<PAGE>

                             COLLABORATION AGREEMENT

     This Collaboration Agreement ("Agreement") is entered into as of December
20, 1999 (the "Effective Date"), by and between Rosetta Inpharmatics, Inc.,
("Rosetta"), a corporation organized and existing under the laws of the State of
Delaware and having a place of business at 12040 - 115th Avenue Northeast,
Kirkland, Washington 98034-6900 and Corixa Corporation ("Corixa"), a corporation
organized and existing under the laws of the State of Delaware and having a
place of business at 124 Columbia Street, Suite 200, Seattle, Washington
98104-2040.

     The parties agree as follows:

     1. BASIS FOR AGREEMENT. Corixa has samples of normal and diseased tissues
and wants to obtain information about the difference between those tissues.
Corixa has or will make certain nucleic acid material including cDNA for
constructing microarrays ("PCR Product" described in Section 2 below) and
ribonucleic acid samples from the normal and diseased tissues for hybridizing to
microarrays ("Sample RNA"). Corixa desires to know which genes are expressed in
cells in the diseased tissue relative to the normal tissue. Rosetta has
expertise in the area of using microarrays and analyzing microarray data to
determine gene expression. The purpose of this Agreement is to set forth the
terms and conditions under which (a) Corixa will supply Rosetta with PCR Product
and Sample RNA, and (b) Rosetta will conduct experiments using microarrays
constructed using PCR Product and hybridized with Sample RNA and provide Corixa
with an analysis of the data generated from such experiments. The procedures
that each party will follow in performing this Agreement are set forth in the
provisions herein and in Appendix A hereto, which is incorporated herein by this
reference.

     2. SUPPLY OF PCR PRODUCT. For each cDNA clone that corresponds to a gene
of interest, Corixa shall supply Rosetta with PCR amplified product from each
cDNA clone ("PCR Product") with [***] of approximately [***] being supplied
per month; however, the number of clones per set can range from [***].
Corixa will use reasonable efforts to deliver the PCR Product to Rosetta
during the first [***] of each month, in order to permit Rosetta to establish
a schedule for its personnel and facilities; this delivery date can be
changed by agreement of the parties. Corixa shall provide no more than [***]
of PCR Product per month to Rosetta for up to [***] unless the parties agree
[***]. The procedures to be used for supply of the PCR Product by Corixa to
Rosetta are set forth in Appendix A under the heading "PCR Product Provided
by Corixa."

     3. USE OF THE PCR PRODUCT BY ROSETTA. Within [***] of receipt of PCR
Product by Rosetta, Rosetta shall employ commercially reasonable efforts to
fabricate [***] microarrays that utilize the PCR Product provided by Corixa.

     4. SUPPLY OF THE SAMPLE RNA. Sample RNA will be in the form of poly A+
RNA in matched sample pairs of no more than [***] per month. Corixa shall
deliver appropriate Sample RNA in [***] to Rosetta within [***] after
delivery of the PCR Product in any given month so that the appropriate
microarrays are available when Sample RNA is received. The procedures to be
used by Corixa for providing Sample RNA to Rosetta are set forth in Appendix
A under the heading "Sample RNA Provided by Corixa."

     5. USE OF SAMPLE RNA BY ROSETTA. Within [***] of receipt
of Sample RNA, Rosetta will (a) label the Sample RNA, (b) hybridize the Sample
RNA to a microarray, (c) scan the microarray, (d) compile the experimental data
("Array Data"), and (e) provide an analysis of the data to Corixa in a written
form agreed upon by the parties.


* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.

<PAGE>

Collaboration Agreement
Corixa/Rosetta Inpharmatics                                          Page 2 of 7

     6. ARRAY DATA ANALYSIS. Information that is the result of the microarray
experiments performed by Rosetta in analyzed form shall be termed herein the
"Analyzed Data." The Analyzed Data, whether or not the result of successful
experiments, shall be disclosed in a written report to Corixa within the
[***] period set forth in Section 5 herein. Array Data associated with
Analyzed Data will be provided to Corixa in spreadsheet form on a floppy disk
or other computer-readable format agreed upon by the parties.

