Document:

<PAGE>
                                                                    Exhibit 10.3

* CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY
BRACKETS, HAS BEEN OMITTED AND FILED WITH THE SECURITIES AND EXCHANGE COMMISSION
PURSUANT TO RULE 406 OF THE SECURITIES ACT OF 1933, AS AMENDED.

                            STOCK PURCHASE AGREEMENT

                               CORIXA CORPORATION

                                OCTOBER 26, 2001

<PAGE>

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                            PAGE
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<S>      <C>                                                                <C>
1.       PURCHASE AND SALE.....................................................1

         1.1      Sale of Shares...............................................1

         1.2      Options of Corixa............................................2

         1.3      Closing Dates................................................2

         1.4      Delivery.....................................................3

         1.5      Rule 144 Reporting...........................................3

         1.6      "Market Stand-Off" Agreements................................3

         1.7      Standstill Covenant..........................................3

         1.8      Cooperation To Satisfy Closing Conditions....................4

2.       REPRESENTATIONS AND WARRANTIES OF CORIXA..............................4

         2.1      Organization and Standing; Certificate and Bylaws............4

         2.2      Authorization................................................4

         2.3      Validity of Shares...........................................4

         2.4      Offering.....................................................4

         2.5      SEC Documents................................................4

         2.6      No Conflict; No Violation....................................5

         2.7      Consents and Approvals.......................................5

         2.8      Absence of Certain Developments..............................5

3.       REPRESENTATIONS AND WARRANTIES OF PURCHASER...........................6

         3.1      Authorization................................................6

         3.2      Investment Representations...................................6

4.       CONDITIONS TO CLOSING.................................................7

         4.1      Conditions to Obligations of Purchaser.......................7

         4.2      Conditions to Obligations of Corixa..........................8

5.       MISCELLANEOUS.........................................................8

         5.1      Dispute Resolution...........................................8

         5.2      Limitation of Liability......................................9

         5.3      Governing Law................................................9

         5.4      Successors and Assigns.......................................9

         5.5      Entire Agreement.............................................9
</TABLE>

                                      -i-

<PAGE>

                                TABLE OF CONTENTS
                                   (continued)

<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>      <C>                                                                <C>
         5.6      Severability.................................................9

         5.7      Amendment and Waiver.........................................9

         5.8      Delays or Omissions..........................................9

         5.9      Notices, etc................................................10

         5.10     Finder's Fees...............................................10

         5.11     Information Confidential....................................11

         5.12     Titles and Subtitles........................................11

         5.13     Counterparts................................................11
</TABLE>

                                      -ii-

<PAGE>

                            STOCK PURCHASE AGREEMENT

        THIS STOCK PURCHASE AGREEMENT (the "AGREEMENT") is made and entered into
as of October 26, 2001, by and between CORIXA CORPORATION, a Delaware
corporation ("CORIXA"), and AMERSHAM HEALTH, INC., a Delaware corporation
("PURCHASER").

                                    RECITALS

        A. Corixa and Amersham PLC (an affiliate of Purchaser) are parties to
that certain Development, Commercialization and License Agreement of even date
herewith (the "LICENSE AGREEMENT").

        B. Corixa and Amersham PLC are parties to that certain Manufacturing and
Supply Agreement of even date herewith (the "MANUFACTURING AGREEMENT").

        C. Pursuant to Section 8.1 of the License Agreement, Purchaser has
agreed to purchase an aggregate of $15,000,000 of common stock, $0.001 par value
per share, of Corixa (the "COMMON STOCK") in accordance with the terms and
conditions of this Agreement.

        NOW, THEREFORE, the Parties hereto agree as follows:

        1. PURCHASE AND SALE.

        Subject to the terms and conditions hereof, and in reliance upon the
representations, warranties and agreements contained herein, Corixa hereby
agrees to issue and sell to Purchaser, and Purchaser hereby agrees to purchase
from Corixa, the aggregate number of shares of Common Stock determined in
accordance with Section 1.1 hereof.

            1.1 SALE OF SHARES. On the First Closing Date (as defined in Section
1.3), Corixa shall issue and sell to Purchaser, and Purchaser shall purchase
from Corixa that number of shares of Common Stock (the "First Closing Shares")
equal to the quotient of [*] divided by the First Closing Purchase Price (as
hereinafter defined). At the sole option of Corixa and subject to Section 1.2,
on the Second Closing Date (as defined in Section 1.3), Corixa shall issue and
sell to Purchaser, and Purchaser shall purchase from Corixa that number of
shares of Common Stock (the "Second Closing Shares") equal to the quotient of
[*] divided by the Second Closing Purchase Price (as hereinafter defined). At
the sole option of Corixa and subject to Section 1.2, on the Third Closing Date
(as defined in Section 1.3), Corixa shall issue and sell to Purchaser, and
Purchaser shall purchase from Corixa that number of shares of Common Stock (the
"Third Closing Shares") equal to the quotient of [*] divided by the Third
Closing Purchase Price (as hereinafter defined). In the event the number of
First Closing Shares, Second Closing Shares or Third Closing Shares includes a
fraction of a share, the number of First Closing Shares, Second Closing Shares
or Third Closing Shares (as applicable) shall be increased to the nearest whole
number of shares and the aggregate First Closing Purchase Price, Second Closing
Purchase Price or Third Closing Purchase Price (as applicable) shall be
increased to equal the First Closing Purchase Price, Second Closing Purchase
Price or Third Closing Purchase Price (as

--------
* Confidential Treatment Requested.

<PAGE>

applicable) times such whole number of shares. The "First Closing Purchase
Price" shall equal [*] percent ([*]%) of the average of the closing prices of
the Common Stock on the Nasdaq National Market, as reported by the Wall Street
Journal, Western Edition (the "Wall Street Journal"), for the [*] trading days
prior to the date of this Agreement and the [*] trading days following and
including the date of this Agreement. The "Second Closing Purchase Price" and
"Third Closing Purchase Price" (as applicable) shall equal the average of the
closing prices of the Common Stock on the Nasdaq National Market, as reported by
the Wall Street Journal for the [*] trading days prior to the Notice Date (as
defined in Section 1.2) and the [*] trading days following and including the
Notice Date.

            1.2 OPTIONS OF CORIXA.

                (a) Purchaser hereby grants Corixa the irrevocable options to
cause Purchaser to purchase (i) the Second Closing Shares at a price per share
equal to the Second Closing Purchase Price and (ii) the Third Closing Shares at
a price per share equal to the Third Closing Purchase Price (together, the
"Options"). Corixa may exercise the Options at any time during a period of 18
months following the date of this Agreement; provided however, that Corixa shall
not exercise the Options within [*] of each other nor shall Corixa exercise more
than one (1) Option in the year 2001. In the event of termination of the License
Agreement and the Manufacturing Agreement, the Options will remain in full
effect and be legally binding obligations of Purchaser.

                (b) To exercise the Options with respect to the Second Closing
Shares or the Third Closing Shares, Corixa shall notify Purchaser in writing (an
"Exercise Notice") specifying the exercise of such Option. The date of delivery
of such Exercise Notice to Purchaser is referred to as the applicable "Notice
Date," and the Option shall be deemed to have been validly exercised on such
Notice Date with respect to the Second Closing Shares or the Third Closing
Shares.

            1.3 CLOSING DATES. The closing of the sale and purchase of the First
Closing Shares (the "First Closing") shall take place on the [*] business day
after the date of this Agreement or such later date as Corixa and Purchaser may
mutually agree or as may be specified in accordance with the last sentence of
this section (the "First Closing Date"). The closing of the sale and purchase of
the Second Closing Shares and the Third Closing Shares (the "Second Closing" and
"Third Closing," respectively) shall take place on the [*] business day after
the applicable Notice Date or such later date as Corixa and Purchaser may
mutually agree or as may be specified in accordance with the last sentence of
this section (the "Second Closing Date" and "Third Closing Date," respectively).
As used hereinafter, the terms "Closing" and "Closing Date" shall refer to the
First, Second or Third Closing and the First, Second or Third Closing Date, as
the context requires; the term "Shares" shall refer to the First, Second and
Third Closing Shares collectively or the First, Second or Third Closing Shares,
if and as the context requires; and the term "Purchase Price" shall refer to the
First, Second and Third Closing Purchase Price collectively or the First, Second
or Third Closing Purchase Price, if and as the context requires. If for any
reason Corixa is unable to satisfy the closing conditions set forth in Section 4
of this

--------
* Confidential Treatment Requested.

                                      -2-

<PAGE>

Agreement as of the scheduled Closing Date, then Corixa shall use its best
efforts to satisfy such conditions at the earliest practicable date, and the
Closing Date shall be rescheduled to such date as Corixa may specify (with at
least five (5) business days prior notice to Purchaser) on which Corixa can
satisfy such closing conditions.

            1.4 DELIVERY. At the Closing, Corixa will execute and deliver to
Purchaser a certificate registered in the name of Purchaser, representing the
Shares to be purchased by Purchaser from Corixa, dated the Closing Date, against
payment of the aggregate Purchase Price for the Shares, by wire transfer, a
check made payable to the order of Corixa, or any combination thereof.

            1.5 RULE 144 REPORTING. With a view to making available to Purchaser
the benefits of certain rules and regulations of the Securities and Exchange
Commission (the "SEC") which may permit the sale of the Shares to the public
without registration, Corixa agrees to use its best efforts to:

                (a) Make and keep public information available, as those terms
are understood and defined in Rule 144 ("Rule 144") under the Securities Act of
1933, as amended (the 1933 Act") or any similar or analogous rule promulgated
under the 1933 Act, as long as the Shares are outstanding;

                (b) File with the SEC, in a timely manner, all reports and other
documents required of Corixa under the 1933 Act and the Securities Exchange Act
of 1934, as amended (the "1934 Act");

                (c) Take all such action (including without limitation the
furnishing of the information described in Rule 144(d)(4)) as may be necessary
to facilitate a sale of the shares by Purchaser to a "qualified institutional
buyer," as such term is defined in Rule 144A of the 1933 Act.

            1.6 "MARKET STAND-OFF" AGREEMENTS. Purchaser hereby agrees that
prior to the second anniversary of the First Closing Date, Second Closing Date
or Third Closing Date, as applicable, it shall not sell or otherwise transfer or
dispose of any of the First Closing Shares, Second Closing Shares or Third
Closing Shares, as applicable held by it. Corixa may impose stop-transfer
instructions with respect to securities subject to the foregoing restriction
until the expiration thereof. Following [*] of the First Closing Date, until
[*], if Purchaser desires to sell or otherwise transfer any Shares, then
Purchaser shall first give 5 days' written notice thereof to Corixa, describing
generally the basis upon which Purchaser proposes to sell or otherwise transfer
or dispose of such Shares.

            1.7 STANDSTILL COVENANT. Other than the purchase of the Shares
contemplated by Section 1 of this Agreement, Purchaser agrees that, during the
term of the License Agreement and Manufacturing Agreement and for [*]
thereafter, neither Purchaser nor any of its affiliates will in any manner,
directly or indirectly, without the written consent of the Company effect,
propose to effect or actively and consciously participate as a partner in (a)
any acquisition of any securities or assets of Corixa or (b) any tender or
exchange offer, merger, business combination, recapitalization or other
extraordinary transaction involving Corixa unless an unaffiliated third

* Confidential Treatment Requested.
                                      -3-
<PAGE>

party has already made an offer for all of the outstanding shares of Corixa and
neither Purchaser nor any of its affiliates possess any prior knowledge of, or
is involved in any manner with such an offer.

            1.8 COOPERATION TO SATISFY CLOSING CONDITIONS. If any actions are
required to satisfy the closing conditions set forth herein, the Parties shall
take such actions as are reasonably required to satisfy such conditions on a
prompt basis.

        2. REPRESENTATIONS AND WARRANTIES OF CORIXA.

        Corixa hereby represents and warrants to Purchaser that the following
matters shall be true as of the Closing:

            2.1 ORGANIZATION AND STANDING; CERTIFICATE AND BYLAWS. Corixa is a
corporation duly organized, validly existing and in good standing under the laws
of the State of Delaware, and has full power and authority to own and operate
its properties and assets and to carry on its business as presently conducted
and as proposed to be conducted. Corixa is qualified as a foreign corporation to
do business in each jurisdiction in the United States in which the ownership of
its property or the conduct of its business requires such qualification, except
where any statutory fines or penalties or any corporate disability imposed for
the failure to qualify would not materially adversely affect Corixa, its assets,
financial condition or operations.

            2.2 AUTHORIZATION. All corporate action on the part of Corixa, its
officers, directors and stockholders necessary for the authorization, execution
and delivery of this Agreement, the performance of all Corixa's obligations
hereunder, and for the authorization, issuance, sale and delivery of the Shares
has been taken or will be taken prior to Closing. This Agreement, when executed
and delivered, shall constitute a valid and legally binding obligation of Corixa
in accordance with its terms, subject to laws of general application relating to
bankruptcy, insolvency and the relief of debtors, and subject to general equity
principles.

            2.3 VALIDITY OF SHARES. The Shares being purchased by Purchaser
hereunder will, upon issuance pursuant to the terms hereof, be duly authorized
and validly issued, fully paid and nonassessable; provided, however, that the
Shares may be subject to restrictions on transfer under state and/or federal
securities laws as set forth herein or as otherwise required by such laws at the
time a transfer is proposed.

