SUB shall purchase, acquire and accept delivery from SELLER
the tangible properties and assets on Schedule 1.1.1 (the "Tangible Assets").
For the avoidance of doubt, the Tangible Assets shall specifically exclude any
and all intellectual property rights, and any and all rights in or to the
compound referred to as QS-21 Adjuvant (as defined in the attached Appendix C),
as well as any and all assets of SELLER not specifically identified herein as
Tangible Assets (the "Excluded Assets").

                  1.1.2    Pursuant to the Patent Purchase Agreement, SELLER
shall sell, convey, assign, transfer and deliver to PARENT and PARENT shall
purchase, acquire and accept delivery of from SELLER certain intangible assets
as more specifically described on Schedule 1.1.2 ("Intangible Assets").

         1.2      Method of Conveyance. The sale, transfer, conveyance,
assignment and delivery by SELLER of the Tangible Assets to SUB in accordance
with Section 1.1 hereof shall be effected on the Closing Date (as defined in
Section 1.6) by SELLER's execution and delivery to SUB of one or more bills of
sale in the form and scope reasonably satisfactory to SUB (the "Conveyance
Documents"). At the Closing, good, valid and marketable title to the Tangible
Assets shall be transferred, conveyed, assigned and delivered by SELLER to SUB
pursuant to the Conveyance Documents, free and clear of any and all liens,
encumbrances, mortgages, security interests, pledges, claims, equities and other
restrictions or charges of any kind or nature whatsoever.

         1.3      Assumption of Liabilities. At the Closing, SUB shall assume
and agree to satisfy and discharge as the same shall become due, the liabilities
and obligations of SELLER that are to be performed after the Closing and
described on Schedule 1.3. The liabilities to be assumed by SUB under this
Agreement are hereinafter sometimes referred to as the "Assumed Liabilities."
Except as expressly set forth in this Section 1.3 and Section 1.4.5, or as
described on

                                       2


Schedule 1.3, neither SUB nor PARENT shall assume or be responsible at any time
for any liability, obligation, debt or commitment of SELLER or any of its
Affiliates (as defined herein), whether absolute or contingent, accrued or
unaccrued, asserted or unasserted, or otherwise, including but not limited to
any liabilities, obligations, debts or commitments of SELLER incident to,
arising out of or incurred with respect to, this Agreement and the transactions
contemplated hereby including any and all sales, income or other taxes arising
out of the transactions contemplated hereby. "Affiliate" means any entity
directly or indirectly controlling, controlled by or under common control with
SUB, PARENT or SELLER, with "control" meaning the possession, direct or
indirect, of the power to direct or cause the direction of the management and
policies of the entity, whether through the ownership of voting securities, by
contract or otherwise. Without limiting the generality of the foregoing, SELLER
expressly acknowledges and agrees that SELLER shall retain, and that neither SUB
nor PARENT shall assume or otherwise be obligated to pay, perform, defend or
discharge, with respect to liabilities incurred prior to the Closing Date (a)
any liability of SELLER for taxes (other than taxes referenced in Section
1.4.5), whether measured by income or otherwise, (b) any liability of SELLER in
connection with the violation of the terms of any SELLER Employee Plan, (c) any
liability of SELLER under any federal, state or local law, rule, regulation,
ordinance, program, permit, license or other legal requirement relating to
health, safety, hazardous materials and environmental matters applicable to the
Manufacturing Site (excluding any such liability that arises as a result of
SUB's or PARENT's actions, or, where an action is required to be taken by law,
rule or regulation, SUB's or PARENT's inaction, including the failure to comply
with any European rules or regulations related to manufacturing practices), or
(d) any liability or obligation of SELLER relating to any default taking place
before the Closing Date under any of the Assumed Liabilities to the extent such
default solely created the liability or obligation.

         1.4      Price. In consideration for the sale of the Tangible Assets
pursuant to this Agreement, the sale of the Intangible Assets pursuant to the
Patent Purchase Agreement, and the licensing of the Licensed Assets pursuant to
the License Agreement (as defined in Section 1.6.1(d)), SUB and/or PARENT shall
deliver to SELLER an aggregate amount (the "Price") of fourteen million two
hundred and fifty thousand US dollars ($14,250,000). Payments shall be made as
follows:

                  1.4.1    The parties acknowledge and agree that PARENT has
already paid SELLER one million US dollars ($1,000,000) (which amount shall be
credited toward the purchase price for the Intangible Assets pursuant to the
Patent Purchase Agreement), of which (i) two-hundred fifty thousand US dollars
($250,000) shall be refundable only in the event SELLER fails to obtain any
consents necessary from the lessor of the Manufacturing Site in order to execute
the Sublease Agreement (as defined in Section 1.6.1(e) hereof), and (ii) the
remaining seven hundred fifty thousand US dollars ($750,000) shall be refundable
only in the event either SUB or PARENT terminates this Agreement pursuant to
Section 8.1(ii) hereof, or SELLER terminates this Agreement pursuant to Section
8.1(i) due to a failure of SELLER to obtain all consents as contemplated in
Section 6.5.

                  1.4.2    Upon execution of this Agreement, PARENT shall
deliver to SELLER one million US dollars ($1,000,000) (which amount shall be
credited toward the purchase price for the Intangible Assets pursuant to the
Patent Purchase Agreement), which shall be refundable only in the event either
SUB or PARENT terminates this Agreement pursuant to Section 8.1(ii)


                                       3


hereof, or SELLER terminates this Agreement pursuant to Section 8.1(i) due to a
failure of SELLER to obtain all consents as contemplated in Section 6.5. PARENT
shall make such payment by delivering to SELLER the aforementioned amount by
official bank check or wire transfer (to an account specified by SELLER in
writing), in next day funds.

                  1.4.3    At the Closing,

                           (a)      PARENT shall deliver to SELLER two million
US dollars ($2,000,000) (which amount shall be credited toward the purchase
price for the Intangible Assets pursuant to the Patent Purchase Agreement).

                           (b)      SUB shall deliver to SELLER six million US
dollars ($6,000,000).

                           (c)      SUB shall deliver to SELLER payment for
SELLER's inventories and raw materials in the amounts set forth in the
applicable invoice(s) as set forth in Section 4.5.

                           (d)      SUB shall deliver to SELLER payment for the
Other Office Assets (as defined in Section 4.5.5 of this Agreement) in the
amounts to be mutually agreed upon in writing by SELLER and SUB.

                           (e)      All payments to SELLER as described in this
Section 1.4.3 shall be made by official bank check or wire transfer (to an
account specified by SELLER in writing), in next day funds.

                  1.4.4    After the Closing, upon the production by SUB of at
least three (3) industrial batches of P45 for a total quantity of 100 grams, in
conformance with the "Release Criteria" for P45 as set forth in Appendix B, and
a total of 10 grams of QA-21 Adjuvant (the "Initial Batches"), provided that SUB
shall attempt in good faith to manufacture the Initial Batches within six (6)
months after the Closing Date, SUB shall deliver to SELLER four million two
hundred fifty thousand US dollars ($4,250,000). In the event SUB fails to
manufacture the Initial Batches and fails to attempt in good faith to do so as
required hereunder, such payment shall become immediately due and payable upon
the sixth (6th) month anniversary of the Closing Date. In the event SUB fails to
manufacture the Initial Batches and has attempted in good faith to do so, such
payment shall become immediately due and payable upon the eighth (8th) month
anniversary of the Closing Date. SUB shall make any such payment set forth in
this Section 1.4.4 by delivering to SELLER the aforementioned amount by official
bank check or wire transfer (to an account specified by SELLER in writing), in
next day funds. PARENT shall provide SUB with all necessary assistance in
furtherance of SUB performing its manufacturing obligations as set forth in this
Section 1.4.4.

                  1.4.5    In the event either SUB or PARENT is required to
withhold any taxes from any of the payments to be made pursuant to this
Agreement or the Related Agreements pursuant to applicable tax laws, then the
amount of such payments shall be increased as necessary so that the net amount
actually received by SELLER will equal the full amount SELLER would have
received had no such withholding been required.

                  1.4.6    BUYER and SELLER acknowledge and agree that none of
the consideration paid by either SUB or PARENT as set forth hereunder shall
constitute


                                       4


consideration for the sublease of the Manufacturing Site premises pursuant to
the Sublease Agreement.

         1.5      Allocation of Price. The Price will be allocated among the
Tangible Assets, Intangible Assets and Licensed Assets in accordance with
Schedule 1.5 attached hereto. Subject to the requirements of Section 1060 of the
Internal Revenue Code and the Treasury regulations thereunder (and any similar
provision of state, local or foreign law, as appropriate), all tax returns and
reports filed by BUYER and SELLER (including, but not limited to Internal
Revenue Service Form 8594) will be prepared consistently with such allocation
and BUYER and SELLER shall use their reasonable best efforts to sustain such
allocation in any subsequent tax audit or tax dispute.

         1.6      Closing. The closing of the sale and purchase of the Tangible
Assets pursuant hereto and the Intangible Assets pursuant to the Patent Purchase
Agreement and the other transactions contemplated hereby (the "Closing"), shall
take place at a time, on a date and at a place to be mutually agreed to by BUYER
and SELLER in writing or, failing such agreement, on the second business day
after the satisfaction or waiver (by the party entitled to grant such waiver) of
the conditions set forth in Sections 5 and 6 hereof; provided, however, that if
on March 1, 2004, (i) the conditions set forth in Section 5 have not been met or
waived, then BUYER shall be entitled to postpone the Closing, by notice to
SELLER, until up to five (5) business days after such condition shall have been
met or waived, or (ii) the conditions set forth in Section 6 have not been met
or waived, then SELLER shall be entitled to postpone the Closing, by notice to
BUYER, until up to five (5) business days after such condition shall have been
met or waived; provided, further, that in no event shall the Closing be
postponed past May 1, 2004 unless BUYER and SELLER shall have agreed in writing
to such postponement, or at such other place or such other time or date as BUYER
and SELLER agree in writing. The date of such Closing is referred to herein as
the "Closing Date."