     7. ROSETTA DEVELOPED SOFTWARE TOOLS. In the event Corixa requires
Rosetta to provide Analyzed Data in other than spreadsheet form, Rosetta
shall use reasonable commercial efforts to develop and provide to Corixa
software tools for interpretation of Analyzed Data on site at Corixa. For
such development efforts by Rosetta, Corixa shall pay Rosetta the sum of
$30,000 (thirty thousand dollars) and a license fee of $3,000 (three thousand
dollars) per year for licensing the software tools. Corixa shall pay Rosetta
[***] upon initiation of such development efforts and the balance of [***]
upon delivery of the software tools to Corixa. The license fee of [***] for
the first-year license of the software tools shall be due upon delivery of the
software tools to Corixa. These development and licensee fees are in addition
to the compensation for services set forth in Section 10. Rights in the
software tools is described in Section 13. The capabilities and features of
the software tools to be provided to Corixa pursuant to this Section 7, if
any, shall be agreed upon between the parties prior to the initiation of any
development work by Rosetta.

     8. QUALITY CONTROL. To determine whether failed results of a microarray
experiment are the result of Rosetta's procedures or material provided by
Corixa, the procedures of this Section 8 will be followed.

          8.1 QUALITY OF PCR PRODUCT AND MICROARRAYS. Procedures to check the
     quality of PCR Product provided by Corixa and the procedure used to
     determine which party should pay for a repeated microarray experiment
     are set forth in Appendix A under the heading "Quality of PCR Products
     and Microarrays." In the event that a set of microarrays are re-printed
     pursuant to the procedures set forth in the section entitled "Quality of
     PCR Product and Microarrays" in Appendix A, Corixa will be invoiced the
     sum of [***] for such re-printing. A set of microarrays shall comprise
     [***] microarrays. If Corixa decides to provide Rosetta with a new batch
     of PCR Product for re-printing a set of microarrays, the parties agree
     to adjust the time-frames set forth in this Agreement in an appropriate
     manner. For microarray experiments that are repeated by Rosetta because
     of inadequate or poor quality PCR Product, Corixa will be invoiced for
     such experiments at the following rates: [***]

          8.2 QUALITY OF SAMPLE RNA. Procedures to check the quality of Sample
     RNA provided by Corixa and the procedure used to determine which party
     should pay for a repeated microarray experiment are set forth in Appendix A
     under the heading "Quality of Sample RNA." For microarray experiments
     repeated by Rosetta because of low Sample RNA quality, Corixa will be
     invoiced for such experiments at the following rates: [***]

     9. RETURN OF UNUSED REAGENTS. All PCR Product and Sample RNA provided by
Corixa that is not used by Rosetta shall be returned to Corixa.

     10. COMPENSATION. As compensation for the services to be provided under
this

* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.

<PAGE>

Collaboration Agreement
Corixa/Rosetta Inpharmatics                                          Page 3 of 7

Agreement, excluding the fees for software development described in Section
7, Corixa will pay Rosetta $500,000.00 (five hundred thousand dollars). This
sum shall be paid on the following schedule: (a) [***]

     11. CONFIDENTIAL INFORMATION. For the purposes of this Agreement, the term
"Confidential Information" shall mean, and collectively include, all non-public
information relating to the business, plans and/or technology of either party
including, but not limited to, technical information including inventions,
methods, plans, processes, specifications, source code, object code,
characteristics, raw data, equipment design, know-how, experience, and trade
secrets, developmental, marketing, sales, operating, performance, and cost
information; computer programming techniques; information relating to the PCR
Product, Sample RNA, Array Data, and Analyzed Data; and all record bearing media
containing or disclosing the foregoing information and techniques including
written business plans, patents and patent applications, grant applications,
notes, and memoranda, whether in writing or presented, stored or maintained in
or by electronic, magnetic, or other means, to the extent that such information,
as of the date of disclosure by the disclosing party to the receiving party, was
not (a) known to the receiving party as evidenced by written documentation; (b)
disclosed in published literature or otherwise generally available to the
public; or (c) obtained from a third party without binder of secrecy, PROVIDED,
HOWEVER, that such third party has no confidentiality obligations to the
disclosing party or any of its affiliates. Rosetta agrees to treat Array Data
and Analyzed Data as Confidential Information disclosed by Corixa to Rosetta
within the scope of this Agreement.

