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                              ACQUISITION AGREEMENT

      THIS ACQUISITION AGREEMENT (this "Agreement"), dated as of September 25,
2000 (the "Execution Date"), between Abgenix, Inc., a Delaware corporation
("Parent"), Abgenix Canada Corporation, an unlimited liability company organized
and existing under the laws of the Province of Nova Scotia ("Abgenix Canada"),
and ImmGenics Pharmaceuticals Inc., a corporation organized and existing under
the laws of the Province of British Columbia (the "Company").

      The parties enter into this Agreement on the basis of the following facts,
understandings and intentions:

      A.    The Company is engaged in the business of research and development
            relating to the generation of monoclonal antibodies, proteins and
            other biological materials and derivatives thereof.

      B.    The Board, after pursuing and considering a number of strategic
            alternatives, has determined that the Acquisition and the
            Arrangement is fair to the Members and is in the best interests of
            the Company and the Members, and wishes Parent to acquire all of the
            voting securities of the Company on the terms and conditions set
            forth in this Agreement (the "Acquisition").

      C.    Parent is prepared to purchase all of the voting securities of the
            Company pursuant to an arrangement under the BC Act, subject to the
            terms and conditions of this Agreement.

      D.    Certain Members of the Company, who in the aggregate own not less
            than seventy-five percent (75%) of the outstanding shares of Company
            Capital Stock (on an "as-converted" basis and assuming the full
            exercise of all outstanding Company Options) as of the Execution
            Date, have entered into the Shareholder Voting Agreement and
            Irrevocable Proxy with Parent dated as of the Execution Date, and
            shall enter into the Escrow Agreement on or prior to the Closing
            Date, in which they agree, among other things, to provide a limited
            indemnity to Parent against certain losses resulting from certain
            breaches of this Agreement by the Company and to establish an escrow
            fund as security therefor.

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

1. DEFINITIONS

      1.1 Definitions.

      The following capitalized terms used throughout this Agreement shall have
the following meanings:

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

      "1934 Act" means the United States Securities Exchange Act of 1934, as
amended.

      "Abgenix Canada" has the meaning assigned it in the introductory
paragraph.

      "Acquisition" has the meaning assigned it in the Recitals hereto.


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      "Acquisition Proposal" has the meaning assigned it in Section 3.2(a).

      "Agreement" means this agreement.

      "Ancillary Agreements" means the Shareholder Voting Agreement and
Irrevocable Proxy, the Support Agreement, the Voting, Exchange and Cash Put
Trust Agreement, the Option Replacement Agreement, the Escrow Agreement and the
Plan of Arrangement.

      "Applicable Corporate Laws" has the meaning specified in Section 2.1(g).

      "Applicable Securities Laws" has the meaning specified in Section 2.1(g).

      "Applicable Regulatory Approvals" means the Authorizations of Governmental
Entities or self-regulatory organizations set forth in Schedule 1.1 hereto.

      "Arrangement" means the arrangement proposed under Section 252 of the BC
Act referred to in the Plan of Arrangement and attached hereto as Exhibit A, and
any amendments thereto or variations thereof made in accordance with its terms,
the terms of this Agreement and the Special Resolution.

      "Authorization" means with respect to any Person, any order, permit,
approval, waiver, license, ruling, consent, exception or similar authorization
(including the lapse, without objection, of a prescribed time under a statute or
regulation that states that a transaction may be implemented if a prescribed
time lapses following the giving of notice without an objection being made) of
any Governmental Entity having jurisdiction over such Person.

      "BC Act" means the Company Act (British Columbia).

      "Board" means the Board of Directors of the Company.

      "Budget 2001" means the budget of the Company attached to Section 3.1 of
the Company Disclosure Schedule.

      "Closing Date" shall mean the date that is two (2) business days following
the satisfaction or waiver of the conditions set forth in this Agreement, or
such other date as the parties hereto shall mutually agree in writing.

      "Closing Time" means 10:00 a.m. (Vancouver time) on the Closing Date.

      "Company" has the meaning assigned it in the introductory paragraph.

      "Company Capital Stock" means, collectively, the Company Common Shares,
Company Class A Shares and Company Class B Shares.

      "Company Class A Shares" means the Class A preferred shares without par
value in the capital of the Company outstanding from time to time.

      "Company Class B Shares" means the Class B preferred shares with a par
value of CDN$1.00 per share in the capital of the Company outstanding from time
to time.

      "Company Common Shares" means the common shares without par value in the
capital of the Company outstanding from time to time.


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      "Company Consents and Waivers" has the meaning assigned it in Section
2.2(b)(vi).

      "Company Convertible Debenture" means that certain debenture convertible
into 343,595 shares of Company Class A Shares held on the Execution Date by
Corixa Corporation.

      "Company Disclosure Schedule" has the meaning assigned it in Section 5.

      "Company Fully Diluted Shares" shall be the aggregate number of Company
Special Shares outstanding as of the Closing Date, plus the aggregate number of
Company Common Shares that would have been purchasable upon exercise of all
Company Options that are vested as of the Closing Date (after giving effect to
the acceleration of such Company Options contemplated hereby) were such Company
Options not replaced in accordance with the terms of the Option Replacement
Agreement.

      "Company Optionholder" means any holder of a Company Option.

      "Company Options" means outstanding options to purchase Company Common
Shares.

      "Company Plan" means the ImmGenics 1996 Stock Option Plan, as amended.

      "Company Special Shares" means the special shares of the Company to which
will be attached the rights, privileges, restrictions and conditions set forth
in the Special Resolution.

      "Confidentiality Agreement" means the Confidentiality Agreement between
the Company and Parent dated August 18, 2000.

      "Court" means the Supreme Court of British Columbia.

      "Effective Date" means the date on which the Final Order is accepted for
filing by the Registrar of Companies for British Columbia under the BC Act
giving effect to the Arrangement.

      "Effective Time" means the time of filing the certified Final Order
effecting the Arrangement, which is expected to be approximately 9:00 a.m.
(Vancouver time) on the Effective Date.

      "Employee Benefit Plan" means any employee benefit or compensation plan,
program, agreement or arrangement whether written or unwritten, including any
profit-sharing, deferred compensation, bonus, change in control, stock option,
stock purchase, pension, retirement, severance, welfare, fringe benefit,
vacation, sick leave, sabbatical, parenting, medical, dental, hospitalization,
life or other insurance or incentive plan, program, agreement or arrangement
offered or sponsored by the Company covering the employees or former employees
of the Company in their capacities as such.

      "Environmental Laws" means all applicable Laws and all agreements with
Governmental Entities relating to public health and occupational safety as they
relate to the environment, or the handling, storage, disposal and discharge of
Hazardous Substances, or the protection of the environment, and all
Authorizations issued pursuant to such Environmental Laws.

      "Environmental Permits" has the meaning assigned it in Section 5.16.

      "Escrow Agreement" means the Escrow Agreement substantially in the form
attached hereto as Exhibit B to be entered into on or prior to the Closing Date
by the Principal Members, the Company, Parent and the Escrow Agent party
thereto, concerning the limited indemnification of Parent against


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certain losses resulting from certain breaches of this Agreement by the Company
and the establishment of an escrow fund as security therefor.

      "Exchange Ratio" means the ratio of Abgenix Common Stock issuable on
exchange of each Company Special Share that will be issued for each Company
Common Share pursuant to the Recapitalization which will be determined on the
SEC Effective Date. The "Exchange Ratio" shall be equal to the Purchase Price
per Share, divided by the Parent Stock Price.

      "Execution Date" has the meaning assigned it in the introductory
paragraph.

      "Fairness Opinion" means the opinion of SG Cowen Securities Corporation as
to the fairness of the consideration of the Acquisition from a financial point
of view to the Members.

      "Final Order" means the order of the Court approving the Arrangement.

      "Governmental Entity" means any (a) multinational, federal, provincial,
state, regional, municipal, local or other government, governmental or public
department, regulatory body, court or tribunal, domestic or foreign, (b) any
subdivision, arbitral body, commission, board, bureau, agency or authority of
any of the foregoing, or (c) any quasi-governmental or private body exercising
any regulatory, expropriation or taxing authority under or for the account of
any of the foregoing.

      "Hazardous Substance" means any pollutant, contaminant, waste of any
nature, hazardous substance, hazardous material, toxic substance, dangerous
substance or dangerous good as defined or identified in or regulated by any
Environmental Laws.

      "Information Circular" means the notice of special meeting and information
circular, including all schedules thereto, prepared by management of the Company
and approved by the Board and sent to Members in connection with the
solicitation of proxies by management of the Company for use at the Meeting.

      "Intellectual Property Rights" means, with respect to an entity, patents
and applications for patents, trademarks, trade names, trade secrets, service
marks, and copyrights, and applications therefor, inventions, technology,
engineering or other processes, object code, products and processes under
development, databases, drawings, designs, formulae, prototypes, proprietary
know-how or information, other confidential information, or other rights or
materials with respect thereto owned or used by such entity, together with all
antecedent derivative works, or in which such entity has any rights or Licenses
to use in the business of such entity.

      "Interim Order" means the order of the Court providing for, among other
things, the calling, holding and conduct of the Meeting and the application for
the Final Order as contemplated under the Plan of Arrangement.

      "Knowledge of the Company" or "the Company's knowledge" or other words of
similar import mean the actual knowledge of any of directors and officers of the
Company, after due inquiry.

      "Laws" means all statutes, regulations, statutory rules, orders,
decisions, written policies or guidelines, general principles of common law, and
terms and conditions of any grant of approval, permission, authority or license
of any Governmental Entity or self-regulatory authority, including NASDAQ, and
the term "applicable" with respect to such Laws and in the context that refers
to one or more Persons, means that such Laws apply to such Person or Persons or
its or their business,


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undertakings, property or securities and emanate from a Governmental Entity or
self-regulatory authority having jurisdiction over the Person or Persons or its
or their business, undertakings, property or securities.

      "Licenses" means licenses, sublicenses, agreements, permissions,
undertaking and understandings pursuant to which any third party is licensed or
authorized to use any Intellectual Property Rights of a party hereto or pursuant
to which a party hereto is authorized to use the Intellectual Property Rights of
any third party (but not including material transfer agreements or
confidentiality agreements that would not otherwise by themselves constitute a
License, or any off-the-shelf shrink wrap licenses).

      "Material Adverse Effect" or "Material Adverse Change" means any material
adverse effect on or change in the business, affairs, operations, assets
(whether tangible or intangible, including licenses, permits, rights, privilege
or other Intellectual Property Rights, whether contractual or otherwise),
capitalization, or financial condition, of the specified entity or on the
ability of such entity to consummate the transactions contemplated by this
Agreement and the Ancillary Agreements; provided, however, that none of the
following shall be deemed either alone or in combination to constitute, and none
of the following shall be taken into account in determining whether there has
been or will be, a Material Adverse Effect or Material Adverse Change on an
entity: (a) any change in the market price or trading volume of such entity's
stock other than such change that is a result of an event or a fact that would
constitute a Material Adverse Effect or Material Adverse Change; (b) any failure
by such entity to meet internal projections, budgets or forecasts; (c) any
adverse change, event or effect, attributable or relating to the announcement or
pendency of this Agreement, the Acquisition or the Arrangement; other than with
respect to Intellectual Property Rights; (d) any adverse change, event or effect
attributable or relating to conditions affecting the industry or industry sector
in which such entity participates, or the U.S. or Canadian economy as a whole;
(e) any adverse change, event or effect attributable or relating to (i)
customary and usual out-of-pocket fees and expenses (including legal,
accounting, investment banking and other fees and expenses) incurred in
connection with the transactions contemplated by this Agreement, or (ii) the
payment of any amounts due to, or the provision of any other benefits to, any
officers or employees under such employment contracts, non-competition
agreements, employee benefit plans, severance arrangements or other arrangements
as set forth in Sections 5.11 and 5.13 of the Company Disclosure Schedule; (f)
any adverse change, event or effect attributable or relating to compliance with
the terms of, or the taking of any action required by, this Agreement or the
taking of any action consented to in writing by the other parties to this
Agreement; (g) any adverse change, event or effect attributable or relating to
actions required to be taken under applicable Laws applicable as of the
Execution Date, or, to the extent permitted under this Acquisition Agreement,
such contracts or agreements as set forth in Section 5.7 of the Company
Disclosure Schedule.

      "Meeting" means the special meetings of the securityholders of the
Company, including any adjournment or postponements thereof, to be convened to
consider and, if thought advisable, to pass the Special Resolution.

      "Members" means the shareholders of the Company.

      "NASDAQ" means the Nasdaq National Market.

      "Ordinary Shares" means the ordinary shares of the Company to be issued
pursuant to the Recapitalization and which has the rights, privileges,
restrictions and conditions set forth in the Special Resolution.

      "Option Replacement Agreement" means an agreement substantially in the
form attached hereto as Exhibit C to be entered into among Parent and the
Company in connection with the Recapitalization.


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      "Parent" has the meaning assigned it in the introductory paragraph.

      "Parent Common Stock" means the common stock, par value $0.0001 per share,
of Parent.

      "Parent Consents and Waivers" has the meaning assigned it in Section
2.2(c)(iv).

      "Parent Disclosure Schedule" has the meaning assigned it in Section 4.

      "Parent Material Adverse Effect" or "Parent Material Adverse Change" means
a material adverse effect on or change or material delay in the ability of
Parent to consummate the transactions contemplated by this Agreement and the
Ancillary Agreements, including its obligations under Section 2.4(d), (e) and
(f) hereof, or any event that would cause the delisting of the Parent Common
Stock from NASDAQ.

      "Parent Plan" shall mean the Abgenix 1999 Non-statutory Stock Option Plan,
as amended.

      "Parent Special Voting Share" means the share of Parent Special Voting
Preferred Stock having substantially the rights, privileges, restrictions and
conditions described in the Voting, Exchange and Cash Put Trust Agreement.

      "Parent Stock Price" shall be equal to the average of the closing prices
of one share of Parent Common Stock, as quoted on NASDAQ, for the five (5)
trading days ending on the day immediately preceding the SEC Effective Date.

      "Patent Disclosure Agreement" means the agreement dated September 12, 2000
entered into by the Company and Parent, among others, relating to the review of
the intellectual property of the Company.

      "Person" includes any individual, firm, partnership, joint venture,
venture capital fund, limited liability company, unlimited liability company,
association, trust, trustee, executor, administrator, legal personal
representative, estate, group, body corporate, corporation, unincorporated
association or organization, Governmental Entity, syndicate or other entity,
whether or not having legal status.

      "Plan of Arrangement" means the plan of arrangement proposed under Section
252 of the BC Act in the form attached as Exhibit A to this Agreement, as
amended, modified or supplemented from time to time in accordance herewith and
any order of the Court.

      "Principal Members" means the Members of the Company who have entered into
the Shareholder Voting Agreement and Irrevocable Proxy and who will enter into
the Escrow Agreement.

      "Purchase Price per Share" means Seventy-five million United States
dollars (US$75,000,000), plus the aggregate exercise price of all vested Company
Options to be replaced on the Closing Date, and then divided by the number of
Company Fully-Diluted Shares as of the Closing Date.

      "Recapitalization" means the capital reorganization to be effected
pursuant to the Plan of Arrangement.

      "Registration Statement" has the meaning assigned to it in Section 2.4(d).

      "Replacement Options" means the options to purchase shares of Parent
Common Stock issued in exchange for the Company Options.


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      "SEC" means the Unites States Securities and Exchange Commission.

      "SEC Effective Date" means the date on which the Registration Statement
becomes effective.

      "Shareholder Voting Agreement and Irrevocable Proxy" means the Shareholder
Voting Agreement and Irrevocable Proxy made and entered into as of the Execution
Date, by certain principal shareholders concerning the voting of their shares of
Company Capital Stock and Company Convertible Debentures to effect the
Recapitalization, the Arrangement and the Acquisition.

      "Special Resolution" means the special resolution to effect the
Recapitalization and the Arrangement passed by 75% of the following: (i) persons
entitled to vote as holders of Company Common Shares and holders of Company
Options, (ii) holders of Company Class A Shares, (iii) holders of Company Class
B Shares, and (iv) holders of Company Convertible Debentures, in each case
present and voting at the Meeting.

      "Support Agreement" means the support agreement substantially in the form
attached hereto as Exhibit D to be entered into among the Company, Parent, and
Abgenix Canada.

      "Tax" has the meaning assigned it in Section 5.17.

      "Trustee" means the trustee or any successor trustee as determined in
accordance with the Voting, Exchange and Cash Put Trust Agreement.

      "Voting, Exchange and Cash Put Trust Agreement" means the voting, exchange
and cash put trust agreement substantially in the form attached as Exhibit E to
be entered into among Parent, Abgenix Canada, the Company and the Trustee.