                  1.6.1    Deliveries of SELLER. At or prior to the Closing,
SELLER shall deliver to BUYER:

                           (a)      the Conveyance Documents,

                           (b)      a certificate executed by an authorized
officer of SELLER, on behalf of SELLER, to the effect that the matters set forth
in Section 5.1 are true and correct and the conditions set forth therein have
been satisfied as of the Closing Date;

                           (c)      a certificate executed by the secretary of
SELLER, dated as of the Closing Date, certifying that all requisite corporate
actions of SELLER to authorize the execution and delivery of this Agreement and
the other documents and instruments to be executed and delivered pursuant to
this Agreement, and the consummation by SELLER of the transactions contemplated
by this Agreement, have been taken;

                           (d)      a license agreement executed by SELLER
substantially in the form attached hereto as Appendix D, pursuant to which SUB
obtains a perpetual, non-terminable, royalty-free, right and license in and to
the Licensed Assets for use in the Field (as defined therein) subject to the
provisions thereof (the "License Agreement");


                                       5



                           (e)      a sublease agreement executed by SELLER
substantially in the form attached hereto as Appendix E, pursuant to which SUB
subleases the Manufacturing Site (the "Sublease Agreement");

                           (f)      a patent purchase agreement executed by
SELLER substantially in the form attached hereto as Appendix F, pursuant to
which PARENT purchases the Intangible Assets (the "Patent Purchase Agreement");

                           (g)      a procedures manual(s) containing all
reasonably necessary control and manufacturing procedures related to and for the
manufacture of P45, QA-21 Adjuvant and the Vaccine as contemplated by this
Agreement, the Patent Purchase Agreement, and the License Agreement (the
"Manual"); and

                           (h)      a Phase I Site Assessment Report prepared
following the "Standard Practice for Environmental Site Assessments: Phase I
Environmental Site Assessment Process, ASTM E-1527-00" (the "Phase I Site
Assessment Report") to be conducted by a consultant retained by SELLER, and
reasonably acceptable to BUYER, with each of BUYER and SELLER bearing liability
of one-half the cost of such consultant's services.

         1.6.2    Deliveries of BUYER. At or prior to the Closing, BUYER shall
deliver to SELLER:

                           (a)      that portion of the Price required to be
         paid at Closing pursuant to Section 1.4.3, and payments for the
         inventories, raw materials, and Other Office Assets pursuant to
         Sections 1.4.3 and 4.5;

                           (b)      a certificate executed by an authorized
         officer of SUB, on behalf of SUB, to the effect that the matters set
         forth in Section 6.1 are true and correct and the conditions set forth
         therein have been satisfied as of the Closing Date;

                           (c)      a certificate executed by an authorized
         officer of PARENT, on behalf of PARENT, to the effect that the matters
         set forth in Section 6.1 are true and correct and the conditions set
         forth therein have been satisfied as of the Closing Date;

                           (d)      a certificate executed by the secretary of
         SUB, dated as of the Closing Date, certifying that all requisite
         corporate actions of SUB to authorize the execution and delivery of
         this Agreement and the other documents and instruments to be executed
         and delivered pursuant to this Agreement, and the consummation by SUB
         of the transactions contemplated by this Agreement, have been taken;

                           (e)      a certificate executed by an authorized
         officer of PARENT, dated as of the Closing Date, certifying that all
         requisite corporate actions of PARENT to authorize the execution and
         delivery of this Agreement and the other documents and instruments to
         be executed and delivered pursuant to this Agreement, and the
         consummation by PARENT of the transactions contemplated by this
         Agreement, have been taken;


                                       6


                           (f)      an agreement for assumption of the Assumed
         Liabilities by SUB containing provisions that are usual and customary
         for assuming the liabilities involved, executed by SUB;

                           (g)      the License Agreement, executed by SUB;

                           (h)      the Sublease Agreement, executed by SUB;

                           (i)      the Patent Purchase Agreement executed by
         PARENT; and

                           (j)      a supply agreement executed by PARENT and
         SUB substantially in the form attached hereto as Appendix G, pursuant
         to which PARENT and SUB agree to supply SELLER with QS-21 Adjuvant on
         the terms set forth therein (the "Supply Agreement").

              SECTION 2 -REPRESENTATIONS AND WARRANTIES OF SELLER

         SELLER, represents and warrants to BUYER as follows:

         2.1      Organization. SELLER is a corporation duly organized, validly
existing and in good standing under the laws of the Commonwealth of
Massachusetts.

         2.2      Authority; Approval Enforceability. SELLER has all requisite
corporate power and authority to enter into this Agreement and to consummate the
transactions contemplated hereby. The execution and delivery of this Agreement
and the consummation of the transactions contemplated hereby, have been duly
authorized by all necessary corporate action on the part of SELLER. This
Agreement has been duly executed and delivered by SELLER. Assuming due
authorization, execution and delivery by BUYER, this Agreement constitutes, and
when delivered at the Closing the Conveyance Documents and Related Agreements
and any conveyance documents thereunder will constitute, the legal, valid and
binding obligations of SELLER, enforceable in accordance with their terms,
subject to bankruptcy, insolvency, fraudulent transfer, reorganization,
moratorium and similar laws of general applicability relating to or affecting
creditors' rights and to general principles of equity.

         2.3      No Violation. To SELLER's knowledge, neither the execution and
delivery of this Agreement, nor the performance by SELLER of its obligations
hereunder, nor the consummation of the transactions contemplated hereby or
thereby, will (i) violate any statute or law or any judgment, decree, order,
regulation or rule of any court or governmental authority to which SELLER is
bound; or (ii) violate, conflict with, result in a breach of or constitute a
default under, any agreement set forth on Schedule 2.3 ("Material Agreements"),
where such violation, conflict, breach or default would have a material adverse
impact on the Tangible Assets. To SELLER's knowledge, the Material Agreements
are the only material agreements to which the Tangible Assets are bound or
subject.

         2.4      Title to Assets; Liens. SELLER owns good, valid and marketable
title to all of the Tangible Assets, free and clear of any and all liens,
encumbrances, mortgages, security interests, pledges, claims, equities and other
restrictions or charges of any kind or nature whatsoever. Upon delivery of and
payment for the Tangible Assets as herein provided, SUB will


                                       7


acquire good, valid and marketable title to all of the Tangible Assets, free and
clear of any and all liens, encumbrances, mortgages, security interests,
pledges, claims, equities and other restrictions or charges of any kind or
nature whatsoever.

         2.5      Condition of Tangible Assets. Except for normal wear and tear
or as otherwise set forth on Schedule 2.5, the Tangible Assets are in
substantially the same condition as on September 30, 2003.

         2.6      reserved.

         2.7      Permits. Set forth on Schedule 2.7 are all of the material
licenses, permits, franchises, orders, registrations, authorizations,
documentations or approvals of any federal, state, local or foreign governmental
or regulatory body relating to the Tangible Assets and the use of the
Manufacturing Site for the manufacture of P45, QA-21 Adjuvant and the Vaccine
(collectively, "Permits") of SELLER. All such Permits are in full force and
effect and, except for those Permits identified in Schedule 2.7 as
"Non-Transferable Permits," such Permits will be transferred to SUB at or prior
to Closing. Prior to the Closing, and for a reasonable time thereafter, SELLER
shall cooperate with SUB, at SUB's sole cost and expense, to assist SUB in
obtaining Permits substantially similar to the Non-Transferable Permits that are
reasonably necessary for SUB to use the Tangible Assets and Manufacturing Site
for the manufacture of P45, QA-21 Adjuvant and the Vaccine as of the Closing
Date.

         2.8      Litigation. Except as otherwise set forth in Schedule 2.8, to
the knowledge of SELLER as of the Effective Date, there are no claims, actions,
suits, investigations or proceedings (regardless of whether formal or informal)
against SELLER pending or threatened in any court or before or by any
governmental authority, or before any arbitrator, relating to and that would
have a material adverse effect (whether covered by insurance or not) on the
Tangible Assets, and to the knowledge of SELLER as of the Effective Date, there
is no basis for any such claim, action, suit, investigation or proceeding.

         2.9      Environmental Matters. Except as set forth on Schedule 2.9 or
where the existence of an item would not have a material adverse effect on the
Manufacturing Site, the Tangible Assets or the operations of SUB at the
Manufacturing Site as were previously conducted by SELLER at the Manufacturing
Site prior to the Effective Date, to the knowledge of SELLER as of the Effective
Date or as of the date of receipt of the Phase I Site Assessment Report with
respect to items first disclosed thereunder to SUB or PARENT, (i) there are no
pending or threatened allegations, claims, liabilities, investigations,
litigation, administrative proceedings, judgments, decrees or orders
(collectively "Environmental Claims") relating to any alleged violation of
Environmental Laws (as defined below) asserted against SELLER or relating to the
Manufacturing Site; (ii) SELLER has obtained all permits under applicable
Environmental Laws necessary for the operation of the Tangible Assets and
Manufacturing Site and related activities; all such permits are in good standing
and SELLER is in compliance with all terms and conditions of these permits;
(iii) all operations or activities upon, or any use of or occupancy of the
Manufacturing Site, or any portion thereof, by SELLER, and any agent, contractor
or employee of SELLER, are now and have been in all respects in compliance with
all applicable Environmental Laws; (iv) SELLER has not caused or permitted the
use, generation, reclamation, transportation, treatment, storage or disposal of
any Hazardous Material (as defined below) in