          11.1. RESTRICTIONS ON USE AND DISCLOSURE OF CONFIDENTIAL INFORMATION.

               11.1.1. Subject to the right of publication pursuant to Section
          12 hereof and Rosetta's right to use Array Data and Analyzed Data
          pursuant to Section 13 hereof, the receiving party agrees to treat as
          confidential and not to use other than to perform this Agreement, and
          not to reverse engineer or decompile any Confidential Information
          disclosed to it by the disclosing party. The receiving party agrees
          not to disclose to any third party any Confidential Information
          disclosed to it by the disclosing party. The receiving party further
          covenants that it will exercise every reasonable precaution to
          preclude the unauthorized disclosure by any of its personnel or
          employees to other parties of any Confidential Information disclosed
          to it by the disclosing party under the provisions of this Agreement.
          The receiving party agrees not to disclose the Confidential
          Information it receives from the disclosing party to anyone except its
          own personnel and employees, who (a) are actively and directly
          evaluating the Confidential Information, and consequently need to know
          such information and (b) are bound by confidentiality, nondisclosure,
          and nonuse obligations AT LEAST AS STRINGENT AS THOSE SET forth in
          this paragraph 11.1.1.

               11.1.2. The obligations of paragraph 11.1.1 hereof will expire
          with respect to each item of Confidential Information five (5) years
          from the termination date of this Agreement.

               11.1.3. Any such information which is characterized as
          Confidential Information on the date of initial disclosure to the
          receiving party shall cease to be Confidential Information and the
          receiving party shall be released from the provisions of paragraph
          11.1.1 hereof on the date when, through no fault or omission on the
          part of the


* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.

<PAGE>

Collaboration Agreement
Corixa/Rosetta Inpharmatics                                          Page 4 of 7


          receiving party, such information becomes (a) disclosed in published
          literature or otherwise generally available to the public, or (b)
          obtained by the receiving party from a third party without binder of
          secrecy, provided, however, that such third party has no
          confidentiality obligations to the disclosing party or any of its
          affiliates.

               11.1.4. Notwithstanding the obligations of paragraph 11.1.1, the
          receiving party shall be permitted to disclose Confidential
          Information that is required to be disclosed by the receiving party to
          comply with applicable laws, court order, or governmental regulations,
          provided that the receiving party provides prior written notice of
          such disclosure to the disclosing party and takes reasonable and
          lawful actions to avoid and/or minimize the degree of such disclosure.
          The prior written notice must be given in sufficient time to permit
          the disclosing party to seek a protective order or some other
          accommodation.

          11.2 TERMS OF THIS AGREEMENT. The parties will keep the terms of this
     Agreement confidential and not disclose them to any third party, except as
     may be required by regulatory agencies or courts or as required by law, and
     will then use all reasonable precautions to keep the terms of this
     Agreement confidential.

     12. PUBLICATION. Publication rights for the Array Data and Analyzed Data
shall belong to Corixa. Corixa agrees that in the event that it decides to
prepare and submit a manuscript that includes Array Data and/or Analyzed Data
for publication, it will include appropriate Rosetta personnel as authors on the
manuscript.