            2.4 OFFERING. Assuming the accuracy of the representations and
warranties of Purchaser contained in Section 3 hereof, the offer, issue, and
sale of Shares are exempt from the registration and prospectus delivery
requirements of the 1933 Act, and the Shares are exempt from registration and
qualification under the registration, permit, or qualification requirements of
all applicable state securities laws.

            2.5 SEC DOCUMENTS.

                (a) As of the First Closing, Corixa will have furnished to
Purchaser the following documents, and the information contained in such
documents, as of their respective dates (or if amended, as of the date of such
amendment), will not contain any untrue statement of

                                      -4-
<PAGE>

a material fact, and will not omit to state any material fact necessary to make
any statement, in light of the circumstances under which such statement was
made, not misleading:

        Corixa's most recent annual report on Form 10-K, together with its proxy
statement for its 2001 Annual Meeting of Stockholders and any additional
Quarterly Reports on Form 10-Q or Current Reports on Form 8-K filed after the
date of such annual report on Form 10-K but prior to the First Closing.

                (b) As of the Second Closing Date, Corixa shall have furnished
to Purchaser the following documents, and the information contained in such
documents, as of their respective dates (or, if amended, as of the date of
amendment), will not contain any untrue statement of a material fact, or omit to
state a material fact necessary to make any statement, in light of the
circumstances under which such statement is made, not misleading.

        Corixa's most recent annual report on Form 10-K, together with its most
recent proxy statement for its Annual Meeting of Stockholders and any additional
Quarterly Reports on form 10-Q or Current Reports on Form 8-K filed after the
date of such annual report on Form 10-K but prior to the Second Closing.

                (c) As of the Third Closing Date, Corixa shall have furnished to
Purchaser the following documents, and the information contained in such
documents, as of their respective dates (or, if amended, as of the date of
amendment), will not contain any untrue statement of a material fact, or omit to
state a material fact necessary to make any statement, in light of the
circumstances under which such statement is made, not misleading.

        Corixa's most recent annual report on Form 10-K, together with its most
recent proxy statement for its Annual Meeting of Stockholders and any additional
Quarterly Reports on form 10-Q or Current Reports on Form 8-K filed after the
date of such annual report on Form 10-K but prior to the Third Closing.

            2.6 NO CONFLICT; NO VIOLATION. The execution, delivery and
performance of this Agreement and consummation of the transactions contemplated
hereby will not (a) conflict with any provisions of the Certificate of
Incorporation or Bylaws of Corixa; (b) result in any material violation or
default of, or permit the acceleration of any obligation under (in each case,
upon the giving of notice, the passage of time, or both), any material mortgage,
indenture, lease, agreement or other instrument, permit, franchise, license,
judgment, order, decree, law, ordinance, rule or regulation applicable to Corixa
or its properties.

            2.7 CONSENTS AND APPROVALS. All consents, approvals, orders, or
authorizations of, or registrations, qualifications, designations, declarations,
or filings with, any governmental authority, required on the part of Corixa in
connection with the valid execution and delivery of this Agreement, the offer,
sale or issuance of the Shares, or the consummation of any other transaction
contemplated hereby have been obtained, or will be effective at the Closing,
except for notices required or permitted to be filed with certain state and
federal securities commissions after the Closing, which notices will be filed on
a timely basis.

            2.8 ABSENCE OF CERTAIN DEVELOPMENTS. As of the Closing, since the
date of the balance sheet set forth in Corixa's most recent annual report on
Form 10-K or Quarterly

                                      -5-
<PAGE>

Report on Form 10-Q referred to Section 2.5, except as Corixa may specify in a
Schedule of Exceptions provided to Purchaser promptly before the Closing, Corixa
shall not have (a) incurred or become subject to any material liabilities
(absolute or contingent) except current liabilities incurred, and liabilities
under contracts entered into, in the ordinary course of business, consistent
with past practices; (b) mortgaged, pledged or subjected to lien, charge or any
other encumbrance any of its assets, tangible or intangible; (c) sold, assigned
or transferred any of its material assets or canceled any material debts or
obligations except in the ordinary course of business, consistent with past
practices; (d) suffered any extraordinary losses, or waived any rights of
substantial value; (e) entered into any material transaction other than in the
ordinary course of business, consistent with past practices; or (f) otherwise
had any material change in its condition, financial or otherwise, except for
changes in the ordinary course of business, consistent with past practices, none
of which individually or in the aggregate has been materially adverse to Corixa.

        3. REPRESENTATIONS AND WARRANTIES OF PURCHASER.

        Purchaser hereby represents and warrants to Corixa as follows:

            3.1 AUTHORIZATION. All corporate action on the part of Purchaser,
its officers, directors and stockholders necessary for the authorization,
execution and delivery of this Agreement and the performance of all Purchaser's
obligations hereunder has been taken or will be taken prior to Closing. This
Agreement, when executed and delivered, shall constitute a valid and legally
binding obligation of Purchaser in accordance with its terms, subject to laws of
general application relating to bankruptcy, insolvency and the relief of
debtors, and subject to general equity principles.

            3.2 INVESTMENT REPRESENTATIONS.

                (a) Purchaser is acquiring the Shares for its own account, not
as nominee or agent, for investment and not with a view to, or for resale in
connection with, any distribution or public offering thereof within the meaning
of the 1933 Act.

                (b) Purchaser understands that (i) the Shares have not been
registered under the 1933 Act by reason of a specific exemption therefrom, that
the Shares must continue to be held by Purchaser, and that Purchaser must,
therefore, bear the economic risk of such investment indefinitely, unless a
subsequent disposition thereof is registered under the 1933 Act or is exempt
from such registration; (ii) the exemptions from registration afforded by Rule
144 (the provisions of which are known to it) promulgated under the 1933 Act
depend on the satisfaction of various conditions, and that, if applicable, Rule
144 may afford the basis for sales only in limited amounts; (iii) each
certificate representing the Shares will be endorsed with the following legend:

                "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
        REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE
        SOLD, TRANSFERRED, ASSIGNED OR HYPOTHECATED UNLESS (A) PURSUANT TO SEC
        RULE 144 OR (B) THERE IS AN EFFECTIVE REGISTRATION STATEMENT UNDER SAID
        ACT COVERING SUCH

                                      -6-
<PAGE>

        SECURITIES OR (C) CORIXA RECEIVES AN OPINION OF COUNSEL FOR THE HOLDER
        OF THESE SECURITIES REASONABLY SATISFACTORY TO CORIXA, STATING THAT SUCH
        SALE, TRANSFER, ASSIGNMENT OR HYPOTHECATION IS EXEMPT FROM THE
        REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF SAID ACT."

And (iv) Corixa will instruct any transfer agent not to register the transfer of
any of the Shares unless the conditions specified in the foregoing legend are
satisfied.

                (c) It has been furnished with such materials and has been given
access to such information relating to Corixa as it or its qualified
representative has requested and it has been afforded the opportunity to ask
questions of and receive answers from the management of Corixa regarding Corixa
and the Shares, all as it has found necessary to make an informed investment
decision.

                (d) Purchaser is an "accredited investor" within the meaning of
Rule 501 of Regulation D promulgated under the 1933 Act and was not organized
for the specific purpose of acquiring the Shares.

                (e) For purposes of the application of state securities laws,
Purchaser represents that it is a corporation organized and existing under the
laws of the state of Delaware.

        4. CONDITIONS TO CLOSING.

            4.1 CONDITIONS TO OBLIGATIONS OF PURCHASER. Purchaser's obligation
to purchase the First Closing Shares at the First Closing, the Second Closing
Shares at the Second Closing and the Third Closing Shares at the Third Closing
is in each case subject to the fulfillment, at or prior to the applicable
Closing, of the following conditions:

                (a) REPRESENTATIONS AND WARRANTIES TRUE. The representations and
warranties made by Corixa in Section 2 hereof shall be true and correct in all
material respects on the date of the Closing with the same force and effect as
if they had been made on and as of said date.

                (b) PERFORMANCE OF OBLIGATIONS. Corixa shall have performed all
obligations and conditions herein required to be performed by it on or prior to
the Closing.

                (c) PROCEEDINGS AND DOCUMENTS. All corporate and other
proceedings in connection with the transactions contemplated at the Closing
hereby and all documents and instruments incident to such transactions shall be
reasonably satisfactory in substance and form to Purchaser and its counsel, and
Purchaser and its counsel shall have received all such counterpart originals or
certified or other copies of such documents as they may reasonably request.

                (d) QUALIFICATIONS, LEGAL INVESTMENT. All authorizations,
approvals, or permits, if any, of any governmental authority or regulatory body
of the United States or of any state that are required in connection with the
lawful sale and issuance of the Shares pursuant to this Agreement shall have
been duly obtained and shall be effective on and as of the Closing.

                                      -7-
<PAGE>

No stop order or other order enjoining the sale of the Shares shall have been
issued and no proceedings for such purpose shall be pending or, to the knowledge
of Corixa, threatened by the SEC or any commissioner of corporations or similar
officer of any other state having jurisdiction over this transaction. At the
time of the Closing, the sale and issuance of the Shares shall be legally
permitted by all laws and regulations to which Purchaser and Corixa are subject.

                (e) COMPLIANCE CERTIFICATE. Corixa shall have delivered to
Purchaser a Certificate, executed by an officer of Corixa, dated the date of the
Closing, certifying to the fulfillment of the conditions specified in
subparagraphs (a) and (b) of this Subsection 4.1.

            4.2 CONDITIONS TO OBLIGATIONS OF CORIXA. Corixa's obligation to
issue and sell the First Closing Shares at the First Closing, the Second Closing
Shares at the Second Closing and the Third Closing Shares at the Third Closing
is in each case subject to the fulfillment to Corixa's satisfaction, at or prior
to the applicable Closing, of the following conditions:

                (a) REPRESENTATIONS AND WARRANTIES TRUE. The representations and
warranties made by Purchaser in Section 3 hereof shall be true and correct in
all material respects on the date of the Closing, with the same force and effect
as if they had been made on and as of said date.

                (b) PERFORMANCE OF OBLIGATIONS. Purchaser shall have performed
and complied with all agreements and conditions herein required to be performed
or complied with by it on or before the Closing.

                (c) QUALIFICATIONS, LEGAL INVESTMENT. All authorizations,
approvals, or permits, if any, of any governmental authority or regulatory body
of the United States or of any state that are required in connection with the
lawful sale and issuance of securities pursuant to this Agreement shall have
been duly obtained and shall be effective on and as of the Closing. No stop
order or other order enjoining the sale of the Shares shall have been issued and
no proceedings for such purpose shall be pending or, to the knowledge of Corixa,
threatened by the SEC or any commissioner of corporations or similar officer of
any other state having jurisdiction over this transaction. At the time of the
Closing, the sale and issuance of the securities hereunder shall be legally
permitted by all laws and regulations to which Purchaser and Corixa are subject.

                (d) COMPLIANCE CERTIFICATE. Purchaser shall have delivered to
Corixa a Certificate, executed by an officer of Purchaser, dated the date of the
Closing, certifying to the fulfillment of the conditions specified in
subparagraphs (a) and (b) of this Subsection 4.2.

        5. MISCELLANEOUS.

            5.1 DISPUTE RESOLUTION. In the event of any controversy or claim
arising out of, relating to or in connection with any provision of this
Agreement, the Parties shall try to settle their differences amicably between
themselves first, by referring the disputed matter to the respective Chief
Financial Officers of each Party and, if not resolved by the Chief Financial
Officers, by referring the disputed matter to the respective Chief Executive
Officers of each Party. Either Party may initiate such informal dispute
resolution by sending written notice of the dispute to the other Party, and,
within 20 days after such notice, such representatives of the

                                      -8-
<PAGE>

Parties shall meet for attempted resolution by good faith negotiations. If such
personnel are unable to resolve a dispute within 30 days of their first meeting
of such negotiations, either Party may seek to have such dispute resolved by
binding arbitration with a single arbitrator under the commercial rules of the
American Arbitration Association. The Parties hereby consent to conduct such
binding arbitration procedures in English in the city of New York, New York.

            5.2 LIMITATION OF LIABILITY. IN NO EVENT SHALL EITHER PARTY, ITS
DIRECTORS, OFFICERS, EMPLOYEES, AGENTS OR AFFILIATES BE LIABLE TO THE OTHER
PARTY FOR ANY INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES,
WHETHER BASED UPON A CLAIM OR ACTION OF CONTRACT, WARRANTY, NEGLIGENCE, STRICT
LIABILITY OR OTHER TORT, OR OTHERWISE, ARISING OUT OF THIS AGREEMENT. For
clarification, the foregoing sentence shall not be interpreted to limit or to
expand the express rights specifically granted in the sections of this
Agreement.

            5.3 GOVERNING LAW. This Agreement shall be governed by and construed
under the laws of the State of Delaware as applied to agreements among Delaware
residents, made and to be performed entirely within the State of Delaware.

            5.4 SUCCESSORS AND ASSIGNS. Except as otherwise expressly provided
herein, the provisions hereof shall inure to the benefit of, and be binding
upon, the successors, assigns, heirs, executors, and administrators of the
parties hereto.

