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                                                                    CONFIDENTIAL
EXHIBIT 10.2

THE CONFIDENTIAL PORTION OF THIS CONTRACT HAS BEEN OMITTED PURSUANT TO
REGULATION 240.25B-2(B) OF THE SECURITIES EXCHANGE ACT OF 1934, AND HAS BEEN
FILED SEPARATELY WITH THE COMMISSION.

          CHIRON CORP. - RIBOZYME PHARMACEUTICALS, INC. COLLABORATION
             REGARDING USE OF RIBOZYMES TO DETERMINE GENE FUNCTION


This Collaboration Agreement ("Agreement") is entered into effective as of May
13, 1996 (the "Effective Date") by and between Chiron Corporation, a Delaware
corporation having a place of business at 4560 Horton Street, Emeryville,
California 94608 ("Chiron"), and Ribozyme Pharmaceuticals, Inc., a Delaware
corporation having a place of business at 2950 Wilderness Place, Boulder,
Colorado 80301 ("RPI").

WHEREAS:

RPI has developed or has licensed proprietary patented and trade secret ribozyme
technology; and

Chiron develops and commercializes products for human diagnostic, prophylactic 
and therapeutic use; and

RPI and Chiron each have certain skills and experience related to the
identification, development and commercialization of products against specific
gene targets; and

RPI and Chiron wish to enter into a collaboration whereby they will evaluate
the use of ribozymes in the identification of gene function for a number of
targeted genetic sequences as set forth herein.

NOW THEREFORE, in consideration of the mutual promises contained herein, the
parties agree as follows:


1.       Definitions.

         1.1        "Affiliate" shall mean any entity which controls, is 
controlled by, or is under common control with, a party hereto. An entity shall
be regarded as being in control of another entity if such party owns or
controls, directly or indirectly, 50 percent or more of the shares of the
subject entity entitled to vote in the election of directors (or, in the case
of an entity that is not a corporation, for the election of the corresponding
managing authority). Notwithstanding the foregoing, Affiliates of Chiron shall
not include Ciba-Geigy Limited ("Ciba") or any Affiliates of Ciba unless and
until Ciba exercises its rights to control the management and affairs of Chiron
pursuant to the Governance Agreement between Ciba and Chiron dated as of
November 20, 1994.

         1.2        "Chiron Proprietary Product Data" shall mean all unpatented 
data, results, and know how which are developed by Chiron in the course of
pursuing development of Ribozyme Products directed against the Targets pursuant
to this Agreement, other than the Screening Results.

         1.3        "Chiron Proprietary Technology" shall mean patents, patent 
applications and trade secrets owned or controlled by Chiron, which Chiron has
the right to license to RPI hereunder, with respect to the Genetic Sequence of
the Target or the use of ribozymes directed toward the Target, other than
Screening Results and Chiron Proprietary Product Data. Without limiting the
foregoing, Chiron Proprietary Technology does not include Chiron's assays or
assay methodologies; and does not include Chiron technology, information, data
or results with respect to aspects of the Target other than its Genetic
Sequence or with respect to therapeutic, diagnostic or prophylactic modalities
addressing such Target other than ribozymes. 

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         1.4        "Collaboration" shall mean the collaboration between the 
parties described in Sections 2 and 3 hereof for the purposes of identifying
gene function.

         1.5        "Confidential Information" shall have the meaning set forth
in Section 15.1.

         1.6        "Definitive Contribution Product" shall mean a product, 
other than a Ribozyme Product, directed toward a Target, which is developed and
commercialized by Chiron, and as to which the Ribozyme Experiments were
critical in causing Chiron to change its development plans, as further defined
in Section 6.1.

         1.7        "Endogenous" delivery of a ribozyme shall mean delivery of a
DNA or RNA vector encoding a ribozyme into a cell, whether in vivo or ex vivo,
for the purpose of expression thereof.

         1.8        "Excluded Targets" shall mean the Genetic Sequences listed 
in Exhibit A, as amended from time to time in accordance with Section 3.5. A
Genetic Sequence shall not be added to Exhibit A as an Excluded Target until
Chiron has received written notice thereof in accordance with Section 17.7.

         1.9        "Exogenous" delivery of a ribozyme shall mean delivery of a 
chemically synthesized ribozyme.

         1.10       "FDA" shall mean the U.S. Food and Drug Administration.

         1.11       "Feasibility Study Targets" shall mean those Genetic 
Sequences identified by Chiron for Feasibility Studies pursuant to Section 2.2.

         1.12       "Genetic Sequence" shall mean a gene or partial sequence 
thereof, or its transcription product or intermediates or portions thereof,
including either DNA or RNA.

         1.13       "IND" shall mean an Investigational New Drug application 
filed with the FDA, or a foreign equivalent thereof or the actual commencement
of clinical trials of a Product in a country in which no IND or equivalent
filing is required.

         1.14       "Manufacturing Cost" shall mean, with respect to any 
Product, the fully-burdened cost, expressed on a per unit manufactured basis,
of manufacturing the bulk or final dosage form of such Product (including
rejected or returned units of such Product), together with packaging thereof,
including the cost of raw materials, direct labor and benefits, and overhead
(including depreciation, indirect costs and general and administrative
expense), all fairly allocable to such Product on a percent utilization basis
as determined in accordance with generally accepted accounting principles and
customary usage in the U.S. pharmaceutical industry.

         1.15       "NDA" shall mean a New Drug Application filed with the FDA 
or a foreign equivalent thereof in the United Kingdom, Germany, France, Italy
or Japan.

         1.16       "Net Sales" shall mean the gross sales price received by a 
party or its Affiliates or sublicensees on sales of Products to non-Affiliate
customers, less (i) normal and customary rebates, cash and trade discounts,
(ii) credits for returns and allowances, (iii) insurance costs borne by the
seller, and transportation charges and (iv) sales or other excise taxes or
duties imposed upon and paid by such party or its Affiliates or sublicensees
with respect to such sales.

                    In the event that a Product is combined with another
biologically active product, or a part of a kit including calibrators, controls
or the like, or with a delivery system not developed under this Agreement then:

                    Net Sales from such sales, for purposes of calculating
royalties due or allocating profits under this Agreement, shall be calculated
by multiplying the Net Sales of that combination by the fraction A/(A+B), where
A is the gross selling price of the Product sold separately in the country of
sale and B is the gross selling price of the other product or delivery system
sold separately in the country of sale. In the event that no such separate
sales are made, Net Sales for purposes of determining royalty payments on such
combination products, shall be a reasonable 


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apportionment of the gross amount invoiced therefor based upon the relative
contribution of the Product to the price of the combination product. Such
apportionment shall be negotiated in good faith between the parties and such
apportionment shall be established prior to the time that a party hereto shall
have the right to sell such combination products.

                    As to diagnostic uses of a Product, "Net Sales" shall have
the foregoing meaning, unless the Product is increased in price by an amount
which reflects the acquisition or leasing cost of an instrument in connection
with the supply of an instrument system. In such event, the "Net Sales" of such
Product for diagnostic uses shall be calculated as follows: (i) the cost of
depreciation of such instrument in a given royalty payment period plus the
actual cost of servicing such instrument in such royalty period will be divided
by the Net Sales of all Products for use on such instrument which are sold to
end-users of such instrument in order to determine a "factor"; (ii) the Net
Sales of such Product will then be multiplied by such factor; and (iii) the
resulting amount will be subtracted from such Net Sales to arrive at the actual
Net Sales of such Product in such royalty payment period.