                                       8


violation of applicable Environmental Laws or in a manner that could require any
removal or remedial action at, on, in or about the Manufacturing Site or at any
other site; (v) SELLER has not assumed the liability of any person for any
Environmental Claims; (vi) no work, repair, remedy, construction or capital
expenditure is required by any applicable Environmental Laws for the continued
lawful use of the Tangible Assets or Manufacturing Site and (vii) SELLER has
kept the Tangible Assets and the Manufacturing Site free of any lien imposed
pursuant to any Environmental Laws. The term "Environmental Laws" shall mean all
federal, state and local laws, statutes and ordinances relating to pollution or
the regulation and protection of human health or the environment, including
without limitation those relating to emissions, discharges, releases or
threatened releases of Hazardous Material or the use or production of biological
agents or otherwise relating to the manufacture, processing, use, treatment,
storage, disposal, transportation or cleanup of Hazardous Material. The term
"Hazardous Material" shall mean (a) oil or other petroleum products; (b)
"hazardous substances" as defined by the Comprehensive Environmental Response,
Compensation, and Liability Act, 42 U.S.C. ss.ss. 9601 et seq.; (c) "hazardous
wastes" as defined by the Resource Conservation and Recovery Act, 42 U.S.C.
ss.ss. 6901 et seq.; (d) "toxic substances" as defined by the Toxic Substances
Control Act, 15 U.S.C. ss.ss. 2601 et seq.; (e) "hazardous materials" as defined
by the Hazardous Materials Transportation Act, 49 U.S.C. ss. 1802; (f)
radioactive materials, including those subject to the Atomic Energy Act, 42
U.S.C. ss.ss. 2011 et seq. and (g) any other pollutant, chemical or substance
that is regulated under Environmental Laws.

         2.10     Brokers' and Finders' Fees. SELLER has not incurred, nor will
it incur, directly or indirectly, any liability for brokerage or finders' fees
or agents' commissions or any similar charges in connection with this Agreement
or the Related Agreements, or the transactions contemplated hereby or thereby.

         2.11     Employment Agreements and Employee Plans. With respect to the
Business Employees (as defined herein), to the knowledge of SELLER, SELLER (i)
has at all times been in substantial compliance with all applicable legal
requirements with respect to (a) employment, employment practices, employment
verification (including, but not limited to, verification required under the
Immigration Reform and Control Act of 1986, as amended), and (b) terms and
conditions of employment and wages, overtime pay, and hours, withholding and
workers' compensation; and (ii) has not illegally discriminated with regard to
employment on the basis of age, color, national origin, race, religion, sex,
handicap, or on the basis of any other legally prohibited category or
classification. With respect to any "Employee Plan" (as defined herein) that
SELLER maintains, participates under or is required to contribute to (i) each
Pension Plan (as defined herein) that is intended to be qualified under Section
401(a) of the Internal Revenue Code has received a favorable determination
letter or opinion letter, as applicable, from the IRS with respect to its
qualified status and with respect to the tax-exempt status of the trust of any
such Pension Plan under Section 501(a) of the Internal Revenue Code or SELLER
has adopted a prototype plan the sponsor of which is not the SELLER, and there
is no matter pending (other than determination letter filings) with respect to
any Employee Plan before the IRS, the Department of Labor, the Securities and
Exchange Commission, the Pension Benefit Guaranty Corporation or any other
federal or provincial government agency; (ii) each Employee Plan, the
administrator and fiduciaries of each Employee Plan, and SELLER have complied in
all material respects with the applicable requirements of ERISA (as defined
herein) (including, but not limited to, the fiduciary responsibilities imposed
by Part 4 of Title I, Subtitle B of ERISA), the


                                       9


Internal Revenue Code and any other applicable rules and regulations governing
each Employee Plan, except where the failure to do so would not be reasonably
expected to have a material adverse effect on the Employee Plan, the
administrator and fiduciaries of the Employee Plan , or SELLER; and (iii) each
Employee Plan has at all times been administered in all material respects in
compliance with its terms and in accordance with all applicable rules and
regulations, except where the failure to do so would not be reasonably expected
to have a material adverse effect on the Employee Plan. For purposes of this
Agreement, the term "Employee Plan" includes any written pension, retirement,
savings, profit-sharing, deferred compensation, disability, medical, dental,
health, life, incentive, severance pay, death benefit, group insurance, stock
option, stock purchase, bonus, or vacation pay trust, contract, agreement, or
policy (including, without limitation, any pension plan as defined in Section
3(2) of the Employee Retirement Income Security Act of 1974, as amended
("ERISA") ("Pension Plan"), and any welfare plan as defined in Section 3(1) of
ERISA ("Welfare Plan")), whether or not any of the foregoing is funded or
insured, (1) which provides benefits to Business Employees and (2) to which
SELLER is a party or by which it is bound or which is maintained by any entity
that, together with SELLER, would be treated as a single employer under Section
414 of the Internal Revenue Code.

         2.12     No Other Representations and Warranties. SELLER SHALL NOT BE
DEEMED TO HAVE MADE TO SUB OR PARENT ANY REPRESENTATION OR WARRANTY, EXPRESS OR
IMPLIED, OTHER THAN AS EXPRESSLY MADE BY SELLER IN THIS AGREEMENT OR THE RELATED
AGREEMENTS. WITHOUT LIMITING THE GENERALITY OF THE FOREGOING, SELLER MAKES NO
REPRESENTATION OR WARRANTY TO SUB OR PARENT WITH RESPECT TO ANY INFORMATION OR
DOCUMENTS MADE AVAILABLE TO SUB OR PARENT OR EITHER OF THEIR COUNSEL,
ACCOUNTANTS OR ADVISORS WITH RESPECT TO THE TANGIBLE ASSETS, INTANGIBLE ASSETS,
LICENSED ASSETS, MANUFACTURING SITE AND/OR BUSINESS EXCEPT AS EXPRESSLY COVERED
IN A REPRESENTATION AND WARRANTY CONTAINED IN THE FOREGOING DOCUMENTS. IN ANY
EVENT, SELLER MAKES NO WARRANTY OF MERCHANTABILITY, SUITABILITY OR FITNESS FOR A
PARTICULAR PURPOSE, OR QUALITY AS TO THE FOREGOING ASSETS, OR ANY PART THEREOF,
OR THE MANUFACTURING SITE OR BUSINESS, OR THE ABSENCE OF ANY DEFECTS THEREIN,
WHETHER LATENT OR PATENT, IT BEING UNDERSTOOD THAT EXCEPT FOR THE
REPRESENTATIONS AND WARRANTIES SET FORTH HEREIN AND IN THE RELATED AGREEMENTS,
THE TANGIBLE ASSETS, INTANGIBLE ASSETS, LICENSED ASSETS, AND MANUFACTURING SITE
ARE TO BE CONVEYED HEREUNDER AND THEREUNDER "AS IS WHERE IS" AT THE CLOSING, AND
IN THEIR THEN PRESENT CONDITION (SUBJECT TO SECTION 2.5 ABOVE WITH RESPECT TO
THE TANGIBLE ASSETS), AND BUYER SHALL RELY UPON ITS OWN EXAMINATION THEREOF.
NOTWITHSTANDING THE FOREGOING, SELLER HEREBY REPRESENTS AND WARRANTS THAT,
EXCEPT WHERE THE FAILURE TO DO SO WOULD NOT BE MATERIAL TO BUYER'S DUE DILIGENCE
INQUIRY, SELLER HAS MADE COMMERCIALLY REASONABLE EFFORTS TO PRODUCE OR MAKE
AVAILABLE TO BUYER ANY AND ALL DOCUMENTS AND INFORMATION (SPECIFICALLY EXCEPTING
ALL DOCUMENTS WHICH RELATE TO THE QS-21 ADJUVANT OR THE MANUFACTURE, SUPPLY,
USE, SALE, OFFER FOR SALE OR IMPORTATION OF THE QS-21 ADJUVANT) IN RESPONSE TO
BUYER'S DUE DILIGENCE INQUIRIES


                                       10


RELATED TO THE TANGIBLE ASSETS, INTANGIBLE ASSETS, LICENSED ASSETS AND/OR THE
MANUFACTURING SITE OR BUSINESS AND THAT AS OF THE EFFECTIVE DATE, SELLER HAS NO
REASONABLE BASIS TO BELIEVE THAT ANY DOCUMENTS OR INFORMATION PROVIDED TO BUYER
IN CONNECTION WITH SUCH INQUIRIES ARE MATERIALLY MISLEADING OR INACCURATE.

               SECTION 3 -REPRESENTATIONS AND WARRANTIES OF BUYER

         BUYER represents and warrants to SELLER as follows:

         3.1      Organization.

                  3.1.1    SUB is duly organized, validly existing and in good
standing under the laws of the State of Delaware, and has the corporate power
and lawful authority to own, lease and operate its assets, properties and
business and to carry on its business as now being conducted.

                  3.1.2    PARENT is duly organized, validly existing and in
good standing under the laws of France, and has the corporate power and lawful
authority to own, lease and operate its assets, properties and business and to
carry on its business as now being conducted.

         3.2      Authority. Each of SUB and PARENT has all requisite corporate
power and authority to enter into this Agreement and to consummate the
transactions contemplated hereby. The execution and delivery of this Agreement
and the consummation of the transactions contemplated hereby have been duly
authorized by all necessary corporate action on the part of SUB and PARENT. This
Agreement has been duly executed and delivered by SUB and PARENT. Assuming due
authorization, execution and delivery by SELLER, this Agreement constitutes, and
when delivered at the Closing the Related Agreements will constitute, the valid
and binding obligations of SUB and PARENT, enforceable in accordance with their
terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization,
moratorium and similar laws of general applicability relating to or affecting
creditors' rights and to general principles of equity.

         3.3      No Violation.

                  3.3.1    To BUYER's knowledge, neither the execution and
delivery of this Agreement, nor the performance by SUB of its obligations
hereunder, nor the consummation of the transactions contemplated hereby will
violate any statute or law or any judgment, decree, order, regulation or rule of
any court or governmental authority to which SUB is bound.

