Document:

<PAGE>

                                                                  EXHIBIT 10.25

ROSETTA INPHARMATICS             ROSETTA                       TEL. 425.820.8900
12040 115TH AVE NE                                             FAX  425.821.5354
KIRKLAND, WA 98034               INPHARMATICS
                                 ROSETTA.ORG

July 31, 1999

                                 VIA FEDERAL EXPRESS

Mr. Vem Norviel
Vice President and General Counsel
Affymetrix, Inc.
3380 Central Expressway
Santa Clara, CA 95051

Dear Mr. Norviel:

In connection with paragraph 4.1 of the Internal Use License Agreement (the
"Agreement") entered into between Affymetrix, Inc. ("Affymetrix"), and
Rosetta Inpharmatics, Inc. ("Rosetta"), with an effective date of November
30, 1998, we are writing to inform you that effective August 1, 1999, Rosetta
desires to increase the number of annual Array Based Experiments ("ABE's")
available under the Agreement from [***]. Per paragraph 3.2 of the agreement,
the step-up to the unlimited number of ABE's will increase the annual license
fee from [***].

In connection with paragraph 5.1 of the agreement, we hereby confirm to you
that Rosetta's ABE usage did not exceed the Maximum Annual ABE's allowed
through the date of this letter. It is our understanding that upon
Affymetrix's receipt of this letter a new anniversary date for purposes of
tracking ABE's will be created and Rosetta will pay the new annual license
fee of [***] pursuant to the provisions of paragraph 4.2 of the
Agreement.

Please contact me if you have questions.

Best regards,

Stephen H. Friend, M.D., Ph.D.
President and Chief Scientific Officer

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

<PAGE>

                         INTERNAL USE LICENSE AGREEMENT

Effective as of Nov. 30, 1998 (the "EFFECTIVE DATE"). Affyrnetrix. Inc., a
Delaware corporation ("Affymetrix") and Rosetta Inpharmatics, Inc., a Delaware
corporation ("Licensee") (each a "Party" and together "the Parties"), agree as
follows:

1. DEFINITIONS.

1.1 "ABE," which stands for Array Based Experiment, means a single experiment
involving hybridization of a labeled sample on a Nucleic Acid Array licensed
hereunder and that is covered at the time and place of the experiment by one or
more valid claims of a patent claim within the Licensed Patents. A "valid claim"
shall include a claim that has not been held to be invalid by a final judgement
from which no appeal can be taken. If labeled samples (including the same
sample) are consecutively hybridized to a single Nucleic Acid Array, then the
number of ABEs is equal to the number of consecutive hybridizations. If two
differently labeled samples arc mixed and simultaneously hybridized to a single
Nucleic Acid Array, then there has been one ABE.

1.2 "Affiliate" means any corporation or other business entity controlled by.
controlling, or wider common control with a Party, but only for so long as such
Affiliate remains an Affiliate of a Party, and only if such Affiliate is bound
in writing by the terms of this Agreement. For this purpose, "control" means
direct or indirect beneficial ownership of more than 50% of; (i) the voting
stock or other controlling equity interest in, or (ii) the revenue, of such
corporation or other business. References to Licensee in this Agreement will
include Licensee's Affiliates.

1.3 "Array Maker" means a device used to fabricate Nucleic Add Arrays by
mechanical fabrication methods. For clarity, the parties understand that
"mechanical fabrication" does not include controlled direction of
electromagnetic energy at a portion of a support (e.g. fabrication through
photolithographic synthesis methods), but does include the use of an inkjet
system to place nucleic acids on a support.

1.4 "Licensed Patent(s)" means the U.S. and Foreign Patents (and reissues,
renewals, and extensions thereof) and Patent applications set forth on Exhibit
A. as well as any U.S. or foreign application (including divisionals,
continuations, and continuations-in-part) claiming priority to any of the
foregoing and patents issuing thereon, as well as reissues, renewals, and
extensions thereof.

1.5 "Nucleic Acid Array" means (i) an array fabricated solely by placing only
fully synthesized nucleic acids (clonal polynucleotides or other presynthesized
polynucleotides, with no further fabrication of nucleic acids) at defined
locations on a solid support or (ii) an array fabricated solely by synthesizing
oligonucleotides using an inkjet head to deposit nucleotides at defined
locations on a solid support without using controlled direction of
electromagnetic energy. In the case of both (i) and (ii), all of such nucleic
acids may not represent more than 8,000 genes/expressed sequence tags; provided,
however, during the periods of this Agreement in which Licensee has purchased an
unlimited number of ABEs there shall be no limit on the number of
genes/expressed sequence tags that Licensee may represent on a single Nucleic
Acid Array.

2. LICENSE. During the term of this Agreement, Affymetrix grants Licensee a
nontransferable, nonsublicensable, nonexclusive, worldwide, royalty-bearing
license under the Licensed Patents, to internally use Array Makers and make
(but not have made, sell, import, distribute or lease) and internally use
Nucleic Acid Arrays made from such Array Makers for analyzing the presence,
absence, or level of expressed messenger RNA in cells for academic and
commercial research use only. For clarity, the Parties understand that
diagnostic applications are not being licensed.

2.1 This Agreement does not grant Licensee a license to:

(a) transfer a Nucleic Acid Array to any third party or

(b) provide services to any third party with respect to a Nucleic Acid Array.
For clarity, the Parties understand that biological research activities
involving Nucleic Add Arrays conducted by Licensee within a collaboration that
meets the requirements of Section 2.1(c)(ii) are permitted; or

(c) distribute, license or otherwise make available to a third party any data
or database that is obtained from the use of a Nucleic Acid Array, except as
follows:

        i) Licensee may license data obtained from a Nucleic Acid Array to a
        third party licensee specifically related to a particular compound,
        drug, target, pathway or transcript state of a cell that has been
        discovered or analyzed through use of the Nucleic Acid Array, provided
        that such third party licensee (or its direct distributors or
        sublicensees) pays substantial consideration for the right to develop
        and market such compound, drug or target with the bone fide intent to do
        so in accordance with such third party licensee's commercial policies in
        effect from time to time; or

         ii) Licensee may transfer data to a third party when such data is
         obtained within a bona fide collaboration with such third party (a
         "Collaborator") in which: (A) the Collaborator provides substantial
         scientific input to experimental design, (B) the collaborative
         relationship is set forth in an agreement signed by the Licensee and
         the Collaborator prior to the use of any Nucleic Acid Arrays to
         generate such data, and (C) Licensee retains material intellectual
         property rights in substantial discoveries or inventions that arise
         from such data, including know-how if there are no patent rights
         directly associated with such know-how and such know-how has
         significant value as compared to other intellectual property arising
         from the collaboration. Bona fide collaborations do not include
         arrangements whose primary purpose is to give third party access to
         data or databases or provide nucleic acid hybridization services, or

         iii) Licensee may transfer data to a third party so long as Licensee
         receives no consideration or other quid-pro-quo for such transfer and
         such data is not made preferentially available to customers of Licensee
         (e.g. such transfer cannot be contingent on the third party and
         Licensee exchanging other goods, services or intellectual property), or

(d) identify polymorphisms in genes/expressed sequence tags or perform
genotyping analysis.

2.2 Licensee may make the data described in Section 2. l(c)(i)-(iii) (`Permitted
Data") available to third parties only pursuant to written agreements containing
obligations that: (a) are no less restrictive than those in Section 2.1; and (b)
explicitly benefit Affymetrix by providing Affymetrix the right to enforce the
provisions of such agreement that correspond to Section 2.1 hereof in the event
that Licensee does not or cannot enforce such provisions itself and (c) prohibit
such third parties from sublicensing or otherwise further distributing such
Permitted Data except as set forth in Section 2.1 (c)(i). Licensee agrees not to
exceed the scope of the licenses grimed under this Agreement.

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

                                       1
<PAGE>

3 ROYALTIES. In consideration of Licensee's right to use at least one Licensed
Patent, Licensee will pay to Affymetrix: (a) an annual "Usage Royalty," and (b)
a one-time license issue fee of $10,000.

3.1 EasyAccess-TM- "Gold" and "Silver" customers are entitled to additional
discounts of [***] from the Usage Royalty, respectively. However, Licensee's
EasyAccess discount shall only apply during those years of this Agreement in
which Licensee has maintained such EasyAccess status fur at least seven
months in such year. In the event Affymetrix substantially redefines the Gold
and Silver EasyAccess marketing programs following the Effective Date,
Affymetrix agrees to offer Licensee discounts similar to those set forth in
this Section consistent with any then-prevailing marketing programs that
require financial commitments similar to the Gold and Silver EasyAccess
programs as of the Effective Date.

3.2 The annual Usage Royalty is set forth in the following table and is based on
the number of ABEs that Licensee is permitted to conduct within a single year
and Licensee's annual research and development budget (including its Affiliates)
as reported in audited financial statements.

<TABLE>
<CAPTION>

# of annual           LICENSEE ANNUAL R&D BUDGET
   ABEs         up to[***]       Between      [***]
                                  [***]
----------------------------------------------------------
<S>             <C>              <C>          <C>
[***]              [***]          [***]        [***]
[***]              [***]          [***]        [***]
[***]              [***]          [***]        [***]
[***]              [***]          [***]        [***]
</TABLE>

3.3 Unused ABEs cannot be canned over from year-to-year. Nucleic Acid Arrays
that are provided to Licensee by a third party that has been licensed by
Affymetrix to provide such Nucleic Acid Arrays to Licensee shall not be included
in the royalty calculation.

4. PAYMENT. Upon execution of this Agreement. Licensee shall pay the license
issue fee. Licensee agrees to pay an annual Usage Royalty at [***] which
corresponds to [***] ABEs ("Maximum Annual ABEs") for use during each year of
this Agreement.

4.1 If during any year of this Agreement Licensee's ABE usage exceeds its
Maximum Annual ABEs: (a) Licensee shall promptly notify Affymetrix, (b)
Licensee's Maximum Annual ABEs and Usage Royalty shall increase to at least the
next higher volume amount (or higher, if Licensee elects) set forth in the above
table, and (c) the anniversary date of this Agreement shall be deemed to be the
date Affymetrix receives such notice. If Licensee notifies Affymetrix in writing
at least [***] prior to the anniversary date of this Agreement that Licensee
desires to increase or decrease their Maximum Annual ABEs, then Licensee's Usage
Royalty obligation shall be adjusted as set forth in the above table for the
next year.

4.2 During each year of this Agreement. Licensee agrees to pay the annual Usage
Royalty in [***] installments commencing at thc end of the first
calendar quarter that follows the Effective Date. If Licensee's ABE usage
exceeds its Maximum Annual ABE, all remaining [***] payments due for such
year shall be immediately due and Licensee's first [***] installments for
Licensee's increased Usage Royalty shall be due at the end of the next [***].

4.3 If within one year following the Effective Date Affymetrix has felled to
enter into at least [***] Qualifying Deal [***], then Affymetrix and Licensee
shall meet to discuss readjusting the annual Usage Royalty fee structure, but
in no event shall the annual Usage Royalty fee structure be decreased by more
than [***]. A "Qualifying Deal" shall mean an agreement between Affymetrix
and a licensee with the following criteria (i) the licensee has a R & D
budget of less than [***], and (ii) the license agreement contains an annual
Usage Royalty fee structure and covenants not to sue that are substantially
similar to the ones set forth in this Agreement or which are more favorable
to Affymetrix than the ones set forth in this Agreement. Any readjustment to
the annual Usage Royalty fee structure shall only persist until Affymetrix
has entered into [***] Qualifying Deal [***], and thereafter, the annual Usage
Royalty fee structure set forth in this Agreement shall be [***].

4.4 In the event Licensee selects a Usage Royalty corresponding to an unlimited
number of annual ABE,, Licensee shall pay Affymetrix an additional annual
royalty of [***] per Datapoint for all ABEs in access of [***] ABEs per year
that arc used in connection with providing data to third parties, where
"Datapoint' shall mean a measurement of the presence, absence, or level of
contiguous sequence of expressed messenger RNA in a single biological sample as
measured by a Nucleic Acid Array.

5.1 AUDIT. On each anniversary of this Agreement, an officer of Licensee will
deliver to Affymetrix a statement certifying (i) that Licensee's ABE usage
did not exceed the Maximum Annual ABE in the preceding year, and (ii) the
number of ABEs used in the preceding year in connection with providing data
to third parties but only if such number exceeds [***], Licensee agrees to
maintain reasonable records to document the number of ABEs that Licensee
uses. Affymetrix may have a nationally recognized accounting firm under
obligations of confidentiality reasonably acceptable to Licensee examine
Licensee's relevant records. At any time during regular business hours end
upon [***]notice, but no more than [***] annually. If such examination
reveals a discrepancy between the royalties payable hereunder and the

royalties actually paid, Licensee will pay all such additional royalties,
together with the maximum interest permitted by law from the date when such
additional royalties would have been due, to Affymetrix [***] days of
receipt of notice from Affymetrix of such discrepancy. Any such examination
will be at Affymetrix' expense; provided that, if a deficiency of more than
[***] is discovered, the examination will be at Licensees expense and
Affymetrix shall not be deemed to have used its annual right to audit
Licensee.