            5.5 ENTIRE AGREEMENT. This Agreement, the License Agreement, the
Manufacturing Agreement and the exhibits hereto and thereto, the Confidentiality
Agreement effective August 10, 2000 between Medi-Physics, Inc. doing business as
Nycomed Amersham Imaging, and the other documents delivered pursuant hereto and
thereto constitute the full and entire understanding and agreement among the
parties with regard to the subjects hereof, and no party shall be liable or
bound to any other party in any manner by any representations, warranties,
covenants, or agreements except as specifically set forth herein or therein.
Nothing in this Agreement, express or implied, is intended to confer upon any
party, other than the parties hereto and their respective successors and
assigns, any rights, remedies, obligations, or liabilities under or by reason of
this Agreement, except as expressly provided herein.

            5.6 SEVERABILITY. In case any provision of this Agreement shall be
invalid, illegal, or unenforceable, it shall, to the extent practicable, be
modified so as to make it valid, legal and enforceable and to retain as nearly
as practicable the intent of the parties, and the validity, legality, and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby.

            5.7 AMENDMENT AND WAIVER. Any term of this Agreement may be amended
and the observance of any term of this Agreement may be waived (either generally
or in a particular instance, either retroactively or prospectively, and either
for a specified period of time or indefinitely), with the written consent of
Corixa and Purchaser. Any amendment or waiver effected in accordance with this
Section shall be binding upon Purchaser, each future holder of the Shares, and
Corixa.

                                      -9-
<PAGE>

            5.8 DELAYS OR OMISSIONS. No delay or omission to exercise any right,
power, or remedy accruing to Purchaser or any subsequent holder of any Shares
upon any breach, default or noncompliance of Corixa under this Agreement, shall
impair any such right, power, or remedy, nor shall it be construed to be a
waiver of any such breach, default or noncompliance, or any acquiescence
therein, or of any similar breach, default or noncompliance thereafter
occurring. It is further agreed that any waiver, permit, consent, or approval of
any kind or character on Purchaser's part of any breach, default or
noncompliance under this Agreement or any waiver on Purchaser's part of any
provisions or conditions of this Agreement must be in writing and shall be
effective only to the extent specifically set forth in such writing, and that
all remedies, either under this Agreement, by law, or otherwise afforded to
Purchaser, shall be cumulative and not alternative.

            5.9 NOTICES, ETC. All notices and other communications required or
permitted hereunder shall be in writing and shall be deemed effectively given
(a) upon personal delivery, (b) on report of successful transmission by
facsimile machine that automatically generates a printed report indicating
whether transmission was completed successfully, at the conclusion of each
transmission, (c) on the first business day after receipted delivery to a
courier service which guarantees next business-day delivery, under circumstances
in which such guaranty is applicable, or (d) on the earlier of delivery or five
(5) business days after mailing by United States certified mail, postage and
fees prepaid, to the appropriate party at the address set forth below or to such
other address as the part so notifies the other in writing:

            if to Corixa, to:         Corixa Corporation
                                      1124 Columbia Street
                                      Suite 200
                                      Seattle, WA  98104
                                      Attn: Chief Financial Officer
                                      Copy to: General Counsel

            if to Purchaser, to:      Amersham Health, Inc.
                                      101 Carnegie Center
                                      Princeton, NJ 08540
                                      Attn:  General Counsel

            with a copy to:           Amersham PLC
                                      Amersham Place
                                      Little Chalfont
                                      Buckinghamshire
                                      ENGLAND HP7 9NA
                                      Attn:  Group Secretary

        Notwithstanding the foregoing, all notices and other communications to
an address outside of the United States shall be sent by telecopy and confirmed
in writing to be sent by first class mail.

            5.10 FINDER'S FEES.

                                      -10-
<PAGE>

                (a) Corixa (i) represents and warrants that it has retained no
finder or broker in connection with the transactions contemplated by this
Agreement and (ii) hereby agrees to indemnify and to hold Purchaser harmless of
and from any liability for any commission or compensation in the nature of a
finder's fee to any broker or other person or firm (and the costs and expenses
of defending against such liability or asserted liability) for which Corixa or
any of its employees or representatives is responsible.

                (b) Purchaser (i) represents and warrants that it has retained
no finder or broker in connection with the transactions contemplated by this
Agreement, and (ii) hereby agrees to indemnify and to hold Corixa harmless of
and from any liability for any commission or compensation in the nature of a
finder's fee to any broker or other person or firm (and the costs and expenses
of defending against such liability or asserted liability) for which Purchaser
or any of its employees or representatives are responsible.

            5.11 INFORMATION CONFIDENTIAL. Purchaser acknowledges that any non
public information received by it pursuant hereto is confidential and for
Purchaser's use only, and it will refrain from using such information or
reproducing, disclosing, or disseminating such information to any other person
(other than its employees, affiliates, agents, or partners having a need to know
the contents of such information and its attorneys, in each case who agree to be
bound by this Section 5.9), except in connection with the exercise of rights
under this Agreement, unless such information becomes available to the public
generally or it is required by a governmental body to disclose such information.

            5.12 TITLES AND SUBTITLES. The titles of the sections and
subsections of this Agreement are for convenience of reference only and are not
to be considered in construing this Agreement.

            5.13 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one instrument.

        The foregoing Agreement is hereby executed as of the date first above
written.

CORIXA CORPORATION                       AMERSHAM HEALTH, INC.

By:/s/ Steven Gillis                     By:/s/ Jeffrey Freedman
   ---------------------------------         -----------------------------------
Printed Name: Steven Gillis              Printed Name: Jeffrey Freedman
             -----------------------                   ------------------------
Title: Chief Executive Officer           Title: Vice President
      ------------------------------            --------------------------------

                                      -11-<PAGE>
                                                                    Exhibit 10.1

                     PRIVATE EQUITY LINE FINANCING AGREEMENT

     PRIVATE EQUITY LINE FINANCING AGREEMENT (this "Agreement"), dated as of
December 3, 2001, between CORIXA CORPORATION, a Delaware corporation (the
"Company"), and BNY CAPITAL MARKETS, INC., a registered broker dealer organized
under the laws of New York and a subsidiary of The Bank of New York (the
"Investor").

                              W I T N E S S E T H:

     WHEREAS, the parties desire that, upon the terms and subject to the
conditions contained herein, the Company may issue and sell to the Investor from
time to time as provided herein, and the Investor shall purchase from the
Company, shares of Common Stock for an aggregate purchase price up to
$75,000,000 on a private placement basis pursuant to an exemption from
registration under Section 4(2) of the Securities Act of 1933;

     WHEREAS, the Investor shall be entitled to resell shares of Common Stock
acquired hereunder pursuant to a resale registration statement established by
the Company pursuant to the terms of the Registration Rights Agreement between
the Company and the Investor which shall be declared effective by the Commission
prior to the delivery of a Draw Down Notice hereunder; and

     NOW THEREFORE, in consideration of the premises, representations,
warranties, covenants and agreements contained herein, and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, intending to be legally bound hereby, the parties hereto agree as
follows:

                                    ARTICLE I

                                   DEFINITIONS

     SECTION 1.01. Certain Definitions. For purposes of this Agreement,
capitalized terms used herein and not otherwise defined shall have the following
respective meanings:

     "Affiliate" of a Person means another Person that directly or indirectly,
through one or more intermediaries, controls, is controlled by, or is under
common control with, such first- mentioned Person. The term "control" (including
the terms "controlling," "controlled by" and "under common control with") means
the possession, direct or indirect, of the power to direct or cause the
direction of the management and policies of a Person, whether through the
ownership of voting securities, by contract or otherwise.

<PAGE>

     "Average Daily Trading Volume" with respect to any Draw Down effected by
the Company shall mean the average daily volume of shares of Common Stock traded
on the Principal Market as reported by Bloomberg Financial during the five (5)
consecutive Trading Day period ending on the Trading Day immediately preceding
the date on which a Draw Down Notice is delivered pursuant to Section 2.03(b)
hereof.

     "Bloomberg Financial" shall mean Bloomberg Financial Markets or an
equivalent reliable reporting service reasonably acceptable to the Company and
hereafter designated by the Investor.

     "Board of Directors" means (i) with respect to a corporation, the board of
directors of the corporation (or any duly authorized committee thereof); (ii)
with respect to a partnership, the Board of Directors (or any duly authorized
committee thereof) of the general partner of the partnership; and (iii) with
respect to any other Person, the board or committee of such Person serving a
similar function.

     "Capital Stock" means, with respect to any Person, any and all shares,
interests, participations or other equivalents (however designated) of corporate
stock, including each class of common stock and preferred stock, of such Person.

     "Change in Control" means (i) the direct or indirect sale, transfer,
conveyance or other disposition (other than by way of merger or consolidation),
in one or a series of related transactions, of all or substantially all of the
properties or assets of the Company and its Subsidiaries taken as a whole to any
"person" (as that term is used in Section 13(d)(3) of the Exchange Act), (ii)
the adoption of a plan relating to the liquidation or dissolution of the
Company, (iii) the consummation of any transaction (including, without
limitation, any merger or consolidation) the result of which is that any
"person" (as defined above) becomes the beneficial owner, directly or
indirectly, of more than 50% of the Voting Stock of the Company, measured by
voting power rather than number of shares, or (iv) the first day on which a
majority of the members of the Board of Directors of the Company are not
Continuing Directors.

     "Closing" shall have the meaning set forth in Section 2.02.

     "Closing Date" shall mean the date on which the Closing occurs.

     "Comfort Letter" shall mean a letter from Ernst & Young LLP or another "Big
Five" independent public accounting firm, in form and substance reasonably
satisfactory to the Investor, addressed to the Investor and dated as of the
Effective Date or the filing date of any Current Report on Form 8-K incorporated
by reference

                                       2
<PAGE>

into the Registration Statement, if such report contains substantial financial
information, (i) confirming that they are independent auditors within the
meaning of the Securities Act and are in compliance with the applicable
requirements relating to the qualification of accountants under Rule 2-01 of
Regulation S-X of the Commission and (ii) stating, as of the Effective Date or
filing date, as applicable, the conclusions and findings of such firm with
respect to the financial information and other matters ordinarily covered by
accountants' "comfort letters" to underwriters in connection with registered
public offerings included in the Registration Statement or Form 8-K, as
applicable.

     "Commission" means the United States Securities and Exchange Commission.

     "Commitment Period" shall mean the period commencing on the Effective Date
and expiring on the earliest to occur of (x) the date on which the Investor
shall have purchased Draw Down Shares pursuant to this Agreement for an
aggregate Purchase Price of $75,000,000, (y) the date this Agreement is
terminated pursuant to Article VII and (z) the date occurring twenty-four (24)
months from the date of this Agreement.

     "Common Stock" shall mean the Company's Common Stock, $.01 par value per
share.

     "Common Shares" shall mean shares of the Company's Common Stock issued or
issuable pursuant to this Agreement.

     "Continuing Directors" shall mean as of any date of determination, any
member of the Board of Directors of the Company who (i) was a member of such
Board of Directors on the date of this Agreement; or (ii) was nominated for
election or elected to such Board of Directors with the approval of a majority
of the Continuing Directors who were members of such Board at the time of such
nomination or election.

        "Daily Draw-Down Proportion" shall mean a fraction, the numerator of
which shall be one (1) and the denominator of which shall be the number of
Trading Days in the applicable Valuation Period, as specified by the Company in
the applicable Draw Down Notice.

     "Draw Down" shall mean each occasion the Company elects to exercise its
right to deliver a Draw Down Notice requiring the Investor to purchase the
Common Shares as specified in such Draw Down Notice, subject to the terms and
conditions of this Agreement.

                                       3
<PAGE>

     "Draw Down Cancellation" shall have the meaning set forth in Section
6.04(a).

     "Draw Down Cancellation Date" shall have the meaning set forth in Section
6.04(a).

     "Draw Down Cancellation Notice" shall have the meaning set forth in Section
6.04(a).

     "Draw Down Date" shall mean any Trading Day during the Commitment Period
that a Draw Down Notice to sell Common Stock to the Investor is deemed delivered
pursuant to Section 2.03(b) hereof.

     "Draw Down Notice" shall mean a written notice to the Investor delivered in
accordance with this Agreement in the form attached hereto as Exhibit A setting
forth the Investment Amount that the Company intends to sell to the Investor
pursuant to such Draw Down and the Floor Price applicable to such Draw Down.

     "Draw Down Share Limitation" shall have the meaning set forth in Section
2.01(c).

     "Draw Down Shares" shall mean all shares of Common Stock issued or issuable
pursuant to a Draw Down that has occurred or may occur in accordance with the
terms and conditions of this Agreement.

     "DWAC Transfer" shall have the meaning set forth in Section 2.04.

     "Effective Date" shall mean the date on which the Commission first declares
effective a Registration Statement registering the resale of the Registrable
Securities as set forth in Section 6.02(a).

     "Exchange Act" means the Securities Exchange Act of 1934.

     "Floor Price" shall mean the lowest VWAP (before taking into account any
discount used to calculate the Purchase Price hereunder) at which the Company
will sell its Common Stock as specified in the Draw Down Notice delivered in
connection with any Draw Down effected pursuant to this Agreement, but in no
event shall the Floor Price be less than $5.00.

     "Food and Drug Act" shall mean the Federal Food, Drug and Cosmetic Act, 21
U.S.C. sections 301 et seq. and the rules and regulations promulgated
thereunder.

     "Governmental Authority" means any federal or state government or political
subdivision thereof and any agency or

                                       4
<PAGE>

other entity exercising executive, legislative, judicial, regulatory or
administrative functions of or pertaining to government.