      1.2 Accounting Matters.

      Unless otherwise stated, all accounting terms used in this Agreement
regarding the Company shall have the meanings attributable thereto under
Canadian generally accepted accounting principles and all determinations of an
accounting nature regarding the Company required to be made shall be made in a
manner consistent with Canadian generally accepted accounting principles. Unless
otherwise stated herein, all accounting terms used in this Agreement regarding
Parent shall have the meanings attributable thereto under United States
generally accepted accounting principles and all determinations of an accounting
nature required to be made regarding Parent shall be made in a manner consistent
with United States generally accepted accounting principles.

2. THE ACQUISITION

      2.1 The Acquisition.

      The parties agree to effect the transaction pursuant to the Arrangement,
pursuant to which the Company shall recapitalize its share capital so that all
holders of shares of Company Capital Stock and the holder of the Company
Convertible Debenture shall become holders of Company Special Shares and the
Company shall create a new class of Ordinary Shares to be acquired by Abgenix
Canada at US$1.00 payable in cash.

            (a)   Under the Arrangement, on the Closing Date (i) the vesting
                  date of all outstanding Company Options under the Company Plan
                  (except for Company Options granted to employees hired after
                  the Execution Date) shall accelerate by


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                  twelve (12) full months and they otherwise shall continue to
                  vest in accordance with their terms at the same rate as prior
                  to the Closing Date, (ii) all other Company Options shall
                  accelerate and/or vest in accordance with their terms, and
                  (iii) the period of exercisability for all Company Options
                  shall be extended by the number of days between the Closing
                  Date and the SEC Effective Date. The Company Plan shall be
                  terminated on the Closing Date and references to the Company
                  Plan in existing option agreements shall be deemed to refer to
                  the Parent Plan.

            (b)   Pursuant to the Option Replacement Agreement, on the Closing
                  Date, Parent shall grant new options (the "Replacement
                  Options") to acquire shares of Parent Common Stock to all
                  Company Optionholders in replacement for each Company Option,
                  whether or not vested and whether or not granted under the
                  Company Plan. No Company Options shall be exercisable during
                  the period between the Closing Date and the SEC Effective
                  Date. On and after the SEC Effective Date, (i) each
                  Replacement Option will be exercisable for that number of
                  whole shares of Parent Common Stock equal to the number of
                  Company Common Shares that were issuable upon exercise of such
                  Company Option immediately prior to the Closing Date,
                  multiplied by the Exchange Ratio, plus cash in lieu of any
                  fractional shares of Parent Common Stock determined in
                  accordance with Section 2.1(i), and (ii) the per share
                  exercise price for the shares of Parent Common Stock issuable
                  upon exercise of such Replacement Option will be equal to the
                  quotient determined by dividing the exercise price per Company
                  Common Share at which such Company Option was exercisable
                  immediately prior to the Closing Date by the Exchange Ratio,
                  rounded up to the nearest whole cent. Parent shall take all
                  corporate actions necessary to reserve for issuance a
                  sufficient number of shares of Parent Common Stock for
                  delivery upon exercise of Replacement Options on the terms set
                  forth in the Option Replacement Agreement.

            (c)   Parent may elect, in its sole discretion, to make the
                  Acquisition itself, or through Abgenix Canada. In the event
                  that Abgenix Canada makes the Acquisition, the term "Parent"
                  as used herein shall include, as appropriate, Abgenix Canada,
                  provided, however, Parent shall be liable to the Company for
                  any default in performance by Abgenix Canada to the extent
                  Abgenix Canada cannot or does not meet its obligations.

            (d)   The Arrangement shall be effected in accordance with all
                  Applicable Corporate Laws and shall be subject only to the
                  conditions set forth in this Agreement. Each of the parties to
                  this Agreement shall use its reasonable best efforts to
                  consummate the Acquisition, subject only to the terms and
                  conditions of this Agreement. Each of the parties to this
                  Agreement shall use its reasonable best efforts to obtain all
                  of the Applicable Regulatory Approvals, waivers and consents
                  required for consummation of the Acquisition and to satisfy
                  the conditions precedent to the Acquisition to the extent they
                  are within its power.

            (e)   The matters described in this Agreement shall be initiated on
                  an expeditious basis and each party shall, and shall use its
                  reasonable best efforts to cause third parties to, meet the
                  schedules and time frames set forth in this Agreement,
                  including reaching agreement as to the form and substance of
                  the legal opinions referenced in Sections 2.2(b)(xiv) and
                  2.2(c)(v) within fifteen (15) days after the Execution


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                  Date. Each of the parties to this Agreement shall use its
                  reasonable best efforts to cause the conditions specified in
                  Section 2.2 to be satisfied within the time periods required
                  thereby, and all matters described in this Agreement shall be
                  carried out in a cooperative manner and the parties will keep
                  each other informed as to progress.

            (f)   The Company shall consult with Parent and its counsel and
                  allow each of them to fully participate in the preparation of
                  all documentation to be sent to the Members, or to any other
                  Person in obtaining any Applicable Regulatory Approvals and
                  any other consents and waivers required for consummation of
                  the Acquisition. All such documentation, including the
                  Information Circular and the Special Resolution, shall be in
                  form and substance reasonably satisfactory to Parent. Each
                  party shall, in a timely and expeditious manner, subject to
                  the Confidentiality Agreement and the Patent Disclosure
                  Agreement, provide to the other parties to this Agreement all
                  information as may be reasonably requested by the other or
                  required by applicable law with respect to such party and its
                  businesses and properties for inclusion in the Information
                  Circular, or in any amendments or supplements to the
                  Information Circular, which information shall comply in all
                  material respects with all applicable legal requirements on
                  the date of mailing of the Information Circular and shall not
                  contain any material misrepresentation or material omission
                  (as defined under Applicable Securities Laws) and the parties
                  supplying such information shall indemnify and save harmless
                  the other parties and the directors and other officers of the
                  other parties from and against any and all claims, suits,
                  actions, causes of actions, liabilities, damages, costs,
                  charges and expenses of every nature and kind whatsoever for
                  which the other parties, their respective directors or
                  officers may become liable by virtue of such information
                  containing a misrepresentation, provided that such information
                  is included in the Information Circular in the form approved
                  by the supplying party, and this indemnity shall survive the
                  filing of the certified Final Order.

            (g)   The Company shall ensure that the Information Circular to be
                  sent to the Members in connection with the Meeting contains
                  all information that is required to be included therein in
                  accordance with all applicable Laws, including all applicable
                  corporate Laws, including the BC Act ("Applicable Corporate
                  Laws") and all state, provincial, United States, Canadian and
                  other foreign applicable securities Laws ("Applicable
                  Securities Laws") and, without limiting the generality of the
                  foregoing, provides its securityholders with information in
                  sufficient detail to permit them to form a reasoned judgment
                  concerning the Acquisition and the Plan of Arrangement.

            (h)   To the extent that a Member not resident in Canada does not
                  provide a certificate issued pursuant to Section 116 of the
                  Income Tax Act (Canada) with a certificate limit acceptable to
                  Parent, Abgenix Canada and the Company, as applicable, shall
                  be authorized to withhold any amounts that it may be required
                  to remit to the Receiver General pursuant to Subsection 116[5]
                  of the Income Tax Act (Canada).

            (i)   As promptly as practicable, but in no event more than two (2)
                  business days, after the SEC Effective Date, Parent shall
                  notify each Member in writing of the occurrence of the SEC
                  Effective Date and the Parent Stock Price. On and after


                                       9
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                  the SEC Effective Date, each Company Special Share shall be
                  exchangeable, in accordance with their terms, the Support
                  Agreement, and the Voting, Exchange and Cash Put Trust
                  Agreement for that fraction of a share of Parent Common Stock
                  equal to the Exchange Ratio. No fraction of a share of Parent
                  Common Stock will be issued upon exchange of Company Special
                  Shares, but in lieu thereof each holder of Company Special
                  Shares who would otherwise be entitled to receive a fraction
                  of a share of Parent Common Stock (after aggregating all
                  fractional shares of Parent Common Stock that otherwise would
                  be received by such holder) shall, upon such exchange receive
                  from the Company an amount of cash (rounded to the nearest
                  whole cent), without interest, equal to the product of (x)
                  such fraction, multiplied by (y) the Parent Stock Price.

      2.2 Conditions Precedent to Closing.

            (a)   Mutual Conditions Precedent. The respective obligations of the
                  parties hereto to complete the transactions contemplated by
                  this Agreement shall be subject to the satisfaction, on or
                  before the Closing Date, of the following conditions
                  precedent, each of which may only be waived by the mutual
                  written consent of Parent and the Company:

                  (i)   the Final Order, in a form reasonably satisfactory to
                        the parties to this Agreement, shall have been obtained
                        and shall have been accepted for filing by the Registrar
                        of Companies under the BC Act at or before 4:30 p.m.
                        (Vancouver time), December 1, 2000, or such other date
                        as may be mutually agreed upon by the parties to this
                        Agreement in writing, and shall not have been set aside
                        or modified in a manner reasonably unacceptable to such
                        parties on appeal or otherwise;

                  (ii)  all Applicable Regulatory Approvals shall have been
                        obtained;

                  (iii) there shall not be in force any order or decree from a
                        Governmental Entity of competent jurisdiction
                        restraining or enjoining the consummation of the
                        transactions contemplated by this Agreement and there
                        shall be no proceeding (other than an appeal made in
                        connection with the Arrangement), of a judicial or
                        administrative nature or otherwise, brought by a
                        Governmental Entity in progress or threatened that
                        relates to or results from the transactions contemplated
                        by this Agreement that would, if successful, result in
                        an order or ruling that would preclude completion of the
                        transactions contemplated by this Agreement in
                        accordance with the terms hereof or would materially
                        alter the terms and conditions of this Agreement or the
                        Arrangement, or would otherwise be inconsistent with the
                        Applicable Regulatory Approvals which have been
                        obtained;

                  (iv)  Parent shall have received the approval of NASDAQ for
                        the listing of the shares of Parent Common Stock
                        issuable pursuant to the terms of the Company Special
                        Shares, the Support Agreement, and the Voting, Exchange
                        and Cash Put Trust Agreement;

            (b)   Additional Conditions Precedent to the Obligations of Parent
                  and Abgenix Canada. The obligations of Parent and Abgenix
                  Canada to complete the


                                       10
<PAGE>

                  transactions contemplated by this Agreement shall, in
                  addition, be subject to the satisfaction, on or before the
                  Closing Date, of the following conditions precedent. Such
                  additional conditions are for the exclusive benefit of Parent
                  and may be waived in writing by Parent, in whole or in part,
                  in its sole discretion, at any time and from time to time:

                  (i)   (x) The representations and warranties made by the
                        Company in this Agreement shall have been true, correct
                        and complete in all respects as of the Execution Date,
                        and shall be true, correct and complete in all respects
                        as of the Closing Date as if made at the Closing Date
                        (or, to the extent such representations and warranties
                        speak as of an earlier date, they shall be true in all
                        respects as of such earlier date) except in each case
                        (A) as qualified by the Company Disclosure Schedule or
                        as otherwise contemplated by this Agreement and (B) for
                        such failures which in the aggregate have not had and
                        would not reasonably be expected to have a Material
                        Adverse Effect on the Company without giving effect to
                        any update to the Company Disclosure Schedule, and
                        without giving effect to any "Material Adverse Effect"
                        or other materiality qualifications, or any similar
                        qualifications, contained or incorporated directly or
                        indirectly in such representations and warranties;
                        provided, however, that such Material Adverse Effect
                        qualifier shall be inapplicable with respect to the
                        representations and warranties contained in Section
                        5.21, which individually shall have been true, complete
                        and correct in all material respects as of the Execution
                        Date and shall be true, complete and correct in all
                        material respects on and as of the Closing Date; (y) all
                        covenants of the Company under this Agreement, or any
                        Ancillary Agreement to be performed by the Company on or
                        before the Closing Date shall have been duly performed
                        by the Company in all material respects; and (z) Parent
                        shall have received a certificate of the Company
                        addressed to Parent and dated the Closing Date, signed
                        on behalf of the Company by its President and Chief
                        Executive Officer together with one director of the
                        Company, confirming the same as at the Closing Date;

                  (ii)  each of the representations and warranties of the
                        Members which are set forth in the Shareholder Voting
                        Agreement and Irrevocable Proxy shall be true, correct
                        and complete in all material respects at the Closing
                        Date, each of their covenants and obligations set forth
                        in the Shareholder Voting Agreement and Irrevocable
                        Proxy to be performed on or before the Closing Date
                        shall have been duly performed in all material respects,
                        other than any such failure to be true, correct and
                        complete, or any such breach which does not have the
                        effect, or could not reasonably be expected to have the
                        effect, of enjoining, prohibiting, or imposing material
                        limitations, damages or conditions on the purchase by,
                        or the sale to, Parent of the Company or the right of
                        Parent to own or exercise full rights of ownership as
                        the sole voting Member, and the Shareholder Voting
                        Agreement and Irrevocable Proxy shall not have been
                        terminated;

                  (iii) the Board shall not have withdrawn, modified or changed
                        any of the recommendations or determinations set forth
                        in Section 2.3, and Parent shall have received
                        documentation to its reasonable satisfaction that any


                                       11
<PAGE>

                        notices, consents or approvals under any shareholder
                        agreement, investment agreement, share purchase
                        agreement, co-sale agreement, registration rights
                        agreement, bonus warrant agreement, penalty warrant
                        agreement, or any other similar agreement required to be
                        obtained in connection with this Agreement, the
                        Arrangement or the Acquisition shall have been obtained
                        or each such agreement, if so requested by Parent in
                        writing, shall have been terminated in its entirety;

                  (iv)  no claim, act, action, suit or proceeding, dispute or
                        formal investigation shall have been threatened or taken
                        before or by any Governmental Entity, and no claim, act,
                        action, suit or proceeding, dispute or investigation
                        shall have been taken by any elected or appointed public
                        official or by any private Person, in Canada or
                        elsewhere, and no law, regulation or policy shall have
                        been enacted, promulgated or applied, whether or not
                        having the force of law;

                        (A)   which, in the reasonable opinion of Parent, has
                              the effect or could reasonably be expected to have
                              the effect of enjoining, prohibiting or imposing
                              material limitations, damages or conditions on the
                              purchase by, or the sale to, Parent, of the
                              Company or the right of Parent to own or exercise
                              full rights of ownership as the sole voting
                              Member; or

                        (B)   which, in the reasonable opinion of Parent, has
                              had or could be expected to have a Material
                              Adverse Effect on the Company;

                  (v)   in the opinion of Parent acting reasonably and in good
                        faith, there shall not have occurred and would not
                        reasonably be expected to occur any Material Adverse
                        Change in the Company;

                  (vi)  all consents or waivers by third parties relating to the
                        Acquisition listed on Schedule 2.2(b)(vi) ("Company
                        Consents and Waivers") shall have been obtained;

                  (vii) there shall not have occurred a Minimum Dissent Event. A
                        "Minimum Dissent Event" shall mean holder(s) of 10% or
                        more of the outstanding Company Common Shares
                        (calculated on an "as-converted" basis and assuming the
                        full exercise of all outstanding Company Options) have
                        voted against the Special Resolution;

                  (viii) such directors of the Company as Parent may specify
                        shall have tendered their resignations to the Company,
                        effective as of the Closing Time, and the Company shall
                        have filled such vacancies with designees of Parent,
                        effective as of the Closing Time;

                  (ix)  80% of the employees listed in Schedule 2.2(b)(ix)
                        attached hereto, shall remain employed by the Company
                        and there shall not have been any resignation notice
                        from more than 20% of the employees listed in Schedule
                        2.2(b)(ix) received by the Company;


                                       12
<PAGE>

                  (x)   the Escrow Agreement shall have been duly executed and
                        delivered and shall be in full force and effect and
                        unmodified;

                  (xi)  the Company shall not have made any Tax election,
                        changed any accounting method with respect to Taxes,
                        filed any amended Return (other than those Returns filed
                        in response to comments from the Canadian tax
                        authorities in relation to claims for federal research
                        and experimental development tax credit, provided that
                        such Returns do not involve any Tax payment by the
                        Company), or settled or compromised any proceeding with
                        respect to a Tax liability; and

                  (xiv) Parent shall have received a legal opinion in form and
                        substance reasonably satisfactory to Parent from counsel
                        for the Company covering the following matters: due
                        incorporation, due execution, due authorization, no
                        violation, capitalization before and after the Closing
                        Date, due issuance and validity, the obtainment of the
                        Interim Order and the Final Order, and the acceptance
                        for filing thereof by the Registrar of Companies for
                        British Columbia, and the enforceability of this
                        Agreement and the Ancillary Agreements.

                  Parent may not rely on the failure to satisfy any of the
            conditions precedent in Sections 2.2(a) or 2.2(b) as a basis for
            non-compliance by Parent with its obligations under this Agreement
            if the conditions precedent in Section 2.2 (a) or 2.2(b) would have
            been satisfied but for a material default by Parent in complying
            with its obligations under this Agreement.