                    As to diagnostic laboratory services involving the use of
Products, "Net Sales" shall mean actual billings for such services, less: (i)
discounts allowed and taken in amounts customary in the market in which the
service occurred and (ii) any tax, charge or duty (other than an income tax)
levied or imposed on the service and (iii) that portion of the remainder
appropriately allocable to non-Product portions of such service (including
labor, etc.); provided, however that if the service is offered in combination
with another diagnostic service or services which are not licensed hereunder,
Net Sales for purposes of determining royalties on the service shall be
calculated by multiplying the Net Sales from the combination by the fraction
A/(A+B), where A is the invoice price of the service and B is the invoice price
of the other service or services in the combination if sold separately. If the
service is not sold separately, Net Sales for the purposes of determining
royalties on the service shall be reasonably estimated on the basis of the
price charged for similar services but which are sold separately.

         1.17       "Non-Definitive Contribution Product" shall mean a product, 
other than a Ribozyme Product, directed toward a Target, which is developed and
commercialized by Chiron, and as to which the Ribozyme Experiments were not
critical in causing Chiron to change its development plans, as further defined
in Section 6.1.

         1.18       "Patent" shall mean U.S. patent  applications and foreign  
counterparts thereof, and all U.S. and foreign patents issuing therefrom,
including any additions, continuations and continuations-in-part, divisions,
reissues, renewals and extensions thereof.

         1.19       "Precommercialization Cost" shall mean, with respect to RPI,
in the case of [ ] Ribozyme Products, and Chiron, in the case of [ ] Ribozyme
Products, the fully burdened cost of performing process development and
manufacturing scale up of a Ribozyme Product, prior to an approved NDA, and
providing such supplies of ribozymes or Ribozyme Product as are needed for
product development, including for clinical trials. Such fully burdened cost
includes, as applicable, the cost of raw materials, direct labor and benefits,
shipping and indirect costs (including depreciation and other indirect costs,
but excluding general and administrative expenses), all fairly allocable to
such Product on a percent utilization basis as determined in accordance with
generally accepted accounting principles and customary usage in the U.S.
pharmaceutical industry. For the purposes of Section 6.5(b),
Precommercialization Costs shall also include all direct and indirect costs
(excluding general and administrative expenses) incurred by Chiron in the
course of preclinical, clinical, regulatory, process and manufacturing
development conducted by Chiron with respect to the Ribozyme Product in
question prior to abandonment of such Ribozyme Product under Section 3.9. For
the purposes of the exclusions in the preceding sentences, "general and
administrative expenses" means expenses associated with the following
functions: human resources, law (including without limitation expenses of
defense, settlement or discharge of liabilities to third parties), business
development, and executive administration. Accounts receivable, accounts
payable and purchasing expenses fairly allocable to the ribozymes produced
hereunder shall be included within Precommercialization Costs; other expenses
associated with general finance functions shall be considered general and
administrative expenses and excluded from Precommercialization Costs.

         1.20       "Product"  shall mean a  Ribozyme Product, a  
Definitive Contribution Product, or a Non-Definitive Contribution Product.

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         1.21       "Research Cost" shall mean the fully-burdened cost of 
producing ribozymes for research use, including, as applicable, the cost of raw
materials; direct labor and benefits; if necessary, royalties due to third
parties; shipping and indirect costs (including depreciation and other indirect
costs, but excluding general and administrative expenses), all fairly allocable
to the ribozymes produced under this Agreement as determined in accordance with
generally accepted accounting principles and customary usage in the U.S.
pharmaceutical industry. For the purposes of the exclusion in the preceding
sentence, "general and administrative expenses" means expenses associated with
the following functions: human resources, law (including without limitation
expenses of defense, settlement or discharge of liabilities to third parties),
business development, and executive administration. Accounts receivable,
accounts payable and purchasing expenses fairly allocable to the ribozymes
produced hereunder shall be included within Research Cost; other expenses
associated with general finance functions shall be considered general and
administrative expenses and excluded from Research Cost.

         1.22       "Ribozyme Experiments" shall mean those studies conducted by
Chiron with ribozymes supplied by RPI pursuant to Article 3.

         1.23       "Ribozyme Product" shall mean a ribozyme product directed 
toward a Feasibility Study Target or directed toward a Target, for therapeutic
or prophylactic or diagnostic use in humans or animals which is developed by a
party pursuant to this Agreement.

         1.24       "RPI Technology" shall mean all Patents, inventions, 
discoveries, improvements, data, materials, formulae, know how or other
technology owned, controlled or acquired by RPI, as of the Effective Date or
during the term of this Agreement, which RPI is free to license hereunder and
which is necessary or useful for the manufacture, use or sale of a Ribozyme
Product. RPI Technology shall include, without limitations, the issued patents
identified on Exhibit B, and foreign counterparts thereof as well as all U.S.
and foreign patents issuing therefrom, including any additions, continuations
or continuations-in-part, divisions, reissues, renewals and extensions thereof.
Notwithstanding the foregoing, RPI Technology shall not include any of RPI's
trade secret processes for the design and synthesis of ribozymes or manufacture
of exogenous ribozymes except to the extent license thereof is necessary to
enable the manufacturing of Ribozyme Products if RPI does not exercise its
manufacturing right under Section 8.1.

         1.25       "Screening Results" shall mean the results of the cell 
culture assays conducted by Chiron pursuant to Section 3.4, and the results of
such animal efficacy studies which Chiron elects to conduct using ribozymes
produced by RPI, pursuant to Section 3.4.

         1.26       "Target" shall mean a Genetic Sequence identified by Chiron 
pursuant to Section 3.2.

         1.27       "Target Polypeptide" shall mean a polypeptide encoded by a 
Target or Feasibility Study Target.

2.       Feasibility Study

         2.1        Purpose.  The parties shall conduct a feasibility study 
to evaluate the use of ribozymes for the determination of gene function.

         2.2        Feasibility Study Targets. Chiron will choose [ ] Genetic
Sequences, other than Excluded Targets, to be Feasibility Study Targets. Chiron
shall notify RPI in writing of the first Feasibility Study Target within ten
days following the Effective Date; and Chiron shall notify RPI in writing of
the remaining four Feasibility Study Targets not later than two months
following the Effective Date, all in accordance with Section 17.7. Once RPI has
received written notice of a Feasibility Study Target, RPI shall not pursue
research (including without limitation gene function identification studies) or
development of, or manufacture, ribozymes directed to such Feasibility Study
Target, either alone or in collaboration with a third party, unless and until
RPI is authorized to proceed with development of Ribozyme Products directed
towards such Feasibility Study Target under Section 2.9 If, prior to the time
at which RPI would otherwise be authorized to pursue a Feasibility Study Target
under Section 2.9, RPI receives a request from a third party to conduct gene
function identification studies only (and not to 

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participate in or grant rights to product research, development or
commercialization) with respect to such Feasibility Study Target, Chiron agrees
to discuss with RPI the possibility of permitting RPI to conduct such gene
function identification studies; provided that the final decision as to whether
such studies will be permitted shall be made by Chiron in its sole discretion.

         2.3        Supply of Ribozymes. RPI shall manufacture and supply to 
Chiron approximately [ ] ribozymes, together with corresponding controls, per
Feasibility Study Target, in approximate amounts of 0.5 mg of each ribozyme and
each control, including available delivery vehicles (owned or controlled by RPI
and available for license hereunder or provided by Chiron) as appropriate for
initial screening. RPI shall manufacture and supply additional ribozymes and
controls for verification of initial effects shown by ribozymes. RPI shall
provide Chiron with the nucleotide sequences and site of cleavage of each
ribozyme provided.