5.2 COVENANTS. licensee covenants not to sue Affymetrix. or its Affiliates or
customers of either regarding any patented technology related to (1) the
sale, distribution, design, development or manufacturing of nucleic acid
probe arrays made using controlled direction of electromagnetic energy at a
support ("Affymetrix NAPAs") and any array readers/scanners, software,
assays, or packaging which may be used with Affymetrix NAPAs or (ii) the use
of Affymetrix NAPAs provided by Affymetrix or its Affiliates to their
customers and any array readers/scanners, software, assays, or packaging
which may be used by such customers with Affymetrix NAPAs; provided, however,
that such covenant not to sue does nor extend to: (A) the sale, distribution,
design, development or manufacturing of nucleic acid probe arrays fabricated
by synthesizing oligonucleotides [***], or (B) the [***], or (C) the [***],
or (D) [***]

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

                                       2

<PAGE>

6. LIMITATIONS. Nothing in this Agreement will be construed as: (a) a warranty
or representation by Affymetrix as to the validity or scope of the Licensed
Patents; (b) a warranty or representation by Affymetrix that anything made,
used, or discovered under the rights granted in this Agreement does not or will
not infringe third party patents; (c) an obligation to bring actions against
third parties for infringement; (d) conferring the right to use any Affymetrix
trademark or designation; (e) conferring by implication, estoppel, or otherwise
any rights under any Affymetrix patents other than the Licensed Patents or any
rights not specifically granted herein; or (f) an obligation to furnish any
know-how not provided in the Licensed Patents. In no event will either Party be
liable for lost or prospective profits or indirect or consequential damages
resulting from this Agreement eve if the other Party has been advised of the
possibility of such damages.

7. INDEMNITY. Licensee will defend, indemnify, and hold Affymetrix harmless from
and against any liability, demands, damages, expenses and losses for death,
personal injury, illness, or property damage arising out of Licensee's use of
any method or apparatus under the Licensed Patents. As used in this Section 7,
"Affymetrix" includes its trustees, officers, agents, and employees. The
technology licensed hereby is experimental, and Licensee will take all
reasonable precautions to prevent death, personal injury, illness, and property
damages from use thereof.

8. TERMS AND TERMINATION. This Agreement will remain in effect for three years
following the Effective Date, and continue thereafter n renewing one year terms
until terminated by either party by providing notice to the other party at least
60 days prior to the anniversary date hereof. If either Party materially fails
to perform any obligations under this Agreement, the other Party may notify the
defaulting party of the default. If the defaulting Party has not materially
cured the default within 30 days after receiving such notice, the other Party
may terminate this Agreement upon 30 days' notice to the defaulting Party. Such
right to terminate will be in addition to, and without prejudice to the exercise
of, any other remedies available in law or equity. Sections 1, 2.2, 5.1, 6, 7,
9.1, 9.2 and 9.3 will survive termination or expiration of this Agreement.

9. GENERAL. Licensee covenants not to benchmark or otherwise compare performance
metrics such as sensitivity and specificity from Licensee's nucleic acid arrays
to any Affymetrix' nucleic acid arrays and disclose such comparison results to
third parties without the prior approval of Affymetrix which shall not be
unreasonable withheld. Licensee agrees not to disparage Affymetrix' personnel,
products or services. Licensee may not assign this Agreement by acquisition of
Licensee's assets or stock, by operation of law, or otherwise, without
Affymetrix's prior consent. In the event Licensee is acquired, Affymetrix will
not unreasonably withhold its consent to such an assignment. Affymetrix' consent
shall be deemed to have been reasonably withheld if Licensee proposes to merge
with an entity that is a party or an Affiliate of a party to litigation with
Affymetrix; provided, however, the foregoing proviso will not be effective in
the event Affymetrix initiates such litigation for the primary purpose of
preventing the assignment of this Agreement. No assignment of this Agreement
will be valid until the assignee has assumed all obligations under this
Agreement and the Usage Royalty has been adjusted to reflect the assignee's R&D
budget. If any provision of this Agreement is held invalid or unenforceable for
any reason, such unenforceability will not affect the enforceability of the
remaining provisions of this Agreement, and all provisions of this Agreement
will be construed so as to preserve the enforceability hereof. The waiver by
either Party of a breach of any provision of this Agreement by the other Party
will not be construed as a waiver of any succeeding breach of the same or any
other provision, nor will any delay on the part of either Party to exercise any
right that it may have hereunder operate as a waiver of any right by such Party.
In the event there is a dispute between the Parties in connection with this
Agreement, neither Party shall file a claim against the other Party in
connection with such dispute until thirty (30) days following notice to the
other Party and the Chief Executive Officer of each Party shall meet and discuss
potential solutions to such dispute during the thirty (30) days following notice
to the other Party and the Chief Executive Officer of each Party shall meet and
discuss potential solutions to such dispute during the thirty (30) day period.
Affymetrix represents and warrants that it owns or is the legal licensee of the
Licensed patents and that it has the right to enter into this Agreement for the
Licensed Patents.

9.1 NOTICE. All requests, consents, notices, and other communications under this
Agreement will be in writing and will be deemed to have been given upon the
confirmed facsimile transmission or prepaid express mailing to the address
below, or at such address as either Party may from time-to-time designate in
writing to the other Party.

To Affymetrix:    Affymetrix, Inc.
                  3380 Central Expressway
                  Santa Clara, CA 95051
                  Attention: General Counsel

To Licensee:      Rosetta Inpharmatics, Inc.
                  12040 115th Avenue N.E.
                  Kirkland, Washington 98034
                  Attention: Chief Operating Officer

9.2 ENTIRE AGREEMENT. This Agreement constitutes the entire agreement between
the parties relating to the subject matter thereof, and all prior negotiations,
representations, agreements, and understandings are merged into, extinguished
by, and completely expressed by it. This Agreement will be construed in
accordance with the laws of California without regard to its conflict of laws
rules.

9.3 CONFIDENTIALITY. The Parties will keep the terms of this Agreement in
confidence, 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.

Signature: /s/ Stephen A. Fodor
           -----------------------------------------------
           Stephen P.A. Fodor, Ph.D.
           President and Chief Executive Officer
           Affymetrix, Inc.

Date: 30 Nov 98
      ----------------------------------------------------

Rosetta Inpharmatics, Inc.

Signature: /s/ John J. King II
          ------------------------------------------------

Name (Print): John J. King, II
              --------------------------------------------

Title: Senior VP & COO
       ---------------------------------------------------

Date: 30 November, 1998
      ----------------------------------------------------

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

                                       3
<PAGE>

                                                               EXHIBIT A

<TABLE>
<CAPTION>

               COUNTRY      PATENT/                  TITLE OF INVENTION               AFFYMETRIX       FEATURE         STATUS
                          APPLICATION                                                  FILE NO.
                                NO.
<S>            <C>        <C>            <C>                                         <C>          <C>                <C>
CATEGORY I       US         5,143,854    Large Scale Photolithographic Solid Phase   1000.1       Peptide Synthesis    Issued
  (CHIPS)                                Synthesis of Polypeptides and Receptor
                                         Binding Screening Thereof
                 US         5,744,305    Very Large Scale Immobilized Polymer        1000.2A1     LESS THAN  400       Issued
                                         Synthesis
                 US         5,445,934    Array of Oligonucleotides On a Solid        1000.1B2     High Density Chip    ISSUED
                                         Substrate
                 AT         AT0476014    VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1           SYNTHESIS        ISSUED
                                         SYNTHESIS
                 AU          651793                                                  1000.1              ALL           ISSUED
                 BE         BE0476014    VERY LARGE SCALE IMMOBILIZED POLYMER                          Synthesis       Issued
                                         SYNTHESIS
                 [***]
                 [***]
                 [***]
                 CH         CH0476014    VERY LARGE SCALE IMMOBILIZED POLYMER         100.1            SYNTHESIS       Issued
                                         SYNTHESIS
                 DE         6901211972   VERY LARGE SCALE IMMOBILIZED POLYMER         100.1            SYNTHESIS       ISSUED
                                         SYNTHESIS
                 DK         DK0476014    VERY LARGE SCALE IMMOBILIZED POLYMER         100.1            SYNTHESIS       ISSUED
                                         SYNTHESIS
                 GB         GB0476014B1  VERY LARGE SCALE IMMOBILIZED POLYMER         100.1/EP            SYNTHESIS       ISSUED
                                         SYNTHESIS
                 HK         641/95       VERY LARGE SCALE IMMOBILIZED POLYMER         100.1/EP         SYNTHESIS       REGISTERED
                                         SYNTHESIS
                 SG         135/95       VERY LARGE SCALE IMMOBILIZED POLYMER         100.1/EP         SYNTHESIS       REGISTERED
                                         SYNTHESIS
                 EPO       0476014B1     VERY LARGE SCALE IMMOBILIZED POLYMER         100.1            SYNTHESIS       ISSUED
                                         SYNTHESIS
                 ES        ES476014      VERY LARGE SCALE IMMOBILIZED POLYMER         100.1            SYNTHESIS       ISSUED
                                         SYNTHESIS
                 [***]
                 FR        FR476014      VERY LARGE SCALE IMMOBILIZED POLYMER         100.1            SYNTHESIS       ISSUED
                                         SYNTHESIS
                 GB        2248840B      SUBSTRATE CARRYING LIGANDS TO SCREEN         100.1         SUBSTRATE CLAIMS   ISSUED
                                         FOR BIOLOGICAL ACTIVITY
                 HK         613/95       SUBSTRATE CARRYING LIGANDS TO SCREEN                       SUBSTRATE CLAIMS   REGISTERED
                                         FOR BIOLOGICAL ACTIVITY
                 SG        526/1994      SUBSTRATE CARRYING LIGANDS TO SCREEN                       SUBSTRATE CLAIMS   REGISTERED
                                         FOR BIOLOGICAL ACTIVITY
                 [***]
                 IL         94551        VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1              ALL           ISSUED
                                         SYNTHESIS

                 IN         174229       VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1              ALL           ISSUED
                                         SYNTHESIS
                 IT        FR476014      VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1             SYNTHESIS      ISSUED
                                         SYNTHESIS
                 RU        5010750.04    VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1                            ALLOWED
                                         SYNTHESIS
                 KR         971577       VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1              ALL           ISSUED
                                         SYNTHESIS
                 LU        LU0476014     VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1             SYNTHESIS      ISSUED
                                         SYNTHESIS
                 MX         180597       VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1         SUBSTRATE CLAIMS   ISSUED
                                         SYNTHESIS
                 NL         191992       VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1                            ISSUED
                                         SYNTHESIS
                 NO         301233       VERY LARGE SCALE IMMOBILIZED POLYMER        1000.1                            ISSUED
                                         SYNTHESIS

</TABLE>

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

<PAGE>

<TABLE>
<CAPTION>

                 COUNTRY      PATENT/                  TITLE OF INVENTION               AFFYMETRIX       FEATURE          STATUS
                            APPLICATION                                                  FILE NO.
                                NO.
  <S>            <C>        <C>            <C>                                         <C>          <C>                  <C>
                   NZ         233886             VERY LARGE SCALE IMMOBILIZED             1000.1                          ISSUED
                                                       POLYMER SYNTHESIS
                  [***]
                   SE        SE 476014           VERY LARGE SCALE IMMOBILIZED             1000.1         SYNTHESIS        ISSUED
                                                       POLYMER SYNTHESIS
                   ZA         9014354            VERY LARGE SCALE IMMOBILIZED             1000.1                          ISSUED
                                                       POLYMER SYNTHESIS
                   AU         672723             VERY LARGE SCALE IMMOBILIZED             1000.1A    REACTORS, READERS    ISSUED
                                                       POLYMER SYNTHESIS
                   EPO       94200059.7          VERY LARGE SCALE IMMOBILIZED             1000.1A    CHIPS, SYNTHESIZER,  ALLOWED
                                                       POLYMER SYNTHESIS                                    ETC.
                  [***]
                   KR         118362             VERY LARGE SCALE IMMOBILIZED             1000.1A           ALL           ISSUED
                                                       POLYMER SYNTHESIS
                  [***]
                   NL        NL 4706014          VERY LARGE SCALE IMMOBILIZED             1000.1A           ALL           ISSUED
                                                       POLYMER SYNTHESIS
                   US         5,405,783      Large Scale Photolithographic Solid Phase    1000.1B       Broad VLSIPS      Issued
                                                 Synthesis of an Array of Polymers
                   US         5,510,270       Synthesis and Screening of Immobilized      1000.1B1      Broad VLSIPS      Issued
                                                     Oligonucleotide Arrays                             Synth/Screening
                                                                                                        Claims
                  [***]
                  [***]
                  [***]
                  [***]
                   AU           663300           VERY LARGE SCALE IMMOBILIZED             1000.2      READER, LINKER      ISSUED
                                                       POLYMER SYNTHESIS                            SCREEN, MENV/PO C,
                                                                                                          VLSIPS
                  [***]
                   IN           178136           VERY LARGE SCALE IMMOBILIZED             1000.2     PROTECTING GROUP     ISSUED
                                                       POLYMER SYNTHESIS