            (c)   Additional Conditions Precedent to the Obligations of the
                  Company. The obligations of the Company to complete the
                  transactions contemplated by this Agreement shall in addition
                  be subject to the satisfaction, on or before the Closing Date,
                  of the following conditions precedent. Such additional
                  conditions are for the exclusive benefit of the Company and
                  may be waived by the Company, in whole or in part, in its sole
                  discretion, at any time and from time to time:

                  (i)   (x) The representations and warranties made by Parent
                        and Abgenix Canada in this Agreement shall have been
                        true, correct and complete in all respects as of the
                        Execution Date, and shall be true, correct and complete
                        in all respects as of the Closing Date as if made at the
                        Closing Date (or, to the extent such representations and
                        warranties speak as of an earlier date, they shall be
                        true in all respects as of such earlier date) except in
                        each case (A) as otherwise disclosed in the Parent
                        Disclosure Schedule or as contemplated by this Agreement
                        and (B) for such failures which in the aggregate have
                        not had and would not reasonably be expected to have a
                        Parent Material Adverse Effect (y) all covenants of
                        Parent and Abgenix Canada under this Agreement or any
                        Ancillary Agreement to be performed on or before the
                        Closing Date shall have been duly performed by Parent
                        and Abgenix Canada, as applicable, in all material
                        respects, and (z) the Company shall have received a
                        certificate of Parent and Abgenix Canada addressed to
                        the Company and dated the Closing Date, signed on behalf
                        of Parent and Abgenix Canada by two


                                       13
<PAGE>

                        authorized senior executive officers of Parent and
                        Abgenix Canada, confirming the same as at the Closing
                        Date;

                  (ii)  no claim, act, action, suit or proceeding, dispute or
                        formal investigation shall have been threatened or taken
                        before or by any Governmental Entity, and no claim, act,
                        action, suit or proceeding, dispute or investigation
                        shall have been taken by any elected or appointed public
                        official or by any private Person, in Canada or
                        elsewhere, and no law, regulation or policy shall have
                        been enacted, promulgated or applied, whether or not
                        having the force of law;

                        (A)   which, in the reasonable opinion of the Company,
                              has the effect or could reasonably be expected to
                              have the effect of enjoining, prohibiting or
                              imposing material limitations, damages or
                              conditions on the ability of the Members to own or
                              exercise full rights of ownership as the holders
                              of the Company Special Shares or to receive Parent
                              Common Stock upon the exchange thereof pursuant to
                              their terms, the Voting, Exchange and Cash Put
                              Trust Agreement and the Support Agreement;

                        (B)   which, in the reasonable opinion of the Company,
                              has had or could reasonably be expected to have a
                              Parent Material Adverse Effect;

                  (iii) in the opinion of the Company acting reasonably and in
                        good faith, there shall not have occurred and would not
                        be reasonably expected to occur a Parent Material
                        Adverse Change;

                  (iv)  all consents or waivers by third parties required for
                        the consummation of the Acquisition listed on Schedule
                        2.2(c)(iv) ("Parent Consents and Waivers") shall have
                        been obtained; and

                  (v)   the Company shall have received a legal opinion in form
                        and substance reasonably satisfactory to the Company
                        from counsel for Parent covering the following matters:
                        due incorporation, due execution, due authorization, no
                        violation, due issuance and validity, and the
                        enforceability of this Agreement and the Ancillary
                        Agreements.

                  The Company may not rely on the failure to satisfy any of the
            conditions precedents in Sections 2.2(a) or 2.2(c) as a basis for
            non-compliance by the Company with its obligations under this
            Agreement if the condition precedent in Sections 2.2(a) or 2.2 (c)
            would have been satisfied but for a material default by the Company
            in complying with its obligations under this Agreement.

      2.3 Company Action.

            (a)   The Company represents and warrants to Parent that the Board
                  has received the Fairness Opinion to the effect that the
                  consideration to be offered to its Members pursuant to the
                  Acquisition is fair from a financial point of view to the
                  Members and that the Board, upon review of the Fairness
                  Opinion and consultation with its advisors, has determined
                  unanimously that:


                                       14
<PAGE>

                  (i)   the Acquisition and the Arrangement is fair to the
                        Members and is in the best interests of the Company and
                        the Members;

                  (ii)  the Board will recommend that Members vote in favor of
                        the Arrangement; and

                  (iii) this Agreement is in the best interests of the Company
                        and the Members.

            (b)   The Company represents that all members of its Board have
                  advised it that they, in their capacity as Members of the
                  Company, intend to vote all of their Company Capital Stock and
                  Company Options in favor of the Special Resolution necessary
                  to effect the Arrangement and the Company shall so represent
                  in the Information Circular.

            (c)   The Company covenants in favor of Parent that it shall:

                  (i)   as soon as reasonably practical, but in no event later
                        than five (5) business days after the Execution Date,
                        apply in a manner acceptable to Parent, acting
                        reasonably, under Section 252 of the BC Act for the
                        Interim Order;

                  (ii)  obtain from the holders of the Company Class A Shares,
                        the Company Class B Shares and, if the Company
                        Convertible Debenture shall not have been converted in
                        accordance with its terms prior to the date of the
                        Meeting to consider the Plan of Arrangement, from the
                        Company Convertible Debenture by way of Special
                        Resolution or otherwise as required by law consent to
                        the Arrangement;

                  (iii) as soon as practicable, but in no event later than
                        thirty (30) calendar days after the issuance of the
                        Interim Order, take all necessary actions to convene and
                        hold the Meeting for the purpose of considering the
                        Special Resolution (and for any other proper purpose as
                        may be set out in the notice for such meeting);

                  (iv)  subject to obtaining any prior approvals as required by
                        the Interim Order, within fifteen (15) calendar days
                        after the Meeting, use its reasonable best efforts to
                        proceed with and diligently pursue the application to
                        the Court for the Final Order;

                  (v)   subject to obtaining the Final Order and the
                        satisfaction or waiver of the other conditions herein
                        contained in favor of each party, send to the Registrar
                        of Companies for British Columbia a certified Final
                        Order and such other documents as may be required in
                        connection therewith under the BC Act to give effect to
                        the Arrangement;

                  (vi)  execute and deliver the Option Replacement Agreement on
                        or prior to the Closing Date; and

                  (vii) use its reasonable best efforts to cause each holder of
                        the Company Options as of the Closing Date to execute
                        and deliver an agreement


                                       15
<PAGE>

                        substantially the same in substance as the Option
                        Replacement Agreement.

      2.4 Parent Action

      Parent covenants in favor of the Company that, it shall:

            (a)   execute and deliver the Option Replacement Agreement on or
                  prior to the Closing Date;

            (b)   execute and deliver and cause Abgenix Canada to execute and
                  deliver the Support Agreement on or prior to the Closing Date;

            (c)   to issue to the Trustee the Parent Special Voting Share on or
                  prior to the Closing Date;

            (d)   within ten (10) days after the Closing Date, file a
                  Registration Statement on Form S-1 (or Form S-3, as the case
                  may be, (the "Registration Statement") with the SEC in order
                  to register under the 1933 Act the shares of Parent Common
                  Stock to be issued from time to time after the SEC Effective
                  Date upon exchange of the Company Special Shares and shall use
                  its reasonable best efforts to cause the Registration
                  Statement; to become effective as soon as reasonably
                  practicable thereafter and to maintain the effectiveness of
                  such Registration Statement, to the extent permitted by law,
                  for a period of four (4) years, or until no Company Special
                  Shares shall be outstanding, whichever is earlier; provided,
                  however, that notwithstanding anything in this Agreement or
                  the Arrangement or any related agreement to the contrary, (a)
                  Parent shall have the right at any time to substitute any
                  other registration statement of Parent for the Registration
                  Statement; in the event of such substitution, the term
                  "Registration Statement" as used in this Agreement shall
                  include such substitute registration statement, as
                  appropriate); and (b) if Parent shall furnish to the holders
                  of Company Special Shares at any time after fifteen (15) days
                  after the SEC Effective Date, a certificate signed by the
                  President or Chief Executive Officer of Parent stating that
                  the Board of Directors of Parent has made the good faith
                  determination that it is in the best interests of the Company
                  to suspend the use of the Registration Statement (and the
                  prospectus relating thereto), then the right of holders of the
                  Company Special Shares to exchange their Company Special
                  Shares for shares of Parent Common Stock shall be suspended,
                  if any of the following events shall occur: (i) pending
                  negotiations relating to, or the consummation of, a
                  transaction or the occurrence of an event that requires
                  additional disclosure of material information by the Parent in
                  the Registration Statement (or the prospectus relating
                  thereto) and which has not been so disclosed; (ii) a material
                  corporate transaction is pending or has occurred, the
                  disclosure of which should be set forth in the Registration
                  Statement and the Board of Directors of Parent shall have
                  determined in good faith that such disclosure would not be in
                  the best interests of Parent and its stockholders; or (iii)
                  the Board of Directors of Parent shall have determined in good
                  faith that it is in the best interests of Parent to suspend
                  the use of the Registration Statement; provided, however, that
                  no suspension of the use of the Registration Statement
                  pursuant to this Section 2.4(d) shall take place unless a
                  similar suspension shall apply to all other registration
                  statements covering Parent Common Stock. Upon the occurrence
                  of any such suspension, Parent shall use


                                       16
<PAGE>

                  its reasonable best efforts to promptly amend or supplement
                  the Registration Statement on a post-effective basis or to
                  take such action as is necessary to make resumed use of the
                  Registration Statement compatible with the Company's best
                  interests, as applicable, so as to permit resumption of
                  exchange of shares of Parent Common Stock for Company Special
                  Shares pursuant to the Registration Statement as soon as
                  possible. During any such period of suspension, Parent shall
                  be under no obligation to process any exchange requests
                  received but not completed prior to the suspension, and any
                  time limits or deadlines for the completion of such exchange
                  shall be tolled for the duration of the suspension;

            (e)   as promptly as reasonably practicable after the Closing Date,
                  if the Parent Common Stock to be issued from time to time
                  after the Effective Date upon the exercise of the Replacement
                  Options are not covered by an effective registration
                  statement, file a registration statement on Form S-8 (or such
                  other applicable form) in order to register under the 1933 Act
                  such Parent Common Stock; and

            (f)   execute, deliver, and cause Abgenix Canada to execute and
                  deliver, the Voting, Exchange and Cash Put Trust Agreement,
                  pursuant to which, among other things, the Trustee, if the SEC
                  Effective Date has not occurred on or prior to the number of
                  days after the Closing Date set forth below, from and after
                  the following dates, shall have the right (on behalf of each
                  holder of the Company Special Shares) to put up to the
                  following percentages (inclusive of any prior puts by such
                  holder) of such holder's initial number of Company Special
                  Shares (including any Company Special Shares subject to the
                  Escrow Agreement) to Parent for an amount of cash equal to the
                  Purchase Price per Share, pursuant to the terms and conditions
                  set forth in the Voting, Exchange and Cash Put Trust
                  Agreement:

                    Number of Calendar Days             Maximum
                    after the Closing Date                Put
                              100                          50%
                              145                          75%
                              190                         100%

      2.5 Solicitation of Proxies.

      The Company shall solicit proxies in connection with the Arrangement.

      2.6 Joint Public Announcement and Joint Press Release.

      All press releases or other public written communications of any sort by
any of the parties to this Agreement relating to this Agreement or the
Arrangement and the method of release for publication thereof shall be provided
for review and comment by the other parties to this Agreement. Each party shall
expeditiously comment on such written communication provided that the party
issuing such written communication shall not be delayed if to do so would be
contrary to any legal or regulatory requirements. Notwithstanding the above, the
parties shall jointly issue a press release upon the execution of this
Agreement.


                                       17
<PAGE>

      2.7 Outstanding Stock Options.

      The Company agrees and represents that the Board has resolved, and has
authorized and directed the Company to, subject to any required approval of any
Governmental Entity, cause the (i) vesting of all outstanding option
entitlements under the Company Plan (except those granted to an employee hired
after the Execution Date) to accelerate by twelve (12) months prior to or
concurrent with the Closing Date, (ii) the period of exercisability of all
outstanding Company Options under the Company Plan to be extended by the number
of days between the Closing Date and the SEC Effective Date, and (iii) the
termination of the Company Plan on the Closing Date.

3. COVENANTS OF THE COMPANY

      3.1 Ordinary Course of Business.

      The Company covenants and agrees that, during the period from the
Execution Date and continuing until the earlier to occur of the termination of
this Agreement or the Closing Time, unless Parent shall otherwise agree in
writing or as otherwise expressly contemplated or permitted by this Agreement,
the Company shall conduct its business only in, and not take any action except
in, the usual, ordinary and regular course of business and consistent with past
practice; to pay its debts and Taxes when due, in the ordinary course in
substantially the same manner as previously paid, except for any debts or Taxes
which are being contested in good faith by the Company, to pay or perform its
other material obligations when due in the ordinary course in substantially the
same manner as previously paid or performed, to maintain and keep its assets
(including its Intellectual Property Rights), properties and equipment in good
repair, working order and condition, in a manner consistent with past practices
and in compliance with applicable agreements or contractual obligations, and to
use its reasonable best efforts, consistent with past practices and policies, to
preserve intact its present business organization and goodwill, and preserve its
relationships with officers, employees and others having material business
dealings with it.

            (a)   Without limiting the generality of the foregoing and except as
                  expressly contemplated by this Agreement, during the period
                  from the Execution Date and continuing until the earlier to
                  occur of the termination of this Agreement or the Closing
                  Time, without the prior written consent of Parent or as
                  otherwise expressly contemplated by this Agreement or by the
                  Budget 2001, the Company shall not, directly or indirectly:

                  (i)   issue, sell, pledge, lease, convey, transfer, assign,
                        license, hypothecate, dispose of, encumber or agree to
                        issue, sell, pledge, lease, convey, transfer, assign,
                        license, hypothecate, dispose of or encumber:

                        (A)   any additional securities of, or any options,
                              warrants, calls, conversion privileges or rights
                              of any kind to acquire any shares of, the Company
                              (other than pursuant to the exercise of Company
                              Options and convertible securities currently
                              outstanding in accordance with their existing
                              terms); provided, however, that the Company may
                              (x) grant Company Options to such number of newly
                              hired employees and consultants contemplated in
                              the Budget 2001 or to employees and consultants
                              hired not more than six (6) months prior to the
                              Execution Date, in an aggregate amount not to
                              exceed options to purchase 200,000 Company Common
                              Shares and (y) effect


                                       18
<PAGE>

                              transfers of shares of Company Capital Stock by
                              Members as permitted under and pursuant to the
                              terms of this Agreement and the Ancillary
                              Agreements;

                        (B)   any Intellectual Property Rights, other than
                              specific-target licenses to antibody-based
                              products granted under current or future
                              codevelopment agreements or licenses granted under
                              current or future material transfer agreements, in
                              each case in such ordinary course of business and
                              as mutually agreed to by Company and Parent, and
                              provided that such agreements and licenses (a)
                              shall not result in (i) more than three targets
                              per licensee, (ii) any transfer of or grant of
                              right to practice any technology, know-how, trade
                              secret or proprietary process or procedures of the
                              Company and (b) shall be on commercially
                              reasonable terms and do not prejudice Parent's
                              rights under this Agreement; or

                        (C)   except in the ordinary course of business, any
                              other material tangible or intangible asset or
                              property of the Company;

                  (ii)  amend or authorize to amend its memorandum, articles,
                        by-laws or other Company organizational documents;

                  (iii) alter, destroy, remove or otherwise fail to retain any
                        books and records of the Company;

                  (iv)  split, combine or reclassify any outstanding Company
                        Common Shares, Company Class A Shares or Company Class B
                        Shares or declare, set aside or pay any dividends or
                        other distributions payable in cash, stock, property or
                        otherwise with respect to the Company Common Shares,
                        Company Class A Shares or Company Class B Shares;

                  (v)   redeem, purchase or offer to purchase any Company Common
                        Shares, Company Class A Shares or Company Class B Shares
                        or other securities of the Company;

                  (vi)  reorganize, amalgamate, merge or otherwise continue the
                        Company with any other Person, corporation, partnership
                        or other business organization whatsoever;

                  (vii) commence to undertake an expansion of its business
                        facilities except as described in Section 3.1 of the
                        Company Disclosure Schedule;

                  (viii) acquire or agree to acquire (by merger, amalgamation,
                        business combination, arrangement, acquisition of stock
                        or assets or otherwise) any Person, or acquire or agree
                        to acquire any material assets;

                  (ix)  guarantee the payment of any indebtedness or incur any
                        indebtedness for money borrowed or issue or sell any
                        non-convertible debt securities other than in accounts
                        receivable incurred in the ordinary course of business
                        or