         2.4        Feasibility Study. Chiron shall use the ribozymes supplied 
by RPI to perform cell culture assays to determine gene function. Chiron may
further elect, in its sole discretion, to proceed with animal efficacy studies
and further Product development for one or more Feasibility Study Targets. In
the event Chiron elects to proceed with animal studies for further elucidation
of gene function or further development of a Ribozyme Product against a
Feasibility Study Target, RPI shall supply the ribozymes necessary for such
studies and Ribozyme Product development. Chiron has no obligation to provide
any results or data with respect to the Feasibility Study, except as agreed
pursuant to Section 15.5.

         2.5        Due Diligence. The parties will perform with due diligence 
their duties to supply the ribozymes, and to complete the cell culture assays
in approximately six months, but no more than nine months, after delivery of
the ribozymes.

         2.6        Payment for Supplies. Chiron shall pay RPI [ ] on delivery 
of the ribozymes supplied pursuant to Section 2.3 hereof. Chiron may request
RPI to conduct specialized delivery work related to such ribozyme supplies for
which Chiron will reimburse RPI its Research Costs in connection therewith. RPI
will be reimbursed by Chiron for RPI's Research Costs of ribozymes supplied for
animal studies under Section 2.4. RPI will be reimbursed its
Precommercialization Cost for all supplies during Product Development.

         2.7        Development. Chiron, in its sole discretion, shall determine
whether to proceed with development of Products against such Feasibility Study
Targets. RPI shall not be entitled to additional compensation related to the
development and commercialization of Products directed towards Feasibility
Study Targets not containing ribozymes. In connection with the development and
commercialization of a Ribozyme Product directed towards a Feasibility Study
Target RPI shall be entitled to receive additional compensation as provided in
Section 6.4 hereof.

         2.8        Success of the Feasibility Study. The parties shall meet 
within [ ] of the conclusion of the last cell culture assay for a Feasibility
Study Target. At such time the parties shall determine if the ribozymes
directed toward the Feasibility Study Targets caused a significant inhibition
of a known functional effect so as to demonstrate that the ribozymes are useful
in establishing the relationship between a genetic sequence and a change in a
biological process. If such an inhibition is shown for [ ] Feasibility Study
Targets, the Feasibility Study described in this Article 2 will be deemed
successful and the Screening Program described in Article 3 shall begin.

         2.9.       [ ]

3.       Screening Program.

         3.1        Purpose. Following successful completion of the Feasibility 
Study, as defined in Section 2.8, Chiron will conduct a screening program to
determine gene function of Targets selected pursuant to Section 3.2.

         3.2        Targets. Chiron, in its sole discretion, shall select as 
many as [ ] Genetic Sequences, other than Feasibility Study Targets or Excluded
Targets, as Targets. Chiron shall notify RPI in writing of the Targets as they
are selected, in accordance with Section 17.7. The number of Genetic Sequences
designated by Chiron as Targets 

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may be increased by mutual agreement of the parties; and may be reduced by
reason of the Excluded Target list as referenced in Section 3.8.

         3.3        Supply of Ribozymes. RPI shall manufacture and supply to 
Chiron approximately [ ] ribozymes, together with corresponding controls, per
Target, in approximate amounts of 0.5 mg of each ribozyme and each control,
including available delivery vehicles (owned or controlled by RPI and available
for license hereunder, or provided by Chiron) as appropriate for initial
screening. RPI shall manufacture and supply additional ribozymes and controls
for verification of initial effects shown by ribozymes.

         3.4        Ribozyme Experiments. Chiron shall use the ribozymes 
supplied by RPI to perform cell culture assays designed to determine or verify
the biological function of Genetic Sequences. Chiron may further elect, in its
sole discretion, to conduct animal efficacy studies and to proceed with Product
development, with respect to some or all Targets. Such further studies and
product development may, in Chiron's sole discretion, use either a ribozyme or
non-ribozyme approach. In the event of the development of Products from such
studies, RPI shall be entitled to additional compensation as provided in
Article 6.

         3.5        Term of Screening Program. The Targets will be selected by 
Chiron from time to time during the Screening Program. Chiron may not select
for screening any Excluded Targets. Chiron shall notify RPI in writing of its
selection of Targets. Selection of Targets and synthesis of ribozymes against
the [ ] Targets is expected to be completed [ ] from initiation of the
Screening Program. If necessary for the completion of Target selection and
ribozyme production, such period may be extended, upon written notice by Chiron
to RPI, for up to an [ ]. Until RPI receives written notice of Chiron's
selection of a Target for screening hereunder, RPI shall be free to notify
Chiron in writing in accordance with Section 17.7 of any Genetic Sequence to be
added to the list of Excluded Targets. RPI shall have the right to add, as an
Excluded Target, any Genetic Sequence as to which (i) RPI has then entered into
or is then discussing collaborative arrangements with third parties, or (ii)
RPI is then conducting, or then intends in good faith to conduct, an internal
research or development program. Exhibit A hereto shall automatically be
amended to include such Genetic Sequence upon Chiron's receipt of such notice.
Once RPI has received notice of a Target selected by Chiron pursuant to Section
3.2, RPI shall not pursue research (including without limitation gene function
identification studies) or development of, or manufacture, ribozymes directed
to such Target, either alone or in collaboration with a third party, unless and
until RPI obtains the right to develop and commercialize Ribozyme Products with
respect to such Target under Sections 3.9 and 4.5. If, prior to the time at
which RPI would otherwise be authorized to pursue a Target under Sections 3.9
and 4.5, RPI receives a request from a third party to conduct gene function
identification studies only (and not to participate in or grant rights to
product research, development or commercialization) with respect to such
Target, Chiron agrees to discuss with RPI the possibility of permitting RPI to
conduct such gene function identification studies; provided that the final
decision as to whether such studies will be permitted shall be made by Chiron
in its sole discretion.

         3.6        Due Diligence. RPI will supply the ribozymes directed toward
the Targets as requested by Chiron with commercially reasonable diligence.
Chiron will complete cell culture assays with commercially reasonable diligence
for each Target within approximately six months, but not more than nine months
from the time RPI delivers to Chiron the ribozymes directed towards such Target.

         3.7        Further Supplies. RPI shall use commercially reasonable due
diligence to manufacture and supply to Chiron such additional ribozymes
directed toward Targets as Chiron shall need and reasonably request for the
performance of animal efficacy studies or further development of Ribozyme
Products.

         3.8        Payments for Supply. Chiron shall pay RPI [ ] for ribozymes
supplied pursuant to Section 3.3, assuming that Chiron selects [ ] Targets.
Such amount shall be paid in installments of [ ] per Target, payable upon
delivery of the ribozymes against each Target. Chiron may request RPI to
conduct specialized delivery work for which Chiron will reimburse RPI its
Research Cost in connection therewith. RPI will be reimbursed by Chiron for
RPI's Research Cost of ribozymes supplied pursuant to Section 3.7. In the event
that, as a result of the Excluded Target list on Exhibit A, Chiron is not able,
in its sole discretion, to choose [ ] Targets, Chiron may proceed with a lesser
number of Targets selected, and the amounts payable under this Section 3.8
shall be reduced accordingly.

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         3.9        Ribozyme Product Development.