                  [***]
                  [***]
                   NZ           240744           VERY LARGE SCALE IMMOBILIZED             1000.2      READER, LINKER      ISSUED
                                                       POLYMER SYNTHESIS                            SCREEN, MENV/PO C,
                                                                                                          VLSIPS
                   ZA           919650           VERY LARGE SCALE IMMOBILIZED             1000.2      READER, LINKER      ISSUED
                                                       POLYMER SYNTHESIS                            SCREEN, MENV/PO C,
                                                                                                          VLSIPS
                  [***]
                   US                            Very Large Scale Immobilized             1000.2A4
                                                       Polymer Synthesis
                   US                            Very Large Scale Immobilized             1000.2A5
                                                       Polymer Synthesis
                   US         5,744,101          Very Large Scale Immobilized             1000.2C   Synthesis Reactor     Issued
                                                       Polymer Synthesis
                   US                           Photolabile Nucleoside Peptide            1000.2D   Protecting groups     Allowed
                                                       Protecting Groups
                   US         5,753,788         Photolabile Nucleoside Peptide            1000.2E   Protecting groups     Issued
                                                       Protecting Groups
                  [***]
                   US         5,424,186          Very Large Scale Immobilized             1000.3     Oligo Synthesis      Issued
                                                       Polymer Synthesis
                  [***]
</TABLE>

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

<PAGE>

<TABLE>
<CAPTION>

                 COUNTRY      PATENT/                  TITLE OF INVENTION               AFFYMETRIX       FEATURE         STATUS
                            APPLICATION                                                  FILE NO.
                                NO.
  <S>            <C>        <C>            <C>                                         <C>          <C>                <C>
                [***]
                 US         5,527,681        Immobilized Molecular Synthesis of         1000.4    Systematic Substitution  Issued
                                            Systematically Substituted Compounds                   at a given position
                 US         5,770,456        Cyclic and Substituted Immobilized         1000.4A   Systematic Substitution  Issued
                                                     Molecular Synthesis                           at a given position
                [***]
CATEGORY 2       US         5,800,992        A Method of Detecting Nucleic Acids         1004B    Nucleic Acid Analysis    Issued
 (ASSAYS)                                                                                             with Arrays
                 US                           Methods for Nucleic Acid Analysis          1004C    Detecting Hybridization  Allowed
                                                                                                  with fluorescent label,
                 US                          A Method of Detecting Nucleic Acids         1004D       Expression 2          Allowed
                [***]
                [***]
                [***]
                [***]
                [***]
CATEGORY 3       US         5,384,261        Very Large Scale Immobilized Polymer        1009                              Issued
(SYNTHESIS)                                 Synthesis Using Mechanically Directed
                                                         Flow Paths
                 US         5,677,195          Combinatorial Strategies For             1009.1                             Issued
                                                     Polymer Synthesis
                 AU          675044            COMBINATORIAL STRATEGIES FOR             1009.1                             ISSUED
                                                     POLYMER SYNTHESIS
                [***]
                [***]
                [***]
                [***]
                [***]
                [***]
CATEGORY H      [***]
(SOFTWARE)      [***]
                [***]
                [***]
                [***]

</TABLE>

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

<PAGE>

<TABLE>
<CAPTION>

               COUNTRY      PATENT/                  TITLE OF INVENTION               AFFYMETRIX       FEATURE         STATUS
                          APPLICATION                                                  FILE NO.
                              NO.
<S>            <C>        <C>            <C>                                         <C>          <C>                <C>
               [***]
               [***]
               [***]
               [***]
CATEGORY       [***]
(DATABASES)    [***]
               [***]
               [***]
               [***]
               [***]
CATEGORY 6     US         5,578,832      Method and Apparatus for Imaging a Sample    1047         Apparatus for      Issued
 (IMAGING)                               on a Device                                             autofocusing on
                                                                                                    a sample.
               US         5,834,758      Method and Apparatus for Imaging a Sample    1047         Apparatus for      Issued
                                         on a Device                                             autofocusing on
                                                                                                    a sample.
               [***]
CATEGORY 7     US         5,631,734      Method and Apparatus for Detection of        1055A          Fluorescence      Issued
(DETECTION)                              Fluorescently Labeled Materials                              detector
                                                                                                   w/autofocus,
                                                                                                     translator,
                                                                                                         Do
               [***]
CATEGORY 8     [***]
(PACKAGING)    [***]
               [***]
               [***]
               [***]
               [***]

</TABLE>

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

                                                                    CONFIDENTIAL

                                LICENSE AGREEMENT

                                     BETWEEN

                                XENOMETRIX, INC.

                                       AND

                            ROSETTA INPHARMATICS INC.

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

<PAGE>

                                LICENSE AGREEMENT

This Agreement (this "AGREEMENT") is made this 12th day of November, 1998 (the
"EFFECTIVE Date"), by and between Xenometrix, Inc. ("XENO"), a Delaware
corporation with principal offices at 2425 North 55th Street, Boulder, CO
80301-5700 and Rosetta Inpharmatics, Inc. ("ROSETTA"), a Delaware corporation
with principal offices at 12040 115th Avenue N.E., Kirkland, WA 98034, to
license certain technology according to the terms and conditions, but subject
to the limitations, set forth in this Agreement.

                                    RECITALS

WHEREAS, XENO is the owner or exclusive licensee of the XENO Patents (as defined
below) and the Harvard Patents (as defined below) relating to certain assays,
technology and intellectual property further described herein, and desires to
non-exclusively license the same to ROSETTA; and

WHEREAS, ROSETTA seeks to obtain certain non-exclusive license rights and
sublicensing rights under the XENO Patents and the Harvard Patents, according to
the terms contained herein;

Now, therefore, in consideration of the foregoing and the covenants and promises
contained herein, the parties agree as follows:

 1.  DEFINITIONS

     1.1. "AFFILIATE" means any corporation or other business entity controlled
          by, or in common control of an entity. Control, as used in the context
          of a business entity, means the ownership directly or indirectly of
          greater than fifty percent (5 0%) of the voting securities of the
          person, corporation, or other entity.

     1.2. "CONFIDENTIAL INFORMATION" means all information, compounds, data, and
          Materials received by either party from the other party pursuant to
          this Agreement including, without limitation, technology of each
          party, subject to the exceptions set forth in Section 5.1.

     1.3.  "FIELD" means gene expression profiling and protein expression
           profiling, including but not limited to, identifying disturbances of
           cell homeostasis and related identified chemicals.

     1.4.  "HARVARD LICENSE AGREEMENT" means the license agreement between the
           President and Fellows of Harvard College ("Harvard") and Venmark
           Ltd., now XENO, executed on January 17, 1992, as amended to date,
           attached hereto as Exhibit C.

     1.5. "HARVARD PATENTS" means all patents and patent, applications listed on
          Exhibit A (Mammalian) and Exhibit B (Bacterial) hereto, including but
          not limited to any reissues, extensions, substitutions, confirmations,
          re-registrations, re-examinations, continuations, divisionals or
          continuations-in-part of the foregoing patents and patent
          applications, as well as all foreign counterparts or equivalents
          thereof.

     1.6. "MATERIALS" means any biological or chemical entity for screening or
          assays, including reagents, cells, promoters, enhancers, vectors,
          plasmids, proteins and fragments thereof, peptides, antigens,
          antibodies, antagonists, agonists, inhibitors, and chemicals.

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

<PAGE>

     1.7. "XENO PATENTS" means all the patents and patent applications listed on
          Exhibits A and B hereto, any patent applications filed prior or
          subsequent to the Effective Date that claim the benefit of an early
          filing date to any of the patent applications listed in Exhibit A and
          Exhibit B, and any reissues, extensions, substitutions, confirmations,
          re-registrations, reexaminations, continuations, divisionals or
          continuations-in-part of the foregoing patents and patent
          applications, as well as all foreign counterparts or equivalents
          thereof.

     1.8. "THIRD PARTY" means any entity other than (i) ROSETTA and any of its
          Affiliates, and (ii) XENO and any of its Affiliates.

 2.  LICENSES

     2.1. GRANT OF LICENSES UNDER THE XENO PATENTS AND THE HARVARD PATENTS FROM
XENO TO ROSETTA.

          2.1.1.  NON-EXCLUSIVE LICENSE TO XENO PATENTS. XENO hereby grants to
                  ROSETTA and its Affiliates a non-exclusive, world-wide license
                  in the Field under XENO's ownership interest in the XENO
                  Patents to make, use, have made, sell, have sold, offer for
                  sale, import, export or otherwise exploit any process,
                  composition of matter or other invention claimed in the
                  XENO Patents, with right of sublicense to corporate
                  partners or collaborators of ROSETTA. Such license shall
                  include the right to grant sublicenses to make, use and
                  have made the XENO Patents solely in conjunction with
                  Rosetta's technology for each sublicensee's internal
                  research purposes and not for the purpose of
                  commercializing such technology.

          2.1.2.  NON-EXCLUSIVE SUBLICENSE TO HARVARD PATENTS UNDER THE HARVARD
                  LICENSE AGREEMENT. XENO hereby grants to ROSETTA and its
                  Affiliates a non-exclusive, world-wide sublicense in the Field
                  under XENO's right to sublicense the Harvard Patents in the
                  Harvard License Agreement to make, use, have made, sell,
                  have sold, offer for sale, import, export, further
                  sublicense or otherwise exploit any process, composition of
                  matter or other invention claimed in the Harvard Patents.
                  Such license shall include the right to grant sublicenses
                  to make, use and have made the Harvard Patents solely in
                  conjunction with Rosetta's technology for each
                  sublicensee's internal research purposes and not for
                  commercializing such technology.

 3.  COMPENSATION

     3.1. COMPENSATION FOR THE XENO PATENTS LICENSE AND HARVARD PATENTS
SUBLICENSE.

          3.1.1.  LICENSES AND RIGHTS. As consideration for the licenses and
                  rights granted to ROSETTA herein, ROSETTA will pay to XENO:

                           a)       Two Hundred Fifty Thousand Dollars
($250,000.00) upon signing of the Agreement, of which [***] to cure XENO's
existing default under the Harvard License Agreement (the "Default") and
provides documentation of such payment to ROSETTA's reasonable satisfaction,
(ii) obtains a certificate, in a form reasonably acceptable to counsel to
ROSETTA, executed by Harvard stating that XENO is no longer in default under
the Harvard License Agreement and it being acknowledged and understood that
the Holdback will be immediately due and payable upon XENO's satisfaction of
clauses (i) and (ii) of this section 3.1.1 and

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

                                      -3-

<PAGE>

                           b)       An annual running royalty of [***] per
annum, payable within thirty (30) days of end of each calendar year.

 4.  REPRESENTATIONS AND WARRANTIES; COVENANTS

     4.1. REPRESENTATIONS AND WARRANTIES OF ROSETTA AND XENO.

          Each party hereby represents and warrants:

                  CORPORATE POWER. Such party is duly organized and validly
                  existing and in good standing under the laws of the state
                  and/or country of its incorporation and has all requisite
                  corporate power and authority to enter into this Agreement and
                  to carry out the provisions hereof.

                  DUE AUTHORIZATION. Such party is duly authorized and has all
                  corporate power necessary to execute and deliver this
                  Agreement and to perform its obligations hereunder.

                  BINDING AGREEMENT. This Agreement is a legal and valid
                  obligation binding upon such party and enforceable in
                  accordance with its terms. The execution, delivery and
                  performance of this Agreement by such party does not conflict
                  with any agreement, instrument or understanding, oral or
                  written, to which it is a party or by which it may be bound,
                  nor violate any law or regulation of any court, governmental
                  body or administrative or other agency having jurisdiction
                  over it.