                                       19
<PAGE>

                        indebtedness incurred in connection with the financing
                        of working capital as contemplated in Budget 2001;

                  (x)   except in the usual, ordinary and regular course of
                        business and consistent with past practice: (A) prepay,
                        satisfy, discharge or settle any claims or liabilities
                        (absolute, accrued, asserted, unasserted, contingent or
                        otherwise) prior to the same being due, except such as
                        have been reserved against in the financial statements
                        of the Company, which are, individually or in the
                        aggregate, material; (B) grant any waiver, exercise any
                        option or relinquish any contractual rights which are,
                        individually or in the aggregate, material; or (C) enter
                        into any interest rate, currency or commodity swaps,
                        hedges or other similar financial instruments;

                  (xi)  make any loans, advances or capital contributions to, or
                        investments in, any other Person (including advances to
                        employees), except that the Company may (x) make routine
                        travel advances to employees in the ordinary course of
                        business, (y) make loans to newly hired employees in
                        connection with their relocation to the Vancouver, B.C.
                        area which does not in any single case exceed CDN
                        $10,000 and in the aggregate exceed CDN $40,000, and (z)
                        invest its cash balances in short-term investment grade
                        debt securities in accordance with past practices;

                  (xii) make or rescind any material express or deemed election
                        relating to Taxes, settle or compromise any material
                        action relating to Taxes, amend any material Tax return
                        except in each case in the ordinary course of business
                        consistent with past practice or as required by law, or
                        except as may be required by applicable law, make any
                        change to any of its accounting methods with respect to
                        Taxes (including its reporting of income or deductions,
                        basis or its write-offs of accounts receivable);

                  (xiii) fail to maintain its existing insurance coverage of all
                        types in effect or, in the event any such coverage shall
                        be terminated or lapse, to the extent available at
                        reasonable cost, procure substantially similar
                        substitute insurance policies which in all material
                        respects are in at least such amounts and against such
                        risks as are currently covered by such policies;

                  (xiv) change its methods of accounting as in effect on May 31,
                        2000 or take any action, other than reasonable and usual
                        actions in the ordinary course of business and
                        consistent with past practice, with respect to
                        accounting policies or procedures;

                  (xv)  modify, amend or terminate any of material contracts or
                        waive, release or assign any material rights or claims;

                  (xvi) take, or agree to commit to take, any action that would
                        cause the representations and warranties of the Company
                        contained herein, individually or in the aggregate, not
                        to be true, correct and complete in all material
                        respects, such that the condition to closing set forth
                        in Section 2.2(b)(i)(x) would not be satisfied;

                  (xvii) close, shut down, or otherwise eliminate any facility
                        or office;


                                       20
<PAGE>

                  (xviii) make or commit to make any capital expenditures that
                        exceeds US$25,000 per month, or make any cash
                        disbursement exceeding US$50,000 for any single item or
                        related series of items;

                  (xix) initiate, compromise or settle any material litigation
                        or arbitration proceeding;

                  (xx)  enter into an agreement, contract, commitment or
                        arrangement to do any of the foregoing, or to authorize,
                        recommend, propose or announce an intention to do any of
                        the foregoing;

                  (xxi) accelerate the vesting of any unvested stock options;

                  (xxii) enter into or modify (or promise to enter into or
                        modify) any employment or compensation or severance
                        policies or arrangements with, or grant any bonuses,
                        salary increases, severance or termination pay to, any
                        officers or directors of the Company or modify any
                        Employee Benefit Plan other than pursuant to agreements,
                        policies or arrangements in effect (without amendment)
                        on the Execution Date or and previously disclosed in
                        writing to Parent or as otherwise described in Section
                        3.1 of the Company Disclosure Schedule;

                  (xxiii) with respect to employees who are not officers or
                        directors, take or promise to take any action other than
                        in the ordinary, regular and usual course of business
                        and consistent with past practice (none of which actions
                        shall be unreasonable or unusual) with respect to the
                        entering into or modifying of any employment or
                        severance policies or arrangements or with respect to
                        the grant of any bonuses, salary increases, stock
                        options, pension benefits, retirement allowances,
                        deferred compensation, severance or termination pay or
                        any other form of compensation or profit sharing or with
                        respect to any increase of benefits payable otherwise
                        than pursuant to agreements, policies or arrangements in
                        effect (without amendment) on the Execution Date and
                        previously disclosed to Parent; or

                  (xxiv) settle or compromise any claim in excess of Twenty Five
                        Thousand Canadian dollars (CDN$25,000) brought by any
                        present, former or purported holder of any securities of
                        the Company in connection with the transactions
                        contemplated by this Agreement or any Ancillary
                        Agreements without the prior written consent of Parent.

            (b)   the Company shall:

                  (i)   carry out the terms of the Interim Order and the Final
                        Order applicable to it and to comply promptly with all
                        requirements under Applicable Corporate Laws with
                        respect to the transactions contemplated by this
                        Agreement and by the Arrangement;

                  (ii)  promptly notify Parent orally and in writing of (A) any
                        material adverse change in the Intellectual Property
                        Rights, any Material Adverse Change of the Company and
                        of the Company obtaining knowledge of any


                                       21
<PAGE>

                        material governmental or third party claims, complaints,
                        investigations or hearings (or communications indicating
                        that the same may be threatened), (B) of any event
                        occurring subsequent to the Execution Date that would
                        render any representation or warranty of the Company
                        contained in this Agreement, if made on or as of the
                        date of such event or the Closing Date, untrue,
                        incorrect or incomplete in any material respect, and (C)
                        of any breach by the Company of any covenant or
                        agreement contained in this Agreement, such that the
                        conditions to closing set forth herein would not be
                        satisfied;

                  (iii) confer on a regular basis with Parent with respect to
                        operational matters;

                  (iv)  give notice to Parent with respect to any debt or Taxes
                        which are being contested in good faith by the Company;

                  (v)   maintain a cash balance of at least Five Million
                        Canadian dollars (CDN$5,000,000); and

                  (vi)  perform all obligations required to be performed by the
                        Company under this Agreement, co-operate with Parent in
                        connection therewith, and do all such other acts and
                        things as may be necessary in order to consummate and
                        make effective, as soon as reasonably practicable, the
                        transactions contemplated in this Agreement and, without
                        limiting the generality of the foregoing, the Company
                        shall:

                        (A)   use its reasonable best efforts to obtain the
                              approvals of holders of the Company Capital Stock,
                              Company Options and Company Convertible Debenture
                              to the Arrangement;

                        (B)   apply for and use its reasonable best efforts to
                              obtain all Applicable Regulatory Approvals
                              relating to the Company and, in doing so, to keep
                              Parent reasonably informed as to the status of the
                              proceedings related to obtaining the Applicable
                              Regulatory Approvals;

                        (C)   apply for and use its reasonable best efforts to
                              obtain the Interim Order and the Final Order prior
                              to December 1, 2000;

                        (D)   use its reasonable best efforts to cause the
                              Company to cease to be a reporting company under
                              the BC Act on or prior to December 1, 2000;

                        (E)   defend all lawsuits or other legal, regulatory or
                              other proceedings challenging or affecting this
                              Agreement, any Ancillary Agreement or the
                              consummation of the transactions contemplated
                              hereby, including the Arrangement;

                        (F)   use its reasonable best efforts to have lifted or
                              rescinded any injunction or restraining order or
                              other order which may adversely affect the ability
                              of the parties to consummate the transactions
                              contemplated hereby;


                                       22
<PAGE>

                        (G)   effect all necessary registrations, filings and
                              submissions of information required by
                              Governmental Entities from the Company; and

                        (H)   use its reasonable best efforts to obtain the
                              Company Consents and Waivers and promptly inform
                              Parent if any such waiver, consent or approval
                              cannot be obtained.

      3.2 Non-Solicitation.

            (a)   The Company shall not, and shall not authorize or permit any
                  of its officers, directors or employees or any investment
                  banker, financial advisor, attorney, accountant or other
                  representative or agent retained by it, directly or
                  indirectly, (i) to solicit, initiate or encourage (including
                  by way of furnishing non-public information), or take any
                  other action intended to facilitate, the making of any
                  proposal that constitutes, or may reasonably be expected to
                  lead to, an offer by any third party (other than Parent) to
                  acquire all or substantially all of the assets of the Company
                  or any equity or other interest in the Company (a)
                  representing more than ten percent (10%) of the voting capital
                  stock of the Company or (b) by any Person that generates,
                  manufactures, markets or distributes monoclonal antibodies for
                  human therapeutic use (an "Acquisition Proposal") or (ii) to
                  participate in any discussions or negotiations regarding an
                  Acquisition Proposal. Without limiting the foregoing, it is
                  understood that any violation of the restrictions set forth in
                  the preceding provisions by any director or officer of the
                  Company or any of its subsidiaries or any investment banker,
                  financial advisor, attorney, accountant or other
                  representative of the Company, acting on behalf of the
                  Company, shall be deemed to be a material breach by the
                  Company of this Agreement.

            (b)   The Board shall not cause or allow the Company to enter into
                  any letter of intent, agreement in principle, acquisition
                  agreement or any other agreement with respect to any
                  Acquisition Proposal.

            (c)   Without limiting the obligation of the Company in Sections
                  3.2(a) and 3.2(b), the Company shall promptly (but in any
                  event within two (2) days) advise Parent orally and in writing
                  of any Acquisition Proposal received or any inquiry regarding
                  the making of an Acquisition Proposal received by an officer
                  or director of the Company, including any request for
                  non-public information, the material terms and conditions (if
                  applicable) of such request, other Acquisition Proposal or
                  inquiry and, if known to the Company, a summary description of
                  the business of the Person making such request, other
                  Acquisition Proposal or inquiry and a statement as to whether
                  such Person is publicly traded.

      3.3 Access to Information.

      Subject to the Confidentiality Agreement and the Patent Disclosure
Agreement between the Company and Parent, the Company shall afford Parent's
officers, employees, counsel, accountants and other authorized representatives
and advisors (the "Representatives") full access, at all reasonable times, on
reasonable notice and on a reasonable basis without unreasonable disruption of
the Company's business or operations, from the Execution Date and until the
expiration of this Agreement, to its business, properties, books, contracts and
records, without limitation, as well as to its management


                                       23
<PAGE>

personnel, and, during such period, the Company shall furnish promptly to Parent
all information concerning its business, properties and personnel, without
limitation, as Parent may reasonably request.

      3.4 Structure of Transaction.

      Each party hereto shall use reasonable best efforts to cooperate with the
other party hereto in structuring the Plan of Arrangement in a tax efficient
manner, including, by completing to the satisfaction of Parent, an internal
corporate reorganization provided that, no such cooperation shall be required
where such structuring shall cause any breach of or default under this Agreement
or any other material adverse tax consequences. The parties intend the Company
Special Shares issued pursuant to the Plan of Arrangement to be issued in a
transaction exempt from registration under the 1933 Act by reason of Section
3(a)(10) thereof and, when issued, such shares of Company Special Shares will
not be subject to resale restriction imposed by the 1933 Act.

4. REPRESENTATIONS AND WARRANTIES OF PARENT AND ABGENIX CANADA

      Parent and Abgenix Canada hereby represent and warrant to the Company as
follows, except to the extent as set forth with particularity as to each Section
in the Parent Disclosure Schedule attached to this Agreement as Schedule 4 and
except as previously disclosed pursuant to reports filed by Parent pursuant to
the 1933 Act or the 1934 Act or the rules or regulations promulgated thereunder.
The Parent Disclosure Schedule shall be arranged in paragraphs corresponding to
the numbered and lettered paragraphs contained in this Agreement and the
disclosure in any paragraph shall qualify other paragraphs in this Agreement
only to the extent that such disclosure specifically references the fact that it
also qualifies or applies to such other specified paragraphs or if it is
reasonably apparent on the face of the disclosure that it is applicable to
another Section of the Parent Disclosure Schedule. Any certificate signed by an
officer of either Parent or Abgenix Canada and delivered to Company at or prior
to the Closing pursuant to Section 2.2(c)(i)(X) shall be deemed to be a
representation and warranty by such party to Company under this Agreement as to
each and every matter stated.

      4.1 Organization and Qualification.

      Parent is a corporation duly incorporated, validly existing and in good
standing under the corporate laws of the State of Delaware and has the requisite
corporate power and authority to carry on its business as it is now being
conducted. Abgenix Canada is an unlimited liability company duly organized,
validly existing and in good standing under the corporate laws of Nova Scotia
and has the requisite corporate power and authority to carry on its business as
it is now being conducted.

      4.2 Authority.

      Each of Parent and Abgenix Canada have the requisite corporate power and
authority to enter into this Agreement and each Ancillary Agreement to which it
is a party and to carry out its respective obligations hereunder and thereunder.
This Agreement and the Ancillary Agreements to which it is a party have been
duly authorized by each of Parent and Abgenix Canada, and no other corporate
proceedings on the part of either Parent or Abgenix Canada are or will be
necessary to authorize this Agreement and the transactions contemplated hereby.
This Agreement has been duly executed and delivered by each of Parent and
Abgenix Canada and constitutes a legal, valid and binding obligation of each of
Parent and Abgenix Canada enforceable against each of Parent and Abgenix Canada
in accordance with its terms, subject to bankruptcy, insolvency, fraudulent
transfer, reorganization, moratorium and other laws relating to or affecting
creditors' rights generally and to general principles of equity.


                                       24
<PAGE>

      4.3 Regulatory Approvals.

      Other than in connection with or in compliance with the provisions of
Applicable Corporate Laws, Applicable Securities Laws, Applicable Regulatory
Approvals, (i) there is no legal impediment to Parent's or Abgenix Canada's
consummation of the transactions contemplated by this Agreement, and (ii) no
filing or registration with, or authorization, consent or approval of, any
domestic or foreign public body or authority is required of Parent or Abgenix
Canada in connection with the making or the consummation of the Acquisition,
except for such filings or registrations which, if not made, or for such
authorizations, consents or approvals which, if not received, would not have a
material adverse effect on the financial condition of Parent and its
subsidiaries taken as a whole or on the ability of Parent or Abgenix Canada to
consummate the transactions contemplated hereby.

      4.4 Capitalization.

      As of the Execution Date, the authorized share capital of Parent consists
of 220,000,000 Shares of Parent Common Stock, of which, as of September 20,
2000, 81,520,244 Shares of Parent Common Stock are issued and outstanding. The
Parent Common Stock to be issued in exchange for the Company Special Shares as
contemplated by the Arrangement will, when issued in accordance with the
provisions of the Company Special Shares set forth in the Plan of Arrangement,
be validly issued, fully paid, and nonassessable, and, issued in compliance with
all applicable federal and state securities laws. As of the Execution Date, the
authorized share capital of Abgenix Canada consists of One Hundred Million
(100,000,000) shares, one of which as of the Execution Date and as of the
Closing Date, is and shall be issued to Parent. There are no options, warrants
or other rights, agreements or commitments of any character whatsoever requiring
the issuance, sale or transfer by Abgenix Canada of any securities of Abgenix
Canada or any securities convertible into, or exchangeable or exercisable for,
or otherwise evidencing a right to acquire, any securities of Abgenix Canada
(including the Special Parent Voting Share). All outstanding shares of Abgenix
Canada have been in accordance with their terms will be, duly authorized and
validly issued, are fully paid and non-assessable.

      4.5 SEC Filings; Parent Financial Statements.

      Except as disclosed on Section 4.5 of the Parent Disclosure Schedule, all
forms, reports and documents filed by Parent with the SEC were prepared in all
material aspects in accordance with the requirements of the 1933 Act or the 1934
Act, as the case may be, and the rules and regulations of the SEC thereunder.
Each of the consolidated financial statements of Parent filed with the SEC, (i)
comply as to form in all material respects with the published rules and
regulations of the SEC with respect thereto, (ii) are prepared in accordance
with GAAP applied on a consistent basis throughout the periods involved (except
as may be indicated in the notes thereto or, in the case of unaudited interim
financial statements, as may be permitted by the SEC under Form 10-Q, 8-K or any
successor form under the 1934 Act) and (iii) fairly present the consolidated
financial position of Parent and its subsidiaries as at the respective dates
thereof and the consolidated results of Parent's operations and cash flows for
the periods indicated, except that the unaudited interim financial statements
may not contain footnotes and were or are subject to normal and recurring
year-end adjustments.

      4.6 No Violations.

      Neither the execution nor the delivery of this Agreement or the Ancillary
Agreements by either Parent or Abgenix Canada, nor the consummation of the
transactions contemplated hereby and by the Acquisition, nor compliance by each
of Parent and Abgenix Canada with any of the provisions hereof will in any
material aspect: violate, or result in a breach of any provision of, require any
consent, approval under, or constitute a default (or an event which, with notice
or lapse of time or both, would constitute a


                                       25
<PAGE>

default) under any of the terms, conditions or provisions of (x) the governing
documents of either Parent or Abgenix Canada or (y) any judgment, order, writ,
decree, statute, rule, regulation, to which either Parent or Abgenix Canada is
subject, or by which either Parent or Abgenix Canada is bound, in each case
under (x) or (y) having a Parent Material Adverse Effect.