     13. INTELLECTUAL PROPERTY.

          13.1 All Array Data and Analyzed Data ("Intellectual Property") shall
     be solely owned by and assigned to Corixa. Rosetta shall have no rights
     in the Intellectual Property except, however, that Corixa hereby grants
     Rosetta a non-exclusive, royalty-free license to use the Intellectual
     Property to research, develop and commercialize products in the field of
     Agrobiology and Agrochemistry. Any inventions or discoveries made solely
     by Rosetta through use of the Intellectual Property in the field of
     Agrobiology and Agrochemistry shall be owned by Rosetta and Rosetta hereby
     grants Corixa an exclusive, royalty-free license to use such inventions
     or discoveries to research, develop and commercialize products in all
     other fields.  Agrobiology and Agrochemistry shall be deemed to mean
     plant and insect-related research, solely for the development of
     herbicides and insecticides to be used on plants. At Corixa's request,
     Rosetta shall promptly execute such instruments as are necessary to
     perfect Corixa's rights to any Intellectual Property.

          13.2 Any and all intellectual property rights to the software tools
     developed by Rosetta pursuant to Section 7 including, but not limited to,
     patents, patent applications, trademarks, copyrights, know-how, moral
     rights, and similar rights of any type under the laws of any governmental
     authority, domestic or foreign, including all applications and
     registrations relating to any of the foregoing, shall remain with Rosetta.
     Upon development of the software tools and payment of the license fee set
     forth in Section 7 to Rosetta, Rosetta grants Corixa a nonexclusive,
     nontransferable, revocable license to use the software tools (in object
     code form only, and without any right to sublicense or make derivative
     works or any changes, modifications, corrections, improvements, or
     extensions of the software tools) for internal use only in the United
     States at Corixa's site located at Seattle, Washington.

* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.

<PAGE>

Collaboration Agreement
Corixa/Rosetta Inpharmatics                                          Page 5 of 7

     14. DISCLAIMER OF REPRESENTATIONS AND WARRANTIES. NEITHER PARTY MAKES ANY
REPRESENTATIONS OR EXTENDS ANY WARRANTIES, EXPRESS OR IMPLIED, AS TO ANY MATTER
WHATSOEVER INCLUDING, WITHOUT LIMITATION, THE PCR PRODUCT, THE SAMPLE RNA, THE
ARRAY DATA OR THE ANALYZED DATA INCLUDING, BUT NOT LIMITED TO, WARRANTIES OF
OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A PARTICULAR PURPOSE. Without
limitation of the foregoing generality, nothing contained herein or in any
disclosure of research conducted by Rosetta shall be construed as extending any
representation or warranty with respect to research using PCR Product or Sample
RNA or the results to be obtained by the use thereof or any products resulting
therefrom, or that use of the Array Data or Analyzed Data will be free from
infringement of patents or other proprietary rights of third parties. Neither
party makes any warranties whatsoever as to the commercial or scientific value
of the Array Data or Analyzed Data. NOTWITHSTANDING ANYTHING HEREIN TO THE
CONTRARY, CORIXA REPRESENTS AND WARRANTS THAT IT HAS THE RIGHT TO TRANSFER THE
PCR PRODUCT AND SAMPLE RNA TO ROSETTA ON THE TERMS AND CONDITIONS OF THIS
AGREEMENT.

     15. INDEMNITY. Corixa agrees to indemnify and hold harmless Rosetta, its
directors, officers, employees, and agents, from all costs, expenses (including
attorneys' fees), interest, losses, obligations, liabilities, and damages paid
or liability for which is incurred by any of said parties, and which arise out
of or are in connection with or are for the purpose of avoiding any and all
claims, demands, actions, causes of action, suits, appeals, and proceedings, all
whether groundless or not, or the settlement thereof, based on any actual or
alleged injuries, damages, or liability of any kind whatsoever (including,
without limitation, personal injury, death, property damage, breach of warranty,
or breach of contract) arising, directly or indirectly, out of (a) any
manufacture, marketing, possession, use, sale, or other disposition of Array
Data and/or Analyzed Data and/or subject matter derived therefrom or by use
thereof by Corixa, its Affiliates, its sublicensees, or anyone claiming by,
through, or under any of them, or (b) any manufacture, possession, or use of PCR
Products or Sample RNA; PROVIDED, HOWEVER, that Corixa shall have no such
obligation to indemnify or hold harmless (x) in connection with Rosetta's
practice of the license granted to it by Corixa pursuant to Section 13.1 hereof
or (y) to the extent that the costs, expenses (including attorneys' fees),
interest, losses, obligations, liabilities, or damages referred to hereinabove
are the result of the negligence or willful misconduct of Rosetta or its
directors, officers, employees or agents. Corixa's indemnification obligations
under this Section 15 arise only if Rosetta: (i) notifies Corixa as soon as it
becomes aware of a claim; (ii) permits Corixa to control the defense and
settlement, at Corixa's expense, of any such claim; and (iii) does not settle
any such claim without the prior written approval and consent of Corixa.