     4.2. TITLE; NO INFRINGEMENT. XENO has full title and ownership of the XENO
          Patents and XENO has all rights to the XENO Patents and the Harvard
          Patents necessary to allow it to perform its obligations as
          contemplated in thiso Agreement. The licenses and sublicenses granted
          by XENO to ROSETTA under this Agreement will in no way constitute an
          infringement or other violation of any copyright, trade secret,
          trademark, patent or other proprietary right of any third party.

     4.3. NEGATION OF WARRANTIES

                  EXCEPT AS EXPRESSLY SET FORTH IN THIS AGREEMENT, XENO MAKES NO
                  REPRESENTATIONS AND EXTENDS NO WARRANTIES OF ANY KIND, EITHER
                  EXPRESSED OR IMPLIED. EXCEPT AS EXPRESSLY SET FORTH IN THIS
                  AGREEMENT, THERE ARE NO (a) EXPRESSED OR IMPLIED WARRANTIES OF
                  MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, OR TO
                  XENO'S KNOWLEDGE THAT THE USE OF THE XENO PATENTS AND HARVARD
                  PATENTS AS CONTEMPLATED IN THIS AGREEMENT WILL NOT INFRINGE
                  ANY PATENT, COPYRIGHT, TRADEMARK, OR OTHER RIGHTS OR (b) ANY
                  OTHER EXPRESSED OR IMPLIED WARRANTIES.

     4.4. HARVARD LICENSE AGREEMENT. XENO hereby represents and warrants that
          (a) [***], the Harvard License Agreement has not at the date hereof
          expired or been terminated by either XENO or Harvard and that XENO
          has not at the date hereof received nor given notice of breach or
          termination for breach of the Harvard License Agreement [***]

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

                                      -4-

<PAGE>

          neither XENO nor Harvard is in default under the Harvard
          License Agreement. XENO covenants to use best efforts to maintain the
          Harvard License Agreement from the date of this Agreement through the
          term of the Harvard License Agreement, including, but not limited to
          (c) complying with its obligations to pay the compensation due for the
          Harvard License Agreement and (d) refraining from entering into any
          modification or termination of the Harvard License Agreement that
          would in anyway affect ROSETTA's rights to the Harvard Patents under
          this Agreement. In the event that the Harvard License Agreement is
          terminated, the sublicense granted to ROSETTA by XENO pursuant to
          Section 2.1.2 with respect to Patent No. 5,811,231, Methods and
          Kits in Mammalian Gene Profiling will survive and any further
          sublicenses granted by ROSETTA to its sublicensee with respect to
          Patent No. 5,811,231, Methods and Kits in Mammalian Gene Profiling
          shall survive.

     4.5. INFRINGEMENT. ROSETTA hereby agrees to notify XENO immediately of any
          claim it receives for alleged patent infringement through use of XENO
          Patents Licenses and Rights.

     4.6. LICENSE AGREEMENT TO A THIRD PARTY. XENO hereby warrants that during
          the term of this Agreement XENO will not license XENO patents and/or
          sublicense Harvard License Agreement to a Third Party under financial
          and legal conditions substantially more favorable than the terms of
          the present Agreement.

5.       CONFIDENTIALITY

     5.1. CONFIDENTIAL INFORMATION. Except as expressly provided herein, the
          parties agree that, for the Term and five (5) years thereafter, the
          receiving party shall keep completely confidential and shall not
          publish or otherwise disclose to another party and shall not use for
          any purpose other than to perform the purposes contemplated by this
          Agreement any Confidential Information furnished to it by the
          disclosing party hereto pursuant to this Agreement, except that to
          the extent that it can be established by the receiving party by
          competent proof that such Confidential Information:

                  (a) was already known to the receiving party, other than under
                  an obligation of confidentiality, at the time of disclosure;

                  (b) was generally available to the public or otherwise part of
                  the public domain at the time of its disclosure to the
                  receiving party;

                  (c) became generally available to the public or otherwise part
                  of the public domain after its disclosure and other than
                  through any act or omission of the receiving party in breach
                  of this Agreement;

                  (d) was lawfully disclosed to the receiving party by a person
                   other than a party hereto; or

                  (e) was independently developed by the receiving party.

     5.2. PERMITTED USE AND DISCLOSURES. Each party hereto may use or disclose
          Confidential Information disclosed to it by the other party to the
          extent such use or disclosure is reasonably necessary in filing or
          prosecuting patent applications, prosecuting or defending litigation,
          complying with applicable law, governmental regulation or court order,
          submitting information to tax or other governmental authorities,
          making a permitted sublicense or otherwise exercising its rights

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

                                      -5-

<PAGE>

          hereunder, provided that if a party is required to make any such
          disclosure of another party's Confidential Information, other than
          pursuant to a confidentiality agreement, it will give reasonable
          advance notice to the latter party of such disclosure and, save to the
          extent inappropriate in the case of patent applications, will use
          reasonable efforts to secure confidential treatment of such
          information prior to its disclosure (whether through protective orders
          or otherwise).

     5.3. CONFIDENTIAL TERMS. Except as expressly provided herein, each party
          agrees not to disclose any material or financial terms of this
          Agreement to another party without the consent of the other party, not
          to be unreasonably withheld; PROVIDED, HOWEVER, each party reserves
          the right to make reasonable disclosures (including the redaction of
          material or financial terms) as required by securities or other
          applicable laws, or to actual or prospective investors or corporate
          partners (including licensees and acquirers), or to accountants,
          attorneys and other professional advisors on a need-to-know basis
          under circumstances that ensure the confidentiality thereof, or to the
          extent required by law. If such Confidential Information is to become
          public information by such disclosure the disclosing party must obtain
          the written consent of the non-disclosing party in order to obtain
          protection of the Confidential Information if necessary.

     5.4. PRESS RELEASE. Notwithstanding the foregoing, the parties shall agree
          upon a press release to announce the execution of this Agreement.
          Thereafter, XENO and ROSETTA may each disclose to Third Parties the
          information contained in such press release without the need for
          further approval by the other.

 6.  TERMINATION

     6.1.1. This Agreement shall continue until the last expiration date of all
          patents licensed under this Agreement and shall survive the
          bankruptcy, insolvency or similar event related to either party.

     6.1.2. Either party shall have the right to terminate this Agreement at any
          time for a material breach of this Agreement by the other party,
          provided that the non-breaching party shall have first given ninety
          (90) days prior written notice (thirty (30) days in the event of
          non-payment of any amounts due under this Agreement) to the
          breaching party describing such breach and stating the
          non-breaching party's intention to terminate this Agreement if such
          breach remains uncured, and the breaching party thereafter fails to
          cure same within thirty (30) days.

     6.1.3. ROSETTA may terminate this Agreement without cause at any time by
          providing written notice to XENO of such termination and such
          termination will be effective ninety (90) days thereafter. Any
          termination pursuant to this Section 6.1.3 shall not relieve
          ROSETTA of any obligation or liability accrued hereunder prior to
          such termination, including ROSETTA's obligation to pay royalties
          accrued or accruable. The licenses granted hereunder and all
          sublicenses granted by ROSETTA under this agreement shall terminate
          in the event the Agreement is terminated by ROSETTA or termination
          by an arbitrator for an uncured breach by ROSETTA.

 7.  MISCELLANEOUS

     7.1. BINDING EFFECT; ASSIGNMENT. This Agreement shall be binding upon the
          parties' respective successors and permitted assigns. Neither party
          may assign this Agreement or any of its rights or

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

                                      -6-

<PAGE>

          obligations hereunder without the prior written consent of the other
          party (not to be unreasonably withheld), and any such attempted
          assignment shall be void; PROVIDED, HOWEVER, that ROSETTA and XENO may
          assign this Agreement as part of a merger or consolidation in which
          the surviving entity assumes all of ROSETTA's and XENO's rights and
          obligations hereunder or a sale of substantially all of the assets or
          stock of such party to which this Agreement relates. The parties
          acknowledge and agree that until the Section 8.4 Amendment is executed
          and delivered, in the event that the Harvard License Agreement is
          terminated, Harvard shall have the option of having this Agreement
          assigned to it or terminating the licenses granted herein.

     7.2. EFFECT OF WAIVER. No waiver of any default, condition, provisions or
          breach of this Agreement shall be deemed to imply or constitute a
          waiver of any other like default, condition, provision or breach of
          this Agreement.

     7.3. LIMITATION OF LIABILITY. NEITHER PARTY SHALL BE LIABLE TO THE OTHER
          FOR ANY SPECIAL, CONSEQUENTIAL, INCIDENTAL, OR INDIRECT DAMAGES
          ARISING OUT OF THIS AGREEMENT, HOWEVER CAUSED, UNDER ANY THEORY OF
          LIABILITY.

     7.4. INDEMNIFICATION. ROSETTA will defend, indemnify and hold XENO, its
          officers, directors, employees, Affiliates and agents harmless against
          any and all liability, loss, damage, claim or expense (including
          attorneys' fees) arising out of (a) a breach of any representation or
          warranty or covenant made by ROSETTA in this Agreement or (b) a suit
          by a Third Party directly relating to the negligence of ROSETTA in the
          performance under this Agreement by ROSETTA; except to the extent such
          claim is caused by the negligence or willful misconduct of XENO or a
          breach of a representation or warranty of XENO. XENO will defend,
          indemnify and hold ROSETTA, its officers, directors, employees,
          Affiliates and agents harmless against any and all liability, loss,
          damage, claim or expense (including attorneys' fees) arising out of
          (x) a breach of any representation or warranty or covenant made by
          XENQ in this Agreement or (y) a suit against ROSETTA, its officers,
          directors, employees, Affiliates or agents by a Third Party related to
          ROSETTA's performance under this Agreement. ROSETTA may, at its
          option, conduct the defense in any such suit by a Third Party and XENO
          agrees to cooperate fully with such defense.

     7.5. LIABILITY INSURANCE. ROSETTA agrees that it shall indemnify, defend,
          and hold XENO harmless from any claim, demand or action by any Third
          Party arising out of ROSETTA's gross negligence or intentional
          misconduct relating to ROSETTA's performance under this Agreement.
          ROSETTA agrees to maintain at its expense general liability coverage
          at a minimum level of Three Million Dollars ($3,000,000) per
          occurrence, to name XENO as an additional insured on ROSETTA's
          general liability policy at all times during the term of this
          Agreement and to furnish XENO, upon reasonable request,
          certificates evidencing such coverage and copies of the applicable
          policies.

     7.6. PATENT DEFENSE COSTS. XENO will use reasonable efforts, at its
          discretion to defend XENO Patents and Harvard Patents at its own
          expense against any infringement by a Third Party, and XENO will
          notify ROSETTA promptly in writing of any such infringement by a Third
          Party known by XENO; PROVIDED, HOWEVER, that (a) ROSETTA, at its
          option, may elect to join any such prosecution of a Third Party
          infringer initiated by XENO at ROSETTA's expense and (b) XENO will
          conduct such prosecution upon the advice and consent of ROSETTA with
          respect to material decisions (including litigation strategy
          decisions) relating to such prosecution. If XENO

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

                                      -7-

<PAGE>

          does not initiate such a prosecution with respect to any individual
          instance of Third Party infringement, ROSETTA may, at its own expense,
          upon the advice and with the consent of XENO, initiate and control
          such prosecution. In the event that ROSETTA is sued by a Third Party
          for infringement of a Third Party's patent, XENO hereby agrees, if
          ROSETTA so requests, to provide ROSETTA with all reasonable advice or
          technical support that ROSETTA may reasonably request at ROSETTA's
          expense.

     7.7. DILIGENCE. ROSETTA agrees to use reasonable commercial efforts to
          fulfill the obligations of the express due diligence provision of the
          Harvard License Agreement as it applies to a sublicense under the
          Harvard License Agreement.

     7.8. FORCE MAJEURE. Neither party shall lose any rights hereunder or be
          liable to the other party for damages or losses (except for payment
          obligations) on account of failure of performance by the defaulting
          party if the failure is occasioned by war, strike, fire, act of God,
          earthquake, flood, lockout, embargo, governmental acts or orders or
          restrictions, failure of suppliers, or any other reason where failure
          to perform is beyond the reasonable control and not caused by the
          negligence or intentional conduct or misconduct of the nonperforming
          party, and such party has exerted all reasonable efforts to avoid or
          remedy such force majeure; PROVIDED HOWEVER, that in no event shall a
          party be required to settle any labor dispute or disturbance. -

     7.9. AMENDMENT. No modification, supplement to or waiver of this Agreement
          or any Addendum hereto or any of their provisions shall be binding
          upon a party hereto unless made in writing and duly signed by an
          authorized representative of both XENO and ROSETTA. In no event may
          the terms of this Agreement be changed, deleted, supplemented or
          waived by any notice, purchase order, receipt, acceptance, bill of
          lading or other similar form of document. A failure of either party to
          exercise any right or remedy hereunder, in whole or in part, or on one
          or more occasions, shall not be deemed either a waiver of such right
          or remedy to the extent not exercised, or of any other right or
          remedy, on such occasion or a waiver of any right or remedy on any
          succeeding occasion.