      4.7 Absence of Parent Material Adverse Changes.

      Since June 30, 2000, and except as specified herein or in the Parent
Disclosure Schedule, there has not occurred any Parent Material Adverse Change.

      4.8 Litigation, etc.

      Except as disclosed in Section 4.8 of the Parent Disclosure Schedule,
there are, at the Execution Date, no actions, proceedings, complaints, suits,
grievances, claims, arbitrations or investigations pending, or to the knowledge
of either Parent or Abgenix Canada threatened, affecting Parent or Abgenix
Canada at law or in equity or before or by any federal, provincial, municipal or
other governmental department, commission, board, bureau, agency or
instrumentality, which action, suit, complaint, grievances, proceeding, claim,
arbitration or investigation involves a possibility of any judgment against or
liability of either Parent or Abgenix Canada which, if successful, would have a
Parent Material Adverse Effect.

      4.9 Ownership of Abgenix Canada; No Prior Activities.

      As of the Effective Date, all of the outstanding shares of Abgenix Canada
are owned by Parent. As of the Effective Date, except for obligations and
liabilities incurred in connection with its incorporation or organization and
transactions contemplated by this Agreement or the Ancillary Agreements and any
other agreements or arrangements contemplated by this Agreement, Abgenix Canada
has not and will not have incurred, directly or indirectly, through any
subsidiary or affiliate, any obligations or liabilities or engaged in any
business activities of any type or kind whatsoever or entered into any
agreements or arrangements with any Person.

5. REPRESENTATIONS AND WARRANTIES OF THE COMPANY

      The Company hereby represents and warrants to Parent and Abgenix Canada as
follows, except to the extent as set forth with particularity as to each Section
in the Company Disclosure Schedule attached to this Agreement as Schedule 5. The
Company Disclosure Schedule shall be arranged in paragraphs corresponding to the
numbered and lettered paragraphs contained in this Agreement and the disclosure
in any paragraph shall qualify other paragraphs in this Agreement only to the
extent that such disclosure specifically references the fact that it also
qualifies or applies to such other specified paragraphs or if it is reasonably
apparent on the face of the disclosure that it is applicable to another Section
of the Company Disclosure Schedule. Any certificate signed by an officer of the
Company and delivered to Parent or Abgenix Canada at or prior to the Closing
pursuant to Section 2.2(b)(i)(z) shall be deemed to be a representation and
warranty by the Company to Parent and Abgenix Canada under this Agreement as to
each and every matter stated.

      5.1 Organization and Qualification.

      The Company is a corporation duly organized, validly existing and in good
standing under the laws of British Columbia, and has the requisite corporate
power and authority to carry on its business as it is now being conducted. The
Company is duly registered to do business and is in good standing in each
jurisdiction listed in Section 5.1 of the Company Disclosure Schedule, such
jurisdictions being all of the


                                       26
<PAGE>

jurisdictions in which the character of its properties, owned or leased, or the
nature of its activities makes such registration necessary, except where the
failure to be so registered or in good standing would not have a Material
Adverse Effect on the Company or on the ability of the Company to consummate the
transactions contemplated hereby. Copies of the Company's constituent documents
(including memorandum, articles, and other organizational agreements), together
with all amendments to date (collectively, the "Company organizational
documents") heretofore delivered to Parent are true, correct and complete as of
the Execution Date and have not been amended or superseded. The minute books of
the Company provided to Parent contain a complete summary of all meetings of the
Board and Members since the time of incorporation of the Company up to the
Execution Date and reflect all transactions referred to in such minutes
accurately in all material respects.

      5.2 Authority Relative to This Agreement.

      Subject to the approval of the Special Resolution by the Members, the
Company has the requisite corporate power and authority to enter into this
Agreement and to carry out its obligations hereunder. The execution and delivery
of this Agreement and the consummation of the transactions contemplated hereby
have been duly authorized by the Board, and no other corporate proceedings on
the part of the Company are necessary to authorize this Agreement and the
transactions contemplated hereby other than by Special Resolution and by each
class of the Company Capital Stock in the manner required by the Company
organizational documents and the BC Act. This Agreement has been duly executed
and delivered by the Company and constitutes a legal, valid and binding
obligation of the Company enforceable against the Company in accordance with its
terms, subject only to applicable bankruptcy, insolvency, fraudulent transfer,
reorganization, moratorium and other laws relating to or affecting creditors'
rights generally and general principle of equity.

      5.3 No Violations.

            (a)   Provided that the Special Resolution and the Acquisition are
                  approved by the Members, except as disclosed in Section 5.3 of
                  the Company Disclosure Schedule, neither the execution nor the
                  delivery of this Agreement by the Company, nor the
                  consummation of the transactions contemplated hereby and by
                  the Acquisition, nor compliance by the Company with any of the
                  provisions hereof will: (i) violate, conflict with, or result
                  in a breach of any provision of, require any consent, approval
                  or notice under, or constitute a default (or an event which,
                  with notice or lapse of time or both, would constitute a
                  default) or result in a right of termination, acceleration,
                  suspension, revocation, impairment, forfeiture or nonrenewal
                  of, or result in the creation of any lien, security interest,
                  charge or encumbrance upon any of the properties or assets of
                  the Company under any of the terms, conditions or provisions
                  of (x) the Company organizational documents or (y) other than
                  the agreements listed in the Company Disclosure Schedule, any
                  note, bond, mortgage, indenture, loan agreement, deed of
                  trust, agreement, judgment, order, writ, decree, statute,
                  rule, regulation, lien, license, permit, franchise,
                  authorization, approval, lease, contract or other instrument
                  or obligation to which the Company is a party, or to which it
                  or any of its properties or assets may be subject, or by which
                  the Company is bound; or (ii) subject to compliance with the
                  statutes and regulations referred to in Section 5.3(b),
                  violate any judgment, ruling, order, writ, injunction,
                  determination, award, decree, statute, ordinance, law, rule or
                  regulation applicable to the Company or any of its properties
                  or assets (except, in the case of each of clauses (i) and (ii)
                  above, for such violations, conflicts, breaches, defaults,
                  terminations, accelerations or creations of liens, security
                  interests, charges or


                                       27
<PAGE>

                  encumbrances which, or any consents, approvals or notices
                  which if not given or received, would not have any Material
                  Adverse Effect on the Company); or (iii) cause the suspension
                  or revocation of any authorization, consent, approval or
                  license currently in effect which suspension or revocation
                  would have a Material Adverse Effect on the Company, or (iv)
                  result in any payment (including severance, unemployment
                  compensation, golden parachute, bonus or otherwise) becoming
                  due to any director or employee of the Company or increase any
                  benefits otherwise payable under any Company benefit plan or
                  result in the acceleration of time of payment or vesting of
                  any such benefits, including the time of exercise of stock
                  options, except as specifically provided in this Agreement. No
                  prior notice, consent or waiver from any Person, other than
                  the Company Consents and Waivers attached hereto as Schedule
                  2.2(b)(vi), is required to consummate the transactions
                  contemplated in this Agreement and the Ancillary Agreements.

            (b)   Other than in connection with or in compliance with the
                  provisions of the laws listed in Section 5.3(b) of the Company
                  Disclosure Schedule, (i) there is no legal impediment to the
                  Company's consummation of the transactions contemplated by
                  this Agreement; and (ii) no filing or registration with, or
                  authorization, consent or approval of any Governmental Entity
                  is required of the Company in connection with the making or
                  the consummation of the Acquisition, except for (A) such
                  filings or registrations which, if not made, or for such
                  authorizations, consents or approvals which, if not received,
                  would not have a Material Adverse Effect on the Company; (B)
                  the Applicable Regulatory Approvals. Notwithstanding the
                  generality of the foregoing, subject to the truth, correctness
                  and completeness of the representations and warranties of
                  Parent regarding its capitalization in Section 4.4 and SEC
                  filings and financial statements in Section 4.5, the
                  transactions contemplated by this Agreement and the
                  Arrangement, either separately or combined, are not subject to
                  pre-merger notification under Part IX of the Competition Act
                  (Canada) or the Hart-Scott-Rodino Antitrust Improvement Act.

      5.4 Compliance with Law.

      The Company is and has always been in compliance with all laws and
regulations applicable to the operation of its business as currently conducted
and proposed to be conducted, except where such non-compliance could not
reasonably be expected to have a Material Adverse Effect on the Company.

      5.5 Restrictions on Business Activities.

      Except as set forth in Section 5.5 of the Company Disclosure Schedule,
there is no agreement, judgement, injunction, order or decree binding upon the
Company, or any notice or claim that has or could reasonably be expected to have
the effect of prohibiting, restricting or materially impairing any business
practice of the Company, any acquisition of property by the Company or the
conduct of business by the Company as currently conducted other than such
agreements, judgments, injunctions, orders or decrees which would not,
individually or in the aggregate, have a Material Adverse Effect on the Company.


                                       28
<PAGE>

      5.6 Capitalization.

      Section 5.6 of the Company Disclosure Schedule sets forth the
capitalization of the Company as of September 25, 2000. As of the Execution
Date, the authorized share capital of the Company consists of 100,000,000
Company Common Shares, 100,000,000 Company Class A Shares and 100,000,000
Company Class B Shares, of which as of the Execution Date and, except for such
issuances as permitted under Section 3.1(a)(i)(A) of this Agreement, as of the
Closing Date, 7,836,537 Company Common Shares, 1,918,000 Company Class A Shares
and 3,616,353 Company Class B Shares are issued and outstanding. In addition,
the Company has issued a debenture in the aggregate principal amount of
US$500,000 which is convertible into 343,595 Company Class A Shares. As of the
Execution Date, 1,612,000 Company Common Shares are issuable upon exercise of
outstanding Company Options at per-share exercise prices ranging from CDN$1.05
to CDN$2.55 for Company Options issued under the Company Plan and 375,000
Company Common Shares are issuable upon exercise of outstanding Company Options
issued outside of the Company Plan at a per-share exercise price of CDN$0.0001.
Except as set forth above, there are no options, warrants or other rights,
agreements or commitments of any character whatsoever requiring the issuance,
sale or transfer by the Company of any securities of the Company (including the
Company Common Shares) or any securities convertible into, or exchangeable or
exercisable for, or otherwise evidencing a right to acquire, any securities of
the Company (including the Company Common Shares). All outstanding shares of the
Company have been, and all shares issuable upon the exercise of outstanding
stock options, in accordance with their terms will be, duly authorized and
validly issued, are fully paid and non-assessable and have been approved by all
requisite action by the Board and/or Members and in compliance with all
Applicable Securities Laws.

      The Ordinary Shares and the Company Special Shares, upon their issuance
pursuant to the Plan of Arrangement on or before the Closing Date, will have
been duly authorized, validly issued, fully paid and non-assessable and will
have been approved by all requisite action by the Board and/or Members and in
compliance with all Applicable Corporate Laws and Applicable Securities Laws. On
the Closing Date, there shall be no Company Common Shares or Company Class A
Shares or Company Class B Shares outstanding, and the Ordinary Shares and the
Company Special Shares shall be the only two outstanding classes of stock in the
Company. The Ordinary Shares issued to Abgenix Canada shall be the only shares
of voting securities in the capital stock of the Company, and there shall not
exist any securities convertible into voting securities of the Company.

      5.7 Material Agreements.

            (a)   Section 5.7 of the Company Disclosure Schedule sets forth each
                  written or oral agreements described in (i) through (xi) below
                  to which it is a party and which has not been terminated in
                  its entirety (each a "Material Contract"). True, correct and
                  complete copies of such Material Contracts have been delivered
                  to Parent or its representatives:

                  (i)   each agreement which involves performance of services or
                        delivery of goods and/or materials by or to it of an
                        amount or value in excess of US$60,000 in any given
                        year;

                  (ii)  each note, debenture, other evidence of indebtedness,
                        guarantee, loan, letter of credit, surety-bond or
                        financing agreement or instrument or other contract for
                        money borrowed, including any agreement or commitment
                        for future loans, credit or financing;

                  (iii) each agreement not in the ordinary course of business;


                                       29
<PAGE>

                  (iv)  each licensing, royalty agreement or other contract with
                        respect to Intellectual Property Rights, including
                        agreements with current or former employees, consultants
                        or contractors regarding the appropriation or the
                        nondisclosure of Intellectual Property Rights (excluding
                        any commercially available software, corporate system
                        software and off-the-shelf shrink wrap license);

                  (v)   each agreement to which the Company is bound which in
                        any manner purports to (A) restrict the Company's
                        freedom to engage in any line of business or to compete
                        with any other Person, or (B) assign to any other Person
                        rights to any material invention, improvement or
                        discovery;

                  (vi)  each joint venture, partnership agreement, limited
                        liability company or other agreement (however named)
                        involving a sharing of profits, losses, costs or
                        liabilities by the Company with any other Person;

                  (vii) each agreement containing covenants which in any way
                        purport to restrict the Company's business activity or
                        purport to limit the freedom of the Company to engage in
                        any line of business, utilize its Intellectual Property
                        Rights or to compete with any Person, excluding
                        confidentiality agreements entered into in the ordinary
                        course of business;

                  (viii) each power of attorney which is currently effective and
                        outstanding with respect to the voting or transfer of
                        any of its securities;

                  (ix)  each agreement providing for capital expenditures after
                        the Execution Date and not included in Budget 2001 in an
                        aggregate amount in excess of US$25,000 per month;

                  (x)   each written warranty, guaranty or other similar
                        undertaking with respect to contractual performance
                        extended by it other than in the ordinary course of
                        business; and

                  (xi)  each lease for real or personal property.

      Except as set forth in Section 5.7 of the Company Disclosure Schedule, all
of the Material Contracts are (i) to the Company's knowledge in full force and
effect and the Company is entitled to all rights and benefits thereunder, and
(ii) represent the legally valid and binding obligations of the other parties
thereto and are enforceable against such parties in accordance with their terms,
except as enforceability may be subject to and limited by laws of general
application relating to bankruptcy, insolvency and the relief of debtors, and
rules of law governing specific performance, injunctive relief or other
equitable remedies. The Company is not, nor to its knowledge is any other party
thereto, in material breach or material default under such Material Contract. To
the Company's knowledge no event has occurred and no other facts or
circumstances exist that with notice or lapse of time or both would constitute a
material breach or material default by any party thereto. Except as set forth in
Section 5.7 of the Company Disclosure Schedule, to the Company's knowledge, no
approval or consent of any Person who or which is a party to any Material
Contract is needed in order that such agreements continue in full force and
effect following consummation of the transactions contemplated herein and in the
Plan of Arrangement. Except as set forth in Section 5.7 of the Company
Disclosure Schedule, no material product liability or liability for breach of
warranty on the part of it under any of the Material Contracts has been asserted
or made and continues to be outstanding, against the Company.


                                       30
<PAGE>

      5.8 Financial Statements.

      The audited balance sheets and statements of loss, deficit and cash flows
for the fiscal years ended August 31, 1999 and 1998, were prepared in accordance
with generally accepted accounting principles in Canada and present fairly, in
all material respects, the financial position of the Company, the results of its
operations and its cash flows for the fiscal years then ended. The unaudited
balance sheets and statements of loss, deficit and cash flows for the nine
months ended May 31, 2000 were prepared in accordance with generally accepted
accounting principles in Canada and present fairly, in all material respects,
the financial position of the Company, the results of its operations and its
cash flows for such nine-month period subject to normal year-end adjustments.
Except as disclosed in such financial statements, the Company had no material
liabilities (whether actual, accrued or contingent, and whether direct or
indirect) at such dates.

      5.9 Transaction Fees.

      The Company has not retained, or entered into any contract, arrangement or
understanding with, any financial adviser, broker, agent, finder or law firm, or
paid or agreed to pay any financial adviser, broker, agent, finder or law firm
on account of this Agreement or any transaction contemplated hereby, except that
SG Cowen Securities Corporation has been retained as the Company's financial
advisor in connection with certain matters including the transactions
contemplated hereby and Blake, Cassels & Graydon LLP, Seed Intellectual Property
Law Group PLLC and Wilson Sonsini Goodrich & Rosati, Professional Corporation,
have been retained as legal counsel. A true and complete copy of the engagement
letter between the Company and SG Cowen Securities Corporation has been provided
to, and shall not be amended without the prior written consent of, Parent. The
Company shall be solely responsible for the fees and costs of SG Cowen
Securities Group and its counsel.