                  3.3.2    To BUYER's knowledge, neither the execution and
delivery of this Agreement, nor the performance by PARENT of its obligations
hereunder, nor the consummation of the transactions contemplated hereby will
violate any statute or law or any judgment, decree, order, regulation or rule of
any court or governmental authority to which PARENT is bound.

         3.4      Brokers' and Finders' Fees. Neither SUB nor PARENT has
incurred, nor will either of them incur, directly or indirectly, any liability
for brokerage or finders' fees or agents'

                                       11


commissions or any similar charges in connection with this Agreement or the
transactions contemplated hereby.

         3.5      Guarantee. To the extent SUB is unable to perform any
obligation pursuant to the transactions contemplated by this Agreement, PARENT
guarantees that it will effect such performance and agrees to bear, at its sole
cost and expense, any and all liability with respect to any failure by SUB to
perform any such obligation.

         3.6      Investigation. SUBJECT TO SECTION 2.12 ABOVE, BUYER
ACKNOWLEDGES THAT IT IS NOT RELYING ON ANY REPRESENTATION OR WARRANTY, EXPRESS
OR IMPLIED, AS TO THE ACCURACY OR COMPLETENESS OF ANY INFORMATION REGARDING THE
TANGIBLE ASSETS FURNISHED OR MADE AVAILABLE TO BUYER OR ANY OF ITS
REPRESENTATIVES, EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT. BUYER HAS
UNDERTAKEN ITS OWN INVESTIGATION OF THE TANGIBLE ASSETS.

                      SECTION 4 -COVENANTS AND AGREEMENTS

         4.1      Corporate Examinations and Investigations. Prior to the
Closing Date, upon reasonable prior written notice to SELLER, BUYER shall be
entitled, through its employees and representatives, to have such additional
access to the Manufacturing Site, Tangible Assets and Intangible Assets and any
and all documentation or other information specifically relating to the Licensed
Assets as is reasonably necessary in connection with the performance by BUYER or
its designees of additional due diligence on the Manufacturing Site, Tangible
Assets, Intangible Assets and Licensed Assets, except as may be in contravention
of any obligations SELLER may have under confidentiality obligations to third
parties and such documents or information would not be material to BUYER's
examination or investigation. Any such investigation and examination shall be
conducted at BUYER's sole expense and at reasonable times and under reasonable
circumstances (including reasonable advance notice to SELLER) so as to minimize
any disruption to or impairment of SELLER's business. Prior to the Closing Date,
BUYER shall have completed all of its due diligence as provided herein.
Notwithstanding the foregoing or any other provision in this Agreement, SELLER
and BUYER acknowledge and agree that SELLER has no obligation, except as may be
expressly set forth in the Supply Agreement, to provide SUB or PARENT with
access to, or information relating to, any documents that relate to QS-21
Adjuvant or the manufacture, supply, use, sale, offer for sale or importation of
QS-21 Adjuvant.

         4.2      Expenses. Each of BUYER and SELLER shall bear its respective
expenses incurred in connection with the preparation, execution and performance
of this Agreement and the transactions contemplated hereby, including without
limitation all fees and expenses of agents, representatives, counsel and
accountants.

         4.3      Authorization from Others. Prior to the Closing, BUYER and
SELLER shall each use its commercially reasonable efforts to obtain all
authorizations, consents and permits of others required to permit the
consummation by it of the transactions contemplated by this Agreement, except to
the extent waived by the other party in writing. To the extent that the
assignment of any assets which are among the Tangible Assets shall require the
consent of other


                                       12


parties thereto and BUYER shall have waived the receipt of such consent at the
Closing, this Agreement shall not constitute an assignment thereof.

         4.4      Related Agreements. From the date hereof until the Closing:

                  4.4.1    PARENT and SELLER shall each use commercially
reasonable efforts to enter into the Patent Purchase Agreement;

                  4.4.2    SUB and SELLER shall each use commercially reasonable
efforts to enter into the Sublease Agreement;

                  4.4.3    SUB and SELLER shall each use commercially reasonable
efforts to enter into the License Agreement; and

                  4.4.4    PARENT, SUB and SELLER shall each use commercially
reasonable efforts to enter into the Supply Agreement.

The Patent Purchase Agreement, the Sublease Agreement, the License Agreement and
the Supply Agreement are collectively referred to as the "Related Agreements."

         4.5      Purchase of Inventories, Raw Materials, and Other Office
Assets. At or prior to the Closing, SUB shall purchase the following
inventories, raw materials, and other office assets from SELLER:

                  4.5.1    SUB shall purchase SELLER's then-current inventory of
P45 at the purchase prices established for each batch of P45, which prices shall
range from $3,000.00 per gram to $6,000.00 per gram, which SUB and SELLER agree
are SELLER's "cost," provided that in no event shall SUB be required to purchase
P45 inventory: (a) that does not meet the Release Criteria, or (b) in excess of
100 grams of P45 or (c) that is not manufactured within the six (6) month period
immediately preceding the Closing Date.

                  4.5.2    In addition, SUB shall purchase SELLER's then-current
inventory of QA-21 Adjuvant at the purchase price of [**] per gram, which
SUB and SELLER agree is SELLER's "cost," provided that in no event shall SUB be
required to purchase QA-21 Adjuvant in excess of 65 grams of QA-21 Adjuvant.

                  4.5.3    In addition, SUB shall purchase SELLER's raw
materials relating to the manufacture of P45 and QA-21 Adjuvant in the
quantities and at the purchase prices set forth on Schedule 4.5.3 hereto, which
prices SUB and SELLER agree are SELLER's "cost." SUB acknowledges that the
prices and quantities set forth on Schedule 4.5.3 are approximate and are
subject to change due to the need of SELLER to use and/or advance-order such raw
materials as well as make final price calculations prior to Closing.

                  4.5.4    No later than three (3) business days before the
Closing, SELLER shall provide SUB with one or more invoices for the above
inventories and raw materials, setting forth the quantities and total costs of
such inventories and raw materials. Such invoices shall be payable by SUB at the
Closing in accordance with Section 1.4.3 above. In addition, the parties
acknowledge and agree that SUB and SELLER shall agree on additional raw
materials and

[**] Portions of this exhibit have been omitted pursuant to a confidential
     treatment request. An unredacted version of this exhibit has been filed
     with the commission.

                                       13


inventories to be purchased by SUB, such raw materials and inventories to also
be invoiced to SUB in accordance with this provision, and paid by SUB at the
Closing.

                  4.5.5    In addition, SUB shall purchase certain other office
assets of SELLER if agreed to by the parties, which may include without
limitation, phone equipment, office furniture and general office equipment (such
agreed to other office assets (if any) are collectively, the "Other Office
Assets"), on terms and conditions to be mutually agreed upon by SUB and SELLER
in writing prior to the Closing.

         4.6      Key Employees; Employment.

                  4.6.1    SUB shall have the right to offer employment to the
"Key Employees" of SELLER involved in the manufacture of P45, QA-21 Adjuvant and
the Vaccine as set forth on Schedule 4.6, without the direct or indirect
interference of SELLER. Prior to the Effective Date, and except as otherwise
expressly set forth on Schedule 4.6, SELLER shall have executed and delivered
retention letters in substantially the form attached hereto as Appendix H
("Retention Letters") to each of the individuals listed on Schedule 4.6,
pursuant to which SUB agrees to pay cash bonuses to such individuals in an
aggregate amount not to exceed $68,000.

                  4.6.2    To the extent some or all of the Key Employees set
forth on Schedule 4.6 accept SUB's offer of employment, SELLER shall terminate
the employment of such Key Employees effective as of 12:01 a.m., eastern
standard time, on the Closing Date and SUB shall be deemed to have hired such
Key Employees effective as of 12:01 a.m., eastern standard time, on the Closing
Date (referred to herein as "Business Employees") upon substantially the same
terms and conditions with substantially the same duties and responsibilities and
at substantially the same rate of pay in effect on the Closing Date while such
individuals were employed by SELLER. With respect to any Key Employee who is not
actively at work on the Closing Date because of a disability, such individual
shall not receive an offer of employment from SUB unless or until the Key
Employee reports to work after termination of the disability, at which time he
or she shall receive an offer of employment from the SUB, upon substantially the
same terms and conditions with substantially the same duties and
responsibilities and at substantially the same rate of pay in effect on the
Closing Date while such individuals were employed by SELLER, and shall terminate
employment with SELLER and be deemed employed by SUB as of the date the employee
reports to work after termination of the disability. Notwithstanding the
preceding sentence, SUB shall assume responsibility for any unpaid accrued
vacation due to any Business Employee pursuant to any current employee benefit
plan, program, agreement or law or regulation as of the Closing Date. Upon the
date any Key Employee becomes a Business Employee, and except as provided in the
applicable Retention Letter, SELLER shall have no liability or obligation with
respect to such Business Employee's employment by SUB.

                  4.6.3    Except as provided herein and consistent with Section
1.3 of the Agreement, SELLER shall retain liability and responsibility for all
amounts or benefits payable under the Employee Plans, including severance, sick
or holiday pay, if any, to any Business Employee, whether or not payable as a
result of the consummation of the transactions contemplated by this Agreement.
Notwithstanding the foregoing, SUB agrees to assume responsibility for any
accrued unpaid vacation pay due to any Business Employee pursuant to an Employee
Plan or law or regulation as of the Closing Date.