    7.10. ENTIRE AGREEMENT. This Agreement, and each Exhibit attached hereto,
          and each supplemental written agreement contemplated hereunder, sets
          forth the entire understanding and agreement of the parties as to the
          subject matter thereof, and there are no other understandings,
          representations or promises, written or verbal, not set forth herein
          or on which either party has relied. If any provisions of any such
          Addendum or supplemental written agreement conflict with any
          provisions set forth in this Agreement, the provisions of this
          Agreement shall take precedence, unless such Addendum or supplemental
          written agreement expressly refers to the specific provision(s) of
          this Agreement that it is intended to replace or modify (and which
          shall be limited in force and effect to such Addendum or supplemental
          written agreement only).

    7.11. NOTICES.  All Notices under this Agreement shall be given in writing
          and shall be addressed to the parties at the following addresses:

                           FOR XENO:

                                    Stephen J. Sullivan
                                    CEO, President and Director
                                    Xenometrix, Inc.
                                    2425 North 55th Street

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

                                      -8-

<PAGE>

                                    Boulder, Colorado 8030 1-5700

                            FOR ROSETTA:

                                    President
                                    Rosetta Inpharmatics
                                    12040 115th Avenue NE
                                    Kirkland, WA 98034

          Notices shall be in writing and shall be deemed delivered when
          received, if delivered by a courier, overnight mail service or the
          like, or a week following mailing, if sent by first-class certified or
          registered mail, postage prepaid.

    7.12. ARBITRATION. The parties recognize that disputes as to certain
          matters may from time to time arise during the term of this Agreement
          which relate to either party's rights and/or obligations hereunder. It
          is the objective of the parties to establish procedures to facilitate
          the resolution of disputes arising under this Agreement in an
          expedient manner by mutual cooperation and without resort to
          arbitration. The parties agree that prior to any arbitration
          concerning this Agreement, XENO's CEO and ROSETTA's CEO or COO will
          meet in person or by video-conferencing in a good faith effort to
          resolve any disputes concerning this Agreement. Within thirty (30)
          days of a formal request by either party to the other, any party
          may, by written notice to the other, have such dispute referred to
          their respective officers designated or their successors, for
          attempted resolution by good faith negotiations, such good faith
          negotiations to begin within thirty (30) days after such notice is
          received. Except as otherwise provided specifically herein, any
          controversy or claim under this Agreement shall be solely settled
          by arbitration by one arbitrator pursuant to the Commercial
          Arbitration Rules of the American Arbitration Association (the
          "Association"); provided that the parties shall first use their
          best efforts to resolve such dispute by negotiation. The
          arbitration shall be conducted in Boulder, Colorado. The arbitrator
          shall be selected by the joint agreement of the parties, but if
          they do not so agree within twenty (20) days of the date of a
          request for arbitration, the selection shall be made pursuant to
          the rules of the Association. The decision reached by the
          arbitrator shall be conclusive and binding upon the parties hereto
          and may be filed with the clerk of any court of competent
          jurisdiction, and a judgment confirming such decision may, if
          desired by any party to the arbitration, be entered in such court.
          Each of the parties shall pay its own expenses of arbitration and
          the expenses of the arbitrator(s) shall be equally shared;
          PROVIDED, HOWEVER, that if in the opinion of the arbitrator(s) any
          claim hereunder or any defense or objection thereto was
          unreasonable, the arbitrator(s) may assess, as part of the award,
          all or any part of the arbitration expenses (including reasonable
          attorneys' fees) against the party raising such unreasonable claim,
          defense or objection. Nothing herein set forth shall prevent the
          parties from settling any dispute by mutual agreement at any time.

    7.13. GOVERNING LAW. This Agreement shall be governed by and construed in
          accordance with the laws of the State of Colorado, without regard or
          giving effect to its principles of conflict of laws.

    7.14. SEVERABILITY AND SURVIVAL. This Agreement is intended to be
          severable. If any provision(s) of this Agreement are or become
          invalid, are ruled illegal by a court of competent jurisdiction or are
          deemed unenforceable under the current applicable law from time to
          time in effect during the term hereof, it is the intention of the
          parties that the remainder of the Agreement shall not be affected
          thereby and shall continue to be construed to the maximum extent
          permitted by law at

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

                                      -9-

<PAGE>

          such time. It is further the intention of the parties that in lieu of
          each such provision which is invalid, illegal, or unenforceable, there
          shall be substituted or added as part of this .Agreement by such court
          of competent jurisdiction a provision which shall be as similar as
          possible, in economic and business objectives as intended by the
          parties to such invalid, illegal or unenforceable provision, but shall
          be valid, legal and enforceable. Unless expressly stated otherwise,
          any provision intended by its meaning to survive, will survive the
          expiration or any other termination of this Agreement.

    7.15. INDEPENDENT CONTRACTORS. The parties hereto are acting as independent
          contractors and shall not be considered partners, joint venturers or
          agents of the other. Neither shall have the right to act on behalf of,
          or to bind, the other.

    7.16. HEADINGS. Captions and paragraph headings are for convenience only
          and shall not form an interpretative part of this Agreement. Unless
          otherwise specifically provided, all references to an Article
          incorporate all Articles or subsections thereunder. This Agreement
          shall not be strictly construed against either party hereto and maybe
          executed in two or more counterparts, each of which will be deemed an
          original and the same instrument.

                            (Signature Page Follows]

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

                                      -10-

<PAGE>

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

By: /s/ Stephen J. Sullivan                        Date: 11/12/98
   -------------------------------------                 ---------------------

Stephen J. Sullivan
CEO and President
For Xenometrix, Inc.

By: /s/ Stephen H. Friend, M.D., Ph.D.             Date: 11/12/98
   -------------------------------------                 ---------------------

Stephen H. Friend, M.D., Ph.D.
President, Chief Scientific Officer
for ROSETTA INPHARMATICS, Inc.

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

                                      -11-

<PAGE>

                                    EXHIBIT A

<TABLE>
<CAPTION>

         PATENT/              FILING DATE            COUNTY              ISSUE DATE                   TITLE
      APPLICATION #

    <S>                       <C>                 <C>                   <C>              <C>

          [***]                   [***]               [***]

        5,811,231                7/21/95                US                9/22/98              Methods and Kits for
                                                                                             Mammalian Gene Profiling
         692434                  1/21/94             Australia            6/11/98
        E160178                  1/21/94              Austria            11/12/97
       0 680 517                 1/21/94              Belgium            11/12/97
        2154265                  1/21/94              Canada
       0 680 517                 1/21/94              Denmark            11/12/97
       0 680 517                 1/21/94                EPC              11/12/97
       0 680 517                 1/21/94              France             11/12/97
    694 06 772,5-08              1/21/94              Germany            11/12/97
       980400301                 1/21/94              Greece             11/12/97
       0 680 517                                     Hong Kong
        E77394                   1/21/94              Ireland            11/12/97
      20035BE/98                 1/21/94               Italy             11/12/97
       6-517147                  1/21/94               Japan
       0 680 517                 1/21/94             Luxembourg          11/12/97
       0 680 517                 1/21/94               Monaco            11/12/97
       0 680 517                 1/21/94             Netherlands         11/12/97
      US94/00583                 1/21/94                PCT
       0 680 517                 1/21/94              Portugal            1/19/98
       9601405-5                 2/13/96             Singapore
       0 680 517                 1/21/94               Spain             11/12/97
       0 680 517                 1/21/94               Sweden            11/12/97
       0 680 517                 1/21/94            Switzerland          11/12/97
       0 680 517                 1/21/94                UK               11/12/97

</TABLE>

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

<PAGE>

                                    EXHIBIT B

<TABLE>
<CAPTION>

         PATENT/              FILING DATE            COUNTY              ISSUE DATE                   TITLE
      APPLICATION #

      <S>                     <C>                 <C>                    <C>             <C>
        5,589,337               1/6/95                 US                 12/31/96        Methods and Diagnostic Kits
                                                                                          for Determining Toxicity
                                                                                          Utilizing Bacterial Stress
                                                                                          Promoters Fused to Report
                                                                                          Genes
         651825                 7.6.93                 EPO                 1/14/98
        5,585,232              4/21/94                 US                 12/17/96        Methods and Diagnostics
                                                                                          Kits for Determining
                                                                                          Toxicity Utilizing E.coli
                                                                                          Stress Promoters Fused to
                                                                                          Reporter Genes
        9601688-6              2/14/96              Singapore
        2,139,667               7/9/93               Canada
        6-503562                7/6/93                Japan
        95-700038               7/6/93                Korea
        07/910793               7/6/92                  US
        45884/95                7/6/93              Australia
         95.004                 7/6/93                Norway

</TABLE>

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

<PAGE>

                                    EXHIBIT C

                            HARVARD LICENSE AGREEMENT

                                LICENSE AGREEMENT

         This Agreement is made and entered into between the President and
Fellows of Harvard College (hereinafter "Harvard") having offices at the
Office for Technology and Trademark Licensing, 124 Mt. Auburn Street, Suite
410, Cambridge, Massachusetts 02138 and Venmark Ltd. (hereinafter
"Licensee"), a New York corporation having offices c/o The Castle Group,
Ltd., 375 Park Avenue, Suite 1501, New York, New York 10022.

         Whereas Harvard is the owner by assignment from Dr. Spencer Farr
(the "Inventor") of the entire right, title and interest in the United States
patent Application yet to be filed described in Exhibit A attached hereto
(which Exhibit shall be amended to include the actual Application when such
Application is filed), in the foreign patent applications corresponding
thereto, and in the inventions described and/or claimed therein; and

         Whereas Harvard is committed to a policy that ideas or creative
works produced at Harvard should be used for the greatest possible public
benefit; and

         Whereas Harvard accordingly believes that every reasonable incentive
should be provided for the prompt introduction of such ideas into public use,
all in a manner consistent with the public interest; and

         Whereas Licensee is desirous of obtaining an exclusive worldwide
license in order to practice the above referenced invention covered by Patent
Rights in the United States and in certain foreign countries, and to
manufacture, have manufactured, use and sell in the commercial market the
products made in accordance therewith; and

         Whereas Harvard is desirous of granting such a license to Licensee
in accordance with the terms of this Agreement.

         Now therefore, in consideration of the foregoing premises, the
parties agree as follows:

                                    ARTICLE 1

                                   DEFINITIONS

     1.1  "Patent Rights" shall mean (i) the United States Patent Application
          yet to be filed described in Exhibit A attached hereto (which Exhibit
          shall be amended to include the actual Application when such
          Application is filed), the inventions described and/or claimed
          therein, and any substitutions, divisions, continuations,
          continuations-in-part, patents issuing thereon r reissues or
          re-examinations thereof and any and all foreign patents and patent
          applications corresponding thereto; (ii) all patent applications to
          the extent assigned to Harvard and to the extent Harvard is able,
          under its obligations to third parties, to grant rights to Licensee
          and on which Inventor is a named inventor, the inventions described
          and/or claimed therein and any substitutions, divisions,
          continuations, continuations-in-part, patents issuing thereon or
          reissues or re-examinations thereof which relate to the design,
          development and/or manufacture of any products incorporating the
          technology identified in (i) to the extent that their use would be in
          any way dominated by the claims in (i) and any and all foreign patents
          and patent applications corresponding thereto; (iii) all patent
          applications to the extent assigned to Harvard and to the extent
          Harvard is able, under its obligations to third parties, to grant
          rights to Licensee and on which Inventor is a named inventor, the
          inventions described and/or claimed therein and any substitutions,
          divisions, continuations, continuations-in-part, patents issuing
          thereon or reissues

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

<PAGE>

          or re-examinations thereof which relate to any improvements in the
          technology incorporated in (i) or (ii) to the extent that their use
          would be in any way dominated by the claims in (i) and any and all
          foreign patents and patent applications corresponding thereto. The
          foreign patents and patent applications corresponding thereto referred
          to in (i), (ii) and (iii) above when filed or issued will be
          automatically incorporated in and added to this Agreement and shall
          periodically be added to Appendix A attached to this Agreement and
          made a part hereof; provided, however, that no failure to periodically
          add such foreign patents and/or patent applications thereto shall be
          considered to exclude such foreign patents and/or patent applications
          from the meaning of "Patent Rights."
         1.2 "Licensed Products" shall mean products or components thereof
claimed in Patent Rights or products or components thereof made in accordance
with or by means of Licensed Processes.