     "Investment Amount" shall mean the aggregate dollar amount (within the
range specified in Section 2.03) of any Draw Down Shares to be purchased by the
Investor with respect to any Draw Down affected by the Company in accordance
with Section 2.03 hereof.

     "Material Adverse Effect" has the meaning set forth in Section 3.01.

     "Maximum Draw Down Amount" with respect to any Draw Down effected by the
Company in accordance with Section 2.03 hereof shall mean the lesser of (i)
$3,500,000 and (ii) 10% of the product of (x) the average of the VWAPs for each
of the five Trading Days immediately preceding the applicable Draw Down Date,
multiplied by (y) the Average Daily Trading Volume of the Common Stock for the
applicable Draw Down Date, multiplied by (z) 5.

     "Maximum Share Amount" shall have the meaning set forth in Section 2.01(c).

     "Minimum Draw Down Amount" shall mean $500,000.

     "Person" means an individual or a corporation, partnership, trust,
incorporated or unincorporated association, joint venture, joint stock company,
Governmental Authority or other entity of any kind.

     "Principal Market" shall mean the Nasdaq National Market, the American
Stock Exchange or the New York Stock Exchange, whichever is at the time the
principal trading exchange or market for the Common Stock.

     "Prospectus Supplement" shall have the meaning set forth in Section
6.02(k).

     "Purchase Price" with respect to each Trading Day during a Valuation Period
shall mean 98% of the VWAP for such Trading Day.

     "Registrable Securities" shall have the meaning given such term in the
Registration Rights Agreement.

     "Registration Rights Agreement" shall mean the agreement regarding the
filing of the Registration Statement for the resale of the Registrable
Securities entered into between the Company and the Investor as of the Closing
Date.

                                       5
<PAGE>

     "Registration Statement" shall have the meaning given such term in the
Registration Rights Agreement.

     "SEC Reports" means the Company's Annual Report on Form 10-K for the
year-ended December 31, 2000, the Company's Quarterly Reports on Form 10-Q for
the quarters ended March 31, 2001, June 30, 2001 and September 30, 2001, the
Company's Current Reports on Form 8-K, filed January 4, 2001, March 26, 2001 and
September 17, 2001 and when used in reference to dates after the date of this
Agreement, any other reports and documents filed by the Company hereafter under
the Exchange Act.

     "Securities Act" means the Securities Act of 1933.

     "Settlement Date" shall mean the Trading Day immediately following the last
Trading Day of the Valuation Period.

     "Trading Day" shall mean any day during which the Principal Market shall be
open for trading.

     "Transaction Documents" means, collectively, this Agreement and the
Registration Rights Agreement.

     "Valuation Period" shall mean the period of one (1) to twenty (20)
consecutive Trading Days (as determined by the Company in its sole discretion
and specified in the applicable Draw-Down Notice) following the Trading Day on
which a Draw Down Notice is delivered or deemed to be delivered pursuant to
Section 2.03(b) hereof.

     "Voting Stock" of any Person as of any date means the Capital Stock of such
Person that is at the time entitled to vote in the election of the Board of
Directors of such Person.

     "VWAP" for any given Trading Day shall mean the daily volume weighted
average price of the Common Stock on such date on the Principal Market as
reported by Bloomberg Financial using the AQR function.

                                   ARTICLE II

                        SALE AND PURCHASE OF COMMON STOCK

     SECTION 2.01. Investments. (a) Purchase and Sale of Common Stock. Subject
to the terms and conditions of this Agreement, the Company, at its sole and
exclusive option, may issue and sell to the Investor, and the Investor shall
purchase from the Company, shares of the Company's Common Stock (subject to the
Maximum Share Amount), based on such number of Draw Downs (subject to the
Maximum Draw Down Amount, the Draw Down Share Limitation and the Minimum Draw
Down Amount) as the Company, in its sole discretion,

                                       6
<PAGE>

shall choose to deliver during the Commitment Period until the aggregate
Investment Amount with respect to Common Shares purchased under this Agreement
equals $75,000,000 or this Agreement is otherwise terminated.

     (b) Draw Downs. Upon the terms and subject to the conditions set forth
herein, on any Trading Day as provided in Section 2.03(b) hereof during the
Commitment Period on which the conditions set forth in Section 6.02 and 6.03
hereof have been satisfied, the Company may exercise a Draw Down by the delivery
of a Draw Down Notice, executed by the Chief Executive Officer, Chief Financial
Officer or Treasurer of the Company, to the Investor. The aggregate number of
Draw Down Shares that the Investor shall be obligated to purchase pursuant to
such Draw Down shall be the sum of the Draw Down Shares issuable in respect of
each day during the Valuation Period, determined on a daily basis during the
applicable Valuation Period in accordance with Section 2.03(c) below (unless
Common Shares may not be sold in respect of any Trading Day during the Valuation
Period as provided by this Agreement). Each Draw Down will be settled on the
applicable Settlement Date following the Draw Down Date.

     (c) Maximum Amount of Draw Down Shares. No more than 19.9% of the shares of
Common Stock outstanding as of the Closing Date (the "Maximum Share Amount") may
be issued and sold pursuant to all Draw Downs hereunder. No more than 4.9% of
the shares of Common Stock outstanding as of the applicable Draw Down Date (the
"Draw Down Share Limitation") may be issued and sold in one Draw Down hereunder.

     SECTION 2.02. Effectiveness. The effectiveness of this Agreement (the
"Closing") shall be deemed to take place concurrently with the execution and
delivery of this Agreement by the parties hereto and the completion of the
closing transactions set forth in the immediately following sentence. At the
Closing, the following closing transactions shall take place, each of which
shall be deemed to occur simultaneously with the Closing: (i) the Company and
the Investor shall execute and deliver the Registration Rights Agreement; (ii)
the Company shall deliver to the Investor a certificate executed by the
Secretary of the Company, signing in such capacity, dated the date of the
Closing (A) certifying that attached thereto are true and complete copies of the
resolutions duly adopted by the Board of Directors of the Company authorizing
the execution and delivery of the Transaction Documents and the consummation of
the transactions contemplated thereby (including, without limitation, the
reservation and issuance of the Common Stock pursuant to this Agreement), which
authorization shall be in full force and effect on and as of the date of such
certificate and (B) certifying and attesting to the office, incumbency, due
authority and specimen signatures of each Person who executed any Transaction
Document for or on behalf of

                                       7
<PAGE>

the Company; (iii) the Company shall deliver to the Investor a certificate
executed by the Chief Executive Officer, Chief Financial Officer or Treasurer of
the Company, signing in such capacity, dated the date of the Closing, confirming
the accuracy of the representations and warranties of the Company contained in
this Agreement; (iv) Orrick, Herrington & Sutcliffe, LLP, counsel to the
Company, shall deliver to the Investor an opinion, dated the date of the Closing
and addressed to the Investor, substantially in the form of Exhibit B attached
hereto; and (v) the Company shall pay the expenses set forth in Section 9.02
hereof by wire transfer to the account designated by the Investor in writing
prior to the Closing.

     SECTION 2.03. Mechanics of Draw Downs. (a) Draw Down Notice. On any Trading
Day during the Commitment Period, the Company may deliver a Draw Down Notice to
the Investor, subject to the satisfaction of the conditions set forth in
Sections 6.02 and 6.03; provided, however, that the Investment Amount for each
Draw Down as designated by the Company in the applicable Draw Down Notice shall
be neither less than the Minimum Draw Down Amount nor more than the Maximum Draw
Down Amount and the number of Draw Down Shares shall not exceed the Draw Down
Share Limitation (as determined as of the applicable Draw Down Date); provided
further, however, that if the Maximum Draw Down Amount as of the applicable Draw
Down Date is less than the Minimum Draw Down Amount, the Company shall not be
entitled to deliver any such Draw Down Notice.

     (b) Delivery of Draw Down Notice. A Draw Down Notice shall be deemed
delivered on (i) the Trading Day that it is received by facsimile or otherwise
(and the Company confirms such delivery by e-mail notice or by telephone
(including voicemail message)) by the Investor if received prior to 12:00 noon,
New York City time on such Trading Day, or (ii) in the event it is received by
facsimile or otherwise (and the Company confirms such delivery by e-mail notice
or telephone (including voicemail message)) subsequent to 12:00 noon, New York
City time, on a Trading Day, the immediately succeeding Trading Day. No Draw
Down Notice may be delivered other than on a Trading Day during the Commitment
Period.

     (c) Determination of Draw Down Shares Issuable. Subject to Section 2.03(d)
and (e) hereof, the number of Draw Down Shares to be purchased by the Investor
with respect to any Draw Down shall be determined on a daily basis during the
applicable Valuation Period and shall equal with respect to any such Trading Day
the quotient of (x) the Daily Draw-Down Proportion, divided by (y) the Purchase
Price for such Trading Day. The portion of the Investment Amount for which Draw
Down Shares may be issued for each Trading Day during the Valuation Period may
not exceed the Daily Draw-Down Proportion.

                                       8
<PAGE>

     (d) Floor Price Limitation. If the VWAP on any Trading Day during a
Valuation Period is less than the Floor Price specified in the applicable Draw
Down Notice, the Company shall not sell and the Investor shall not purchase the
Draw Down Shares otherwise to be purchased for such Trading Day. In such case,
the Investment Amount shall be reduced by the Daily Draw-Down Proportion of the
Investment Amount for each such Trading Day.

     (e) Minimum Trading Hours Limitation. In the event that the Common Stock is
not listed and approved for trading on a Principal Market and free from any
halts or suspensions of trading (whether imposed generally on such Principal
Market or specifically with respect to the Common Stock) for a period of at
least six (6) hours on any Trading Day during a Valuation Period, then the
Company shall not sell and the Investor shall not purchase the Draw Down Shares
otherwise to be purchased in respect of such Trading Day. In such case, the
Investment Amount shall be reduced by the Daily Draw-Down Proportion of the
Investment Amount for each such Trading Day.

     SECTION 2.04. Settlements. Subject to the provisions of Section 6.04, on
each Settlement Date the Company shall, unless the Investor otherwise instructs
the Company to transmit shares of Common Stock to the Investor by other means,
cause the Transfer Agent to electronically transmit shares of Common Stock to
the Investor (by crediting the account of the Investor's prime broker, as
designated by the Investor, with The Depository Trust Company through its
Deposit Withdrawal Agent Commission system ("DWAC Transfer")) representing the
Draw Down Shares to be purchased by the Investor on such Settlement Date with
respect to the Draw Down Period immediately preceding such Settlement Date
pursuant to Section 2.03(c) hereof against delivery by the Investor of the
portion of the Investment Amount representing the Draw Down Shares to be
purchased on such Settlement Date by wire transfer of immediately available
funds to an account designated in writing by the Company at least one Trading
Day prior to the Settlement Date. In addition, on or prior to each such
Settlement Date, each of the Company and the Investor shall deliver all
documents, instruments and writings required to be delivered by either of them
pursuant to this Agreement in order to implement and effect the transactions
contemplated herein. The Investor acknowledges that although the Draw Down
shares acquired from the Company pursuant to a DWAC Transfer do not bear a
restrictive legend, they constitute "restricted securities" within the meaning
of the Securities Act and the Investor agrees it will transfer the Draw Down
Shares through the facilities of The Depository Trust Company only pursuant to
the Registration Statement or pursuant to a transaction exempt from registration
under the Securities Act.

                                       9
<PAGE>

     SECTION 2.05. Damages for Late Delivery or Non-Delivery of Draw Down
Shares; Investor Right to Void Draw Down Notice. (a) In the event the Draw Down
Shares are not delivered by the Company on any Settlement Date, the Company will
pay the Investor, the actual damages, if any, incurred by the Investor as a
result of such late delivery or non-delivery. For purposes of the foregoing, the
actual damages of the Investor shall mean the actual costs, penalties and
interest expense incurred by the Investor resulting from its failure to deliver
on the Settlement Date any Draw Down Shares it was entitled to receive from the
Company on any Settlement Date to any unaffiliated third party to whom it had
agreed to deliver shares of Common Stock. The Investor agrees to act in good
faith to minimize its actual damages in any such event and shall provide the
Company with a detailed calculation of its actual damages and supporting
documentation therefore. Except as provided by Section 2.05(c) below, such
amount may be offset by the Investor against the portion of the Investment
Amount otherwise payable by the Investor with respect to such Draw Down Shares
or future payment obligations of the Investor with respect to subsequent Draw
Down Notices. No amounts shall be payable in the event the Investor does not
incur any actual damages.

     (b) The Company may not deliver a Draw Down Notice in the event (1) all
prior required deliveries of Draw Down Shares have not been made or (2) the
Company has not paid any amounts owed to the Investor pursuant to Section
2.05(a) unless, in connection with such notice, the Company shall have advised
the Investor in writing that the Investor may offset the amounts payable by the
Company (which amount shall be set forth in such notice and shall be consistent
with the Investor's calculation thereof) against the portion of the Investment
Amount otherwise payable by the Investor with respect to such Draw Down Notice.