      5.10 Absence of Changes.

      Since August 31, 1999, and except to the extent specifically described in
Sections 5.7, 5.10 and 5.21 of the Company Disclosure Schedule, the Company has
conducted its business only in the ordinary and normal course, no liability or
obligation of any nature (whether absolute, accrued, contingent or otherwise)
material to the Company has been incurred other than in the ordinary course of
business, and there has not been any Material Adverse Change in the Company.
Without limiting the generality of the preceding sentence, since May 31, 2000,
there has not been (i) any material damage, destruction or loss, whether or not
covered by insurance to the assets or properties of the Company, (ii) any waiver
by the Company of a valuable right or of a material debt owed to it, (iii) any
satisfaction or discharge of any lien, claim or encumbrance or payment of any
obligation by the Company except in the ordinary course of business and that is
not material to the assets, properties, financial condition, result of
operation, or business of the Company as currently conducted or proposed to be
conducted, (iv) any material change or amendment to a material contract or
arrangement by which the Company or any of its assets or properties is bound,
(v) any material change in any compensation arrangement or agreement with any
officer, director or key employee, (vi) any sale, assignment or transfer of any
Intellectual Property Rights, (vii) any mortgage, pledge, transfer of a security
interest in, or lien created by the Company with respect to, any of its material
properties or assets, or (viii) any agreement or commitment by the Company to do
any of the foregoing items.

      5.11 Employment and Labor Relations.

            (a)   Section 5.11 of the Company Disclosure Schedule lists, as of
                  August 31, 2000, the name, current annual compensation rate
                  (including bonus and commissions), title, accrued bonus,
                  accrued sick leave, accrued severance pay and accrued


                                       31
<PAGE>

                  vacation benefits of each present employee of the Company,
                  employment, managerial, advisory, consulting and severance
                  agreements involving employees or former employees of the
                  Company or under which the Company may benefit or be bound,
                  contingent or otherwise; and lists any employee handbook(s)
                  (other than the employment agreements and Employee Benefit
                  Plans otherwise listed on the Company Disclosure Schedule).
                  Other than as disclosed in Section 5.7 or Section 5.11 of the
                  Company Disclosure Schedule, as an employment agreement or as
                  an Employee Benefit Plan, or as provided under the British
                  Columbia Employment Standards Act, the Company is not a party
                  to any employment agreement or Employee Benefit Plan, or to
                  any written or oral policy, agreement, obligation or
                  understanding which contains any specific agreement as to
                  notice of termination or severance pay in lieu thereof or
                  which cannot be terminated without cause and without further
                  compensation. The Company has not and shall not enter into any
                  other agreements or understandings with any of their
                  directors, officers or employees creating rights in respect of
                  loss or termination of office or employment in the event the
                  Acquisition is successful, without the prior written consent
                  of Parent other than as specifically contemplated hereby. The
                  Company is not bound by or subject to (and none of its assets
                  (including Intellectual Property Rights) or properties is
                  bound by or subject to) any written or oral, expressed or
                  implied, contract, commitment or arrangement including any
                  collective agreement with any labor union, and no labor union
                  has requested or sought or attempted or threatened to attempt
                  to represent any of the employees, representatives or agents
                  of the Company. Other than as set forth on Section 5.11 of the
                  Company Disclosure Schedule, the Company is not aware that any
                  officer or key employee intends to terminate their employment
                  or services with the Company.

            (b)   Except as set forth in Section 5.11 of the Company Disclosure
                  Schedule, (i) there has not been for a period of thirty-six
                  (36) consecutive months prior to the Execution Date, nor is
                  there existing or threatened any strike, slowdown, picketing
                  or work stoppage with respect to the Company, and (ii) the
                  Company has not engaged in any unfair labor practices and no
                  unfair labor practice complaint or arbitration proceeding is
                  pending or, threatened against the Company. No trade union has
                  applied to have the Company declared a related or successor
                  employer pursuant to applicable labor relations legislation.
                  Except as disclosed in Section 5.11 of the Company Disclosure
                  Schedule, no notice has been received by the Company of any
                  complaint filed by any of the employees employed by the
                  Company against the Company claiming that the Company has
                  violated applicable labor relations legislation, human rights
                  legislation, pay equity legislation, employment standards
                  legislation or any other employment-related legislation or
                  common law and no such complaint is threatened against the
                  Company, nothing has occurred which would reasonably be
                  expected to lead to such a claim or complaint against the
                  Company.

            (c)   Except as set forth in Section 5.11 of the Company Disclosure
                  Schedule, to the Company's knowledge, there are no outstanding
                  assessments, penalties, fines, levies, charges, surcharges,
                  other amounts due or owing pursuant to any applicable
                  workplace safety and insurance, health and safety and labor
                  standards legislation in respect of the Company and the
                  Company has not been reassessed in any material respect under
                  such legislation during the past three (3) years; and


                                       32
<PAGE>

                  (ii) no audit of the Company is currently being performed
                  pursuant to any applicable workplace safety and insurance
                  legislation.

            (d)   The Company has paid in full to its employees all wages,
                  salaries, commissions, bonuses, benefits under the Employee
                  Benefit Plans and other compensation due and payable to or on
                  behalf of such employees and all amounts due or accrued due
                  for vacation pay are reflected in the Company's financial
                  statements. All accruals for premiums for employment insurance
                  and Canada pension plan shall be reflected on the Company's
                  financial statements.

            (e)   Except as disclosed in Section 5.11 of the Company Disclosure
                  Schedule, no employee is on short term disability leave, long
                  term disability leave, extended absence, pregnancy or parental
                  leave, or receiving benefits pursuant to the applicable
                  workplace safety and insurance legislation or on any other
                  leave. Section 5.11 of the Company Disclosure Schedule sets
                  out each person's expected return to work date.

      5.12 United States Relationship.

      The level of ownership by U.S. holders of Company Capital Stock (on an "as
converted" basis) does not exceed ten percent (10%) of the total number of
outstanding Company Capital Stock (on an "as converted" basis). The term "U.S.
holder" means any Person whose address appears on the records of the Company,
any voting or other trustee, any depository, any share transfer agent or any
Person acting in a similar capacity on behalf of the Company, as being located
in the United States.

      5.13 Employee Benefit Plans.

            (a)   Except as disclosed in Section 5.13(a) of the Company
                  Disclosure Schedule, the Company has no Employee Benefit Plans
                  and has made no promises with respect to increased benefits
                  under such plans or otherwise.

            (b)   No employment agreement or Employee Benefit Plan is subject to
                  the Employee Retirement Income Security Act of 1974, as
                  amended.

            (c)   Each Employee Benefit Plan has been operated in material
                  compliance with its terms and complies in all material
                  respects with all applicable Laws and its obligations in
                  respect of each Employee Benefit Plan in accordance with its
                  terms.

            (d)   No actions, suits, claims or investigations by any Person
                  (other than routine claims for benefits in the ordinary
                  course) are pending, or to the Company's knowledge threatened,
                  with respect to any Employee Benefit Plan, and, to the
                  Company's knowledge, there are no facts which could give rise
                  to any such actions, suits or claims or investigations (other
                  than routine claims for benefits in the ordinary course).

            (e)   Except as set forth in Section 5.13 of the Company Disclosure
                  Schedule, which includes the total dollar amounts of any such
                  required payments and any penalties relating thereto, all
                  contributions, insurance premiums, taxes and any other
                  payments (including any past amounts or repayment obligations
                  under any expatriate tax equalization plan, program or
                  arrangement) required with respect


                                       33
<PAGE>

                  to any Employee Benefit Plan have or will have been paid as of
                  the Closing Date. As of the most recent valuation date, there
                  are no unfunded benefit liabilities on either a going-concern
                  or solvency basis with respect to any Employee Benefit Plan
                  that is required, in accordance with its terms or by Law, to
                  be funded and nothing has occurred since the date of the last
                  valuation which would have an Material Adverse Effect on the
                  Company.

            (f)   Parent has been provided with true, correct and complete
                  copies of each Employee Benefit Plan as currently in effect
                  (including the plan document, trust agreement and other
                  funding or insurance instruments, if any, relating thereto)
                  and copies of all other material documents, contracts,
                  agreements or arrangements and governmental filings relating
                  to all such Employee Benefit Plans or to employees or former
                  employees of the Company.

            (g)   Each Employee Benefit Plan and related funding arrangement
                  that is intended to qualify for tax-favored status qualifies
                  for such status, and, to the extent an approval process is
                  available, has been approved for such status by the
                  appropriate government authority (or has been submitted for
                  such approval within the applicable time period), and nothing
                  has occurred and no condition exists that is likely to cause
                  the loss or denial of such tax-favored status.

            (h)   Except as provided under British Columbia employment standards
                  legislation or as set forth in Section 5.13 of the Company
                  Disclosure Schedule or as otherwise required pursuant to this
                  Agreement, each Employee Benefit Plan (including any such plan
                  covering former employees of the Company) may be amended or
                  terminated by the Company or Parent without incurring any
                  liability thereto on or at any time after the Closing Date.

            (i)   Except as provided under British Columbia employment standards
                  legislation or as set forth in Section 5.13 of the Company
                  Disclosure Schedule, no employee or former employee of the
                  Company shall accrue or receive additional benefits, service
                  or accelerated rights to payment of benefits or become
                  entitled to severance, termination allowance or similar
                  payments under any Employee Benefit Plan or employment
                  agreement covering employees or former employees of the
                  Company as a result of the transactions contemplated by this
                  Agreement.

            (j)   None of the Employee Benefit Plans (other than pension plans)
                  provides benefits to retired employees of the Company or their
                  beneficiaries or dependents.

      5.14 Books and Records.

      The corporate records and minute books of the Company have been maintained
in accordance with all applicable statutory requirements and are complete and
accurate in all material respects. Without limiting the generality of the
foregoing, the books, records and accounts of the Company, in all material
respects, (i) have been maintained in accordance with good business practices on
a basis consistent with prior years, (ii) are stated in reasonable detail and
accurately and fairly reflect the transactions and dispositions of the assets
and the issuances of securities of the Company (iii) accurately and fairly
reflect the basis for the Company's financial statements. The Company has
devised and maintains a system of internal accounting controls sufficient to
provide reasonable assurances that (i) transactions are executed in accordance
with management's general or specific authorization; and (ii) transactions are
recorded as necessary (A) to permit preparation of financial statements in
conformity with Canadian generally


                                       34
<PAGE>

accepted accounting principles or any other criteria applicable to such
statements and (B) to maintain accountability for assets.

      5.15 Litigation, etc.

      Except as disclosed in Section 5.15 of the Company Disclosure Schedule,
there are, at the Execution Date, no actions, suits, proceedings, claims,
arbitrations or investigations pending, or to the knowledge of the Company
threatened, affecting the Company at law or in equity or before or by any
federal, provincial, municipal or other governmental department, commission,
board, bureau, agency or instrumentality, which action, suit, proceeding, claim,
arbitration or investigation involves a possibility of any judgment against or
liability of the Company which, if successful, would have a Material Adverse
Effect on the Company. Neither the Company nor its assets and properties, is
subject to any outstanding judgment, order, writ, injunction or decree that has
had or is reasonably likely to have a Material Adverse Effect on the Company or
that could reasonably be expected to prevent or materially delay consummation of
the transactions contemplated by this Agreement or the Arrangement.

      5.16 Environmental.

      Except for any matters that, individually or in the aggregate, would not
have a Material Adverse Effect on the Company:

            (a)   all operations of the Company have been conducted, and are
                  now, in compliance with all Environmental Laws;

            (b)   the Company is in possession of, and in compliance with, all
                  permits, authorizations, certificates, registrations,
                  approvals and consents necessary under Environmental Laws to
                  own, lease and operate its properties and to conduct its
                  businesses as it is now being conducted or as proposed to be
                  conducted (collectively the "Environmental Permits"); and

            (c)   except as set forth in Section 5.16 (c) of the Company
                  Disclosure Schedule, the Company is not aware of, and is not
                  subject to:

                  (i)   any Environmental Laws which require or may require any
                        work, repairs, construction, change in business
                        practices or operations, or expenditures, including
                        capital expenditures for facility upgrades,
                        environmental investigation and remediation
                        expenditures, or any other such expenditures;

                  (ii)  any Environmental Laws which require or may require any
                        work, repairs, construction, change in business
                        practices or operations, or expenditures, including
                        capital expenditures for facility upgrades,
                        environmental investigation and remediation
                        expenditures, or any other such expenditures;

                  (iii) has not received any written demand or written notice
                        with respect to liability, by contract or operation of
                        applicable Laws, under Environmental Laws applicable to
                        the Company or any predecessor entities, divisions or
                        any formerly owned, leased or operated properties or
                        assets of the foregoing, including liability with
                        respect to the presence, release or discharge of
                        Hazardous Substances;


                                       35
<PAGE>

                  (iv)  any changes in the terms or conditions of any
                        Environmental Permits or any renewal, modification,
                        revocation, reissuance, alteration, transfer or
                        amendment of such Environmental Permits, or any review
                        by, or approval of, any Governmental Entity of such
                        Environmental Permits that are required in connection
                        with the execution or delivery of this Agreement, the
                        consummation of the transactions contemplated hereby or
                        the continuation of business of the Company following
                        such consummation; or

                  (v)   is not aware of any circumstances which could cause any
                        Environmental Permit revoked, modified or rendered
                        non-renewable upon payment of the Permit Fee.

      5.17 Tax Matters.

            (a)   For purposes of this Agreement, the following definitions
                  shall apply:

                  (i)   "Tax" or "Taxes" shall mean all taxes, however
                        denominated, including any interest, penalties or other
                        additions that may become payable in respect thereof,
                        imposed by any federal, territorial, state, local or
                        foreign government or any agency or political
                        subdivision of any such government, which taxes shall
                        include, without limiting the generality of the
                        foregoing, all income, capital, or profits taxes
                        (including, but not limited to, federal income and
                        capital taxes and provincial income and capital taxes),
                        payroll and employee withholding taxes, unemployment
                        insurance, social insurance taxes, sales and use taxes,
                        goods and services taxes, ad valorem taxes, excise
                        taxes, franchise taxes, gross receipts taxes, business
                        license taxes, occupation taxes, real and personal
                        property taxes, stamp taxes, environmental taxes,
                        transfer taxes, workers' compensation and other
                        governmental charges, and other obligations of the same
                        or of a similar nature to any of the foregoing, which
                        the Company is required to pay, withhold or collect.

                  (ii)  "Returns" shall mean all reports, estimates,
                        declarations of estimated tax, information statements
                        and returns relating to, or required to be filed in
                        connection with, any Taxes, including any schedule or
                        attachment thereto, and including any amendment thereof.

            (b)   All Returns required to be filed by or on behalf of the
                  Company have been duly filed on a timely basis and such
                  Returns are true, complete and correct in all material
                  respects. Except as disclosed in Section 5.17 of the Company
                  Disclosure Schedule, all Taxes shown to be payable on the
                  Returns or on subsequent assessments with respect thereto have
                  been paid in full on a timely basis, and no other Taxes are
                  payable by the Company with respect to items or periods
                  covered by such Returns. The Company has withheld and paid all
                  Taxes required to have been withheld and paid in connection
                  with amounts paid or owing to any employee, independent
                  contractor, creditor, stockholder or other third party.

            (c)   The unpaid Taxes of the Company as of the Execution Date do
                  not exceed the accruals for Taxes in the Company's books and
                  records, as determined in


                                       36
<PAGE>

                  conformity with generally accepted accounting principles
                  applicable in Canada as of the Execution Date.

            (d)   For all periods ending on and after August 31, 1995, Parent
                  has been furnished by the Company true, correct and complete
                  copies of (i) all relevant portions of income tax audit
                  reports, statements of deficiencies, closing or other
                  agreements received by the Company or on behalf of the Company
                  relating to Taxes, and (ii) all required federal and
                  provincial income or franchise tax Returns for the Company.

            (e)   Except as disclosed in Section 5.17 of the Company Disclosure
                  Schedule, no deficiencies exist or have been asserted with
                  respect to Taxes of the Company. Except as disclosed in
                  writing to Parent prior to the Execution Date, the Company is
                  not a party to any action or proceeding for assessment or
                  collection of Taxes, nor has such event been asserted or to
                  the knowledge of the Company threatened against the Company or
                  any of its assets. No waiver or extension of any statute of
                  limitations is in effect with respect to Taxes or Returns of
                  the Company. Except as disclosed in Section 5.17 of the
                  Company Disclosure Schedule, the Returns of the Company have
                  never been audited by a government or taxing authority, nor is
                  any such audit in process, pending or to the knowledge of the
                  Company, threatened which resulted in or could result in a
                  reassessment of Taxes owing by the Company. The Company is not
                  a party to any Tax allocation or sharing agreement, and has no
                  liability for the Taxes of any Person under any provision of
                  Canadian or foreign law, or as a transferee or successor, by
                  contract, or otherwise.