                                       14


                  4.6.4    SUB and SELLER acknowledge that the transactions
provided for in this Agreement may result in obligations on the part of SELLER
and one or more of its employee benefit plans that is a welfare benefit plan
(within the meaning of Section 3(1) of ERISA) to comply with the health care
continuation requirements of Part 6 of Title 1 of ERISA and Internal Revenue
Code Section 4980B, as applicable ("COBRA"). SUB and SELLER expressly agree that
SUB and SUB's benefit plans shall have no responsibility for compliance with
such COBRA continuation requirements (i) for qualified beneficiaries who
previously elected to receive continued coverage under SELLER's ERISA benefit
plans or who between the Effective Date and the Closing Date elect to receive
continued coverage, or (ii) with respect to those employees or former employees
of SELLER who may become eligible to receive such continued coverage as a result
of the transactions provided for in this Agreement. Notwithstanding the
preceding sentence or any other provision in this Agreement, SUB shall reimburse
each Business Employee 100% of the actual premium incurred by such Business
Employee for purposes of maintaining COBRA coverage with the SELLER, where
entitlement to such COBRA coverage resulted from the transactions provided for
in this Agreement. SUB shall provide reimbursement as provided in the preceding
sentence only for premiums paid for health care coverage for periods during
which the Business Employee is employed by SUB. SELLER shall not be liable for
any federal, state, or local taxes due in connection with the reimbursement of
such premiums.

                  4.6.5    Except as specifically set forth in this Agreement
and consistent with Section 1.3 of the Agreement: (i) neither SUB nor PARENT
shall assume, continue or maintain any Employee Plan; (ii) no assets or
liabilities of any Employee Plan shall be transferred to, or assumed by SUB or
PARENT, or any employee plan maintained by either; (iii) SELLER shall be solely
liable and responsible for funding and/or paying any benefits under any Employee
Plan, including any termination benefits and other employee entitlements under
such plans by or attributable to employees of SELLER as of the Closing Date.

                  4.6.6    Nothing in this Agreement, express or implied, shall
confer upon any employee of SELLER, or any representative of any such employee,
any rights or remedies, including any right to employment or continued
employment for any period, of any nature whatsoever.

         4.7      Non-Transferable Permits. From the date hereof until the
Closing, SUB shall use its reasonable best efforts to obtain Permits (temporary
or otherwise) substantially similar to any Non-Transferable Permits SELLER is
unable to transfer to SUB.

         4.8      Access to Records and Files. From and after the Closing, BUYER
shall preserve such computer files, books, accounts, records, Permits and other
similar information transferred to or otherwise obtained by SUB or PARENT
pursuant to the terms of this Agreement or the Related Agreements (including any
modifications and additions thereof made by SUB or PARENT after the Closing)
(collectively, "Records"). For a period of five (5) years after the Closing,
BUYER hereby grants and shall grant to SELLER full access to and the right and
license to, at SELLER's sole cost and expense, reference, use and make copies
and extracts of, such Records, for any reasonable purposes of SELLER related to
(a) the Excluded Assets, other than the Intangible Assets, or (b) any assets in
the case of (i), (ii) or (iii) of the next sentence. The five (5) year
limitation in the preceding sentence shall not apply, and for the avoidance of
doubt, no time limitation shall apply, if SELLER seeks such access or exercise
of its right or


                                       15


license (i) to Permits, (ii) in connection with any actual, threatened or
potential litigation involving SELLER, or (iii) in connection with any inquiry
from any taxing or regulatory authority or agency for so long as any party
hereto may have any potential liabilities with respect thereto. Notwithstanding
the foregoing, to the extent SELLER requires physical access to the
Manufacturing Site, visits by SELLER shall be made during normal business hours
upon prior written request and shall not unreasonably interfere with the
business or activities of SUB. For the avoidance of doubt, nothing contained in
this Section 4.8 shall be interpreted to interfere with or contradict SELLER's
rights pursuant to the Sublease. Further notwithstanding the foregoing, in the
event that BUYER desires to be released of its obligations under this Section
4.8 at any time after the fifth year anniversary of the Closing with respect to
certain Records, it shall notify SELLER thereof in writing. Thereafter, the
parties shall meet and cooperate to identify those such Records which SELLER
desires to retain. BUYER shall then transfer to SELLER those Records identified
by SELLER pursuant hereto, and BUYER shall thereafter have the right to dispose
of the Records.

         4.9      Further Assurances. Each of BUYER and SELLER shall use its
reasonable commercial efforts to perform and fulfill all conditions and
obligations to be performed and fulfilled by such party under this Agreement and
further to ensure that, to the extent in its control or capable of influence by
it, no breach of any of SUB's, PARENT's or SELLER's representations, warranties,
covenants and agreements hereunder or contemplated hereby occurs or exists on or
prior to the Closing Date, to the end that the transactions contemplated by this
Agreement shall be carried out. Without limiting the generality of the
foregoing, following the Closing Date, each of BUYER and SELLER shall execute
such documents, further instruments of transfer, assumption and assignment and
other papers and take such further actions as may be reasonably required to
carry out the transactions contemplated hereby.

         4.10     Seller Assistance; Pre-Closing Access. From the Effective Date
until the six month anniversary of the Closing Date, SELLER agrees to provide to
SUB, to the extent it is reasonably capable, within a reasonable time after
receipt of a written request from SUB during normal business hours and at SUB's
sole cost and expense, reasonably necessary and appropriate assistance through
qualified personnel of SELLER, to the extent SELLER has such qualified
personnel, provided such assistance does not interfere in any manner with the
business or activities of SELLER, at the Manufacturing Site, in connection with
the manufacture by SUB of the Initial Batches pursuant to Section 1.4.4. In the
event SUB fails to manufacture the Initial Batches by the six month anniversary
of the Closing Date and has attempted in good faith to do so, until the eight
month anniversary of the Closing Date, SELLER agrees to provide to SUB, to the
extent it is reasonably capable, within a reasonable time after receipt of a
written request from SUB during normal business hours and at SUB's sole cost and
expense, reasonably necessary assistance through qualified personnel of SELLER,
to the extent SELLER has such qualified personnel, provided such assistance does
not interfere in any manner with the business or activities of SELLER, at the
Manufacturing Site, in connection with the manufacture by SUB of the Initial
Batches pursuant to Section 1.4.4. In addition, prior to the Closing, in
coordination with SUB, SELLER agrees to permit employees of SUB, at SUB's sole
cost and expense, during normal business hours and upon prior written request,
to access the Manufacturing Site as is reasonably necessary for the purpose of
observing the manufacturing process related to the production of QS-21 Adjuvant,
provided such access does not unreasonably interfere with the business or
activities of SELLER. For the avoidance of doubt, nothing contained in this



                                       16


Section 4.10 shall be interpreted to interfere with or contradict SELLER's
rights pursuant to the Sublease.

         4.11     Reorganization of Equipment for the Benefit of Seller. From
and after the Closing Date, in the event that SELLER requests that SUB move
equipment, fixtures or any other personal property located in the Manufacturing
Site for the benefit of SELLER, SUB shall so move such personal property at the
sole expense of SELLER and only to the extent that SUB believes such
reorganization of personal property does not unreasonably interfere with the
business or activities of SUB.

                       SECTION 5 -CONDITIONS PRECEDENT TO
                        THE OBLIGATION OF BUYER TO CLOSE

         The obligation of BUYER to enter into and complete the Closing is
subject, at the option of BUYER acting in accordance with the provisions of this
Agreement with respect to termination hereof, to the fulfillment of the
following conditions, any one or more of which may be waived by it except as set
forth below:

         5.1      Representations and Warranties True. The representations and
warranties of SELLER contained in this Agreement shall be true in all material
respects on and as of the Closing Date with the same force and effect as though
made on and as of the Closing Date, except where the failure of such
representations and warranties would not have a material adverse effect on the
Tangible Assets, Intangible Assets or the Licensed Assets. SELLER shall have
performed and complied in all material respects with all covenants and
agreements required by this Agreement to be performed or complied with by it on
or prior to the Closing Date, subject to those exceptions which could not
reasonably be expected to have a material adverse effect on the Tangible Assets,
Intangible Assets or Licensed Assets.

         5.2      Litigation. No action, suit or proceeding shall have been
instituted before any court or governmental or regulatory body, or instituted or
threatened by any governmental or regulatory body, to restrain, modify or
prevent the carrying out of the transactions contemplated hereby, or to seek
damages or a discovery order in connection with such transactions.

         5.3      Deliveries of Seller. SELLER shall have made each of the
deliveries of SELLER as set forth in Section 1.6.1 above.

         5.4      Rights to be Secured With Respect to Third Parties. SELLER
shall have secured any authorizations, consents, permits, waivers, or rights
with respect to third parties necessary to enable SELLER to consummate the
transactions contemplated by this Agreement and the Related Agreements, as set
forth in paragraphs 1 through 3 on Schedule 5.4 hereto. BUYER and SELLER agree
that the consent referred to in paragraph 1 on Schedule 5.4 may not be waived by
BUYER.

         5.5      Necessary Permits. SUB shall have received all Permits set
forth on Schedule 2.7 hereto unless identified in such schedule as
"Non-Transferable Permits."

         5.6      Legal Opinion. BUYER shall have received the opinion of Palmer
& Dodge LLP, counsel to SELLER, addressed to BUYER substantially in the form as
set forth on


                                       17


Appendix I hereto. In rendering such opinion, counsel may rely as
to factual matters on certificates of officers and/or directors of SELLER and on
certificates of governmental officials.

         5.7      Employees. Offers of employment extended to Curtis Bille and
Rich Kilmer, by SUB shall have been accepted by such individuals.

         5.8      Phase I Site Assessment Report. Delivery of the Phase I Site
Assessment Report identifying no Recognized Environmental Condition (as defined
in ASTM E-1527-00) which would have a material adverse effect on the
Manufacturing Site, the Tangible Assets or the operations of SUB at the
Manufacturing Site as were previously conducted by SELLER at the Manufacturing
Site prior to the Effective Date, unless (a) such Recognized Environmental
Condition had previously been disclosed to SUB or PARENT in paragraphs 1 through
5 on Schedule 2.9 hereto or (b) SELLER accepts in writing prior to the Closing
responsibility for remediating such Recognized Environmental Condition in
accordance with applicable Environmental Laws (each an "Unaccepted Condition").