     (c) In the event the Company, acting in good faith, disputes in writing the
determination by the Investor of the amount of its actual damages resulting from
the failure of the Company to deliver Draw Down Shares on a Settlement Date (or
deliver such Draw Down Shares at all), the Company may continue to deliver Draw
Down Notices for a period of 30 days following such Settlement Date without
paying the Investor such damages, whether in cash or by offset, provided that
the aggregate Investment Amount drawn down during such 30-day period does not
exceed $7,500,000. Notwithstanding any payment of damages by the Company,
whether in cash or by offset, if the Company, acting in good faith, disputes the
determination by the Investor of the amount of its actual damages, such payment
shall in no manner constitute an agreement by the Company with the Investor's
calculations. The Company may deliver Draw Down Notices for up to an additional
90 days from the date of payment (not to extend beyond 120 days from the

                                       10
<PAGE>

Company challenges the Investor's calculations. If the Company and the Investor
have not resolved their dispute by such time as to the amount of actual damages
incurred by the Investor, the ability of the Company to deliver Draw Down
Notices shall thereafter be suspended until such matter is resolved.

                                   ARTICLE III

                  REPRESENTATIONS AND WARRANTIES OF THE COMPANY

     As a material inducement to the Investor to enter into this Agreement, the
Company hereby represents and warrants to the Investor that, except as set forth
on the Disclosure Schedules delivered by the Company to the Investor and
attached hereto, on and as of the date of this Agreement:

     SECTION 3.01. Organization and Standing. The Company and each of its
subsidiaries is a corporation duly organized, validly existing and in good
standing under the laws of the jurisdiction of its incorporation and has all
requisite corporate power and authority necessary for it to own its properties
and assets and to carry on its business as it is now being conducted (and, to
the extent described therein, as described in the SEC Reports). The Company and
each of its subsidiaries is duly qualified to transact business and is in good
standing in each foreign jurisdiction in which the character of the properties
owned or leased by it or the nature of its businesses makes such qualification
necessary, except where the failure to so qualify or be in good standing would
not have a material adverse effect on the business, assets, operations,
properties or condition (financial or otherwise) of the Company and its
subsidiaries, taken as a whole, or any adverse effect on the Company's ability
to consummate the transactions contemplated by, or to execute, deliver and
perform its obligations under, each of the Transaction Documents (a "Material
Adverse Effect").

     SECTION 3.02. Securities of the Company. The authorized Capital Stock of
the Company consists of 100,000,000 shares of Common Stock and 10,000,000 shares
of preferred stock; as of November 21, 2001, 41,406,481 shares of Common Stock,
12,500 shares of Series A Preferred Stock and 37,500 shares of Series B
Preferred Stock were outstanding and 14,592,276 shares of Common Stock were
reserved for issuance upon exercise of outstanding convertible securities,
warrants or options or pursuant to the Company's 2001 Stock Incentive Plan, 2001
Employee Stock Purchase Plan, 1997 Directors' Stock Option Plan, 1995 Coulter
Pharmaceutical, Inc. Equity Incentive Plan, 1996 Coulter Pharmaceutical, Inc.
Employee Stock Purchase Plan, 1996 Genquest, Inc. Stock Option Plan, 1988
Anergen, Inc. Stock Option Plan, 1992 Anergen, Inc. Consultant Plan, 1995
Anergen, Inc. Director Option Plan, 1986 Ribi Immunochem Research, Inc. Stock
Option

                                       11
<PAGE>

Plan, 1996 Ribi Immunochem Research, Inc. Director Option Plan and 1996 Ribi
Immunochem Research, Inc. Stock Option Plan (the "Plans"). Except as set forth
in the SEC Reports, the Company has no other authorized, issued or outstanding
equity securities or securities containing any equity features, or any other
securities convertible into, exchangeable for or entitling any person to
otherwise acquire any other securities of the Company containing any equity
features. The Company has no stock option, incentive or similar plan other than
the Plans. All of the outstanding shares of Capital Stock of the Company have
been duly and validly authorized and issued, and are fully paid and
nonassessable. The Common Shares (in an amount up to the Maximum Share Amount)
have been duly and validly authorized and have been duly reserved for issuance,
and will remain available for issuance, pursuant to this Agreement. When issued
against payment therefore as provided in this Agreement, the Common Shares will
be validly issued, fully paid and nonassessable, free and clear of all
preemptive rights, claims, liens, charges, encumbrances and security interests
of any nature whatsoever. Except as set forth in this Section 3.02 or the SEC
Reports, there are no outstanding options, warrants, conversion rights,
subscription rights, preemptive rights, rights of first refusal or other rights
or agreements of any nature outstanding to subscribe for or to purchase any
shares of Common Stock of the Company or any other securities of the Company of
any kind binding on the Company. The issuance of the Common Shares pursuant to
this Agreement is not subject to any preemptive rights, rights of first refusal
or other similar limitation. Except as otherwise required by law, there are no
restrictions upon the voting or transfer of any shares of the Company's Common
Stock pursuant to the Company's Certificate of Incorporation or bylaws. Except
as provided herein or in the other Transaction Documents, there are no
agreements or other obligations (contingent or otherwise) that may require the
Company to repurchase or otherwise acquire any shares of its Common Stock.

     SECTION 3.03. Authorization; Enforceability. The Company has the corporate
power and authority to execute, deliver and perform the terms and provisions of
each of the Transaction Documents to be executed, delivered or performed by it
and has taken all necessary corporate action to authorize the execution,
delivery and performance by it of, and the consummation of the transactions
contemplated by, the Transaction Documents. No other corporate proceeding on the
part of the Company is necessary, and no consent of any shareholder of the
Company is required, for the valid execution and delivery by the Company of the
Transaction Documents, and the performance and consummation by the Company of
the transactions contemplated by the Transaction Documents to be performed by
the Company. The Company has duly executed and delivered, or concurrently
herewith is executing and delivering, each of the Transaction Documents.
Assuming the due execution of

                                       12
<PAGE>

this Agreement and the Registration Rights Agreement by the Investor, this
Agreement and the Registration Rights Agreement constitute the valid and binding
obligations of the Company, enforceable against the Company in accordance with
each of their respective terms, except as enforceability may be limited by
applicable bankruptcy, insolvency, reorganization, moratorium or similar laws
affecting the enforcement of creditors' rights generally and by general
principles of equity (regardless of whether enforcement is sought in a
proceeding in equity or at law).

     SECTION 3.04. No Violation; Consents.

     (a) The execution, delivery and performance by the Company of the
Transaction Documents and the consummation of the transactions contemplated
thereby to be performed by the Company do not and will not (i) contravene the
applicable provisions of any law, statute, rule, regulation, order, writ,
injunction, judgment or decree of any court or Governmental Authority to or by
which the Company or any of its subsidiaries or any of its respective property
or assets is bound, (ii) violate, result in a breach of or constitute (with due
notice or lapse of time or both) a default or give rise to an event of
acceleration under any contract, lease, loan or credit agreement, mortgage,
security agreement, trust indenture or other agreement or instrument to which
the Company is a party or by which it or any of its subsidiaries is bound or to
which any of its respective properties or assets is subject, nor result in the
creation or imposition of any lien, security interest, charge or encumbrance of
any kind upon any of the properties, assets or Capital Stock of the Company or
any of its subsidiaries, or (iii) violate any provision of the organizational
and other governing documents of the Company or any of its subsidiaries.

     (b) No consent, approval, authorization or order of, or filing or
registration with, any court or Governmental Authority or other Person is
required to be obtained or made by the Company for the execution, delivery and
performance of the Transaction Documents or the consummation of any of the
transactions contemplated thereby (other than (i) the registration of the resale
of the Common Shares with the Commission and (ii) the filing of a Form D with
the Commission and compliance with any state "blue sky" laws as contemplated by
the Registration Rights Agreement, except for those consents or authorizations
previously obtained and those filings previously made.

     SECTION 3.05. Securities Act Representations. The Company has not offered
or sold and will not offer or sell any shares of its Capital Stock in this
offering other than to the Investor. Assuming the accuracy of the Investor's
representations pursuant to Section 4.02 hereof, the sale of the Common Shares
hereunder

                                       13
<PAGE>

will be exempt from the registration requirements of the Securities Act. Neither
the Company, nor any of its Affiliates, or, to its knowledge, any Person acting
on its or their behalf has engaged in any form of general solicitation or
general advertising (within the meaning of Regulation D under the Securities
Act) in connection with the offer or sale of the Common Shares hereunder.
Neither the Company, nor any of its Affiliates, nor any Person acting on its or
their behalf has, directly or indirectly, made any offers or sales of any
security or solicited any offers to buy any security other than pursuant to this
Agreement under circumstances that would require registration under the
Securities Act of the Common Shares to be issued under this Agreement. The
Company is eligible to use Form S-3 under the Securities Act to file the
Registration Statement (as defined in the Registration Rights Agreement). The
Company has not provided the Investor with any material non-public information
that, according to applicable law, rule or regulation, should have been
disclosed publicly by the Company prior to engaging in the transactions
contemplated by the Transaction Documents but that has not been so disclosed.

     SECTION 3.06. Solvency; No Default. (a) The Company is, and upon giving
effect to the transactions contemplated hereby to be performed by it as of the
Closing will be, Solvent. "Solvent" means that, as of the date of determination,
(i) the then fair saleable value of the assets of the Company (on a consolidated
basis) exceeds the then total amount (on a consolidated basis) of its debts and
other liabilities (including any guarantees and other contingent, subordinated,
unmatured or unliquidated liabilities whether or not reduced to judgment,
disputed or undisputed, secured or unsecured), (ii) the Company has sufficient
funds and cash flow to pay its liability on its existing debts as they become
absolute and matured without taking into account future lease payments under
operating leases or payments due one year or more after the date of this
Agreement under financing leases, (iii) final judgments against the Company in
pending or, to the Company's knowledge, threatened actions for money damages
will not be rendered at a time when, or in an amount such that, the Company will
be unable to satisfy any such judgments promptly in accordance with their terms
(taking into account (a) the maximum reasonable amount of such judgments in any
such actions (other than amounts that would be remote), (b) the earliest
reasonable time at which such judgments would be rendered and (c) any reasonably
expected insurance recovery with respect thereto), and (iv) the Company does not
have unreasonably small capital with which to engage in its present business.

     (b) The Company is not, and immediately after the consummation of the
transactions contemplated hereby to be performed by the Company will not be, in
default of (whether upon the passage of time, the giving of notice or both) its

                                       14
<PAGE>

organizational and other governing documents, or any provision of any security
issued by the Company, or of any agreement, instrument or other undertaking to
which the Company is a party or by which it or any of its property or assets is
bound, or the applicable provisions of any law, statute, rule, regulation,
order, writ, injunction, judgment or decree of any court or Governmental
Authority to or by which the Company or any of its property or assets is bound,
which default or violation, either individually or in the aggregate, could
reasonably be expected to have a Material Adverse Effect.

     SECTION 3.07. No Brokers. Other than Shoreline Pacific, LLC, no broker,
finder, agent or similar intermediary is entitled to any broker's, finder's,
placement or similar fee or other commission in connection with the transactions
contemplated hereby based on any agreement, arrangement or understanding with
the Company.

     SECTION 3.08. SEC Reports; Financial Condition; No Adverse Changes. (a) The
audited consolidated financial statements of the Company and the related notes
thereto as of December 31, 2000 reported on by Ernst & Young LLP, independent
auditors, contained in the SEC Reports, present fairly the consolidated
financial position, results of operations and cash flows of the Company at such
date and for the periods set forth therein. The unaudited consolidated financial
statements of the Company and related notes thereto as of March 31, 2001, June
30, 2001 and September 30, 2001 (such audited and unaudited financial
statements, collectively, the "Financial Statements") contained in the SEC
Reports present fairly the consolidated financial position, results of
operations and cash flows of the Company at such date and for the periods set
forth therein. The Financial Statements, including the related schedules and
notes thereto, have been prepared in accordance with generally accepted
accounting principles in the United States as in effect on the date of filing of
such documents with the Commission, applied on a consistent basis (except for
changes concurred in by the Company's independent public auditors) unless
otherwise expressly stated therein. Except as disclosed in the SEC Reports, from
and after September 30, 2001, there has been no sale, transfer or other
disposition by the Company of any material part of the business, property or
securities of the Company (other than the grant of options and warrants and
shares of Common Stock issued upon the exercise of outstanding options and
warrants) and no purchase or other acquisition of any business, property or
securities by the Company material in relation to the financial condition of the
Company.

     (b) Except as are fully reflected or reserved against in the Financial
Statements and the notes thereto, there are no liabilities or obligations with
respect to the Company or any of

                                       15
<PAGE>

its subsidiaries of any nature whatsoever (whether absolute, accrued, contingent
or otherwise and whether or not due) that, either individually or in the
aggregate, after taking into account (a) the maximum reasonable amount of any
liability that may arise on account of any litigation or any other contingent
liability or obligation (other than amounts that would be remote), (b) the
earliest reasonable time at which any such liability or obligation may become
due and (c) any reasonably expected insurance recovery with respect thereto,
could reasonably be expected to have a Material Adverse Effect.

     (c) Since September 30, 2001, except as set forth in the SEC Reports, there
has been no development or event, nor any prospective development or event known
to the Company or any of its subsidiaries, or any litigation, proceeding or
other action seeking an injunction or other restraining order, damages or other
relief from a court or administrative agency of competent jurisdiction pending,
threatened or, to the knowledge of the Company, contemplated, or any action of
any Governmental Authority, that has had or could reasonably be expected to have
a Material Adverse Effect.