                    (a) Following generation of cell culture data on the
function of a particular Target, Chiron shall have [ ] from the conclusion of
cell culture assays (including cell culture assays conducted with the controls
supplied by RPI) related to a particular Target to notify RPI in writing of
Chiron's intent to pursue further research and development of a Ribozyme
Product directed toward such Target. If Chiron does not notify RPI within such
time period, Chiron shall be deemed to have abandoned research and development
of Ribozyme Products directed toward such Target for the purposes of Section
3.9(f). To the extent permitted under the terms of the Collaborative Research,
Development and Commercialization Agreement between the parties effective as of
July 15, 1994 (the "1994 Agreement"), Chiron may, in its sole discretion,
propose such Target as an additional or substitute Named Target under the 1994
Agreement. For clarity of understanding, Chiron is not authorized to remove
targets from the 1994 Agreement and place them under this Agreement.
Alternatively, Chiron may elect, in its sole discretion, to pursue development
and commercialization of a Ribozyme Product against such Target under the terms
of this Agreement.

                    (b) [ ]

                    (c) Once Chiron has elected to proceed with development of
a Ribozyme Product against a Target, Chiron shall not be deemed to have
abandoned such development so long as Chiron is actively conducting research or
development of a Ribozyme Product against such Target, in accordance with a
commercially reasonable research and development plan, which will include a
program involving expenditures of not less than the lesser of [ ] employees per
year for preclinical research prior to formal toxicology; and thereafter shall
proceed with development of such product with commercially reasonable
expenditures appropriate to the applicable stage of development. It is
understood that the level of resources will change over the course of the
development program.

                    (d) Chiron may, in its sole discretion, elect to abandon
research and development with respect to any Ribozyme Product at any time. In
the event that Chiron elects to abandon all Ribozyme Products with respect to a
Target, Chiron agrees to notify RPI in writing within thirty (30) days
following such abandonment.

                    (e) From the time RPI receives notice under Section 3.9(a)
of Chiron's intent to proceed with a Ribozyme Product, and while Chiron is
pursuing research, development or commercialization of Ribozyme Products
against a Target under this Agreement, RPI agrees that it will not pursue
research, development or commercialization, and it will not license any third
party to research, develop or commercialize any product containing ribozymes
against such Target or any Precluded Genetic Sequence (as defined in Section
4.5), all further subject to Section 4.5.

                    (f) In the event that Chiron abandons research, development
and commercialization of all Ribozyme Products with respect to a Target, except
as otherwise provided in Section 4.5, RPI shall be free, alone or with a third
party, at its sole discretion, to develop Ribozyme Products against such Target
and its Precluded Genetic Sequences, and RPI shall have the right to utilize
the Screening Results and Chiron Proprietary Product Data in connection with
such development and commercialization, all subject to the terms of this
Agreement, including payment of royalties due under Section 6.5(a). RPI shall
further have the right to negotiate a royalty bearing license under other
Chiron Proprietary Technology for the development and commercialization of
ribozyme products against such Target, pursuant to Sections 4.2 and 6.5(c).

4.       Grants.

         4.1        By RPI. Subject to the terms and conditions of this 
Agreement, (and further subject to the terms and conditions required by third
party licensors in any sublicense as to which Chiron becomes a sublicensee) RPI
hereby grants Chiron an exclusive worldwide license under the RPI Technology,
to (i) conduct the Feasibility Study with respect to the Feasibility Study
Targets; (ii) conduct the Ribozyme Experiments with respect to the Targets;
(iii) develop, make and have made (subject to Section 8.1), use and sell
Ribozyme Products developed by Chiron and (iv) manufacture Ribozyme Products
developed by RPI for which Chiron has the right to manufacture pursuant to
Section 8.2. Chiron shall have the right to sublicense its rights under (iii)
to any third party in Chiron's discretion, 

<PAGE>   8

and to sublicense its rights under (iv) to an Affiliate of Chiron, or, with
RPI's consent, which shall not be unreasonably withheld, to a third party,
provided that, in each case, such sublicense is subject to the terms and
conditions of this Agreement.

         4.2        By Chiron. Subject to the terms and conditions of this 
Agreement, Chiron hereby grants RPI an option to obtain a non-exclusive
worldwide royalty bearing license, with the right to sublicense, under Chiron
Proprietary Technology relating to a Target to develop, make and have made
(subject to Section 8.2), use and sell Ribozyme Products directed against such
Target which are developed or commercialized by RPI pursuant to Section 3.9.
Such license shall bear a commercially reasonable royalty and shall be subject
to other commercially reasonable terms to be negotiated by the parties in good
faith.

         4.3        Ownership of Technology. (a) Subject to the rights expressly
granted in this Agreement, as between the parties hereto, (i) Chiron and its
licensors retain all rights in the Screening Results, Chiron Proprietary
Technology and Chiron Proprietary Product Data and all other technology of
Chiron not specifically governed by this Section 4.3, and (ii) RPI and its
licensors retain all rights in the RPI Technology and all technology of RPI not
specifically governed by this Section 4.3.

                    (b) New inventions arising from activities under this
Agreement shall be owned as follows:

                              (i)  Chiron shall own all right title and interest
in and to any inventions or discoveries made solely by employees or assignors
of Chiron, whether alone or with third parties;

                              (ii)  RPI shall own all right, title and interest 
in and to any inventions or discoveries made solely by employees or assignors of
RPI, whether alone or with third parties; and

                              (iii) Chiron and RPI shall jointly own all 
right, title and interest in and to any inventions or discoveries made jointly
by employees or assignors of Chiron, on the one hand, and employees or
assignors of RPI, on the other hand.

                    (c) Chiron shall own all data arising from the Feasibility
Study, all Screening Results, and all data and information arising from the
research, development and commercialization of Products by Chiron.

                    (d) RPI shall own all data and information arising from
research, development and commercialization of Ribozyme Products by RPI.

         4.4        No Other Rights.  Except as expressly  provided in this 
Agreement neither party shall have any license or other right to use Technology
of the other party.

         4.5        [ ]

         (b) "Precluded Genetic Sequence," with respect to a [ ] or a Target,
shall mean a Genetic Sequence that Chiron has notified RPI encodes a
polypeptide that is [ ] with respect to such [ ]. A polypeptide is considered
to be functionally contiguous to a Target Polypeptide if the former can
directly influence the activity of the latter, or the latter can directly
influence the activity of the former, for example, as in an enzyme-substrate
relationship. A polypeptide is considered to be physically contiguous to a
Target Polypeptide if the former forms a complex with the latter, either
directly by binding to each other or, indirectly, by binding to each other
through an intermediary, for example, as in a transcription factor complex or
the Factor VIIa/Tissue Factor/FactorXa complex.

         (c) For a period of [ ] after receipt by RPI of notice from Chiron,
pursuant to Section 2.7 or Section 3.9(a) that Chiron intends to pursue
research or development of a Ribozyme Product against a Feasibility Study
Target or a Target, RPI shall not pursue research, development or
commercialization of a product directed toward a Precluded Genetic Sequence
with respect to such Feasibility Study Target or Target, alone or with a third
party through collaboration or license. RPI's obligations under this Section
4.5(c) shall terminate in the event that data as to the effectiveness of
ribozymes against the Precluded Genetic Sequence becomes publicly known other
than as a 

<PAGE>   9

result of breach by RPI of its obligations under Article 15. Notwithstanding
the foregoing, if a Precluded Genetic Sequence has been added to the Excluded
Target list pursuant to Section 3.5 prior to receipt by RPI of notice pursuant
to Section 2.7 or 3.9(a) of Chiron's intent to pursue Ribozyme Products
directed toward the applicable Feasibility Study Target or Target, the
restrictions of this Section 4.5(c) shall not apply to such Precluded Genetic
Sequence.