                        SECTION 6 -CONDITIONS PRECEDENT
                      TO THE OBLIGATION OF SELLER TO CLOSE

         The obligation of SELLER to enter into and complete the Closing is
subject, at the option of SELLER acting in accordance with the provisions of
this Agreement with respect to termination hereof, to the fulfillment of the
following conditions, any one or more of which may be waived:

         6.1      Representations and Warranties True. The representations and
warranties of BUYER contained in this Agreement shall be true in all material
respects on and as of the Closing Date with the same force and effect as though
made on and as of the Closing Date. BUYER shall have performed and complied in
all material respects with all covenants and agreements required by this
Agreement to be performed or complied with by it on or prior to the Closing
Date.

         6.2      Litigation. No action, suit or proceeding shall have been
instituted before any court or governmental or regulatory body, or instituted or
threatened by any governmental or regulatory body, to restrain, modify or
prevent the carrying out of the transactions contemplated hereby, or to seek
damages or a discovery order in connection with such transactions.

         6.3      Deliveries of Buyer. BUYER shall have made each of the
deliveries of BUYER as set forth in Section 1.6.2 above.

         6.4      Employees. SUB shall have delivered evidence of at least five
(5) accepted offers of employment from SUB to the individuals listed on Schedule
4.6 hereto, such offers of employment to offer each individual substantially the
same terms and conditions with substantially the same duties and
responsibilities and at substantially the same rate of pay as in effect on the
Closing Date while such individual was employed by SELLER.

         6.5      Rights With Respect to Third Parties. SELLER and BUYER shall
have secured any authorizations, consents, permits, waivers, or rights with
respect to third parties necessary to enable SELLER and BUYER to consummate the
transactions contemplated by this Agreement


                                       18


and the Related Agreements, as set forth in paragraphs 1 through 3 on Schedule
5.4 hereto and on Schedule 6.5 hereto, respectively. In addition, SELLER shall
have secured the third party consents as set forth in paragraphs 4 and 5 on
Schedule 5.4 hereto.

         6.6      Purchase of Inventories, Raw Materials, and Other Office
Assets. SUB shall have purchased the inventories of P45 and QA-21 Adjuvant, and
the raw materials relating to the manufacture thereof, and the Other Office
Assets, in accordance with the provisions of Sections 1.4.3 and 4.5 above.

                           SECTION 7 -INDEMNIFICATION

         7.1      By Seller. Subject to the other provisions of this Section 7,
from and after the date hereof, SELLER shall indemnify and hold harmless BUYER
and its Affiliates and their respective officers, directors, employees and
agents (each a "BUYER Indemnitee") from and against any loss, liability, cost or
expense (including reasonable legal fees and expenses) (collectively, "Losses")
suffered or incurred by any such BUYER Indemnitee to the extent arising out of
or resulting from (i) any breach of any representation or warranty of SELLER in
this Agreement, the Patent Purchase Agreement, or the License Agreement; (ii)
any breach of any covenant or undertaking of SELLER in this Agreement, the
Patent Purchase Agreement, or the License Agreement; (iii) liabilities of SELLER
accrued prior to the Closing other than the Assumed Liabilities; (iv) subject to
Section 7.13, the operation and ownership by SELLER of the Tangible Assets, the
practice and ownership by SELLER of the Intangible Assets, and the practice (and
ownership, if applicable) by SELLER of the Licensed Assets, prior to the Closing
(including without limitation, with respect to QS-21 Adjuvant); and (v) subject
to Section 7.13, the operation by SELLER of the Manufacturing Site prior to the
Closing.

         7.2      By Buyer. Subject to the other provisions of this Section,
from and after the date hereof, SUB and PARENT shall, jointly and severably,
indemnify and hold harmless SELLER and its Affiliates and their respective
officers, directors, employees and agents (each a "SELLER Indemnitee") from and
against any and all Losses suffered or incurred by any such SELLER Indemnitee to
the extent arising out of or resulting from (i) any breach of any representation
or warranty of SUB or PARENT under this Agreement, the Patent Purchase
Agreement, or the License Agreement; (ii) any breach of any covenant or
undertaking of SUB or PARENT in this Agreement, the Patent Purchase Agreement,
or the License Agreement; (iii) the Assumed Liabilities; (iv) the operation and
ownership of the Tangible Assets, the practice and ownership of the Intangible
Assets, and the practice of the Licensed Assets, from and after the Closing; (v)
the operation of the Manufacturing Site from and after the Closing; and (vi) the
manufacture, use, sale, offer for sale or importation by or on behalf of SUB or
PARENT or any Affiliates thereof of any of P45, QA-21 Adjuvant or animal health
care vaccines containing or comprising P45 and/or QA-21 Adjuvant, including
without limitation, a vaccine protective against feline leukemia virus.

         7.3      Threshold. Neither SELLER, with respect to Sections 7.1(i) and
7.1(ii) nor BUYER, with respect to Sections 7.2(i) and 7.2(ii) shall have any
liability for Losses hereunder to the other until the aggregate of the (a)
amount of all claims for Losses then made by and (b) amount of all Losses
previously paid to BUYER or SELLER, as applicable, pursuant to this

                                       19


Section 7 exceeds the sum of $500,000, in which event all sums shall be
recoverable, subject to the provisions of this Section 7.

         7.4      Minimum Claim. Neither SELLER nor BUYER shall have any
liability hereunder to the other with respect to any claim for Losses if the
amount of such claim is less than $25,000, and any such claim shall not be taken
into account in computing the limitation in Section 7.3 above.

         7.5      Maximum Liability; Limitation on Liability. The aggregate
liability of SELLER, with respect to Sections 7.1(i) and 7.1(ii) or BUYER, with
respect to Sections 7.2(i) and 7.2(ii) for indemnification under this Agreement
in respect of all liabilities for Losses shall not exceed 30% of the Price.
EXCEPT WITH RESPECT TO A PARTY'S INDEMNIFICATION OBLIGATIONS UNDER THIS
AGREEMENT FOR THIRD PARTY CLAIMS, IN NO EVENT SHALL BUYER OR SELLER BE LIABLE TO
THE OTHER FOR ANY INCIDENTAL, INDIRECT, CONSEQUENTIAL, SPECIAL, EXEMPLARY OR
PUNITIVE DAMAGES (INCLUDING LOST OR ANTICIPATED REVENUES OR PROFITS RELATING TO
THE SAME) ARISING FROM ANY CLAIM FOR LOSSES RELATING TO THIS AGREEMENT, WHETHER
SUCH CLAIM IS BASED ON CONTRACT, TORT (INCLUDING NEGLIGENCE) OR OTHERWISE, EVEN
IF AN AUTHORIZED REPRESENTATIVE OF SUCH PARTY IS ADVISED OF THE POSSIBILITY OR
LIKELIHOOD OF SAME.

         7.6      Claims Period. No claim for Losses shall be brought against
SELLER (with respect to Sections 7.1(i) and 7.1(ii)) or SUB or PARENT (with
respect to Sections 7.2(i) and 7.2(ii)) after the 18-month anniversary of the
Closing Date (the date on which notice is so given being the "Claim Date"),
except for any such claim with respect to Section 4.8 hereto.

         7.7      Indemnification Procedures. Any SELLER Indemnitee or BUYER
Indemnitee (each, an "Indemnitee") intending to claim indemnification for any
Loss under this Section shall promptly notify the party from whom
indemnification is sought (the "Indemnifying Party") of any Loss after the
Indemnitee is aware thereof, setting forth the nature of the claim and the basis
for indemnification under this Agreement, and with respect to any Losses arising
or resulting from third-party claims, demands, suits or judgments, the
Indemnifying Party shall assume, at its sole cost and expense, the defense
thereof with counsel mutually satisfactory to the parties; provided, however,
that any Indemnified Party shall have the right to retain its own counsel
reasonably acceptable to the Indemnifying Party, at the expense of the
Indemnifying Party, if representation of such Indemnified Party by the counsel
retained by the Indemnifying Party would be inappropriate because of actual or
potential differences in the interests of such Indemnitee and any other party
represented by such counsel. The Indemnified Party shall cooperate fully with
the Indemnifying Party in such defense and will permit the Indemnifying Party to
conduct and control such defense and disposition of such claim, suit or action
(including all decisions relative to litigation, appeal and settlement). The
Indemnifying Party agrees to keep the Indemnified Party informed of the progress
in the defense and disposition of such claim and to consult with the Indemnified
Party with regard to any proposed settlement. The Indemnifying Party agrees not
to enter into any settlement which would have a material adverse effect on the
other party hereto without prior written consent of the other party hereto,
which consent shall not be unreasonably withheld or delayed.


                                       20


         7.8      Third Party Recoveries. If SELLER makes a payment with respect
to any claim for Losses under the representations or warranties set forth herein
and SUB or PARENT subsequently receives from a third party or under the terms of
any insurance policy a sum in respect of the same claim, SUB or PARENT, as
applicable, shall repay SELLER such amount as is equal to the sum subsequently
received.

         7.9      Legislation. Neither SUB nor PARENT shall have the right to
bring any warranty claim against SELLER if and to the extent that such warranty
claim occurs as a result of any legislation not in force at the date of this
Agreement that takes effect retrospectively or occurs as a consequence of a
change in the interpretation of the law after such date in any jurisdiction; or
to the extent that it relates to any loss for which SUB or PARENT is indemnified
by insurance (or for which it would be so indemnified if at the relevant time
there had been maintained valid and adequate insurance cover of a type in force
in relation to SELLER at the date of this Agreement).

         7.10     Contingent Liabilities. If any potential warranty claim shall
arise by reason of a liability which is contingent only, then SELLER shall not
be under any obligation to make any payment pursuant to such warranty claim
until such time as the contingent liability ceases to be contingent and becomes
actual.