     SECTION 3.09. Use of Proceeds; Federal Regulations. No part of the net
proceeds from the sale of the Common Stock issued hereunder will be used in a
manner that would violate the provisions of Regulation T, U or X of the Board of
Governors of the Federal Reserve System. The Company will not use such proceeds
other than for or in connection with general working capital purposes.

     SECTION  3.10.  Subsidiaries.  The Company has no  subsidiaries  other than
those set forth in the SEC Reports or those that conduct no active business.

     SECTION 3.11. No Integrated Offering. Neither the Company, nor any of its
Affiliates, nor to its knowledge any Person acting on its or their behalf, has,
directly or indirectly, made any offers or sales of any security or solicited
any offers to buy any security under circumstances that would require
registration under the Securities Act of the offer and sale of the Common Stock
hereunder.

     SECTION 3.12. No Litigation. Except as disclosed in the SEC Reports, no
litigation or claim (including those for unpaid taxes), or environmental
proceeding against the Company or any of its subsidiaries is pending, threatened
or, to the Company's best knowledge, contemplated that, if determined adversely,
would (after taking into consideration any reasonably expected insurance
recovery with respect thereto) have a Material Adverse Effect on the Company.

                                       16
<PAGE>

     SECTION 3.13. Environmental Matters. The Company and each of its
subsidiaries is in compliance in all material respects with all applicable state
and federal environmental laws, and no event or condition has occurred that may
interfere in any material respect with the compliance by the Company or any of
its subsidiaries with any environmental law or that may give rise to any
liability under any environmental law that, individually or in the aggregate,
would have a Material Adverse Effect.

     SECTION 3.14. Intellectual Property. The Company (and/or its subsidiaries)
owns or has licenses to use certain patents, copyrights and trademarks
("intellectual property") associated with its business. The Company and its
subsidiaries have all intellectual property rights that are needed to conduct
the business of the Company and its subsidiaries as it is now being conducted as
disclosed in the SEC Reports. To the Company's knowledge, the intellectual
property rights that the Company (and/or its subsidiaries) owns are valid and
enforceable. To the Company's knowledge, the use of such intellectual property
by the Company (and/or its subsidiaries') does not infringe upon or conflict
with any right of any third party, and, except as disclosed in the SEC Reports
neither the Company nor any of its subsidiaries has received notice, written or
otherwise, of any such infringement or conflict other than with respect to
alleged infringements or conflicts that, individually or in the aggregate, if
determined adversely to the Company would not have a Material Adverse Effect.
Except as set forth in the SEC Reports, the Company has no knowledge of any
infringement of its (and/or its subsidiaries) intellectual property by any third
party.

     SECTION 3.15. Insurance. The Company and each of its subsidiaries are
insured by insurers of recognized financial responsibility against such losses
and risks and in such amounts as management of the Company believes to be
prudent. The Company has no reason to believe that it and its subsidiaries will
not be able to renew its existing insurance coverage as and when such coverage
expires or to obtain similar coverage from similar insurers as may be necessary
to continue its business without a significant increase in cost.

     SECTION 3.16. Related Party Transactions. Except as disclosed in the SEC
Reports and except for such transactions for which disclosure pursuant to
Regulation S-K would not be required in an annual report on Form 10-K or another
report required to be filed by the Company under the Exchange Act, none of the
officers, directors, employees or 5% or greater shareholders of the Company is
presently a party to any transaction with the Company or any of its subsidiaries
(other than for services as employees, officers and directors), including any
contract, agreement or other arrangement providing for the furnishing of

                                       17
<PAGE>

services to or by, providing for rental of real or personal property to or from,
or the advances of money or otherwise requiring payments to or from any such
officer, director, employee or shareholder or, to the knowledge of the Company,
any corporation, partnership, trust or other entity in which any such officer,
director, employee or shareholder has a substantial interest or is an officer,
director, trustee or partner with an affiliated company.

     SECTION 3.17. Permits. The Company and each of its subsidiaries is in
possession of all franchises, grants, authorizations, licenses, permits,
easements, variances, exemptions, consents, certificates, approvals and orders
necessary to own, lease and operate its properties and to carry on its business
as it is now being conducted (collectively, the "Company Permits"), and there is
no action pending or, to the knowledge of the Company, threatened regarding
suspension or cancellation of any of the Company Permits except for such Company
Permits the failure of which to possess, or the cancellation or suspension of
which, would not, individually or in the aggregate, have a Material Adverse
Effect. Neither the Company nor any of its subsidiaries is in conflict with, or
in default or violation of, any of the Company Permits that individually or in
the aggregate could reasonably be expected to have a Material Adverse Effect.

     SECTION 3.18. Internal Accounting Controls. The Company and each of its
subsidiaries maintain a system of internal accounting controls sufficient in the
judgment of the Company's Board of Directors to provide reasonable assurance
that (i) transactions are executed in accordance with management's general or
specific authorizations, (ii) transactions are recorded as necessary to permit
preparation of financial statements in conformity with generally accepted
accounting principles and to maintain asset accountability, (iii) access to
assets is permitted only in accordance with management's general or specific
authorization and (iv) the recorded accountability for assets is compared with
the existing assets at reasonable intervals and appropriate action is taken with
respect to any differences.

     SECTION 3.19. Tax Returns. The Company has filed or caused to be filed all
Federal tax returns and all material state and local tax returns required to
have been filed by it and has paid or caused to be paid all taxes shown to be
due and payable by it on such returns or on any assessments received by it,
except any such tax, the validity or amount of which is being contested in good
faith by appropriate proceedings and as to which the Company has set aside on
its books adequate reserves with respect thereto in accordance with generally
accepted accounting principles. Neither the Company nor its subsidiaries has
received any tax

                                       18
<PAGE>

assessment, notice of audit, notice of proposed adjustment or deficiency notice
from any taxing authority.

     SECTION 3.20. Disclosure. The representations and warranties of the Company
in this Agreement and the statements contained in the SEC Reports (at the time
they were filed with the SEC and, except as modified by subsequent SEC Reports)
and the schedules, certificates and exhibits furnished to the Investor by or on
behalf of the Company in connection herewith did not and do not contain any
untrue statement of a material fact and do not omit to state any material fact
necessary to make the statements herein or therein not misleading. The SEC
Reports contain all material information concerning the Company required to be
set forth therein, and no event or circumstance has occurred or exists since
September 30, 2001, that would require the Company to disclose such event or
circumstance in order to make the statements in the SEC Reports not misleading
as of the date of the Closing that has not been so disclosed. The Company hereby
acknowledges that the Investor is and will be relying on the SEC Reports and the
Company's representations, warranties and covenants contained herein in making
an investment decision with respect to the Common Shares and will be relying
thereon (together with future reports filed with the Commission) in connection
with any transfer of Common Shares.

                                   ARTICLE IV

            REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE INVESTOR

     The Investor hereby acknowledges, represents, warrants and covenants, to
the Company as follows:

SECTION 4.01. Authorization; Enforceability; No Violations; Consents.

     (a) The Investor is duly organized, validly existing and in good standing
under the laws of its jurisdiction, has all requisite power and authority to
execute, deliver and perform the terms and provisions of this Agreement and the
Registration Rights Agreement and has taken all necessary action to authorize
the execution, delivery and performance by it of this Agreement and the
Registration Rights Agreement and to consummate the transactions contemplated
hereby and thereby to be performed by it.

     (b) The execution, delivery and performance by the Investor of this
Agreement and the Registration Rights Agreement and the consummation by the
Investor of the transactions contemplated hereby and thereby to be performed by
it do not and will not violate any provision of (i) the Investor's
organizational documents or (ii) any law, statute, rule, regulation, order,

                                       19
<PAGE>

writ, injunction, judgment or decree to which the Investor is subject. The
Investor has duly executed and delivered this Agreement and has executed and
delivered, or concurrently herewith is executing and delivering, the
Registration Rights Agreement. Assuming the due execution hereof and thereof by
the Company, each of this Agreement and the Registration Rights Agreement
constitutes the valid and binding obligation of the Investor, enforceable
against the Investor in accordance with its terms, except as enforceability may
be limited by applicable bankruptcy, insolvency, reorganization, moratorium or
similar laws affecting the enforcement of creditors' rights generally and by
general principles of equity (regardless of whether enforcement is sought in a
proceeding in equity or at law).

     (c) No consent, approval, authorization or order of, or filing or
registration with, any court or Governmental Authority or other Person,
including the National Association of Securities Dealers, is required to be
obtained or made by the Purchaser for the execution, delivery and performance of
the transactions contemplated thereby, except for those consents or
authorizations previously obtained and those filings previously made.

     SECTION 4.02. Securities Act Representations; Legends.

     (a) The Investor understands that: (i) the offering and sale of the Common
Shares to be issued and sold hereunder is intended to be exempt from the
registration requirements of the Securities Act; (ii) the initial offer and sale
of the Common Shares issuable hereunder has not been registered under the
Securities Act or any other applicable securities laws and such securities may
be resold only if registered under the Securities Act and any other applicable
securities laws or if an exemption from such registration requirements is
available; and (iii) the Company is required to register any resale of the
Common Shares under the Securities Act and any other applicable securities laws
only to the extent provided in the Registration Rights Agreement.

     (b) The Investor represents that the Common Shares to be acquired by the
Investor pursuant to this Agreement are being acquired for its own account and
not with a view to, or for sale in connection with, any distribution thereof or
(other than the resale of such Common Shares pursuant to an effective
registration statement as contemplated by the Registration Rights Agreement) in
violation of the Securities Act or any other securities laws that may be
applicable.

     (c) The Investor represents that the Investor is not an affiliate (as such
term is defined in the Securities Act) of the Company.

                                       20
<PAGE>

     (d) The Investor represents that the Investor (i) is an "accredited
investor" as that term is defined in Rule 501(a) of Regulation D under the
Securities Act, (ii) has sufficient knowledge and experience in financial and
business matters so as to be capable of evaluating the merits and risks of its
investment in the Common Stock and is capable of bearing the economic risks of
such investment, including a complete loss of its investment in the Common
Shares; (iii) believes that its investment in the Common Shares is suitable for
it based upon its objectives and financial needs, and the Investor has adequate
means for providing for its current financial needs and business contingencies
and has no present need for liquidity of investment with respect to the Common
Shares; and (iv) has not purchased, sold or entered into any put option, short
position or similar arrangement with respect to the Common Shares, and will not,
for the term of this Agreement purchase, sell or enter into any such put option,
short position or similar arrangement in any manner that violates the provisions
of the Securities Act or the Exchange Act.

     (e) The Investor acknowledges that no oral or written statements or
representations have been made to the Investor by or on behalf of the Company in
connection with the offering and sale of the Common Shares hereunder other than
those set forth in the SEC Reports, or as set forth herein or in the other
Transaction Documents, and the Investor represents that it is not subscribing
for the Common Shares as a result of, or in response to, any advertisement,
article, notice or other communication published in any newspaper, magazine or
similar media or broadcast over television or radio, or presented at any seminar
or meeting.

     (f) The Investor acknowledges that the Securities Act restricts the
transferability of securities, such as the Common Shares, issued in reliance
upon the exemption from the registration requirements of the Securities Act
provided by Section 4(2) thereunder, and that, unless sold pursuant to the
Registration Statement, the transfer of such Common Shares is restricted.

     (g) The Investor has been furnished with all materials relating to the
business, finances and operations of the Company and materials relating to the
offer and sale of the Common Shares which have been requested by the Investor.
The Investor has been afforded the opportunity to ask questions of the Company.
The Investor understands that its investment in the Common Shares involves a
significant degree of risk.

     SECTION 4.03. No Brokers. No broker, finder, agent or similar intermediary
is entitled to any broker's, finder's, placement or similar fee or other
commission in connection with

                                       21
<PAGE>

the transactions contemplated hereby based on any agreement, arrangement or
understanding with the Investor.

     SECTION 4.04. Trading Guidelines. The Investor has the right to sell shares
of Common Stock during and after the Commitment Period. The Investor agrees,
however, that during the Commitment Period, the Investor will not directly or
indirectly offer to sell, contract to sell or otherwise sell, dispose of, loan,
pledge or grant any rights with respect to any shares of Common Stock other than
(i) the shares of Common Stock which the Investor has purchased under this
Agreement or (ii) shares of Common Stock that the Investor already holds prior
to such offer, contract, sale, loan or pledge (including for this purpose, in
the case of a Draw Down Notice that has been delivered, the number of Draw Down
Shares issuable in connection with such Draw Down Notice (assuming that the
number of Draw Down Shares to be issued pursuant to such Draw Down Notice equals
the Investment Amount specified in such Draw Down Notice divided by ninety-eight
percent (98%) of the Floor Price)). The Investor further agrees to use
commercially reasonable efforts to ensure that its affiliates comply with the
foregoing restrictions.

                                    ARTICLE V

                                    COVENANTS

     SECTION 5.01. Exemption from Registration; Limitation on Issuance of
Securities.

     The Company will not make any offer to sell, solicit any offer to buy,
agree to sell or sell any security or right to acquire any security, except at
such time and in such manner so as not to cause the loss of any of the
exemptions for the offer and sale of the Common Shares from the registration
requirements under the Securities Act or under the securities or "blue sky" laws
of any jurisdiction in which such offer, sale or issuance is made.

     SECTION 5.02. Transfer Restrictions.