5.       Intellectual Property.

         5.1        Preparation, Filing and Prosecution of Patent Applications;
Maintenance of Issued Patents.

                    5.1.1 Preparation and Filing. When inventions which may
reasonably be considered to be patentable have been conceived by employees of a
party or others acting on behalf of a party in the performance of its
activities contemplated by this Agreement, the party owning such invention
shall have the right, in its sole discretion, to file United States and foreign
patent applications, consistent with its patent policy with respect to its
other patentable inventions, discoveries, improvements or other technology. The
party owning such invention shall control the preparation and filing of such
applications.

                    5.1.2 Prosecution and Maintenance. Subject to Section
5.1.3, RPI and Chiron each shall have the right, in its sole discretion, to
control the prosecution, grant and maintenance of patent applications and
patents covering its inventions, and to select all patent counsel or other
professionals to advise, represent or act for it in all matters relating to
such patent applications and patents. All costs incurred in connection
therewith shall be borne by the party taking action with respect to such patent
applications and patents. Each party shall inform the other party at reasonable
regular intervals, or at such other party's reasonable request, about the
status of any portions of such patent applications or patents which are
licensed to the other party hereunder and are applicable to such other party's
Products.

                    5.1.3 Abandonment of Patent Rights. In the event that a
party (the "Original Owning Party" for the purposes of this Section 5.1.3)
elects not to file a patent application in any country, or decides to abandon a
pending application or granted patent in any country, and the patent in
question has been, or the patent application in question would, under the terms
of the licenses granted herein, be exclusively licensed to the other party
hereunder and is applicable to the other party's Products, the Original Owning
Party shall provide at least 90 days prior written notice to the other party
and shall give such other party the opportunity, subject to the abandoning
party's existing contractual obligations to third parties, to file or maintain,
and control the prosecution of, such application or patent at such other
party's own expense, at the Owning Party's discretion either in the name of the
original owning Party or in such other party's own name; provided, that the
Original Owning Party shall receive a perpetual, irrevocable, fully paid-up,
royalty-free, nonexclusive, worldwide license, with the right to sublicense
(subject to the licenses granted, and the limitations set forth, in this
Agreement), to make and have made, use and sell or otherwise distribute
products incorporating, exploiting, or made using, such patents or renewals and
extensions thereof. For clarity of understanding, this Section 5.1.3 is not
applicable to Chiron Proprietary Technology.

         5.2        Infringement Actions by Chiron or RPI Against Third Parties.

                    (a) Each party (the "Notifying Party") shall notify the
other party in writing if it becomes aware of any material infringement by a
third party of such other party's intellectual property rights in such other
party's technology. The party that owns any such technology, (the "Owning
Party" for purposes of Section 5.2) shall have the right to abate such
infringement and to retain any recoveries as a result of abatement of such
third party infringement;

                    (b) Notwithstanding the foregoing, if Chiron is the
Notifying Party and if the sales of such infringing product in a country, on a
dollar-demonstrated basis, represent at least 15 percent of the combined sales
in such country of the infringing product and a Product sold by Chiron for the
same Target or Feasibility Study Target pursuant to this Agreement, then Chiron
may, at its own expense, undertake commercially reasonable efforts to abate
such infringement on behalf of RPI if RPI has not, within 180 days after RPI's
receipt of Chiron's written 

<PAGE>   10

notice of infringement by a third party, caused such infringement to cease, or
reasonably demonstrated that there is in fact no material infringement by the
alleged third party infringer, or filed a lawsuit against the alleged third
party infringer. Any action by one party on behalf of the other party pursuant
to this Section 5.2 (b) shall be undertaken in a commercially reasonable
manner, shall not result in any transfer of ownership rights in the infringed
technology between Chiron and RPI, and shall not, without such other party's
written consent, involve any settlement or consent to any adverse judgment that
will diminish the rights of such other party. The parties shall share any funds
recovered as a result of legal action taken under this Section 5.2(b) against a
third party infringer as follows. In the event of recovery from the action in
question, each party shall be entitled to reimbursement of its direct costs in
bringing such action. The remainder of the amount recovered shall be paid to
Chiron, but shall be subject to royalty payments to RPI in the same manner as
if such remaining recovery constituted Net Sales of a Product hereunder.

         5.3        Infringements. If RPI or Chiron is sued by a third party 
for patent infringement because of the manufacture, use or sale of Products,
the party which has been sued shall promptly notify the other party in writing
of the institution of such suit. The party sued shall defend the action at its
expense, and the other party shall cooperate in connection with such defense at
the expense of the sued party.

         5.4        Notification of Issued Patents and Patent Term Extensions. 
Each party shall notify the other promptly upon: (i) issuance of any patents
directed to such party's inventions licensed hereunder, or (ii) receipt of
notification of any extension of the term of any patent directed to such
party's inventions licensed hereunder, pursuant to the U.S. Drug Price
Competition and Patent Term Restoration Act of 1984, or any similar foreign
statute or regulation, where the Patent in question is applicable to Products.

         5.5        Markings. On or in connection with each Product sold by 
either party, such party shall legibly mark or provide an appropriate notice of
the other party's Patent rights in a reasonable form and substance approved in
advance by the other party in writing and shall provide at the other party's
request proof of compliance with this requirement.

6.       Payment of Royalties.

         6.1        Determination of Effect of Collaboration. The parties will
mutually decide, in good faith, for each Product, other than a Ribozyme
Product, whether the Ribozyme Experiments were critical in causing Chiron to
change its development plans. Such Ribozyme Experiments will be critical in
causing such a change in the following circumstances: (i) if Chiron has a group
of related candidate genes or sequences as to which it has not selected which
to pursue, and the Ribozyme Experiments determine which of such group Chiron
selects; or (ii) if Chiron has previously selected one of a group of related
candidate genes and the Ribozyme Experiments cause Chiron to change its
selection to another gene or gene sequence designated as a Target under Section
3; or (iii) if the Ribozyme Experiments cause Chiron to select or change the
clinical indication it is pursuing with respect to a Target included under
Section 3; or (iv) upon such other criteria as the parties mutually agree.

         6.2        Non-Definitive Contribution Products. If Chiron proceeds to
develop Non-Definitive Contribution Products, with respect to which the
Ribozyme Experiments were not critical in changing Chiron's development plan as
determined in accordance with Section 6.1, Chiron agrees to pay RPI [ ] upon
NDA approval of [ ] Non-Definitive Contribution Product. [ ] If the Ribozyme
Experiments do not provide any information with respect to any Target, no
milestone will be payable under this Section 6.2.

         6.3        Definitive Contribution. If Chiron proceeds to develop 
Definitive Contribution Products, with respect to which the Ribozyme
Experiments were critical in changing Chiron's development plan, as determined
in accordance with Section 6.1 above, Chiron agrees to make the following
payments to RPI with respect to each such Product:

                    Milestone payments:  [ ] on IND filing
                                         [ ] on NDA approval
<PAGE>   11

         Provided that [ ] of such milestone payments for a [ ]; such [ ] will
be applied so [ ] for any period will not be reduced by more than [ ].

                    Royalty:  [ ] of Net Sales

         6.4        Ribozyme Products.

                    (a)        Chiron agrees to pay milestones to RPI on 
Ribozyme Products arising from this Agreement as follows:

                    [ ] on IND filing
                    [ ] on commencement of Phase II Clinical Studies
                    [ ] on commencement of Phase III Clinical Studies
                    [ ] on NDA approval
                    Total per Product:  [ ]

         Provided that the milestones paid for all products under this
Agreement will not exceed [ ] in the aggregate; and [ ] of such milestone
payments for a Product will be creditable against royalties for such Product;
and such credit will be applied such that royalties payable for any period will
not be reduced by more than [ ] and shall not be less than [ ] of Net Sales.