         1.3 "Licensed Processes" shall mean the processes claimed in Patent
Rights and any and all inventions, designs, drawings, specifications, ideas,
discoveries, trade secrets, know-how, codes, formulas, techniques and data
which have been developed or acquired by the Inventor and to which Harvard
has ownership rights.

         1.4 "Net Sales" shall mean the amount billed or invoiced on sales of
Licensed Products or Licensed Processes less:

                  (a)      Customary trade, quantity or cash discounts and
                           non-affiliated brokers' or agents' commissions
                           actually allowed and taken;

                  (b)      Amounts repaid or credited by reason of rejection or
                           return; and/or

                  (c)      To the extent separately stated on purchase orders,
                           invoices or other documents of sale, taxes levied on
                           and/or other governmental charges made as to
                           production, sale, transportation, delivery or use and
                           paid by or on behalf of Licensee.

In the event of a use or sale of Licensed Products or Licensed Processes
solely for clinical testing or research and development purposes for which
Licensee receives no revenue, then no royalty shall be due or payable to
Harvard pursuant to the Article 3 or otherwise.

     1.5  "Affiliates" shall mean any company, corporation, or business in which
          Licensee owns or controls at least fifty percent (50%) of the voting
          stock.
          1.6 "Field" shall mean all potential fields or use of the Patents
Rights, the Licensed Products and the Licensed Processes, including, but not
limited to, molecular biology and toxicology.

          1.7 "Sublicensee" shall mean an entity which Licensee has granted
(a) the right to manufacture and market the Licensed Products, or (b) the
right to sublicense the Licensed Processes to others, or (c) the right to
practice the Licensed Processes as part of the business of tasting
toxicological responses of any products on behalf of other entities except
when that right is granted to the purchaser of a kit containing a Licensed
Product to allow such purchaser to use such kit.

                                    ARTICLE 2

                                      GRANT

     2.1  Harvard hereby grants to Licensee and Licensee accepts, subject to the
          terms and conditions hereof, a worldwide exclusive license in the
          Field, under Patent Rights, to make and have made, to use and have
          used, to sell and have sold, to distribute and have distributed and to
          market and

                                      -2-

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

<PAGE>

          have marketed the Licensed Products, and to practice the Licensed
          Processes, for the life of the Patent Rights. Such license shall
          include the right to grant sublicenses, and Licensee agrees to give
          Harvard thirty (30) days written notice of the identity of any
          sublicensee prior to executing any sublicense agreement with respect
          to the Patent Rights. Harvard agrees it will not grant licenses to
          others except as required by Harvard's obligations in paragraph 2.2(a)
          or as permitted in paragraph 2.2(b). Licensee agrees during the period
          of exclusivity of this license in the United States that any Licensed
          Product produced for sale in the United States will be manufactured
          substantially in the United States.

     2.2  The granting and acceptance of this license is subject to the
following conditions:
                  (a) Harvard's "Statement of Policy in Regard to Inventions,
Patents and Copyrights" dated March 17, 1986, Public Law 96-517, Public Law
98-620, in each case, as in effect on the date the particular patent Right
becomes a Patent Right subject to this Agreement. Any right granted in this
Agreement greater than that permitted under Public Law 96-517 or Public Law
98-620, in each case, as in effect on the date the particular Patent Right
becomes a Patent Rights, subject to this Agreement, shall be subject to
modification as may be required to conform to the provisions of those statutes.

                  (b) Harvard shall have the right to make and to use, for
its own research purposes only and not for any commercial purpose, the
subject matter described and claimed in Patent Rights.

                  (c) Licensee shall use reasonable effort to effect
introduction of the Licensed Products into the commercial market as soon as
practicable, consistent with sound and reasonable business practices and
judgments; thereafter, until the expiration of this Agreement, Licensee shall
endeavor to keep Licensed Products reasonably available to the public;
recognizing, however, that this provision shall not affect Licensee's right
to freely determine pricing for the Licensed Products and Licensed Processes.

                  (d) After giving Licensee [***] prior written detailed
notice, Harvard shall have the right to terminate this License as to a
particular country or render this license non-exclusive as to a particular
country at any time after [***] from the date of license if, in Harvard's
reasonable judgment, at the end of the [***] notice period Licensee EITHER:

     (i)  has not put the license subject matter into commercial use in such
          country directly or through a sublicense, and is not keeping the
          licensed subject matter reasonably available to the public in such
          country, OR
                           (ii) is not demonstrably engaged in research,
         development, manufacturing, marketing or licensing program, as
         appropriate, directed toward this end in such country.

In making this determination Harvard shall take into account the normal
course of such programs conducted with sound and reasonable business
practices and judgment and shall take into account the reports provided
hereunder by Licensee.

                  (e) All sublicenses granted by Licensee hereunder shall
include a requirement that the sublicensee use reasonable efforts to bring
the subject matter of the sublicense into the commercial market as soon as
practicable, consistent with sound and reasonable business practices and
judgment. Copies of all sublicense agreements shall be provided to Harvard.

     2.3  If this license is terminated with respect to a particular country or
          rendered non-exclusive as to a particular country by Harvard in
          accordance with Section 2.2 hereof, or if this license is terminated
          in accordance with Section 8.2 hereof, Harvard may at its sole option
          extend the period of exclusivity, extend the license on a
          non-exclusive basis, or, in the case of a termination under Section
          2.2 or 8.2, permit the license to terminate.

                                      -3-

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

<PAGE>

         2.4 Harvard hereby grants to Licensee the right to extend the
licenses granted or to be granted in paragraphs 2.1 and 2.3 to an Affiliate
subject to the terms and conditions hereof.

         2.5 All rights reserved to the United States Government and others
under Public Law 96-517 and 98-620, in each case, as in effect on the date
the particular Patent Rights becomes subject to this Agreement shall remain
and shall in no way be affected by this Agreement.

                                    ARTICLE 3

                                    ROYALTIES

     3.1  Licensee shall pay to Harvard a non-refundable license fee in the sum
          of [***] upon execution of this Agreement. Licensee shall also pay
          Harvard [***] within sixty (60) days after a non-temporary order of
          the Food and Drug Administration or the Environmental Protection
          Agency requiring the use of a Licensed Product or Licensed Process
          where Licensee, together with its Affiliates and Sublicensees,
          constitutes the market leader in terms of Net Sales of such Licensed
          Product or Licensed Process.
          3.2 (a) Licensee shall pay to Harvard, during the term of the license
of paragraph 2.1, a royalty of [***]of the Net Sales of all Licensed Products
sold (i.e., sales of kits containing a Licensed Product) by Licensee and its
Affiliates. Licensee shall pay to Harvard, during the term of the license of
paragraph 2.1, a royalty of [***] of the Net Sales of all Licensed Processes
sold (i.e., toxicology tasting services performed for others by employees of
Licensee or its Affiliate) by Licensee and its Affiliates. Licensee shall pay to
Harvard, during the term of the license of paragraph 2.1 and before a patent is
issued with respect to any Paten Right, a royalty of [***] of the
sublicensing income (i.e., royalties and license issue fees) which Licensee and
its Affiliates receive from End-User Sublicensees for sublicenses of the
Licensed Processes. Licensee shall pay to Harvard, during the term of the
license of paragraph 2.1 and after a patent is issued with respect to any Patent
Right, a royalty of [***] of the sublicensing income (i.e., royalties and
license issue fees) which Licensee and its Affiliates receive from End-User
Sublicensees for sublicenses of the Licensed Processes. Licensee shall pay to
Harvard, during the term of the license of paragraph 2.1, a royalty of [***]
of the sublicensing income i.e., royalties and license issue fees) which
Licensee and its Affiliates receive from Sublicensees for sublicenses of the
Licensed Products or Licensed Processes. No multiple royalties shall be due
because the sale or sublicense of any Licensed Product or Licensed Process is
described in more than one sentence of this Section 3.2(a). In the event of any
such overlap, the sentence which most accurately describes the relevant
transaction at issue shall prevail.

                  (b) If this license is converted to a non-exclusive one as
to a particular country or if other non-exclusive licenses are granted
pursuant to Section 2.3 hereof, the royalty payable by Licensee with respect
to Net Sales of Licensed Products or Licensed Processes the subject of such
non-exclusive license shall not exceed the royalty being paid by other
licensees to Harvard during the tem of the non-exclusive license. On Net
Sales or sublicenses between Licensee and its Affiliates, royalties ahll be
payable on the resale or subsublicense only.

     3.3  (a) As further consideration for the licensure of Patent Rights, upon
          the closing of the first round of equity investment in License,
          Licensee agrees to issue to Harvard shares of Licensee's Class B
          Common Stock which shall be convertible into [***] of Licensee's
          Class A Common Stock on a fully diluted basis. The Class B Common
          Stock shall have the characteristics, rights, preferences and
          privileges set forth in the Certificate of Incorporation of the
          Licensee and set forth herein as Exhibit B. Such characteristics,
          rights, preferences and privileges shall not be amended without the
          consent of Harvard.
                  (b) In the event that Harvard adopts a policy which requires
Harvard to divest all

                                      -4-

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

<PAGE>

interests Harvard may have in entities which license technology from Harvard,
then until the Licensee's shares are publicly traded, Harvard may, after giving
Licensee ninety (90) days notice, require that Licensee purchase Harvard's
shares at the last offered price or, if no offered price exists, at a price of
[***] of the amount invested in Licensee as of that date.

     3.4  Harvard shall have the right to terminate this license in the event
          that Licensee does not pay to Harvard at least the following amounts
          in license maintenance fees and/or minimum royalties:
                  Third calendar year, 1994                   [***]
                  Next calendar year                          [***]
                  Next calendar year and each
                           year thereafter                    [***]

                                    ARTICLE 4

                                    REPORTING

     4.1  Licensee shall provide written annual reports within sixty (60) days
          after June 30 of each calendar year which shall include but not be
          limited to: reports of progress on research and development,
          regulatory approvals, manufacturing, sublicensing, marketing and sales
          during the preceding twelve (12) months as well as plans for the
          coming year. If progress differs from that anticipated in the plan
          provided under Section 4.1 hereof, Licensee shall explain the reasons
          for the difference and propose a modified plan for Harvard's review
          and comment. Licensee shall also provide any reasonable additional
          data Harvard requires to evaluate Licensee's performance.
         4.2 Licensee shall report to Harvard the date of first sale of Licensed
Products (or results of Licensed Processes) in each country within thirty (30)
days of occurrence.

         4.3 Licensee agrees to submit to Harvard within sixty (60) days after
the calendar half years ending June 30 and December 31, reports setting forth
for the preceding six (6) month period the amount of the Licensed Products sold
by Licensee, its Affiliates and sublicensees in each country, the Net Sales
thereof, and the amount of royalty due thereon and with each such royalty report
to pay the amount of royalty due. Such report shall be certified as correct by
an officer of Licensee and shall include a detailed listing of all deductions
from Net Sales, sublicensee income or from royalties as specified herein. If no
royalties are due to Harvard for any reporting period, the written report shall
so state. All royalties due hereunder shall be payable in United States dollars.
Conversion of foreign currency to U.S. dollars shall be made at the conversion
rate existing in the United States on the date of royalty payments by Licensee.
Payments which are more than sixty (60) days past due and which are not the
subject of a good faith controversy between the parties hereto shall be subject
to an interest charge of [***] per month.

         4.4 (a) Harvard's Office of Technology and Trademark Licensing ("OTTL")
agrees that at all times, both during the term and after the termination of this
Agreement, it will keep in confidence and trust all information provided to it
hereunder by Licensee or provided to it by any third party pursuant to Section
5.1 hereof (the "Proprietary Information"), and it will not use or disclose any
Proprietary Information or anything directly relating to it without the written
consent of the Licensee. OTTL warrants that OTTL shall not disclose Proprietary
Information to officers or employees of either OTTL or Harvard, except if such
disclosure is necessary to perform its obligations under this Agreement. OTTL
shall be responsible for maintaining adequate internal procedures sufficient to
fulfill its obligations under this Section 4.4. OTTL acknowledges that the
Proprietary Information constitutes a unique and valuable asset of the Licensee,
which is secret and confidential and which will be communicated to OTTL in
confidence and that any disclosure or other use of the Proprietary Information
other than for the sole benefit of the Licensee would be wrongful and would
cause irreparable harm to the Licensee.