            (f)   Other than as disclosed in Section 5.17 of the Company
                  Disclosure Schedule, the Company has provided adequate
                  accruals in its financial statements for the year ended August
                  31, 1999 (or such amounts are fully funded) for all pension or
                  other employee benefit obligations of the Company arising
                  under or relating to each of the pension or retirement income
                  plans or other employee benefit plans or agreements or
                  policies maintained by or binding on the Company.

      5.18 Disclosure.

      No representation or warranty of the Company contained in this Agreement
or in any other document, certificate or written statement furnished to Parent
by or on behalf of the Company for use in connection with the transactions
contemplated by this Agreement contains any untrue statement of a material fact
or omits to state a material fact (known to the Company, in the case of any
document not furnished by it) necessary in order to make the statements
contained herein or therein not misleading in light of the circumstances in
which the same were made. To the Company's knowledge, there exists no facts
(other than matters of a general economic nature) that, individually or in the
aggregate, could reasonably be expected to result in a Material Adverse Effect
and that have not been disclosed herein or in such other documents, certificates
and statements furnished to Parent for use in connection with the transactions
contemplated hereby.

      5.19 Reporting Issuer Status.

      The Company is not a "reporting issuer" in any province or territory of
Canada.


                                       37
<PAGE>

      5.20 Subsidiaries.

      The Company has no subsidiaries.

      5.21 Intellectual Property.

            (a)   Part I of Section 5.21(a) of the Company Disclosure Schedule
                  (the "Intellectual Property Disclosure Schedule") sets forth a
                  true, correct and complete list of all of the Company's
                  patents, filed patent applications, trademarks, tradenames and
                  all Licenses of the Company. True, correct and complete copies
                  of all such Licenses have been delivered to Parent. Except as
                  disclosed in Part II of Section 5.21(a) of the Company
                  Disclosure Schedule, all such Licenses (i) are in full force
                  and effect and unmodified, and the Company is entitled to all
                  rights and benefits thereunder, without qualification or
                  limitation, and (ii) represent the legally valid and binding
                  obligations of the other parties thereto and are enforceable
                  against such parties in accordance with their terms, subject
                  only to applicable bankruptcy, insolvency, fraudulent
                  transfer, reorganization, moratorium and other laws relating
                  to or affecting creditors' rights generally and general
                  principles of equity. The Company is not, nor, to the
                  knowledge of the Company, is any other party thereto, in
                  material breach or material default under such Licenses. To
                  the knowledge of the Company, no event has occurred and no
                  other facts or circumstances exist that with notice or lapse
                  of time or both would constitute a material breach or material
                  default by any party to any License. Except for Licenses set
                  forth in Part III of Section 5.21(a) of the Company Disclosure
                  Schedule, no approval or consent of any Person is needed or
                  required in order that the Company's Licenses continue in full
                  force and effect following consummation of the transactions
                  contemplated in this Agreement and in the Plan of Arrangement.
                  Except as set forth in Part IV of Section 5.21(a) of the
                  Company Disclosure Schedule, no material product liability or
                  liability for breach of warranty on the part of it under any
                  License has been asserted or made and continues to be
                  outstanding, against the Company. Without limiting the
                  preceding sentence, there has not been any actual or alleged
                  "Decline in Performance" (nor have there been any facts or
                  circumstances that with notice or lapse of time or both would
                  constitute a "Decline in Performance") or grant or request for
                  "Sublicense," as such terms are defined in the Corixa
                  Collaborative Research and Development Agreement dated
                  November 4, 1998, as amended.

            (b)   The Company has secured valid written assignments from all
                  officers, agents, employee, former employee or consultant of
                  the Company, without limitation, who contributed to the
                  creation or development of the Company's Intellectual Property
                  Rights, of the rights to such contributions that the Company
                  does not already own by operation of law and no such officers,
                  agents, employee, former employee or consultant retains, nor,
                  to the Company's knowledge, has any of them transferred or
                  conveyed to any Person, any interest or right in relation to
                  the Intellectual Property Rights of the Company, and the
                  Company has provided true, correct and complete copies of such
                  assignment to Parent and has attached all forms thereof used
                  by the Company in Section 5.21(b) of the Company Disclosure
                  Schedule.

            (c)   Except as set forth in Section 5.21(c) of the Company
                  Disclosure Schedule, the Company, to its knowledge, owns or
                  possesses or has obtained valid and


                                       38
<PAGE>

                  enforceable licenses or other rights to use all Intellectual
                  Property Rights which are necessary or useful and actually
                  used in the conduct of the Company's business as conducted as
                  of the effective date of the Patent Disclosure Agreement.
                  Except as set forth in Section 5.21(c) of the Company
                  Disclosure Schedule, the Company has the rights to use, sell,
                  license, sublicense, assign, transfer, convey or dispose of
                  the Intellectual Property Rights which are necessary or useful
                  and actually used in the conduct of the Company's business as
                  conducted as of the effective date of the Patent Disclosure
                  Agreement, and the products, processes and materials covered
                  thereby, except as the rights of the Company may be limited in
                  accordance with the contractual terms of the Licenses
                  identified in Part I of 5.21 (a) of the Company Disclosure
                  Schedule.

            (d)   Except as set forth in Section 5.21(d) of the Company
                  Disclosure Schedule, pursuant and subject to the limitations
                  of the Patent Disclosure Agreement, as applicable, the Company
                  has provided representatives of Parent with access to the
                  ImmGenics Patent Portfolio and the ImmGenics Technologies
                  (each as defined therein) and provided Schwegman, Lundberg,
                  Woessner & Kluth, P.A., with access to the ImmGenics Cell
                  Culture Technology (as defined therein). Except as provided in
                  Section 5.21(d) of the Company Disclosure Schedule, none of
                  the information described in the preceding sentence or
                  provided pursuant to the Patent Disclosure Agreement is untrue
                  or incorrect in any material respect or omits any material
                  fact or information related thereto.

            (e)   To the knowledge of the Company after due inquiry by the
                  Company of its patent advisor(s), except as set forth in Part
                  I of Section 5.21(e) of the Company Disclosure Schedule,
                  neither the Company nor the operations of the Company as
                  conducted on or before the effective date of the Patent
                  Disclosure Agreement conflict with or infringe, and no one has
                  asserted to the Company that such operations conflict with or
                  infringe any Intellectual Property Rights owned, possessed or
                  used by any third party. Except as set forth in Part II of
                  Section 5.21(e) of the Company Disclosure Schedule, there are
                  no claims, disputes, actions, proceedings, suits or appeals
                  pending against the Company with respect to any Intellectual
                  Property Rights, and, to the knowledge of the Company, none
                  has been threatened against the Company. Except as set forth
                  in Parts I or II of Section 5.21(e) of the Company Disclosure
                  Schedule, to the knowledge of the Company, there are no facts
                  or alleged facts which would reasonably serve as a basis for
                  any claim that the Intellectual Property Rights which are
                  necessary or useful and actually used in the conduct of the
                  Company's business as conducted on or before the effective
                  date of the Patent Disclosure Agreement, or the use, license
                  or transfer of such Intellectual Property Rights, including,
                  without limitation, the development, manufacture, use, sale or
                  other disposition of any or all products or services presently
                  being used, furnished or sold in the conduct of the business
                  of the Company as it has been and is now being conducted,
                  violate or infringe on the Intellectual Property Rights of any
                  third party. Except as set forth in Part I or II of Section
                  5.21(e) of its Company Disclosure Schedule, to the knowledge
                  of the Company after due inquiry by the Company of its patent
                  advisor(s), the Intellectual Property Rights of the Company
                  referred to in the preceding sentence are free of any
                  unresolved ownership disputes with respect to any third party
                  and to the knowledge of the Company, after due inquiry by the
                  Company of its patent advisor(s), there is no unauthorized
                  use, infringement or misappropriation of any of its
                  Intellectual


                                       39
<PAGE>

                  Property Rights by any third party, including, without
                  limitation, any employee or former employee of the Company.
                  The Company has not entered into any agreement granting any
                  third party the right to bring infringement actions with
                  respect to, or otherwise to enforce rights with respect to,
                  any of its Intellectual Property Rights.

            (f)   Other than as disclosed pursuant to the Patent Disclosure
                  Agreement, there are no other proceedings before any patent or
                  trademark authority or otherwise relating to Intellectual
                  Property Rights owned or used by the Company to which the
                  Company is a party. The Company has the exclusive right to
                  file, prosecute and maintain any such applications for
                  patents, copyrights or trademarks and the patents and
                  registrations that issue therefrom.

            (g)   The Company has taken all measures that are reasonable and
                  appropriate to maintain the confidentiality of the
                  Intellectual Property Rights used or proposed to be used in
                  the conduct of its business the value of which to the Company
                  is contingent upon maintenance of the confidentiality thereof.
                  Without limitation, the Company has complied with all express
                  and/or implied obligations of confidentiality in relation to
                  Intellectual Property Rights owned by third parties.

            (h)   The data, information, results and conclusions set forth in
                  the reports provided by the Company to Parent as listed in
                  Schedule 5.21 (h) hereto are true, correct and complete in all
                  material aspects.

      5.22 Insurance.

      The Company has policies of insurance in force as of the Execution Date
naming the Company as an insured which, having regard to the nature of such risk
and the relative cost of obtaining insurance, are reasonable and provide a level
of protection against loss comparable to similarly situated companies in British
Columbia.

      5.23 Property.

      Except as disclosed in Section 5.23 of the Company Disclosure Schedule,
the Company has good, marketable and sufficient title to such real and personal
property interests, including fee simple estate of and in real property, leases,
easements, rights of way, permits or licenses from land owners or authorities
permitting the use of land by the Company, necessary to permit the operation of
its businesses as presently owned and conducted except for such failure of title
that would not individually or in the aggregate have a Material Adverse Effect
on the Company. The Company has no plan to expand its facilities except as
described in Section 5.23 of the Company Disclosure Schedule.

      5.24 Licenses, Etc.

      Except as they relate to Intellectual Property Rights, which are subject
to the representations and warranties set forth in Section 5.21 of this
Agreement, the Company has, owns, possesses, or has obtained and is in
compliance with, all franchises, licenses, permits, certificates, orders, grants
and other authorizations of or from any individual, entity, or Governmental
Entity necessary to conduct its businesses as now conducted except for such
failure that would individually or in the aggregate not have a Material Adverse
Effect on the Company. Except as they relate to Intellectual Property Rights,
which are subject to the representations and warranties set forth in Section
5.21 of this Agreement, the Company has not granted rights to manufacture,
produce, assemble, license, market or sell its research findings,


                                       40
<PAGE>

products or services to any other Person and is not bound by any agreement that
affects the Company's exclusive right to develop, manufacture, assemble,
distribute, market or sell its research findings, products or services.

      5.25 Registration Rights and Other Member Rights.

      Except as disclosed in Section 5.25 of the Company Disclosure Schedule,
the Company has not granted or agreed to grant or been under any obligation to
grant any registration rights, including "demand" or "piggyback" rights, and no
Member otherwise has any right to compel the Company to register or otherwise
qualify the securities of the Company for public sale in Canada or the United
States. Except as contemplated in this Agreement and except as set forth in the
Company's organizational documents, no voting or similar agreements exist
related to the Company's securities which are presently outstanding or that may
hereafter be issued.

      5.26 Significant Customers and Suppliers.

      No customer or supplier (including any private or public research
foundation or Governmental Entity) that was significant to the Company during
the period covered by the Financial Statements or that has been significant
thereafter, has terminated, materially reduced or to the knowledge of the
Company threatened to terminate or materially reduce its purchases from or
provision of products or services, or award of research grants, as the case may
be, to the Company.

6. ADDITIONAL AGREEMENTS

      6.1 Other Filings.

      Parent and the Company each have filed, or as promptly as practicable
hereafter, shall prepare and file, any applicable filings, including the filing
necessary to obtain the Applicable Regulatory Approvals, required under
Applicable Corporate Laws, the Investment Canada Act (Canada), the Competition
Act (Canada), Applicable Securities Laws or any other applicable law relating to
the Acquisition, the Information Circular and the transactions contemplated
hereby.

      6.2 Further Assurances.

      Subject to the terms and conditions herein provided, each of the parties
hereto agrees to use its reasonable best efforts to take, or cause to be taken,
all action and to do, or cause to be done, all things necessary, proper or
advisable to consummate and make effective as promptly as practicable the
transactions contemplated by this Agreement, including the Arrangement, and to
cooperate with each other in connection with the foregoing, including using
reasonable best efforts to obtain all necessary consents, approvals and
authorizations as are required to be obtained under any federal, provincial,
state or foreign law or regulations, to defend all lawsuits or other legal
proceedings challenging this Agreement or the consummation of the transactions
contemplated hereby, including the Acquisition, to cause to be lifted or
rescinded any injunction or restraining order or other order adversely affecting
the ability of the parties to consummate the transactions contemplated hereby,
including the Acquisition, and to effect all necessary registrations and other
filings and submissions of information requested by governmental authorities.


                                       41
<PAGE>

      6.3 Fees and Expenses.

      Except as provided for in the Patent Disclosure Agreement, all fees, costs
and expenses incurred in connection with this Agreement and the transactions
contemplated hereby shall be paid by the party incurring such fees, costs or
expenses.

      6.4 Compliance with Contracts.

      Unless otherwise contemplated in this Agreement or in the Ancillary
Agreements, Parent agrees that, from and after the Closing Date, it shall cause
the Company to fulfil its obligations pursuant to (i) all such employment
contracts to which the Company is a party listed in Section 5.11 of the Company
Disclosure Schedule, as such agreements may be amended from time to time, and to
the extent said agreements are not terminated on or prior to the Closing Date,
(ii) termination, severance and retention plans of the Company listed in Section
5.13 of the Company Disclosure Schedule, as such plans may be amended from time
to time, and to the extent such plans are not terminated on or prior to the
Closing Date; and (iii) indemnity agreements entered into between the Company
and any past or present officers or directors of the Company as listed in
Section 5.7 of the Company Disclosure Schedule, and the indemnification and
exculpation provisions in the Company organizational documents, which
indemnification and exculpation provisions will not be amended, repealed or
otherwise modified for a period of six (6) years from the Closing Date in any
manner that would adversely affect the rights thereunder of any such officer or
directors; provided, that, this Section 6.4 shall not restrict or prohibit
Parent from dissolving the Company, reorganizing the capital of the Company,
transferring the assets of the Company to another entity, causing the Company to
assume the liabilities of another entity or otherwise reorganizing or
restructuring the Company or its businesses if as part of such transaction or
reorganization Parent causes the obligations under this Section 6.4 to be
assumed by Parent.

      6.5 Tax Election

      After the Closing Date, Parent shall cause the Company to elect, in its
tax return for the taxation years ending concurrently with the Closing Date,
that the provisions of subsection 256(9) of the Income Tax Act (Canada) do not
apply, so that the acquisition of control of the Company will be deemed to have
occurred simultaneously with the Closing Time and not at any earlier time.

      6.6 Officers' and Directors' Insurance

      If the Arrangement is completed, Parent agrees to seek to secure at
commercially reasonable rates directors' and officers' liability insurance on a
"trailing" or "run-off" basis for the Company's current and former directors and
officers (whether such insurance is maintained independently of or included
under Parent's directors' and officers' insurance policy), covering claims made
prior to or within six (6) years following the Effective Date. Coverage of such
directors' and officers' insurance shall be substantially equivalent in scope
and coverage to that provided by the Company's current directors' and officers'
insurance policy. Notwithstanding the foregoing, in no event or circumstance
shall Parent be obligated to pay any premiums or other amounts in respect of
such insurance that would exceed Fifty Thousand Canadian dollars (CDN$50,000) in
the aggregate.

7. TERM, TERMINATION, AMENDMENT AND WAIVER

      7.1 General

      This Agreement shall be effective from the Execution Date until the
earlier of the termination of this Agreement pursuant to Section 7.2 and the
completion of the steps contemplated in the Plan of


                                       42
<PAGE>

Arrangement, provided that any obligations under Sections 6.3, 7 and 8 shall
survive the termination of this Agreement.