                    (b) Subject to the adjustments set forth in subsections 6.4
(c), (d), (e) and (f) below, Chiron agrees to pay royalties on total Net Sales
of Products containing ribozymes arising from this Agreement as follows:

                    Annual Net Sales                          Royalty

                    up to $100,000,000                        [ ] of Net Sales
                    $100-500,000,000                          [ ] of Net Sales
                    over $500,000,000                         [ ] of Net Sales

                    (c) If the total cost of goods to Chiron, including
royalties to RPI under this Section 6.4, all costs of all other product
components, cost of finishing, filing and packaging, and all royalties and
other obligations to third parties, and all other costs, exceeds [ ] of Net
Sales, [ ].

                    Subject to the provisions of Section 8.1(a), RPI's  
royalties shall be reduced as necessary [ ]:

                    Annual Net Sales                          Royalty

                    up to $100,000,000                        [ ] of Net Sales
                    $100-500,000,000                          [ ] of Net Sales
                    over $500,000,000                         [ ] of Net Sales

                    (d) In the event that the manufacture, use or sale of a
Ribozyme Product in any jurisdiction would not infringe a claim of an issued
Patent within the RPI Technology, the royalty otherwise payable under this
Section 6.4 shall be automatically reduced by [ ] of Net Sales.

                    (e) The provisions of Sections 6.4(a), (b), (c) and (d)
above are applicable to Ribozyme Products for human therapeutic or prophylactic
use. The parties acknowledge that the pricing and margins in the diagnostic and
veterinary markets differ significantly from the human therapeutic and
prophylactic markets, and, as a result, different compensation hereunder is
appropriate for Ribozyme Products in the diagnostic or veterinary markets..
Accordingly, if a Ribozyme Product has diagnostic or veterinary uses, the
parties shall negotiate in good faith commercially reasonable reductions in the
milestone payments and royalty rates set forth in Section 6.4, so as to render
the compensation hereunder appropriate for the diagnostic and veterinary
markets.

<PAGE>   12

                    (f) The compensation payable by Chiron to RPI under this
Article 6 includes all RPI obligations to third parties under the licenses set
forth in Exhibit B. Without limiting any other rights and remedies of Chiron
hereunder, in the event that any such third party license is terminated, Chiron
shall have the right to deduct from payments to RPI hereunder all costs
incurred by Chiron in obtaining licenses to such third party technology
directly from such third party.

         6.5        Royalties on Products Developed by RPI. (a) If RPI exercises
its right to use the Screening Results, and, subject to Section 6.5(b), the
Chiron Proprietary Product Data, RPI agrees to pay royalties to Chiron with
respect to total Net Sales of Products developed by RPI pursuant to Section 3.9
as follows:

                    Annual Net Sales                          Royalty

                    up to $100,000,000                        [ ] of Net Sales
                    $100-500,000,000                          [ ] of Net Sales
                    over $500,000,000                         [ ] of Net Sales

                    (b) The provisions of Section 6.5(a) above are applicable
to Ribozyme Products for human therapeutic or prophylactic use. The parties
acknowledge that the pricing and margins in the diagnostic and veterinary
markets differ significantly from the human therapeutic and prophylactic
markets, and, as a result, different compensation hereunder is appropriate for
Ribozyme Products in the diagnostic or veterinary markets. Accordingly, if a
Ribozyme Product has diagnostic or veterinary uses, the parties shall negotiate
in good faith commercially reasonable reductions in the royalty rates set forth
in Section 6.5(a), so as to render the compensation hereunder appropriate for
the diagnostic and veterinary markets.

                    (c) If Chiron abandons a Ribozyme Product in accordance
with Section 3.9, RPI shall have the right to license Chiron Proprietary
Product Data related to such Ribozyme Product on the following terms: RPI will
increase the royalty otherwise due to Chiron under this Section 6.5(a) [ ]
until such time as all Precommercialization Costs and all other costs
(excluding general and administrative costs) incurred by Chiron and reasonably
attributable to the development of the licensed Chiron Proprietary Product Data
are recouped through such [ ]. Thereafter royalties shall revert to those
stated in Section 6.5(a).

                    (d) If, in connection with such Ribozyme Products, RPI
wishes to license other Chiron Proprietary Technology, including, without
limitation rights under patents or patent applications governing the Target,
the terms of such licenses will be separately negotiated by the parties in good
faith pursuant to Section 4.2, and will [ ].

7.       Conduct of Collaboration and Product Development.

         7.1        A party developing a Product pursuant to this Agreement 
shall control all decisions with respect to such Product, in its discretion,
and shall bear its own expenses in connection with such development.

         7.2        (a) RPI agrees to use commercially reasonable efforts to 
supply to Chiron such quantities of ribozymes as are reasonably required by
Chiron for product development and clinical trials of Ribozyme Products, and,
if it has elected to manufacture the Ribozyme Product for Exogenous delivery
pursuant to Article 8, to conduct such process development and scale up as may
be reasonably required, all subject to reimbursement of its
Precommercialization Costs.

                    (b) If Chiron has elected to exercise its manufacturing
rights under Section 8.2 for a Ribozyme Product developed by RPI for Endogenous
delivery, Chiron agrees to use commercially reasonable efforts to supply to RPI
such quantities of such Ribozyme Product as are reasonably required by RPI for
product development and clinical trials, and to conduct such process
development and scale up as may be reasonably required, all subject to
reimbursement of its Precommercialization Costs.

<PAGE>   13

         7.3        Compliance With Applicable Laws and Regulations. Each party 
shall fulfill its obligations under this Agreement in a manner which complies
with all applicable laws and regulations and applicable good laboratory,
clinical and manufacturing practices. Each party shall provide reasonably
sufficient time, equipment, facilities, personnel and other resources to
fulfill such obligations. Each party may subcontract third parties to assist
such party in fulfilling its obligations under this Agreement; provided, that:
(i) such party shall closely monitor the activities of its subcontractor to
ensure that each such subcontractor complies with all applicable laws and
regulations and applicable good laboratory, clinical and manufacturing
practices, and (ii) each such subcontractor shall sign a confidentiality
agreement at least as protective of the parties' proprietary information as
this Agreement.

         7.4        Development Reports. During the Term of this Agreement, 
each party shall provide the other party with annual progress reports, (i) of
such party's research and development activities, with respect to Products
arising hereunder and (ii) such party's progress in obtaining the regulatory
approvals that it is required to obtain with respect to such Products; provided
that such progress reports shall not be required to disclose confidential data
or results of either party or any third party licensees or collaborators of
such party.

         7.5        [ ]

         If a resolution to the dispute is not reached through the preceding
process, the matter shall be submitted to binding arbitration, to be held under
similar confidentiality obligations to Chiron, at which RPI shall be
represented by the third party appointed as above, or a replacement reasonably
acceptable to Chiron.

8.       Manufacturing of Products.

         8.1        Products for Exogenous Delivery. Subject to the terms and
conditions of Section 8.3, RPI has the right to be the exclusive worldwide
manufacturer of any ribozyme based Product for Exogenous delivery developed by
Chiron. The transfer price to be paid by Chiron to RPI for such Products shall
be determined by the parties in good faith based on the principles set forth in
this Section 8.1. In the event that RPI is unable or unwilling to manufacture
any Product, in accordance with this Article 8, for timely delivery in
necessary quantities and in accordance with required quality standards, Chiron
shall have the right to have such Product manufactured by Chiron or a third
party, provided, however, that Chiron or such third party is able to
manufacture such Product for timely delivery in necessary quantities and in
accordance with required quality standards.