     The Investor acknowledges that any proposed offer, sale, pledge or other
transfer of Common Shares prior to the date that is two (2) years from the date
of issuance (or such other date as may be required pursuant to Rule 144 under
the Securities Act (or similar successor provision) as in effect from time to
time), in the absence of registration under the Securities Act, is limited.
Accordingly, prior to such passage of time or such registration, the Common
Shares may be offered, sold, pledged or otherwise transferred only (i) to the
Company, (ii) in an offshore transaction in accordance with Rule 904 under the
Securities Act,

                                       22
<PAGE>

(iii) pursuant to any other exemption from registration provided by the
Securities Act, (iv) pursuant to Rule 144 under the Securities Act or (v)
pursuant to an effective registration statement under the Securities Act; in the
case of any transfer pursuant to clause (ii) or (iii), the Company shall be
entitled to receive an opinion of the selling Investor's counsel, in form and
substance reasonably satisfactory to the Company, to the effect that
registration is not required in connection with such disposition.

     SECTION 5.03. Reservation of Common Shares. The Company shall at all times
reserve and keep available, free from preemptive rights, out of its authorized
but unissued shares of Common Stock or its issued shares of Common Stock held in
its treasury, or both, 8,200,000 shares of Common Stock (less the number of
Common Shares previously issued hereunder) to provide for the issuance of the
Common Shares to be issued hereunder.

     SECTION 5.04. Stock Listing. The Company shall have the 8,200,000 shares of
Common Stock approved for quotation or listing, prior to issuance, upon the
Principal Market upon which the Common Stock is listed or traded at the time of
issuance of such Common Shares and shall use its best efforts to maintain such
listing.

     SECTION 5.05. Reporting Status. The Company's Common Stock is registered
under Section 12(g) of the Exchange Act. So long as the Investor beneficially
owns any Registrable Securities, the Company shall timely file all reports
required to be filed with the SEC pursuant to the Exchange Act, and the Company
shall not terminate its status as an issuer required to file reports under the
Exchange Act even if the Exchange Act or the rules and regulations thereunder
would permit such termination.

     SECTION 5.06. No Integration. The Company shall not make any offers or
sales of any security (other than the Common Shares) under circumstances that
would require registration of the Common Shares being offered or sold hereunder
under the Securities Act.

     SECTION 5.07. Registration Rights. The Company shall cause the Registration
Rights Agreement to remain in full force and effect and the Company shall comply
in all respects with the terms thereof.

     SECTION 5.08. Issuance of Draw Down Shares. The sale and issuance of the
Draw Down Shares shall be made in accordance with the provisions and
requirements of Section 4(2) of the Securities Act and any applicable state law.

                                   ARTICLE VI

                                       23
<PAGE>

                       CONDITIONS TO DELIVERY OF DRAW DOWN

                      NOTICES AND CONDITIONS TO SETTLEMENT

     SECTION 6.01. Conditions Precedent to the Obligation of the Company to
Issue and Sell Common Stock. The obligation hereunder of the Company to issue
and sell the Draw Down Shares to the Investor incident to each Settlement is
subject to the satisfaction, at or before each such Settlement, of each of the
conditions set forth below.

     (a) Accuracy of the Investor's Representation and Warranties. The
representations and warranties of the Investor shall be true and correct in all
material respects as of the date when made and as of the date of each such
Settlement as though made at each such time (except for representations and
warranties specifically made as of a particular date which shall be true and
correct in all material respects as of the date when made).

     (b) Performance by the Investor. The Investor shall have performed,
satisfied and complied in all respects with all covenants, agreements and
conditions required by this Agreement to be performed, satisfied or complied
with by the Investor at or prior to such Settlement.

     SECTION 6.02. Conditions Precedent to the Right of the Company to Deliver a
Draw Down Notice. The right of the Company to deliver a Draw Down Notice
hereunder is subject to the satisfaction, on the date of delivery of such Draw
Down Notice, of each of the following conditions:

     (a) Effective Registration Statement. (I) As set forth in the Registration
Rights Agreement, the Registration Statement shall have previously been declared
effective and shall remain effective and sales of all of the Registrable
Securities (including all of the Draw Down Shares issued with respect to all
prior Draw Downs and all of the Draw Down Shares expected to be issued in
connection with the Draw Down specified by the current Draw Down Notice
(assuming for such purpose that the Purchase Price applicable to such Draw Down
is the Floor Price)) may be made by the Investor thereunder and (i) neither the
Company nor the Investor shall have received notice that the Commission has
issued or intends to issue a stop order with respect to the Registration
Statement or that the Commission otherwise has suspended or withdrawn the
effectiveness of the Registration Statement, either temporarily or permanently,
or intends or has threatened to do so, (ii) no other suspension of the use or
withdrawal of the effectiveness of the Registration Statement or related
prospectus shall exist and (iii) no event specified in Section 2.1(e) of the
Registration Rights Agreement shall have occurred and be continuing.

                                       24
<PAGE>

     (II) The Company shall not have failed to obtain effectiveness of the
Registration Statement within 90 days from the Closing Date, and the
Registration Statement, after its initial effectiveness, shall not have lapsed
in effect such that sales of all of the Registrable Securities otherwise cannot
be made thereunder (whether by reason of the Company's failure to amend or
supplement the prospectus included therein in accordance with the Registration
Rights Agreement or otherwise) for more than thirty (30) consecutive Trading
Days or more than ninety (90) Trading Days in any twelve (12) month period after
the Registration Statement becomes effective;

     (b) Accuracy of the Company's Representations and Warranties. The
representations and warranties of the Company shall be true and correct in all
material respects as of the date when made and as of the applicable Draw Down
Date as though made at such time (except for representations and warranties
specifically made as of a particular date which shall be true and correct in all
material respects as of the date when made).

     (c) Performance by the Company. (I) Subject to Section 2.05, the Company
shall have performed, satisfied and complied in all material respects with all
covenants, agreements and conditions required by this Agreement and the
Registration Rights Agreement to be performed, satisfied or complied with by the
Company at or prior to such date, nor shall there have occurred an Event of
Default under this Agreement.

     (II) The Company shall not have (i) failed to issue shares of Common Stock
to the Investor on any Settlement Date as provided herein, (ii) failed to remove
any restrictive legend (or to withdraw any stop transfer instructions in respect
thereof) on any certificate or any shares of Common Stock issued to the Investor
on any Settlement Date as and when required by this Agreement or the
Registration Rights Agreement, or (iii) failed to fulfill its obligations
pursuant to this Agreement (or made any announcement, statement or threat that
it does not intend to honor the obligations described in this paragraph), and
any such failure shall continue uncured (or any announcement, statement or
threat not to honor its obligations shall not be rescinded in writing) for five
(5) days after the Company shall have been notified thereof in writing by the
Investor; provided that notice in respect of a breach pursuant to clause (i)
shall not be given if and so long as the Company, shall not have delivered
shares on a Settlement Date and (A) shall not have paid the Investor actual
damages resulting there from within the 30-day period following the Settlement
Date or (B) shall have paid the Investor actual damages resulting there from but
shall have disputed the Investor's determination thereof, during the 90-day
period following payment, in each case as contemplated by Section 2.05(c).

                                       25
<PAGE>

     (d) No Injunction. No statute, rule, regulation, executive order, decree,
ruling or injunction shall have been enacted, entered, promulgated or endorsed
by any court or governmental authority of competent jurisdiction or any
self-regulatory organization having authority over the matters contemplated
hereby that prohibits or directly and adversely affects any of the transactions
contemplated by this Agreement, and no proceeding shall have been commenced that
may have the effect of prohibiting or adversely affecting any of the
transactions contemplated by this Agreement.

     (e) Material Adverse Changes. For the thirty (30) days preceding the date
of delivery of such Draw Down Notice, no event known to the Company that had or
is reasonably likely to have a Material Adverse Effect shall have occurred
(provided that any changes resulting from general economic or market conditions
or conditions affecting the biopharmaceutical industry in general or
fluctuations in the market price of the Company's Common Stock shall not be
deemed to constitute a "Material Adverse Effect" for purposes hereof).

     (f) No Suspension of Trading In or Delisting of Common Stock. The trading
of the Common Stock (including without limitation the Draw Down Shares) shall
not have been suspended by the Commission, the Principal Market or the NASD and
the Common Stock (including without limitation the Draw Down Shares) shall have
been approved for listing or quotation on and shall not have been delisted from
the Principal Market.

     (g) Comfort Letter. The Comfort Letter(s) in respect of the Registration
Statement, any Form 10-K covering the Company's most recently completed fiscal
year for which the Company has filed a Form 10-K or any Form 8-K containing
substantial financial information incorporated by reference into the
Registration Statement shall have been delivered prior to the date of delivery
of such Draw Down Notice, reasonably satisfactory in form and substance to the
Investors, and shall not have been rescinded.

     (h) No Knowledge. The Company shall have no knowledge of any event that
would reasonably be expected to have the effect of causing such Registration
Statement to be suspended or otherwise ineffective (which event is more likely
than not to occur within the Valuation Period for such Draw Down Notice).

     (i) Trading Cushion. The Valuation Period for any previous Draw-Down Notice
shall have expired.

     (j) Maximum Share Amount. In no event may the Company issue a Draw Down
Notice to sell (i) an Investment Amount to the extent that the sum of (x) the
number of shares of Common Stock

                                       26
<PAGE>

represented by the quotient of (a) the requested Investment Amount, divided by
(b) the Floor Price set forth in such Draw Down Notice, plus (y) the cumulative
total of all Common Shares issued under all previous Draw Downs effected
pursuant to this Agreement, would exceed the Maximum Share Amount or (iii) a
number of shares in excess of the Draw Down Share Limitation.

     (k) Prospectus Supplement. A supplement to the prospectus included in the
Registration Statement (the "Prospectus Supplement"), in form and substance to
be agreed upon by the parties, setting forth information regarding the Draw Down
including, without limitation, the Draw Down Date, the Investment Amount, the
number of shares sold to the Investor in connection with all previous Draw
Downs, if not previously disclosed in an SEC Document, and any additional
information required by SEC rules and regulations, including Item 507 of
Regulation S-K, shall have been filed with the Commission and sufficient copies
thereof delivered to the Investor on the Trading Day immediately following the
delivery of the Draw Down Notice.

     (l) Outside Counsel Letter. A letter of outside counsel with respect to the
Registration Statement, rendered in form and substance in which "10b-5" letters
are typically delivered, shall have been delivered, dated as of the date of
delivery, which date shall not be earlier than the later to occur of (i) the
effective date of the Registration Statement, (ii) the date of any filing of a
Form 8-K by the Company subsequent to the effective date of the Registration
Statement and (iii) the date of filing by the Company subsequent to the
effective date of the Registration Statement of an Annual Report on Form 10-K.

     SECTION 6.03. Documents Required to be Delivered on each Draw Down Date.
The Investor's obligation to purchase Common Shares pursuant to a Draw Down
hereunder shall additionally be conditioned upon the delivery to the Investor on
or before the Draw Down Date of a certificate in form and substance reasonably
satisfactory to the Investor, executed by an executive officer of the Company to
the effect that all conditions to the delivery of such Draw Down Notice shall
have been satisfied as at the date of such certificate (which certificate shall
not be required if the foregoing representations shall be set forth in the Draw
Down Notice).

     SECTION 6.04. Draw Down Cancellation.

     (a) Mechanics of Draw Down Cancellation. If at any time during a Valuation
Period, (i) any of the events specified in Section 5.09 of this Agreement shall
occur, (ii) any of the conditions precedent to a Draw Down set forth in Section
6.02 shall no longer be satisfied as of any date during the Valuation Period,
(iii) the Company discovers that the document referred to

                                       27
<PAGE>

in Section 6.03 or the Comfort Letter(s) would not be deliverable in the precise
form so delivered if delivered as of such date during the Valuation Period, or
(iv) the Company determines reasonably and in good faith that the issuance and
sale of Draw Down Shares during such Valuation Period could reasonably be
expected to have a significant adverse effect on the trading or market prices
for the Common Stock, then the Company shall cancel the Draw Down (a "Draw Down
Cancellation") immediately by delivering written notice to the Investor
specifying the reasons therefore (the "Draw Down Cancellation Notice"), by
facsimile (simultaneously sent by e-mail and with telephonic advice of the
sending (which requirement will be deemed satisfied by leaving of recorded
message)). The Draw Down Cancellation Notice shall be deemed delivered on (i)
the Trading Day it is received by facsimile or otherwise by the Investor if such
notice is received prior to 9:30 a.m., New York City time, or (ii) the
immediately succeeding Trading Day if it is received by facsimile or otherwise
after 9:30 a.m., New York City time, on a Trading Day, or at any time on a day
which is not a Trading Day. No Draw Down Cancellation Notice may be deemed
delivered on a day that is not a Trading Day. "Draw Down Cancellation Date"
shall be the date the Draw Down Cancellation Notice is deemed delivered pursuant
to the preceding sentence.