      7.2 Termination.

      This Agreement may be terminated at any time prior to the Closing Date as
provided below, provided that the right to terminate this Agreement under any
provision of this Section 7.2 shall not be available to any party if such
party's material failure to fulfil any obligation under this Agreement has been
the cause of or resulted in the failure of the Arrangement to occur on or before
such termination:

            (a)   by written agreement of the parties hereto;

            (b)   by Parent or the Company, if the Final Order shall not have
                  been issued on or before December 1, 2000;

            (c)   by Parent, if the Special Resolution is not approved by the
                  Members at the Meeting, as required by the Interim Order;

            (d)   by Parent, if any one of the conditions for the benefit of
                  Parent set forth in Section 2.2(b) have not been satisfied or
                  waived by Parent on or before 10 a.m. (Vancouver time)
                  December 1, 2000;

            (e)   by Parent, if a Minimum Dissent Event or a Material Adverse
                  Change of the Company shall have occurred;

            (f)   by the Company, if any one of the conditions for the benefit
                  of the Company set forth in Section 2.2(c) have not been
                  satisfied or waived by the Company on or before 10 a.m.
                  (Vancouver time), December 1, 2000;

            (g)   by the Company, if a Parent Material Adverse Change shall have
                  occurred;

            (h)   by either Parent or the Company if a Governmental Entity shall
                  have issued an order, decree or ruling or taken any other
                  action, in any case having the effect of permanently
                  restraining, enjoining or otherwise prohibiting the
                  Acquisition or the Arrangement, which order, decree, ruling or
                  other action shall have become final and nonappealable;

            (i)   by Parent, if the Board shall withdraw, modify or change any
                  recommendation regarding the Arrangement, or shall have failed
                  to include in the Information Circular the favorable
                  recommendation to the Members;

            (j)   by Parent, in the event that the Principal Members have not
                  complied with or performed, in all material respects, their
                  covenants and obligations under the Shareholder Voting
                  Agreement and Irrevocable Proxy to be complied with or
                  performed at or prior to the Closing Date;

            (k)   by Parent, in the event that the Shareholder Voting Agreement
                  and Irrevocable Proxy shall have been terminated in accordance
                  with the terms thereof.

      Neither Parent nor the Company may exercise any termination right pursuant
to Section 7.2 hereof, unless Parent or the Company, as the case may be, has
delivered a written notice to the other


                                       43
<PAGE>

parties hereto specifying in reasonable detail all breaches of covenants,
representations and warranties or other matters which Parent or the Company, as
the case may be, is asserting as the basis for the exercise of the termination
right, as the case may be. If any such notice is delivered, provided that Parent
or the Company, as the case may be, is proceeding diligently to cure such
matter, if such matter is susceptible to being cured, the other parties hereto
may not terminate this Agreement as a result thereof until the earlier of
December 1, 2000, and the expiration of a period of thirty (30) days from such
notice. For the avoidance of doubt, in the event that such matter is cured
within the time period referred to herein, this Agreement may not be terminated
pursuant to Section 7.2 as a result of the breach identified in the relevant
notice.

      7.3 Effect of Termination.

      In the event of the termination of this Agreement as provided in Section
7.2, this Agreement shall forthwith become void and there shall be no liability
on the part of Parent or the Company hereunder, except as set forth in Sections
8.8 and this Section 7.3. Nothing contained in this Section 7.3 shall relieve
any party from liability for any breach of any provision of this Agreement prior
to the date of termination. No termination of this Agreement shall affect the
obligations of the parties pursuant to the Confidentiality Agreement, the Patent
Disclosure Agreement, except to the extent specified therein.

      7.4 Amendment.

      This Agreement may be amended by mutual written agreement among the
parties hereto. This Agreement may not be amended except by an instrument in
writing signed by the appropriate officers on behalf of each of the parties
hereto.

      7.5 Waiver.

      Parent and the Company may (i) extend the time for the performance of any
of the obligations or other acts of the other, (ii) waive compliance with any of
the other's agreements or the fulfilment of any conditions to its own
obligations contained herein, or (iii) waive inaccuracies in any of the other's
representations or warranties contained herein or in any document delivered by
the other party hereto; provided, however, that any such extension or waiver
shall be valid only if set forth in an instrument in writing signed on behalf of
such party.

8. GENERAL PROVISIONS

      8.1 Notices.

      All notices and other communications given or made pursuant hereto shall
be in writing and shall be deemed to have been duly given or made as of the date
delivered or sent if delivered personally or sent by facsimile transmission or
sent by prepaid overnight courier to the parties at the following address (or at
such other addresses as shall be specified by either party by notice to the
other):


                                       44
<PAGE>

            (a) if to Parent or to Abgenix Canada:

            c/o Abgenix, Inc.
            7601 Dumbarton Circle
            Fremont, California, U.S.A. 94555
            Attention:  Mr. Kurt Leutzinger
            cc: Daniel Hunt, Esq.
            Telephone: (510) 608-6500
            Facsimile: (510) 608-6511

      with a copy to:

            Stikeman Elliott
            Barristers & Solicitors
            Suite 1700, Park Place
            666 Burrad Street
            Vancouver, Canada V6C 2X8
            Attention: Jonathan S. Drance, Esq.
            Telephone: (604) 631-1361
            Facsimile: (604) 681-1825

            O'Melveny & Myers LLP
            Embarcadero Center West
            275 Battery Street
            San Francisco, California, U.S.A  94111-3305
            Attention: Peter T. Healy, Esq.
            Telephone: (415) 984-8833
            Facsimile: (415) 984-8701

            (b) if to the Company:

            ImmGenics Pharmaceuticals Inc.
            Third Floor
            6660 North West Marine Drive
            Vancouver, British Columbia V6T 1Z3
            Attention: Dr. Kevin B. Leslie
            Telephone: (604) 732-7526
            Facsimile: (604) 221-5032

      with a copy to:

            Blake, Cassels & Graydon LLP
            Barristers and Solicitors
            Suite 2600, Three Bentall Centre
            595 Burrard Street
            Vancouver, British Columbia V7X 1L3
            Attention: Catherine E. Wade, Esq.
            Telephone: (604) 631-3300
            Facsimile: (604) 631-3309


                                       45
<PAGE>

            and:

            Wilson Sonsini Goodrich & Rosati
            Professional Corporation
            One Market
            Suite 3300, Spear Street Tower
            San Francisco, California U.S.A. 94105
            Attention: Michael S. Dorf, Esq.
            Telephone: (415) 947-2000
            Facsimile: (415) 947-2099

      8.2 Interpretation.

      The headings contained in this Agreement are for reference purposes only
and shall not affect in any way the meaning or interpretation of this Agreement.
Unless otherwise indicated, all references to an "Article" or "section" followed
by a number and/or a letter refer to the specified Article or Section of this
Agreement. The terms "this Agreement", "hereof", "herein" and "hereunder" and
similar expressions refer to this Agreement (including the Schedules hereto) and
not to any particular Article, Section or other portion hereof and include any
agreement or instrument supplementary or ancillary hereto; the words "including"
and "includes" mean "including (or includes) without limitation," and the phrase
"the aggregate of," "the total of," "the sum of," or a phrase of similar meaning
means "the aggregate (or total or sum), without duplication, of," and in the
computation of periods of time from a specified date to a later specified date,
unless otherwise expressly stated, the word "from" means "from and including"
and the words "to" and "until" each mean "to but excluding." The term "business
day" herein means any day on which commercial banks are open for business in
both Vancouver, British Columbia, and San Francisco, California. Unless the
context otherwise requires, words importing the singular include the plural and
vice versa and words importing any gender shall include all genders. For
purposes of this Agreement, the obligations of the Company, Parent and Abgenix
Canada to use "best efforts" to obtain waivers, consents and approvals to loan
agreements, leases and other contracts shall not include any obligation to agree
to an adverse modification of the terms of such documents or to prepay or incur
additional obligations to such other parties.

      8.3 Schedules.

      The following Schedules and Exhibits are annexed to this Agreement and are
hereby incorporated by reference into this Agreement and form part hereof:

            Schedule 1.1 - Applicable Regulatory Approvals
            Schedule 2.2(b)(vi) - Company Consents and Waivers
            Schedule 2.2(b)(ix) - Employees
            Schedule 2.2(c)(iv) - Parent Consents and Waivers
            Schedule 4 - Parent Disclosure Schedule
            Schedule 5 - Company Disclosure Schedule
            Schedule 5.21(i) - List of Technical Reports

            Exhibit A - Plan of Arrangement
            Exhibit B - Escrow Agreement
            Exhibit C - Option Replacement Agreement
            Exhibit D - Support Agreement
            Exhibit E - Voting, Exchange and Cash Put Trust Agreement


                                       46
<PAGE>

      8.4 Date for Any Action.

      In the event that any date on which any action is required to be taken
hereunder by any of the parties hereto is not a business day, such action shall
be required to be taken on the next succeeding day which is a business day.

      8.5 Miscellaneous.

      This Agreement and all agreements to which Parent and the Company are
parties referred to herein: (i) constitutes, together with the Confidentiality
Agreement and the Patent Disclosure Agreement the entire agreement and
supersedes all other prior agreements and understandings, both written and oral,
among the parties, or any of them, with respect to the subject matter hereof,
(ii) shall be binding upon and inure to the benefit of the parties and their
respective successors and assigns and is not intended to confer upon any other
Person any rights or remedies hereunder, except for the provisions of Sections
6.4, 6.5 and 6.6 hereof and (iii) may be executed in two or more counterparts
which together shall constitute a single agreement. The parties shall be
entitled to rely upon delivery of an executed facsimile copy of this Agreement,
and such facsimile copy shall be legally effective to create a valid and binding
agreement among the parties hereto. This Agreement shall be governed, including
as to validity, interpretation and effect, by the laws of British Columbia and
the federal laws of Canada applicable therein. Each of the parties hereto agrees
that any action or proceeding arising out of or relating to this Agreement may
be instituted in the courts of the Province of British Columbia and waives any
objection which it may have now or hereafter to the venue of any such action or
proceeding, irrevocably submits to the jurisdiction of the said courts in any
such action or proceeding. The parties hereto agree that irreparable damage
would occur in the event that any of the provisions of this Agreement were not
performed in accordance with their specific terms or were otherwise breached. It
is accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and provisions hereof in any court of British Columbia having
jurisdiction, this being in addition to any other remedy to which they are
entitled at law or in equity.

      8.6 Publicity.

      So long as this Agreement is in effect and except as required by
applicable laws and the rules, regulations and policies of any applicable stock
exchange, each of Parent and the Company promptly shall advise, consult and
cooperate with the other prior to issuing, or permitting any of its
subsidiaries, directors, officers, employees or agents to issue, any press
release or other statement to the media or any third party with respect to this
Agreement or the transactions contemplated hereby.

      8.7 Assignment.

      Except as expressly permitted by the terms hereof, neither this Agreement
nor any of the rights, interests or obligations hereunder shall be assigned by
either of the parties without the prior written consent of the other party.
Notwithstanding the foregoing, Parent may assign its rights under this Agreement
to a wholly-owned subsidiary, in which event Parent shall continue to be liable
to the Company for any default in performance by such subsidiary.

      8.8 Survival of Representations and Warranties.

      The representations and warranties made by the parties hereto shall remain
in full force and effect until the earlier of (a) the termination of this
Agreement and (b) the Closing Date, except for such longer period as otherwise
specifically provided in the Escrow Agreement; provided, however, that the
representations and warranties made by the Company in Section 5.21 -
Intellectual Property, shall survive


                                       47
<PAGE>

the termination of this Agreement and the Closing Date and shall remain in full
force and effect until the date of termination of the Escrow Agreement.
Notwithstanding any provision to the contrary, nothing in this Agreement shall
be construed to limit any party's remedies in law or equity against fraud and
wilful misconduct.

      8.9 Time is of the Essence.

      Time shall be of the essence of this Agreement.

      8.10 Currency.

      Except as expressly indicated otherwise, all sums of money referred to in
this Agreement are expressed and shall be payable in United States dollars. All
payments shall be in immediately available funds.

      8.11 Severability.

      Whenever possible, each provision of this Agreement shall be interpreted
in such manner as to be effective and valid under applicable law. Any provision
of this Agreement that is invalid or unenforceable in any jurisdiction shall be
ineffective to the extent of such invalidity or unenforceability without
invalidating, rendering unenforceable or altering the remaining provisions
hereof, and any such invalidity or unenforceability in any jurisdiction shall
not invalidate or render unenforceable such provision in any other jurisdiction.


                                       48
<PAGE>

9. EXECUTION

      Parent, Abgenix Canada and the Company have caused this Agreement to be
executed as of the date first written above by their respective officers
thereunto duly authorized.

                                    "PARENT"
                                    ABGENIX, INC.

                                    By:
                                       ---------------------------------
                                    Its:
                                        --------------------------------

                                    By:
                                       ---------------------------------
                                    Its:
                                        --------------------------------


                                    "ABGENIX CANADA"
                                    ABGENIX CANADA CORPORATION

                                    By:
                                       ---------------------------------
                                    Its:
                                        --------------------------------

                                    By:
                                       ---------------------------------
                                    Its:
                                        --------------------------------


                                    "COMPANY"
                                    IMMGENICS PHARMACEUTICALS INC.

                                    By:
                                       ---------------------------------
                                    Its:
                                        --------------------------------

                                    By:
                                       ---------------------------------
                                    Its:
                                        --------------------------------


                                       49
<PAGE>

                                  SCHEDULE 1.1
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                         APPLICABLE REGULATORY APPROVALS

Canada

o     Supreme Court of British Columbia - Final Order

o     exemption orders from the provincial securities regulators from the
      registration, prospectus delivery and continuous disclosure requirements
      with respect to the transactions provided for in the Arrangement and the
      Ancillary Agreements in form and substance satisfactory to Parent and the
      Company

United States and Other

o     approval of NASDAQ regarding the listing of the Parent Common Stock
      subject to official notice of issuance
<PAGE>

                               SCHEDULE 2.2(b)(vi)
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                          COMPANY CONSENTS AND WAIVERS

1.    REGISTRATION RIGHTS AGREEMENT between the Company and Corixa Corporation,
      dated November 4, 1998, as amended:

      o     AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT between the
            Company, Nomura International plc, International Biotechnology Trust
            plc and Corixa Corporation, dated 16 May, 2000

2.    SHAREHOLDER AGREEMENT between the Company and certain shareholders, dated
      12 May, 2000

3.    CO-SALE AGREEMENT between the Company and certain shareholders, dated 4
      November, 1998, as amended:

      o     AMENDED AND RESTATED CO-SALE AGREEMENT between the Company and
            certain shareholders, dated 12 May, 2000

4.    LICENSE AGREEMENT among BR Centre Limited, the Company and Dr. John W.
      Schrader, dated May 9, 1994, as amended (Article 16)

      o     LICENSE AGREEMENT AMENDMENT among BR Centre Limited, the Company and
            Dr. John W. Schrader, dated May 9, 1994

      o     ASSIGNMENT AGREEMENT among BR Centre Limited and The University of
            British Columbia Foundation, dated March 10, 1998

5.    OFFER TO SUB-LEASE between the Company and Discovery Parks Inc, dated May
      30, 1997, as amended

      o     MODIFICATION OF LEASE between the Company and Discovery Parks Inc,
            dated April 1, 1998

      o     MODIFICATION OF LEASE between the Company and Discovery Parks Inc,
            dated December 16, 1998

      o     MODIFICATION OF LEASE between the Company and Discovery Parks Inc,
            dated June 1, 1999

      o     MODIFICATION OF LEASE between the Company and Discovery Parks Inc,
            dated April 1, 2000

      o     MODIFICATION OF LEASE between the Company and Discovery Parks Inc,
            dated July 16, 2000
<PAGE>

                               SCHEDULE 2.2(b)(ix)
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                                    EMPLOYEES

John Babcook
Ian Foltz
Palaniswami Rathanaswami
Jaspal Kang
Chad King
<PAGE>

                               SCHEDULE 2.2(c)(iv)
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                           PARENT CONSENTS AND WAIVERS

      None.
<PAGE>

                                   SCHEDULE 4
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                           PARENT DISCLOSURE SCHEDULE

      Section 4.5

      A report on Form 8-K required to be filed by the Parent to the SEC on or
before December 31, 1999 was filed in January 2000.
<PAGE>

                                   SCHEDULE 5
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                           COMPANY DISCLOSURE SCHEDULE

As appended.
<PAGE>

                                SCHEDULE 5.21(i)
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                            LIST OF TECHNICAL REPORTS

1.    The summary of data generated in the three collaborative programs between
      Millennium Biotherapeutics, Inc. and the Company sent to Dr. Geoff Davis,
      Chief Scientific Officer of Parent with an accompanying letter dated
      August 8, 2000.

2.    The interim report of the data generated with respect to anti-IL-8
      antibodies sent to Dr. Geoff Davis, Chief Scientific Officer of Parent
      with an accompanying letter dated September 11, 2000.

3.    The Affinity Report dated September 25, 2000.
<PAGE>

                                    EXHIBIT A
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                           FORM OF PLAN OF ARRANGEMENT

As appended.
<PAGE>

                                    EXHIBIT B
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                            FORM OF ESCROW AGREEMENT
<PAGE>

                                    EXHIBIT C
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                      FORM OF OPTION REPLACEMENT AGREEMENT
<PAGE>

                                    EXHIBIT D
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

                            FORM OF SUPPORT AGREEMENT
<PAGE>

                                    EXHIBIT E
                       attached to and forming part of the
               Acquisition Agreement (the "Agreement") dated as of
        September 25, 2000 between Parent, Abgenix Canada and the Company

              FORM OF VOTING, EXCHANGE AND CASH PUT TRUST AGREEMENT