                                      -5-

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

<PAGE>

                  (b) Notwithstanding the foregoing, the parties agree that, at
all such times, Harvard is free to use or disclose, as the case may be, (i)
information in the public domain not as a result of the breach of this
Agreement, (ii) Harvard's own skill, knowledge, know-how and experience to
whatever extent and in whatever way it wishes, and (iii) information which
Harvard is by law, including Public Law 960517 and 98-620, required to disclose

     4.5  Licensee agrees to consult with Harvard regarding its intention to
          seek financing from the public markets and to inform Harvard
          substantially in advance of its intentions and to copy Harvard on all
          drafts of offering memorandums coincidental with Licensee's receipt of
          same. In any event, Licensee agrees that it will not seek financing
          from the public markets until at least one of the following has
          occurred:
                  (a) Licensee has obtained a cumulative minimum investment of
[***], and such funds have been allocated for use;

                  (b) [***] from the execution of this Agreement have passed;

                  (c) Approval, recommendation or requirement of use for the
Licensed Products or Licensed Processes has been obtained from any Federal
regulatory agency;

                  (d) Licensee has in excess of [***]; or

                  (e) Licensee has reduced the Licensed Products or Licensed
Processes to practice in the form of a saleable kit.

                                    ARTICLE 5

                                 RECORD KEEPING

     5.1  Licensee shall keep, and shall require its Affiliates and sublicensees
          to keep, accurate and correct records of Licensed Products or Licensed
          Processes made, used or sold under this Agreement, appropriate to
          determine the amount of royalties due hereunder to Harvard. Such
          records shall be retained for at least [***] following a given
          reporting period. On reasonable prior written notice to Licensee, such
          records shall be available during normal business hours for inspection
          at the expense of Harvard by Harvard's Internal Audit Department or by
          a Certified Public Accountant selected by Harvard and approved by
          Licensee for the sole purpose of verifying reports and payments
          hereunder. Such accountant shall not disclose to Harvard any
          information other than information relating to accuracy of reports and
          payments made under this Agreement. In the event that any such
          inspection shows an underreporting and underpayment in excess of [***]
          for any twelve (12) month period, then Licensee shall pay the cost
          of such examination. Licensee shall be entitled to receive from
          Harvard copies of all reports prepared by or on behalf of Harvard in
          the exercise by Harvard of its rights hereunder.
                                    ARTICLE 6

               DOMESTIC AND FOREIGN PATENT FILING AND MAINTENANCE

         6.1 Subject to the provisions of Section 6.3 hereof, Licensee shall
reimburse Harvard for all reasonable out-of-pocket expenses Harvard has incurred
for the preparation, filing, prosecution and maintenance of Patent Rights and
shall reimburse Harvard for all such future reasonable out-of-pocket expenses.
Harvard shall take responsibility for the preparation, filing, prosecution and
maintenance of any and all patent applications and patents included in Patent
Rights, provided however that Harvard shall first consult with Licensee as to
the preparation, filing, prosecution and maintenance of such patent

                                      -6-

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

<PAGE>

applications and patents and shall furnish to Licensee copies of documents
relevant to any such preparation, filing, prosecution or maintenance.

         6.2 Harvard and Licensee shall cooperate fully in the preparation,
filing, prosecution and maintenance of Patent Rights and of all patents and
patent applications licensed to Licensee hereunder, executing all papers and
instruments or requiring members of Harvard to execute such papers and
instruments so as to enable Harvard to apply for, to prosecute and to maintain
patent applications and patents in Harvard's name in any country. Each party
shall provide to the other prompt notice as to all matters which come to its
attention and which may affect the preparation, filing, prosecution or
maintenance of any such patent applications or patents. Either party may give
notice to the other of any foreign country in which such party wishes to seek
patent protection for all or any part of the Patent Rights. In the case of such
a designation by Licensee (and the provision of reasonable assurance of payment
by it of the expenses to be incurred) Harvard may not refuse to seek such patent
protection in the country so designated.

         6.3 Harvard shall submit a written request to Licensee for any
reasonable out-of-pocket expenses incurred by it in complying with Sections 6.1
and 6.2 hereof. Licensee is obligated to reimburse any reasonable expenses
incurred by Harvard for action in support of Patent Rights unless after
providing written notice to Licensee, Harvard is notified in writing in advance
of any such action that such action should not be taken. If, within sixty (60)
days of such request, Licensee elects not to pay the expenses of a patent
application or patent included within Patent Rights, Licensee shall thereby
surrender its rights under such patent or patent application.

                                    ARTICLE 7

                                  INFRINGEMENT

         7.1 With respect to any Patent Rights under which Licensee is
exclusively licensed pursuant to this Agreement, Licensee or its sublicensee
shall have the right to prosecute in its own name and at its own expense any
infringement of such patent, so long as such license is exclusive at the time of
the commencement of such action. Harvard agrees to notify Licensee promptly of
each infringement of such patents of which Harvard is or becomes aware. Licensee
shall reimburse Harvard for its reasonable out-of-pocket expenses incurred in
connection with any protection of the non-exclusively licensed Patent Rights pro
rata in the proportion the aggregate amount of such expenses bears to the total
number of non-exclusive licensees of such Patent Rights. Failure by either party
to commence an action which is contemplated by this Section 7.1 shall not
constitute a breach of this Agreement.

         7.2 If Licensee or its sublicensee elects to commence an action as
described above or if an action is commenced against the Licensee or its
sublicensee by a third party and Harvard is a legally indispensable party to
such action, Harvard shall have the right either to join the action as a
co-plaintiff or to assign to Licensee all of Harvard's right, title and interest
in each patent which is a part of the Patent Rights and is the subject of such
action (subject to all Harvard's obligations to the government and others having
rights in such patent). In the event Harvard joins the action as a co-plaintiff,
Harvard shall jointly control the action with the Licensee or its sub-licensee.
In the event that Harvard makes such an assignment, such assignment shall be
irrevocable, and such action by Licensee on that patent or patents shall
thereafter be brought or continued without Harvard as a party, if Harvard is no
longer an indispensable party. Notwithstanding any such assignment to Licensee
by Harvard and regardless of whether Harvard is or is not an indispensable
party, Harvard shall cooperate fully with Licensee in connection with any action
commenced by or against Licensee or any sublicensee. In the event that any
patent is assigned to Licensee by Harvard, pursuant to this paragraph, such
assignment shall require Licensee to continue to meet its obligations under this
Agreement as if the assigned patent or patent

                                      -7-

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

<PAGE>

application were still licensed to Licensee.

         7.3 Licensee shall reimburse Harvard for any reasonable out-of-pocket
costs it incurs as part of an action contemplated by this Article 7,
irrespective of whether Harvard shall become a co-plaintiff in any such action
(such reimbursement to be on the pro rata basis set forth in Section 7.1 in the
case of an action relating to non-exclusively licensed Patent Rights); provided,
however, that Licensee shall have no obligation to reimburse Harvard for any
costs which Licensee notifies Harvard will duplicate costs incurred or to be
incurred by Licensee.

         7.4 If Licensee or its sublicensee elects to commence an action as
described above, Licensee may reduce, by up to [***] the royalty due to
Harvard earned under the patent subject to suit by [***] of the amount of the
expenses and costs of such action, including attorney fees. In the event that
such [***] expenses and costs exceed the amount of royalties withheld by
Licensee for any calendar year, Licensee may to that extent reduce the royalties
due to Harvard from Licensee in succeeding calendar years, but never by more
than [***] of the royalty due in any one year.

         7.5 Recoveries or reimbursements from such action shall first be
applied to reimburse Licensee and Harvard for litigation costs not paid from
royalties (if any) and then to reimburse Harvard for royalties withheld. Any
remaining recoveries or reimbursements shall be shared equally by Licensee and
Harvard.

         7.6 In the event that Licensee and its sublicensee, if any, elect not
to exercise their right to prosecute an infringement of the Patent Rights
pursuant to the above paragraphs, Harvard may do so at its own expense,
controlling such action and retaining all recoveries therefrom.

                                    ARTICLE 8

                            TERMINATION OF AGREEMENT

         8.1 This Agreement, unless extended or terminated as provided herein,
shall remain in effect for the life of the last to expire patent in Patent
Rights.

         8.2 (a) The following events shall constitute an event of default under
this Agreement (an "Event of Default"):

                           (i)   Licensee shall fail to make any royalty payment
         which is not the subject of good faith controversy between the parties
         hereto within ten (10) days after the same shall have become due; or

                           (ii)  Licensee shall consent to the appointment of a
         receiver, trustee or liquidator of itself or of a substantial part of
         its property, or Licensee shall admit in writing its inability to pay
         its debts generally as they come due or shall make a general assignment
         for the benefit of creditors; or

                           (iii) Licensee shall file a voluntary petition in
         bankruptcy or a voluntary petition or an answer seeking reorganization
         in a proceeding under any bankruptcy laws (as now or hereafter in
         effect) or an answer admitting the material allegations of a petition
         filed against Licensee in any such proceeding; or

                           (iv)  an order, judgment or decree shall be entered
         in any proceeding by any court of competent jurisdiction appointing,
         without the consent of Licensee, a receiver, trustee or

                                      -8-

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

         liquidator of Licensee or of any substantial part of its property, or
         sequestering any substantial part of its property, and any such order,
         judgment or decree of appointment or sequestration shall remain in
         force undismissed, unstayed or unvacated for a period of 90 days after
         the date of entry thereof;

                           (v)   a petition against Licensee in a proceeding
         under applicable bankruptcy laws or other insolvency laws as now or
         hereafter in effect, shall be filed and shall not be withdrawn or
         dismissed within 90 days thereafter, or if, under the provisions of
         any law providing for reorganization or winding-up of corporations
         which may apply to Licensee, any court of competent jurisdiction
         shall assume jurisdiction, custody or control of Licensee or of any
         substantial part of its property and such jurisdiction, custody or
         control shall remain in force unrelinquished, unstayed or unterminated
         for a period of 90 days;

                           (vi)  failure to make minimum royalty payments under
         the Article 3 of this Agreement, or failure to comply with the
         reporting and due diligence requirements under Articles 2 and 4 of this
         Agreement unremedied after thirty (30) days notice; or

                           (vii) failure to comply with Article 9.3 of this
         Agreement.

                  (b)      The parties acknowledge and agree that no failure by
Licensee to meet any of the other obligations or duties herein set forth of any
kind or nature whatsoever shall be considered a material breach of this
Agreement, an "Event of Default" or the grounds for the termination of this
Agreement by Licensor.

     8.3  On the occurrence of an Event of Default, and if such Event of Default
          has not been remedied within ninety (90) days after the date of notice
          in writing of such Event of Default has been given to the Licensee by
          Harvard, Harvard may terminate this Agreement by written notice.
     8.4  Any sublicenses granted by Licensee under this Agreement shall provide
          for termination or assignment to Harvard, at the option of Harvard, of
          Licensee's interest therein upon termination of this Agreement.
     8.5  Licensee shall have the right to terminate this Agreement by giving
          thirty (30) days advance written notice to Harvard to that effect and
          paying a [***]; provided, however, that no such termination fee
          shall be payable in the event that any patent or claim included within
          the Patent Rights are held invalid or unenforceable. Upon termination,
          a final report shall be submitted and any royalty payments and
          unreimbursed patent expenses due to Harvard become immediately
          payable.
          8.6      Sections 4.4, 8.5, 9.2, 9.3 and 9.4 of this Agreement shall
                  survive termination.

                                    ARTICLE 9

                                     GENERAL

     9.1  Harvard represents and warrants that the entire right, title, and
          interest in the patent applications or patents comprising the Patent
          Rights have been assigned to it and that Harvard has the authority to
          issue licenses under said Patent Rights. Harvard does not warrant the
          validity of the Patent Rights licensed hereunder and makes no
          representations whatsoever with regard to the scope of the licensed
          Patent Rights or that such Patent Rights may be exploited by Licensee,
          an Affiliate, or sublicensee without infringing other patents however,
          Harvard has no reason to believe that the Patent Rights are invalid or
          that exploitation by Licensee, an Affiliate or sublicensee of the
          Patent Rights will infringe other patents.
          9.2 HARVARD EXPRESSLY DISCLAIMS ANY AND ALL IMPLIED OR EXPRESS

                                      -9-

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

WARRANTIES AND MAKES NO EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY OR
FITNESS OF THE TECHNOLOGY, LICENSED PROCESSES OR LICENSED PRODUCTS CONTEMPLATED
BY THIS AGREEMENT.

         9.3      (a) Licensee shall indemnify, defend and hold harmless
Harvard and its directors, governing board members, trustees, officers,
faculty, medical and professional staff, employees, students, and agents and
their respective successors, heirs and assigns (the "Indemnitees"), against
any liability, damage, loss or expenses (including reasonable attorneys' fees
and expenses of litigation) incurred by or imposed upon the Indemnitees or
any one of them in connection with claims, suits, actions, demands, judgments
arising out of any theory of product liability (including, but not limited
to, actions in the form of tort, warranty, or strict liability) concerning
any product, process or service made, used or sold pursuant to any right or
license granted under this Agreement. The above indemnification shall apply
whether or not such liability, damage, loss or expense is attributable to the
negligent activities of the Indemnitees.