     16. TERM AND TERMINATION. This Agreement may expire or be terminated, as
follows:

          16.1. COMPLETION OF WORK. This Agreement shall expire on December 31,
     2000.

          16.2. BY BREACH. In the event either party shall materially breach
     any of the terms, conditions and agreements contained in this Agreement
     to be kept, observed and performed by it, then the other party may
     terminate this Agreement, at its option and without prejudice to any of
     its other legal and equitable rights and remedies, by giving the party
     who committed the breach sixty (60) days notice in writing, particularly
     specifying the breach, unless the notified party within such sixty (60)
     days period shall have rectified the breach.

          16.3. BY ROSETTA. Rosetta may terminate this Agreement by giving
     Corixa ninety (90) days notice in writing setting forth the effective date
     of such termination.

          16.4. BY CORIXA. Corixa may terminate this Agreement by giving Rosetta
     ninety (90) days notice in writing setting forth the effective date of such
     termination.


* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.

<PAGE>

Collaboration Agreement
Corixa/Rosetta Inpharmatics                                          Page 6 of 7

     17. SURVIVAL OF OBLIGATIONS. The rights and obligations of Sections 11, 12,
13, 14, and 15 shall survive expiration or termination of this Agreement. In the
event of early termination of this Agreement pursuant to paragraphs 16.2, 16.3,
or 16.4, Rosetta shall provide Corixa with Array Data and Analyzed Data and
Corixa shall pay Rosetta for work completed prior to termination.

     18. NO OBLIGATION TO LICENSE. Nothing contained herein shall be construed
by implication or otherwise (a) so as to obligate either of the parties to enter
into an agreement for purchase of or license to any products, technology, or
services; or (b) as the grant of any right or license by either party to any
Confidential Information or any intellectual property rights, except for the
rights provided in Section 13.

     19. GENERAL PROVISIONS. The following general provisions shall apply to
this Agreement:

          19.1. NOTICES. All notices and communications provided for hereunder
     shall be in writing and shall be mailed, faxed, or otherwise delivered to
     the business address or fax number of the respective parties
     aforementioned, or to such other address or fax number as either party
     shall designate in writing to the other.

          19.2. BENEFITS. All terms and provisions of this Agreement shall bind
     and inure to the benefit of the parties hereto, and upon their respective
     successors and assigns.

          19.3. COUNTERPARTS. This Agreement may be executed simultaneously in
     one or more counterparts, each of which shall be deemed to be original but
     all of which together shall constitute one and the same Agreement.

          19.4. CONSTRUCTION AND INTERPRETATION. This Agreement shall be
     construed and fairly interpreted in accordance with its terms, without any
     strict construction in favor of or against either party. Ambiguities shall
     not be interpreted against the drafting party. Any ambiguities in this
     Agreement shall be interpreted in accordance with the objectives stated in
     Section 1. In construing or interpreting this Agreement, the word "or"
     shall not be construed as exclusive, and the word "including" shall not be
     limiting. The use of the singular or plural form shall include the other
     form and the use of the masculine, feminine or neuter gender shall include
     the other genders. All captions and headings in this Agreement are for
     convenience only and shall not be considered as substantive parts of this
     Agreement or determinative in the interpretation of this Agreement.

          19.5. ENTIRE UNDERSTANDING. This Agreement constitutes the entire
     understanding between the parties hereto with respect to the subject matter
     hereof. No modifications, extensions or waiver of any provisions hereof or
     release of any right hereunder shall be valid, unless the same is in
     writing and is consented to by both parties hereto.