         The principles governing the transfer price of Products manufactured
by RPI hereunder are as follows:

         (a) If total cost of goods to Chiron, including the transfer price
payable under this Section 8.1, all royalties payable to RPI under Section 6.4,
all costs of all other product components, the cost of finishing, filling and
packaging, all royalties and other obligations to third parties, and all other
costs, exceeds [ ],

                    (i)   RPI agrees to reduce any manufacturing compensation
         payable pursuant to this Section 8.1 as needed to bring such total
         cost of goods to [ ], provided that Section 8.1(a)(iii) will then
         apply.

                    (ii)  If, following the reduction referenced in Section
         8.1(a)(i) above, the total cost of goods still [ ] adjusted pursuant
         to Section 6.4(c), provided that Section 8.1(a)(iii) will then apply.

                    (iii) Notwithstanding the above, in no case will RPI's
total profits (consisting of its manufacturing profits plus royalties payable
hereunder pursuant to Section 6.4(b) or 6.4(c) as applicable) be less than [ ],

         (b) As a consequence of Section 8.1(a), if [ ] of Net Sales, the
transfer price to RPI under this Section 8.1 will be reduced as provided in
Section 8.1(a). Such level of [ ] is referred to herein as the [ ]. The
transfer price structure adopted pursuant to this Section 8.1 shall provide
both (i) incentives which operate to induce RPI to continue to reduce its
Manufacturing Costs (and thereby increase its manufacturing profit) at all
levels of such Manufacturing Costs, and (ii) reasonable sharing between RPI and
Chiron of the benefit of Manufacturing Cost 

<PAGE>   14

reductions at all levels of Manufacturing Costs below the [ ]. Exhibit C sets
forth an example of such a transfer price structure. However, the parties
acknowledge that many factors which are unknown as of the Effective Date may
affect the profitability to RPI of manufacturing a Product, such as Product
configuration, dosage, pricing, sales volumes and the like. Such factors may
require adoption of a [ ] which is a variant of that set forth in Exhibit C or
different [ ]. Based on the actual circumstances applicable to a particular
Product, the parties agree to negotiate in good faith to determine a transfer
price structure which meets the requirements of subparts (i) and (ii) of this
Section 8.1(b), is consistent with the intent of the transfer price structure
described in Exhibit C, and is fair and commercially reasonable to both
parties.

         8.2        Products for Endogenous Delivery.

         (a)        Chiron retains the right to manufacture  Ribozyme  Products 
for Endogenous delivery developed by Chiron or its sublicensees.

         (b)        Subject to the terms and conditions of Section 8.3, Chiron 
has the right to be the exclusive worldwide manufacturer of any ribozyme based
Product for Endogenous delivery developed by RPI pursuant to Section 2.9 or
Section 3.9. The transfer price to be paid by RPI to Chiron shall be determined
by the parties in good faith based on the principles set forth in this Section
8.2. In the event that Chiron is unable or unwilling to manufacture any
Product, in accordance with this Article 8, for timely delivery in necessary
quantities and in accordance with required quality standards, RPI shall have
the right to have such Product manufactured by RPI or a third party; provided,
however, that (i) RPI or such third party is able to manufacture such Product
for timely delivery in necessary quantities and in accordance with required
quality standards; and (ii) nothing in this Agreement shall be construed to
grant RPI any right or license under any Confidential Information or
intellectual property of Chiron, except for the Chiron Proprietary Technology
and the Chiron Proprietary Product Data as specifically set forth in this
Agreement. Without limiting the foregoing, nothing herein shall be construed to
grant to RPI any right or license under any Chiron technology related to any
gene transfer systems, delivery systems, or the manufacture or use thereof. Any
such licenses must be separately negotiated by the parties, and shall be
subject to separate compensation.

The principles governing the transfer price of Products manufactured by Chiron
hereunder are as follows:

                              (aa) The parties shall establish a maximum for
                    total cost of goods, expressed as a percentage of net
                    sales, after taking into account royalties payable to
                    Chiron under this agreement, as well as royalties payable
                    under any separately negotiated licenses of technology of
                    Chiron, known third party royalty obligations, and other
                    known factors influencing the cost of a particular Product.
                    Based on the royalties payable to Chiron both hereunder and
                    under any separately negotiated licenses to technology of
                    Chiron, the parties shall also establish a minimum total
                    profit amount for Chiron, expressed as a percentage of net
                    sales, and consisting of manufacturing profits plus all
                    such royalties payable to Chiron. If total cost of goods to
                    RPI exceeds the maximum amount for total cost of goods
                    referenced above, the manufacturing profit to Chiron shall
                    be reduced to bring the total cost of goods under such
                    maximum amount, provided that, in no event shall Chiron's
                    total profits be less than the agreed upon minimum total
                    profit amount referenced above. Unless separately
                    negotiated, no reduction in royalties payable to Chiron
                    shall arise in the event of cost of goods exceeding such
                    maximum amount.

                              (bb) Based on Section 8.2(b)(aa), the parties 
                    shall determine the Transfer Price Reduction Point for such
                    Product. The transfer price structure adopted pursuant to
                    this Section 8.2(b) shall provide both (x) incentives which
                    operate to induce Chiron to continue to reduce its
                    Manufacturing Costs (and thereby increase its manufacturing
                    profit) at all levels of such Manufacturing Costs, and (y)
                    reasonable sharing between RPI and Chiron of the benefit of
                    Manufacturing Cost reductions at all levels of
                    Manufacturing Costs below the Transfer Price Reduction
                    Point. Exhibit C, if adjusted to reflect the maximum amount
                    for total cost of goods and the minimum total profit amount
                    determined under Section 8.2(b)(aa), would set forth an
                    example of such a transfer price structure. However, the
                    parties acknowledge that many factors which are unknown as
                    of the Effective Date may affect the profitability to
                    Chiron of manufacturing a Product, such as Product
                    configuration, dosage, pricing, sales volumes and the like.
                    Such factors may require adoption of a transfer price
                    structure which is a variant of that set

<PAGE>   15
                    forth in Exhibit C or different transfer price structure. 
                    Based on the actual circumstances applicable to a
                    particular Product, the parties agree to negotiate in good
                    faith to determine a transfer price structure which meets
                    the requirements of subparts (x) and (y) of this Section
                    8.2(b)(bb), is consistent with the intent of the transfer
                    price structure described in Exhibit C, and is fair and
                    commercially reasonable to both parties.

         8.3        Manufacturing Standards. As to any party determined to be 
the manufacturer of a Product pursuant to Section 8.1 or Section 8.2, such
party shall manufacture such Product in accordance with all relevant statutory
and regulatory requirements, and specifications and quality standards approved
by the developing party.

         8.4        Other Manufacturing. Except as provided herein a party 
developing a Product shall have the right, in its sole discretion, to have such
Product manufactured by third parties or to manufacture such Product itself.

         8.5        In the event that either party exercises its right to 
manufacture Products for the other party pursuant to Section 8.1 or 8.2, the
parties shall enter into a separate Supply Agreement, to be negotiated in good
faith, and containing terms consistent with those set forth herein and other
commercially reasonable terms, including without limitation commitments for
timely development of necessary manufacturing capacity, record keeping and
audit rights, and other customary terms and conditions.