                  (b) Licensee agrees, at its own expense, to provide attorneys
reasonably acceptable to Harvard to defend against any actions brought or filed
against any party indemnified hereunder with respect to the subject of indemnity
contained herein, whether or not such actions are rightfully brought.

                  (c) Beginning at the time as any such product, process or
service is being commercially distributed or sold (other than for the purpose of
obtaining regulatory approvals) by Licensee or by a sublicensee, Affiliate or
agent of Licensee, Licensee shall, at its sole cost and expense, procure and
maintain comprehensive general liability insurance in amounts not less than
$2,000,000 per incident limited to $2,000,000 annual aggregate and naming the
Indemnitees as additional insureds. During clinical trails of any such product,
process or service, Licensee shall, at its sole cost and expense, procure and
maintain comprehensive general liability insurance in amounts not less than
$500,000 per incident limited to $500,000 annual aggregate, naming the
Indemnitees as additional insureds. Such comprehensive general liability
insurance (or self-insurance, as the case may be) shall provide (i) product
liability coverage and (ii) broad form contractual liability coverage for
Licensee's indemnification under this Agreement. If Licensee elects to
self-insure all or part of the limits described above (including deductibles or
retentions which are in excess of $250,000 annual aggregate) such self-insurance
program must be reasonably acceptable to Harvard and the Risk Management
Foundation of the Harvard Medical Institutions, Inc. The minimum amounts of
insurance coverage required shall not be construed to create a limit of
Licensee's liability with respect to its indemnification under this Agreement.

                  (d) Licensee shall provide Harvard with written evidence of
such insurance upon request of Harvard. Licensee shall provide Harvard with
written notice at least fifteen (15) days prior to the cancellation, non-renewal
or material change of such insurance; if Licensee does not obtain replacement
insurance providing comparable coverage within such fifteen (15) day period,
Harvard shall have the right to require Licensee, its affiliates, and
sublicensees to cease engaging in any business activities relating to the Patent
Rights until proper insurance is obtained.

                  (e) Licensee shall maintain such comprehensive general
liability insurance beyond the expiration or termination of this Agreement
during (i) the period that any product, process, or service, relating to, or
developed pursuant to, this Agreement is being commercially distributed or sold
by Licensee and (ii) a reasonable period after the period referred to in (e)(i)
above which in no event shall be less than five (5) years.

         9.4      Licensee shall not use Harvard's name or any adaptation of
it in any advertising, promotional or sales literature without the prior
written consent of Harvard. Harvard shall not unreasonably withhold its
consent to any disclosure which describes the scope and nature of the
parties'

                                      -10-

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

participation accurately and appropriately.

         9.5  Without the prior written approval of Harvard, the entire
license granted pursuant to this Agreement shall not be transferred by
Licensee to any party other than to a successor to the business interest of
Licensee relating to the Patent Rights. This Agreement shall be binding upon
the successors, legal representatives and assignees of Harvard and Licensee.

         9.6  The interpretation and application of the provisions of this
Agreement shall be governed by the laws of the Commonwealth of Massachusetts.

         9.7  Licensee agrees to comply with all applicable laws and
regulations. In particular, it is understood and acknowledged that the
transfer of certain commodities and technical data is subject to United
States laws and regulations controlling the export of such commodities and
technical data, including all Export Administration Regulations of the United
States Department of Commerce. These laws and regulations, among other
things, prohibit or require a license for the export of certain types of
technical data to certain specified countries. Licensee hereby agrees and
gives written assurance that it will comply with all United States laws and
regulations controlling the export of commodities and technical data, that it
will be solely responsible for any violation of such by Licensee or its
Affiliates or sublicensees, and that it will defend and hold Harvard harmless
in the event of any legal action of any nature occasioned by such violation.

         If to Harvard:             Office for Technology and
                           Trademark Licensing
                           Harvard University
                           124 Mt. Auburn Street, Suite 410
                           Cambridge, MA  02138

         If to Licensee:            c/o The Castle Group, Ltd.
                           375 Park Avenue, Suite 1501
                           New York, NY  10022

or such other address as either party may request in writing.

         9.9  Should a court of competent jurisdiction later consider any
provision of this Agreement to be invalid, illegal, or unenforceable, it shall
be considered severed from this Agreement. All other provisions, rights and
obligations shall continue without regard to the severed provision, provided
that the remaining provisions of this Agreement are in accordance with the
intention of the parties.

         9.10 In the event of any controversy or claim arising out of or
relating to any provision of this Agreement or the breach thereof, the parties
shall try to settle such conflicts amicably between themselves. Subject to the
limitation stated in the final sentence of this section, any such conflict which
the parties are unable to resolve shall be settled through arbitration conducted
in accordance with the rules of the American Arbitration Association. The demand
for arbitration shall be filed within a reasonable time after the controversy or
claim has arisen, and in no event after the date upon which institution of legal
proceedings based on such controversy or claim would be barred by the applicable
statute of limitation. Such arbitration shall be held in Boston, Massachusetts.
At the request of any party, arbitration proceedings will be conducted in the
utmost secrecy; in such case all documents, testimony and records shall be
received, heard and maintained by the arbitrator in secrecy under seal,
available for the inspection only of the parties and their respective attorneys
and their respective experts who shall agree in advance and in writing to
receive all such information in secrecy until such information shall become
generally known. The award through arbitration shall be final and binding.
Either party may

                                      -11-

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

enter any such award in a court for judicial acceptance of the award and an
order of enforcement, as the case may be. Notwithstanding the foregoing,
either party may, without recourse to arbitration, assert against the other
party a third-party claim or cross-claim in any action brought by a third
party, to which the subject matter of this Agreement may be relevant.

         9.11 This Agreement constitutes the entire understanding between the
parties and neither party shall be obligated by any condition or
representation other than those expressly stated herein or as may be
subsequently agreed to by the parties hereto in writing.

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their duly authorized representatives.

         The effective date of this Agreement is January 17, 1999.

The President and Fellows               Venmark Ltd.
of Harvard College

Name:     /s/                           By:     /s/

Title:  Joyce Brinton, Director         Name:   /s/ [illegible]
        Office for Technology and
        Trademark Licensing

Date:     1/17/92                       Title:  Chairman and Pres.

                                  Date: January 17, 1992

                                      -12-

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

<PAGE>

                                    Exhibit A

                                 (To Be Amended)

Entire United States Patent Application, as may be drafted and amended, relating
to the work of [***]

*Confidential Treatment is requested for the language that has been underscored
or marked. Such language has been deleted from the copy filed with the SEC.

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

XENOMETRIX
2860 Wilderness Place
Boulder, Colorado  80301

Phone:  (303) 447-1773
Fax:  (303) 447-1758

                                January 10, 1996

Harvard University
Office of Technology and Trademark Licensing
Attn:  Kevin J. Heyeck
124 Mt. Auburn Street, Suite 410 South
Cambridge, MA  02138

Ladies and Gentlemen:

This is our understanding of the agreement reached in recent conversations
     between the President and Fellows of Harvard College (Harvard) and
     Xenometrix, Inc. (Xenometrix). Harvard and Xenometrix are identified
     together as the Parties.

The agreements stated in this letter are contingent on execution of this letter
     by both Parties.

Cattox-TM- Amendment Xenometrix agrees that within three days of receipt of this
     letter executed by the Parties it will execute the Amendment to the License
     Agreement between Xenometrix, Inc. and President and Fellows of Harvard
     College dated January 18, 1992 (the Amendment), said Amendment executed by
     Harvard on 7/12/95, a copy of which is attached as Exhibit 1. Xenometrix
     agrees that by executing the Amendment Xenometrix will be obligated to pay
     royalties to Harvard under Article 3 of the License Agreement with respect
     to the technology addressed in the Amendment, said technology called the
     Cattox-TM- Assay, since the inception of the License Agreement.

Royalty Reports and Payment Xenometrix agrees that it will prepare and deliver
     to Harvard royalty reports on the Cattox-TM- Assay from inception of sales
     through December 31, 1995 within 21 calendar days of receipt of this letter
     executed by the Parties, calculating the royalty due Harvard on 100% of
     such sales. Xenometrix will enclose with the reports payment for any
     royalty due.

Schiestl Technology Harvard agrees that as of December 31, 1995, Harvard owns no
     interest in the patents and patent applications set forth in Exhibit 2 (the
     Yeast Del-TM- Assay and the Mammalian Del Assay), except that Harvard
     represents that it ownss the continuation-in-part application number [***].
     Together, the Yeast Del-TM- Assay and the Mammalian Del Assay are
     identified as the Schiestl Technology. Harvard makes no representations
     about its ownership of improvements to the Schiestl Technology made after
     December 31, 1995.

*Confidential Treatment is requested for the language that has been underscored
or marked. Such language has been deleted from the copy filed with the SEC.

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

Treck Assay Xenometrix agrees that within three days of receipt of this letter
     executed by the Parties it will pay to Harvard [***], the minimum
     royalties for 1994 and 1995 on the license agreement between Harvard and
     Xenometrix dated 8-3-92 (the Treck License), plus interest calculated from
     the original payment dates, as provided under the license. Xenometrix
     hereby notifies Harvard that, under the terms of the Treck License as set
     forth in paragraph 8.5 of said License, Xenometrix terminates said License
     and releases all rights it has to the technology addressed by said License.
     Harvard hereby waives the [***] termination fee set forth in paragraph
     8.5 of the Treck License.

Sincerely yours,                        Agreed,

Xenometrix, Inc.                        The President and Fellows of Harvard
                                        College

/s/

Edson D. de Castro                      By:   /s/
Chief Executive Officer
                                 Title: Joyce Brinton, Director Office for
                                        Technology and Trademark Licensing

Date:  1/10/96                                Date:  1/11/96

                                      -2-

*Confidential Treatment is requested for the language that has been underscored
or marked. Such language has been deleted from the copy filed with the SEC.

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

                               HARVARD UNIVERSITY
                  OFFICE FOR TECHNOLOGY AND TRADEMARK LICENSING

                   AMENDMENT TO THE LICENSE AGREEMENT BETWEEN

                                 XENOMETRIX INC
                                       AND
                    PRESIDENT AND FELLOWS OF HARVARD COLLEGE

                             DATED JANUARY 18, 1992

The License Agreement executed on January 18, 1992, between President and
    Fellows of Harvard College (HARVARD) and Xenometrix Inc, is hereby amended
    to incorporate into PATENT RIGHTS, HARVARD's ownership interest in the
    jointly owned, International Patent Application No. [***], and its
    priority application, [***].

Upon termination of the License Agreement, or its conversion from exclusive to
    non-exclusive, or upon subsequent removal of the above rights from the
    License Agreement, the parties agree that each may license their respective
    ownership interests in these jointly owned application(s), throughout the
    world, without accounting to the other.

The effective date of this amendment shall be January 21, 1993.

Agreed and accepted:

The President and Fellows              XENOMETRIX, INC.
of Harvard College

          /s/
                                             Signature

     Joyce Brinton, Director Office for
     Technology and Trademark Licensing                                Title

Date:          7/1[?]/9[?]
                                             Date

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

                                    Exhibit 2

Entire Patent Applications and Issued Patents, as may be drafted and amended,
     relating to the work of Dr. Robert Schiestl corresponding to:

I.   The Yeast Del assay, including:

         (a)      United States patent 4,997,757 ("Process for Detecting
                  Potential Carcinogens," issued march 5, 1991), and all
                  reissues and extensions thereof;

         (b)      European patent application 324,258 ("Process for Detecting
                  Potential Carcinogens," published July 19,1989) and all
                  Letters Patent which may be granted for the invention(s) of
                  said European patent application, and all extension, renewals,
                  and continuations thereof, including, but not limited to,

                  (i)      France patent 0324258
                  (ii)     Germany patent P3883364.6
                  (iii)    Sweden patent 88312099.0
                  (iv)     Switzerland patent P324258.4
                  (v)      United Kingdom patent 0324258

         (c)      Canada patent 1322943 issued October 12, 1993

II.  The Mammalian Del assay, including United States patent application
     [***] and all Letters Patent of the United States which may be granted
     thereon and all reissues and extensions thereof, and all applications for
     Letters patent which may hereafter be granted for the invention(s) of said
     U.S. patent application in any country or countries foreign to the United
     States, and all extensions, renewals, and reissues thereof.

Non-Profiled Document

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

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00012-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00012-of-00352.parquet"}]]