          19.6. CHOICE OF LAW. This Agreement shall be governed by the laws of
     the State of Washington, excluding choice of law principles that would
     cause the law of any other jurisdiction to apply.

          19.7. AMENDMENT. This Agreement may be amended only by a written
     agreement signed by both Parties hereto.

* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.

<PAGE>

Collaboration Agreement
Corixa/Rosetta Inpharmatics                                          Page 7 of 7

          19.8. WAIVER. Waiver of any provision of this Agreement shall not be
     deemed a waiver of any other provision of this Agreement.

          19.10. FORCE MAJEURE. The failure of any party to perform hereunder as
     a result of governmental action, laws, orders, or regulations, or as a
     result of events, such as war, acts of public enemies, fires, floods,
     earthquakes, acts of God or any causes of like kind beyond the reasonable
     control of such party is excused for so long as such cause exists, but only
     to the extent such failure is caused by such law, order, regulation, or
     event.

          19.11. SUBSEQUENT DISCUSSIONS. The parties agree to discuss in good
     faith the use of other technologies resident at Rosetta for providing
     Corixa with expression data. Such technologies include, but are not
     limited to, ink-jet produced microarrays and a proprietary RNA
     amplification procedure.

     IN WITNESS WHEREOF, the parties hereto have caused their duly authorized
representatives to execute this Agreement as of the date and year first written
above.

CORIXA CORPORATION                     ROSETTA INPHARMATICS, INC.

BY /s/  Mark McDade                    BY /s/ John J. King, II
----------------------------------     ----------------------------------


       MARK MCDADE                               JOHN J. KING, II
----------------------------------     ----------------------------------
       PRINT NAME                                   PRINT NAME


          PRESIDENT &                       SR. VICE PRESIDENT,
  CHIEF OPERATING OFFICER                  CHIEF OPERATING OFFICER
----------------------------------     ----------------------------------
         TITLE                                       TITLE


       22 DEC '99                                  DECEMBER 21, 1999
----------------------------------     ----------------------------------
         DATE                                          DATE


* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.

<PAGE>

                                   APPENDIX A

PCR PRODUCT PROVIDED BY CORIXA


Corixa shall supply Rosetta with at least [***]. The PCR product shall be
[***]. The PCR product will be [***].

QUALITY OF PCR PRODUCT AND MICROARRAYS

Rosetta will test the quality of the PCR Product and microarrays using the
following criteria:

  a) Rosetta will [***]. Rosetta personnel will inform [***]. If the latter
is true, [***].

  b) Rosetta will examine [***]. Rosetta personnel will [***]. If the latter
is true, [***].

  c) Rosetta will [***]. The results of [***].

       1) If less than [***].

       2) If more than [***].

       3) If the [***].

       4) If more than [***].

If a microarray experiment has been deemed [***]. If the microarray
experiment has been deemed [***]. If Corixa decides to [***].

  d) Once a set of [***.] The results of [***].

       1) If less than [***], then the [***].

       2) If more than [***], then [***].

       3) If the array is deemed [***], then the [***].

       4) If more than [***].

If a microarray experiment has been deemed [***]. If the above tests indicate
[***].

SAMPLE RNA PROVIDED BY CORIXA.

Corixa shall provide Rosetta with [***]. Samples shall be provided to Rosetta
[***]. Samples shall be [***].

* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.


<PAGE>

(Cont.)


QUALITY OF SAMPLE RNA

For quality control purposes [***]. In addition, up to [***]. The Sample RNA
and labeling quality will be assessed. [***].

    If the [***].

    If the [***].

The parties agree that the numbers used as criteria for assessing quality of
sample RNA [***].

In the event that a microarray experiment [***]. In the case where [***]. In
no circumstances will [***]. If the above tests indicate [***].















* Material has been omitted pursuant to a request for confidential treatment,
  and such material has been filed separately with the SEC.


                                        A-1