         7.11     No Third Party Beneficiaries. SELLER's representations and
warranties set forth in this Agreement are made exclusively to BUYER and are not
transferable or assignable, and no third party shall rely thereon.

         7.12     Exclusive Remedy. BUYER and SELLER each acknowledge and agree
that, from and after the Closing, their sole and exclusive remedy with respect
to any and all claims relating to breaches of representations, warranties,
covenants and undertakings contained in this Agreement, the Patent Purchase
Agreement, or the License Agreement shall be pursuant to the indemnification
provisions set forth in this Section 7. In furtherance of the foregoing, BUYER
and SELLER hereby waive, from and after the Closing, to the fullest extent
permitted under applicable law, any and all rights, claims and causes of action
they may have against each other relating to breaches of representations,
warranties, covenants and undertakings in this Agreement, the Patent Purchase
Agreement, or the License Agreement arising under or based upon any federal,
state or local statute, law (including common law), ordinance, rule or
regulation or otherwise.

         7.13     Liabilities Under Prior Agreements. Notwithstanding any other
provision of this Section 7 or of the Prior Agreements, the parties hereto
acknowledge and agree that the following provisions shall apply with respect to
any loss, liability, cost, or expense (including reasonable legal fees and
expenses) (collectively, "Prior Losses") arising out of an action or inaction of
either party under the Prior Agreements:

                  (a)      Indemnification by PARENT. PARENT shall indemnify and
hold harmless SELLER and its Affiliates and their respective officers,
directors, employees and agents (each a "SELLER Indemnitee") from and against
any and all Prior Losses suffered or incurred by any such SELLER Indemnitee
resulting from any third-party claim, demand, suit or judgement arising out of
or resulting from (i) the development, pre-clinical or clinical testing,


                                       21


manufacture, use, sale, offer for sale or importation of the Vaccine , provided
that such Prior Loss does not arise out of or result from any event for which
SELLER has indemnification obligations pursuant to Section 7.13(b) below, (ii)
the gross negligence or willful misconduct of PARENT or its Affiliates, or (iii)
the breach of any representation, warranty or covenant of PARENT under the Prior
Agreements, in each case, except to the extent that such Prior Loss is
attributable to the gross negligence or willful misconduct of SELLER or its
Affiliates.

                  (b)      Indemnification by SELLER. SELLER shall indemnify,
defend, and hold harmless PARENT and its Affiliates and their respective
officers, directors, employees and agents (each a "PARENT Indemnitee") from and
against any and all Prior Losses suffered or incurred by any such PARENT
Indemnitee resulting from any third-party claim, demand, suit or judgement to
the extent arising out of or resulting from (i) the failure of the Vaccine to
meet the Release Criteria at the time of shipment under the Prior Agreements
(ii) the gross negligence or willful misconduct of SELLER or its Affiliates, or
(iii) the breach of any representation, warranty or covenant of SELLER under the
Prior Agreements, in each case, except to the extent that such Prior Loss is
attributable to the gross negligence or willful misconduct of PARENT or its
Affiliates. For the avoidance of doubt, SELLER acknowledges that although it was
not a party to certain of the Prior Agreements, for purposes of this Section
7.13(b), the term SELLER shall include SELLER's predecessors under and parties
to the Prior Agreements.

                  (c)      Conditions to Indemnification for Prior Losses. Any
SELLER Indemnitee or PARENT Indemnitee (each, a "Section 7.13 Indemnitee")
intending to claim indemnification under this Section 7.13 shall promptly notify
the party from whom indemnification is sought (the "Section 7.13 Indemnifying
Party") of any Prior Losses after the Section 7.13 Indemnitee is aware thereof,
setting forth the nature of the claim and the basis for indemnification under
this Agreement, and the Section 7.13 Indemnifying Party shall assume, at its
sole cost and expense, the defense thereof with counsel mutually satisfactory to
the parties; provided, however, that any Section 7.13 Indemnitee shall have the
right to retain its own counsel reasonably acceptable to the Section 7.13
Indemnifying Party, at the expense of the Section 7.13 Indemnifying Party, if
representation of such Section 7.13 Indemnitee by the counsel retained by the
Section 7.13 Indemnifying Party would be inappropriate because of actual or
potential differences in the interests of such Section 7.13 Indemnitee and any
other party represented by such counsel. The Section 7.13 Indemnitee shall
cooperate fully with the Section 7.13 Indemnifying Party in such defense and
will permit the Section 7.13 Indemnifying Party to conduct and control such
defense and disposition of such claim or suit (including all decisions relative
to litigation, appeal and settlement). The Section 7.13 Indemnifying Party
agrees to keep the Section 7.13 Indemnitee informed of the progress in the
defense and disposition of such claim or suit and to consult with the Section
7.13 Indemnified Party with regard to any proposed settlement. The Section 7.13
Indemnifying Party agrees not to enter into any settlement which would have a
material adverse effect on the other party hereto without prior written consent
of the other party hereto, which consent shall not be unreasonably withheld or
delayed.



                                       22


                      SECTION 8 -TERMINATION OF AGREEMENT

         8.1      Termination. This Agreement may be terminated on or prior to
the Closing as follows:

                           (i)      at the election of SELLER upon written
notice to BUYER from SELLER if, on or after May 1, 2004, any one or more of the
conditions to the obligation of SELLER to close has not been fulfilled;

                           (ii)     at the election of SUB or PARENT upon
written notice to SELLER if, on or after May 1, 2004, any one or more of the
conditions to the obligation of BUYER to close has not been fulfilled;

                           (iii)    at the election of SELLER upon written
notice to BUYER from SELLER, if SUB or PARENT has breached any representation,
warranty, covenant or agreement contained in this Agreement and has not, within
thirty (30) days of receipt by SUB or PARENT, as applicable, of written notice
from SELLER of such breach of representation, warranty, covenant or agreement,
cured such breach;

                           (iv)     at the election of SUB or PARENT upon
written notice to SELLER if SELLER has breached any representation, warranty,
covenant or agreement contained in this Agreement and has not, within thirty
(30) days of receipt by SELLER of written notice from SUB or PARENT, as
applicable, of such breach of representation, warranty, covenant or agreement,
cured such breach; or

                           (v)      by mutual written agreement of SELLER and
BUYER.

         8.2      Effect of Termination. If this Agreement is terminated and the
transactions contemplated hereby are not consummated as provided above, each and
every representation and warranty contained in this Agreement or any Schedule
hereto, or any certificate, document or other instrument delivered by the
parties in connection herewith, shall expire and none of the parties hereto
shall be under any liability whatsoever with respect to any such representation
or warranty; provided, however, that notwithstanding the foregoing, each party
hereto shall be and remain liable to the other parties hereto in the event that
the failure so to close hereunder shall occur as a consequence of the failure of
a party to fully perform its covenants and agreements hereunder or the material
breach by a party of its representations or warranties contained herein. In the
event that PARENT is entitled to a return of any amounts paid to SELLER pursuant
to Sections 1.4.1 or 1.4.2, SELLER shall make such payment(s) by delivering to
PARENT the aforementioned amounts by official bank check or wire transfer (to an
account specified by PARENT in writing), in next day funds within two (2)
business days of the termination of this Agreement.

                            SECTION 9 -MISCELLANEOUS

         9.1      Confidentiality. Each party hereto acknowledges and agrees
that each such party shall be bound by that certain Mutual Confidential
Disclosure Agreement by and between SELLER and PARENT dated as of July 31, 2003
(as amended by that certain First Amendment to Mutual Confidential Disclosure
Agreement dated as of October 5, 2003) attached hereto as


                                       23


Appendix J and incorporated herein by reference (as may be amended from time to
time by mutual written agreement of SELLER and PARENT) with respect to
Confidential Information (as defined therein) disclosed or otherwise obtained
pursuant to, or in connection with, this Agreement and/or the Related
Agreements.

         9.2      Uniform Commercial Code And United Nations Convention
Warranties. EXCEPT AS OTHERWISE EXPRESSLY SET FORTH HEREIN, ALL UNIFORM
COMMERCIAL CODE WARRANTIES AND UNITED NATIONS CONVENTION ON THE INTERNATIONAL
SALE OF GOODS WARRANTIES ARE EXPRESSLY DISCLAIMED BY THE PARTIES HERETO.

         9.3      Public Announcements. Prior to the Closing, SELLER and BUYER
shall agree on the content of a public disclosure for such public disclosure to
be issued by one or more of the parties hereto within a reasonable time after
the Closing. Thereafter, no party hereto shall issue any press releases or
public disclosure relating to this Agreement or the Related Agreements without
the prior written consent of the other parties hereto, which consent shall not
be unreasonably withheld or delayed, provided, however, that (i) a party hereto
may, without the prior consent of any other party hereto, issue such press
release or public disclosure as may be required by law or the rules and
regulations of the New York Stock Exchange, Nasdaq, the Securities and Exchange
Commission, or Euronext Paris and (ii) once any press release or other public
disclosure is approved for disclosure by all the parties hereto, any party
hereto may make a subsequent public disclosure of the contents of such approved
press release or other public disclosure. Notwithstanding any other provision of
this Agreement, the parties hereto (and each of their directors, officers,
employees, representatives, or other agents) may disclose to any and all
persons, without limitation of any kind, the tax treatment and tax structure of
the transactions contemplated by this Agreement and all materials of any kind
(including opinions or other tax analyses) that are provided to any party hereto
relating to such tax treatment and tax structure.