     (b) Effect of Draw Down Cancellation. If a Draw Down Cancellation Notice
has been delivered to the Investor after a Draw Down Date, the Valuation Period
for such Draw Down shall end on the Draw Down Cancellation Date. In such event,
the Investment Amount relating to such Draw Down shall be reduced by the Daily
Draw-Down Proportion with respect to each Trading Day during the period
beginning on and including the Draw Down Cancellation Date and ending on the
last Trading Day of such Valuation Period. Anytime a Draw Down Cancellation
Notice is delivered to the Investor, such Draw Down shall remain effective as to
the portion of the Investment Amount not canceled pursuant to the preceding
sentence. Notwithstanding anything to the contrary contained in Section 6.04 or
the delivery of a Draw Down Cancellation Notice under Section 6.04(a)(iv) or
otherwise, the Company shall remain obligated to issue and sell to the Investor
on the terms of this Agreement shares of Common Stock to satisfy any sales or
similar arrangement entered into by the Investor in connection with a Draw Down
Notice prior to the Draw Down Cancellation Date with respect thereto. The
Investor shall promptly notify the Company in writing of the number of shares
which the Company shall be obligated to deliver with respect to any Draw Down
Notice that is the subject of a Draw Down Cancellation Notice.

                                   ARTICLE VII

                                   TERMINATION

                                       28
<PAGE>

     SECTION 7.01. Term. Subject to the provisions of Section 7.02, the term of
this Agreement shall run until the end of the Commitment Period. Notwithstanding
the foregoing, the Company may terminate this Agreement at any time provided
that, simultaneously with such termination, it shall make any payment required
by Section 9.13.

     SECTION 7.02. Termination by the Investor. The Investor may terminate the
right of the Company to effect any Draw Downs under this Agreement upon one (i)
Trading Day's notice if any of the following events (each, an "Event of
Default") shall occur:

     (a) The Company or any subsidiary shall make an assignment for the benefit
of creditors, or apply for or consent to the appointment of a receiver or
trustee for it or for all or substantially all of its property or business; or
such a receiver or trustee shall otherwise be appointed;

     (b) Bankruptcy, insolvency, reorganization or liquidation proceedings or
other proceedings for relief under any bankruptcy law or any law for the relief
of debtors shall be instituted by or against the Company or any subsidiary of
the Company;

     (c) The Company shall fail to maintain the listing of the Common Stock on a
Principal Market or trading in such Common Stock shall otherwise be halted or
suspended for a period of ten (10) consecutive Trading Days;

     (d) The Registration Statement shall not have been declared effective by
the Commission on or before the date which is 90 days from the date of this
Agreement; or

     (e) a Change of Control shall have occurred.

                                  ARTICLE VIII

                NON-DISCLOSURE OF MATERIAL NON-PUBLIC INFORMATION

     SECTION 8.01. Non-Disclosure of Material Non-Public Information.

     (a) The Company covenants and agrees that it shall refrain from disclosing,
and shall cause its officers, directors, employees and agents to refrain from
disclosing, any material non-public information to the Investor without also
disseminating such information to the public, unless prior to disclosure of such
information the Company identifies such information as being material non-public
information and provides the Investor and its advisors and representatives with
the opportunity to accept or refuse to accept such material non-public
information for review.

                                       29
<PAGE>

     (b) The Company acknowledges and understands that the Investor is entering
into this Agreement and the Registration Rights Agreement at the request of the
Company and in good faith reliance on the Company's representation set forth in
Section 3.05 of this Agreement that the Company has not provided the Investor
with any material non-public information that, according to applicable law, rule
or regulation, should have been disclosed publicly by the Company prior to
engaging in the transactions contemplated by the Transaction Documents but that
has not been so disclosed.

                                   ARTICLE IX

                                  MISCELLANEOUS

     SECTION 9.01. Press Releases and Disclosure. The Company shall issue a
press release describing the material terms of the transactions contemplated
hereby as soon as practicable following the Closing Date, and shall file with
the Commission a Current Report on Form 8-K describing the material terms of the
transactions contemplated hereby. No party hereto shall issue any press release
or make any other public disclosure related to this Agreement or any of the
transactions contemplated hereby without the prior written approval of the other
party hereto, except as may be necessary or appropriate in the opinion of the
party seeking to make disclosure to comply with the requirements of applicable
law or stock exchange rules. If any such press release or public disclosure is
so required, the party making such disclosure shall consult with the other party
prior to making such disclosure, and the parties shall use all reasonable
efforts, acting in good faith, to agree upon a text for such disclosure that is
satisfactory to all parties.

     SECTION 9.02. Expenses. The Company will pay the reasonable attorneys' fees
and expenses of the Investor in connection with the negotiation of the
Transaction Documents subject to a maximum of $30,000 payable at the Closing
unless the Company agrees otherwise.

     SECTION 9.03. Notices. All notices, demands, requests, consents, approvals
or other communications required or permitted to be given hereunder or that are
given with respect to this Agreement shall be in writing and shall be personally
served or deposited in the mail, registered or certified, return receipt
requested, postage prepaid or delivered by reputable air courier service with
charges prepaid, or transmitted by hand delivery, telegram, telex or facsimile,
addressed as set forth below, or to such other address as such party shall have
specified most recently by written notice: (i) if to the Company to: Corixa
Corporation, 1124 Columbia Street, Seattle WA 98104, Attention: Michelle Burris,
Sr. Vice President and Chief Financial Officer;

                                       30
<PAGE>

Facsimile No.: 206-754-5994 with copies (which shall not constitute notice) to:
Orrick, Herrington & Sutcliffe LLP, 719 Second Avenue, Suite 900, Seattle, WA
98104, Attention: Stephen M. Graham and Alan C. Smith; Facsimile No.:
206-839-4301; and (ii) if to the Investor, BNY Capital Markets, Inc., 32 Old
Slip (15th Floor), New York, NY 10286, Attention: Raymond Lang, Managing
Director; Facsimile No.: 212-804-5052, with copies (which shall not constitute
notice) to: Latham & Watkins, 885 Third Avenue, Suite 1000, New York, New York
10022, Attention: Robert A. Zuccaro, Esq.; Facsimile No.: 212-751-4864. Notice
shall be deemed given on the date of service or transmission if personally
served or transmitted by telegram, telex or facsimile. Notice otherwise sent as
provided herein shall be deemed given on the third business day following the
date mailed or on the next business day following delivery of such notice to a
reputable air courier service.

     SECTION 9.04. Entire Agreement. This Agreement (together with the other
Transaction Documents and all other documents delivered pursuant hereto and
thereto) constitutes the entire agreement of the parties with respect to the
subject matter hereof and supersedes all prior and contemporaneous agreements,
representations, understandings, negotiations and discussions between the
parties, whether oral or written, with respect to the subject matter hereof.

     SECTION 9.05. Amendment and Waiver. This Agreement may not be amended,
modified, supplemented, restated or waived except by a writing executed by the
party against which such amendment, modification or waiver is sought to been
enforced. Waivers may be made in advance or after the right waived has arisen or
the breach or default waived has occurred. Any waiver may be conditional. No
waiver of any breach of any agreement or provision herein contained shall be
deemed a waiver of any preceding or succeeding breach thereof nor of any other
agreement or provision herein contained. No waiver or extension of time for
performance of any obligations or acts shall be deemed a waiver or extension of
the time for performance of any other obligations or acts.

     SECTION 9.06. No Assignment; No Third Party Beneficiaries. This Agreement
and the rights, duties and obligations hereunder may not be assigned or
delegated by the Company or the Investor. Any purported assignment or delegation
of rights, duties or obligations hereunder shall be void and of no effect. This
Agreement and the provisions hereof shall be binding upon and shall inure to the
benefit of each of the parties and their respective successors. This Agreement
is not intended to confer any rights or benefits on any Persons other than as
set forth above.

                                       31
<PAGE>

     SECTION 9.07. Severability. This Agreement shall be deemed severable, and
the invalidity or unenforceability of any term or provision hereof shall not
affect the validity or enforceability of this Agreement or of any other term or
provision hereof. Furthermore, in lieu of any such invalid or unenforceable term
or provision, the parties hereto intend that there shall be added as a part of
this Agreement a provision as similar in terms to such invalid or unenforceable
provision as may be possible and be valid and enforceable.

     SECTION 9.08. Further Assurances. Each party hereto, upon the request of
any other party hereto, shall do all such further acts and execute, acknowledge
and deliver all such further instruments and documents as may be necessary or
desirable to carry out the transactions contemplated by this Agreement.

     SECTION 9.09. Titles and Headings. Titles, captions and headings of the
sections of this Agreement are for convenience of reference only and shall not
affect the construction of any provision of this Agreement.

     SECTION 9.10. GOVERNING LAW; SUBMISSION TO JURISDICTION; ETC. (A) THIS
AGREEMENT SHALL BE GOVERNED BY, INTERPRETED UNDER, AND CONSTRUED IN ACCORDANCE
WITH THE INTERNAL LAWS OF THE STATE OF NEW YORK APPLICABLE TO AGREEMENTS MADE
AND TO BE PERFORMED WITHIN THE STATE OF NEW YORK WITHOUT GIVING EFFECT TO
PRINCIPLES OF CONFLICTS OF LAWS THEREOF.

     SECTION 9.11. Counterparts. This Agreement may be executed in counterparts,
each of which shall be deemed an original, all of which taken together shall
constitute one and the same instrument.

     SECTION 9.12. Reporting Entity for the Common Stock. The reporting entity
relied upon for the determination of the VWAP, trading price or trading volume
of the Common Stock on any given Trading Day for the purposes of this Agreement
shall be Bloomberg Financial.

     SECTION 9.13. Commitment Fee Payment. In the event Company shall not issue
Draw Down Shares for an aggregate Investment Amount of at least $7,500,000 prior
to the termination of this Agreement, the Company shall pay the Investor the
amount of $375,000 (pro rated for issuances prior to the termination of this
Agreement, payable two business days following termination of this Agreement. In
no event shall the Investor receive payment from the Company pursuant to this
Section 9.13 on more than one occasion.

     SECTION 9.14. Adjustments for Stock Splits, etc. The Maximum Share Amount,
the minimum Floor Price and calculations of the

                                       32
<PAGE>

Average Daily Trading Volume shall be equitably adjusted to reflect stock
splits, stock dividends, reverse stock splits and similar events.

                                       33
<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by the undersigned, thereunto duly authorized, as of the date first set
forth above.

                            CORIXA CORPORATION

                            By:/s/ STEVEN GILLIS
                               -------------------------------
                               Name:  Steve Gillis
                               Title: Chief Executive Officer

                             BNY Capital Markets, Inc.

                             By:
                               -------------------------------
                                Name:
                                Title:

                                       34

<PAGE>
     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by the undersigned, thereunto duly authorized, as of the date first set
forth above.

                            CORIXA CORPORATION

                            By:
                               -------------------------------
                               Name:
                               Title:

                             BNY Capital Markets, Inc.

                             By: /s/ WESLEY PRITCHETT
                               -------------------------------
                                Name:  Wesley Pritchett
                                Title: Authorized Signatory

                                       34
<PAGE>

                                    EXHIBIT A

                               CORIXA CORPORATION

                                DRAW DOWN NOTICE

[Date]

BNY Capital Markets, Inc.
32 Old Slip, (15th Floor)
New York, NY 10286

Attn: Raymond Lang

     Reference is made to the Private Equity Line Financing Agreement between
Corixa Corporation (the "Company") and BNY Capital Markets, Inc. dated as of
____ __, 2001. The Company confirms that all conditions to the delivery of this
Draw Down Notice are satisfied as of the date hereof.

Effective Date of Delivery of Draw Down Notice (determined pursuant to Section
2.03(b)):
         --------------------

Number of Days in Valuation Period: ___________________

First Date of Valuation Period:
                                -------------------

Last Date of Valuation Period:
                               ---------------------

Settlement Date:
                 --------------------

Draw Down Amount (not to exceed Maximum Draw Down Amount):
                                                           -----

Calculation of Maximum Draw Down Amount:
                                         ------------------

Floor Price Limitation (if none specified, $5.00):

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

                               CORIXA CORPORATION

                            By:
                                ------------------------------
                                Name:
                                Title:

                                       35
<PAGE>

                                    EXHIBIT B

     Form of Opinion of Orrick, Herrington & Sutcliffe, LLP

               (a) The Company is a corporation duly incorporated, validly
existing and in good standing under the laws of the State of Delaware.

               (b) As of the date of this opinion letter, the authorized
capitalization of the Company is as set forth in Section 3.02 of the Financing
Agreement.

               (c) Each Agreement has been duly executed and delivered and
constitutes a valid and binding obligation of the Company enforceable against
the Company in accordance with its terms.

               (d) When issued to and paid for by you in compliance with the
provisions of the Finance Agreement and the Resolutions, the Draw Down Shares
will be validly issued, fully paid and nonassessable and free of statutory
preemptive rights, or to our knowledge, other similar rights.

               (e) The execution, delivery and performance of and compliance
with the Agreements and the issuance of the Draw Down Shares (i) have been duly
authorized by all necessary corporate action of the Company, (ii) have not
resulted and will not result in any violation of, or conflict with, the
Company's Certificate of Incorporation or Bylaws, and (iii) have not resulted
and will not result in any material violation of, or conflict with, or
constitute a material default under, (A) any Material Agreement to which the
Company is a party or by which it is bound, or (B) any statute, rule or
regulation or, to our knowledge, any judgment or order of federal securities
law, Delaware corporate law or New York law to which the Company is a party, or
by which the Company is bound.

               (f) No consent, approval or authorization of or designation,
declaration or filing with, any governmental authority on the part of the
Company is required in connection with the valid execution and delivery of the
Agreements, or the offer, sale or issuance of the Draw Down Shares, except the
filings under applicable securities laws.

                                       36
<PAGE>

               (g) The offer and sale of the Draw Down Shares are exempt from
the registration requirements of the Securities Act of 1933, as amended.

                                       37

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