         9.4      Notices. Any notice or other communication required or
permitted hereunder shall be in writing and shall be deemed given (a) when
delivered personally, (b) on the next business day after timely delivery to an
overnight courier (postage prepaid), or (c) on the third business day after
deposit in the United States mail (certified or registered mail return receipt
requested, postage prepaid), as follows:

                           (i)      if to SUB or PARENT, to:

                                    Virbac S.A.
                                    1 ere Avenue
                                    2065 m L.I.D.
                                    06516 CARROS
                                    FRANCE
                                    Attn: Pierre Pages, Chief Operating Officer
                                          and Gerard Sicsic, General Counsel


                                       24


                                    With a copy to:

                                    Gardner Carton & Douglas LLP
                                    1301 K Street, NW
                                    Suite 900, East Tower
                                    Washington, DC  20005-3317
                                    Attn:  Patrick Rock, Esq.


                           (ii)     if to SELLER, to:

                                    Antigenics Inc.
                                    3 Forbes Rd.
                                    Lexington, MA  02421
                                    Attn: Vice President, Business Development

                                    With a copy to:

                                    Antigenics Inc.
                                    630 Fifth Avenue, Suite 2100
                                    New York, NY  10111
                                    Attn: Associate General Counsel

         Any party hereto may by notice given in accordance with this Section
9.4 to the other parties hereto designate another address or person for receipt
of notices hereunder.

         9.5      Entire Agreement; Prior Agreements. This Agreement (including
the Schedules and Appendices hereto), the Related Agreements and all other
documents executed in connection with the consummation of the transactions
contemplated herein and therein, contain the entire agreement among the parties
hereto with respect to the subject matter contained herein and therein, and
supersedes all prior agreements, written or oral, with respect thereto.
Notwithstanding the foregoing, the parties acknowledge and agree that, with
respect to the Prior Agreements and the Other Prior Agreements, this Agreement
shall supersede and terminate the Prior Agreements and the Other Prior
Agreements subject to, and only upon, the Closing. For the avoidance of doubt,
the Letter Agreement dated September 30, 2002 related to the Mastitis Agreement
(as defined therein) and the Release dated October 11, 2002 related thereto
shall remain in effect.

         9.6      Waivers and Amendments; Non-Contractual Remedies; Preservation
of Remedies. No modification of any of the terms of this Agreement shall be
deemed to be valid unless it is in writing and signed by the party against whom
enforcement is sought. No course of dealing or usage of trade shall be used to
modify the terms and conditions herein. No delay on the part of any party in
exercising any right, power or privilege hereunder shall operate as a waiver
thereof nor shall any waiver on the part of any party of any such right, power
or privilege, nor any single or partial exercise of any such right, power or
privilege, preclude any further exercise thereof or the exercise of any other
such right, power or privilege. The rights and remedies herein provided are
cumulative and are not exclusive of any rights or remedies that any party may
otherwise have at law or in equity. The rights and remedies of any party based
upon, arising out of or otherwise in respect of any inaccuracy in or breach of
any representation, warranty, covenant or agreement contained in this Agreement
shall in no way be limited by the


                                       25



fact that the act, omission, occurrence or other state of facts upon which any
claim of any such inaccuracy or breach is based may also be the subject matter
of any other representation, warranty, covenant or agreement contained in this
Agreement (or in any other agreement between the parties) as to which there is
not inaccuracy or breach.

         9.7      Governing Law; Dispute Resolution. This Agreement shall be
governed by and construed and enforced in accordance with the laws of the
Commonwealth of Massachusetts without regard to the conflicts of law principles
thereof. Except for the right of any party to apply to a court of competent
jurisdiction for a temporary restraining order, a preliminary injunction,
specific performance or other equitable relief to preserve the status quo or
prevent irreparable harm, any dispute, other than disputes regarding the
construction, validity or enforcement of patents, arising between the parties
relating to, arising out of or in any way connected with this Agreement or any
term or condition hereof, or the performance by either party of its obligations
hereunder, whether before or after termination of this Agreement, shall be
resolved as follows:

                  9.7.1    The parties hereto shall, through their duly
authorized representatives, attempt in good faith for fifteen (15) business days
to resolve the dispute.

                  9.7.2    If the dispute can not be resolved by the parties
hereto within fifteen (15) business days, then any party hereto may bring such
matter in a federal or state court in the Commonwealth of Massachusetts, to
whose exclusive jurisdiction all parties hereto consent pursuant to Section 9.9.

         9.8      Governing Language. This Agreement has been prepared in the
English language and the English language shall control its interpretation. All
consents, notices, reports and other written documents to be delivered or
provided by any party under this Agreement shall be in the English language, and
in the event of any conflict between the provisions of any document and the
English language translation thereof, the terms of the English language
translation shall control.

         9.9      Enforceability in Jurisdictions; Consent. The parties hereto
intend to and hereby confer jurisdiction to enforce the provisions of this
Agreement upon the courts of the Commonwealth of Massachusetts. Each of the
parties hereto consents to the jurisdiction of said court or courts in the
Commonwealth of Massachusetts and to service of process by certified mail,
return receipt requested, or by any other manner provided by law. In the case of
any claim involving the parties hereto, any legal action, suit or proceeding
arising out of or relating to such claim may be instituted against such persons
in any state or federal court located in the Commonwealth of Massachusetts and
each such party agrees not to assert, by way of motion, as a defense, or
otherwise, in any such action, suit or proceeding, any claim that it is not
subject personally to the jurisdiction of such courts, that the action, suit or
proceeding is brought in an inconvenient forum, that the venue of the action,
suit or proceeding is improper or that this Agreement or the subject matter
hereof may not be enforced in or by such court. The provisions of this Section
9.9 shall be subject to the provisions of Section 9.7.

         9.10     Survival. Notwithstanding the Closing, the provisions of this
Agreement and the Related Agreements shall, to the extent that they remain to be
performed or are capable of


                                       26


existing, remain in full force and effect and shall be binding on, and
enforceable by, the parties hereto or their respective successors or assignees.

         9.11     Binding Effect; No Assignment. This Agreement shall be binding
upon and inure to the benefit of the parties hereto and their respective
successors, permitted assigns and legal representatives. Neither this Agreement
nor any interest hereunder shall be assignable by any party hereto without the
prior written consent of all other parties hereto; provided that (a) any party
hereto may assign its rights hereunder without such prior written consent to an
entity that acquires all or substantially all of its business or the assets to
which this Agreement and the Related Agreements relate, whether by merger,
consolidation, reorganization, acquisition, sale or otherwise and (b) SELLER may
assign its rights hereunder to any of its Affiliates. Notwithstanding any
assignment permitted by this Section 9.11, the assigning party shall not be
relieved of its liabilities or obligations under this Agreement without the
written consent of all other parties hereto.

         9.12     Variations in Pronouns. All pronouns and any variations
thereof refer to the masculine, feminine or neuter, singular or plural, as the
context may require.

         9.13     Counterparts. This Agreement may be executed by the parties
hereto in separate counterparts, each of which when so executed and delivered
shall be an original, but all such counterparts shall together constitute one
and the same instrument. Each counterpart may consist of a number of copies
hereof each signed by less than all, but together signed by all of the parties
hereto.

         9.14     Severability. Nothing contained herein shall be construed to
require the commission of any act contrary to law. Should one or more provisions
of this Agreement be or become invalid, the parties hereto shall substitute, by
mutual consent, valid provisions for such invalid provisions which valid
provisions in their economic and other effects are sufficiently similar to the
invalid provisions that it can be reasonably assumed that the parties hereto
would have entered into this Agreement with such valid provisions. In case such
valid provisions cannot be agreed upon, the invalidity of one or several
provisions of this Agreement shall not affect the validity of this Agreement as
a whole or the validity of any portions hereof, unless the invalid provisions
are of such essential importance to this Agreement that it is to be reasonably
assumed that the parties hereto would not have entered into this Agreement
without the invalid provisions.

         9.15     Knowledge. As used in this Agreement, the phrases "to the
knowledge of," "known," "aware," "know" and similar phrases of SELLER shall mean
the "knowledge" of the current directors, officers and Key Employees of SELLER
as well as the following individuals with various responsibilities for SELLER:
Lori Baranauskas, Brian Clark, Jeff Clark, Andrea Dellatto, Mario DiPaola,
Lauren Foster, Neal Gordon, Christine Klaskin, Michael Kouchakdjian, Deanna
Petersen and Claudia Wernick. For purposes of the preceding sentence,
"knowledge" with respect to conduct, a fact or circumstance, or a result, means
knowing or being aware that a person is engaging or has engaged in conduct, that
a fact or circumstance exists, or that a result is more likely than not to
occur; having a firm belief that a fact or circumstance exists or that a result
is more likely than not to occur; or being aware of a high probability of the
existence of a


                                       27


fact or circumstance, unless the person actually believes that the fact or
circumstance does not exist.

         9.16     Appendices; Schedules. The Appendices and Schedules are a part
of this Agreement as if fully set forth herein. All references herein to
Sections, subsections, clauses, Appendices and Schedules shall be deemed
references to such parts of this Agreement, unless the context shall otherwise
require.

         9.17     Headings. The headings in this Agreement are for reference
only, and shall not affect the interpretation of this Agreement.



                            [SIGNATURE PAGE FOLLOWS]





















                                       28



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

                                    SELLER:


                                    ANTIGENICS INC., a Massachusetts corporation
                                    and a wholly-owned subsidiary of ANTIGENICS
                                    INC., a Delaware corporation



                                    By:  /s/ Garo H. Armen
                                        ---------------------------------------<
                                    Name:  Garo Armen, PhD
                                    Title: Chief Executive Officer



                                    PARENT:



                                    VIRBAC, S.A., a French corporation



                                    By:  /s/ Pierre PAGES
                                        ----------------------------------------
                                    Name:  Pierre PAGES
                                    Title: Directeur General



                                    SUB:



                                    PP MANUFACTURING CORPORATION,
                                    a Delaware corporation


                                    By:  /s/ Pierre PAGES
                                        ----------------------------------------
                                    Name:  Pierre PAGES
                                    Title: President