9.       Royalty Records and Reports.

         9.1        Reports. Within 60 days after the end of any quarter during 
the term of this Agreement commencing with the quarter in which the first
commercial sale of a Product subject to payment of royalties hereunder occurs
and including the quarter during which this Agreement expires or is terminated,
each party will provide the other quarterly reports as set forth in this
Section 9. With respect to all Products subject to royalties hereunder, such
report shall include gross revenues and Net Sales, on a country-by-country
basis, from sales of Products by such party, or its Affiliates or sublicensees,
together with the calculation of royalties due to the other party hereunder
with respect to such Net Sales. In such reports, gross revenues, Net Sales and
royalties shall be (A) expressed in U.S. dollars for sales of Products invoiced
in U.S. dollars, and (B) expressed in the currency in which the gross revenues
were received, if such gross revenues were not received in U.S. dollars,
together with the U.S. dollar equivalent of such amounts, calculated in
accordance with the procedures used generally by the reporting party for
converting sales in foreign currencies to U.S. Dollars.

         9.2        Records.

                    9.2.1 Sales Records. Each party selling a Product shall
keep,. and shall require its Affiliates and sublicensees to keep, detailed
records of Product sales, which records shall be sufficiently complete to
enable all amounts specified in Section 9.1 and Article 6 to be determined or
calculated. Such records shall be retained for a period of at least five years
after the date on which such costs were incurred or such revenues were
received.

                    9.2.2 Costs. Each party shall keep detailed records of
Research Costs and Precommercialization Costs with respect to which such party
seeks reimbursement or payment under this Agreement. Such records shall be
retained for a period of at least five years after the date on which such costs
were incurred. If either party fails to keep such records, then such party
shall not be entitled to reimbursement of the costs in question.

         9.3        Audits. Each party shall make available, and shall require 
its Affiliates and sublicensees to make available, the records described in
Section 9.2 for inspection during the period referred to in Section 9.2 by a
certified public or chartered accountant retained by the other party for such
purpose and subject to the reasonable approval of the party being audited,
solely for the purpose of verifying the amount of royalties or costs payable to
such other party. Such inspections may be made no more than once in each
calendar year, at reasonable times mutually agreed upon by the parties after at
least 15 days written notice to the audited entity. The accountant shall
execute a reasonable confidentiality agreement prior to commencing any such
inspection, shall be authorized to disclose to the auditing party only the
amounts of royalties or costs payable hereunder. Such inspections shall be at

<PAGE>   16

the expense of the auditing party, unless net sales are underreported, or costs
are over-reported by an amount in excess of five percent of the correct amount,
in which case the cost of the audit shall be paid by the party whose books and
records, or whose Affiliate's or sublicensee's books and records, were audited.

         9.4        Withholding Taxes. The selling party shall be entitled to 
deduct from the royalties payable hereunder the amount of any withholding
taxes, value-added taxes or other taxes, levies or charges with respect to such
amounts, other than United States taxes, payable by the selling party, its
Affiliates or sublicensees, or any taxes required to be withheld by the selling
party, its Affiliates or sublicensees, to the extent the selling party, its
Affiliates or sublicensees pay to the appropriate governmental authority on
behalf of the non-selling party such taxes, levies or charges. The selling
party shall use reasonable efforts to minimize any such taxes, levies or
charges required to be withheld on behalf of the non-selling party by the
selling party, its Affiliates or sublicensees. The selling party promptly shall
deliver to the non-selling party proof of payment of a such taxes, levies and
other charges, together with copies of all communications from or with such
governmental authority with respect thereto.

10.      Payment Procedures.

         10.1       Timing.  Royalties are payable under Article 6, for any 
quarter, within 90 days after the end of such quarter.

         10.2       Payment Method. Payments under this Agreement shall be made
by wire transfer of U.S. funds to a bank account designated by the party
receiving such payments. In the event that payments arising from sales of
Products in a particular country cannot be remitted in whole or in part to the
U.S. because of legal restrictions, the parties shall consult and endeavor to
resolve the problem in a manner satisfactory to the party to which such
payments are owed; provided that at the owed party's request, payments arising
from sale of Products in such country shall be made, at the owed party's
election either by payment in the U.S. of such amount by a U.S. parent of the
seller of the Product or by wire transfer to a bank account in the country of
sale designated by such party.

11.      Term and Termination.

         11.1       Term. This Agreement shall become effective on the Effective
Date and, unless terminated earlier in accordance with the provisions of this
Article 11 or extended by mutual agreement of the parties, shall expire in a
given country upon the later to occur of (A) the expiration, cancellation or
revocation in such country of the last claim of an issued patent covering such
Product and contained within the other party's Technology; or (B) the tenth
anniversary of the first commercial sale of such Product in such country. At
such time, the party which is commercializing such Product shall have a royalty
free, perpetual, nonexclusive license under the other party's technology
licensed to it under this Agreement to develop, improve, make, have made, use
and sell such Product.

         11.2       Default. If either party defaults in the performance of any 
of its material obligations hereunder and if after notice thereof such default
is: (i) a payment default and is not corrected within 30 days or (ii) other
kind of default not corrected within 60 days, then the non-defaulting party, at
its option, may, in addition to any other remedies it may have, terminate this
Agreement by giving written notice of termination to the defaulting party.

         11.3       Survival. Except as otherwise set forth herein, or as 
otherwise agreed, the parties' rights and obligations pursuant to the following
Articles and Sections shall survive any termination of this Agreement in
accordance with their terms:

                    (a) In all events: Article 1, Section 4.3, Section 4.4,
Section 5.1.1, Section 5.3, Section 9.2, Section 9.3, Article 11, Section 12.3,
Article 13, Article 14, Article 15, Article 16, Section 17.1, Section 17.2,
Section 17.7, and Section 17.9.

                    (b) In the event that the termination arrangement causes
one or both parties to continue to develop, make, have made, use or sell any
Products, such provisions of this Agreement as are applicable thereto.

<PAGE>   17

The provisions of Sections 15 and 16 shall survive any termination of this
Agreement for a period of three years after such termination. Termination of
this Agreement shall not relieve the parties of any obligation accruing prior
to such termination.

12.      Representations and Warranties.

         12.1       By Both Parties. Each party represents that it (i) has all 
right, power and authority necessary to enter into this agreement and to grant
the rights granted herein, (ii) has obtained all approvals and authorizations
that it is required to obtain in connection with this Agreement under
applicable laws and regulations, and (iii) has not entered, and will not enter,
into any arrangements or agreements inconsistent with this Agreement.

         12.2       By RPI.  RPI hereby represents and warrants as follows:

                    As of the Effective Date, each of the Licenses listed in
Exhibit B is in full force and effect. During the term of this Agreement, RPI
agrees to perform all of its obligations under such Licenses (including all
obligations in order to maintain the exclusivity of the Licenses), and RPI
further agrees that it will not terminate any of such Licenses without Chiron's
prior consent. RPI shall immediately notify Chiron in the event that RPI
receives notice of its alleged breach or non-compliance pursuant to any of such
Licenses and shall take all steps necessary to cure or otherwise remedy the
alleged breach. RPI shall immediately notify Chiron in the event that RPI
becomes aware of any alleged breach by USB of its obligations to UPI under such
Licenses (including those obligations necessary to maintain the exclusivity of
the Licenses). During the term of this Agreement, RPI shall take all steps
necessary to cure or otherwise remedy the alleged breach by USB.

         12.3       Disclaimer of Warranties. NEITHER PARTY MAKES ANY WARRANTIES
OTHER THAN THE WARRANTIES EXPRESSLY MADE IN THIS AGREEMENT, AND EACH PARTY
SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS OF A
PARTICULAR PURPOSE OR NONINFRINGEMENT WITH RESPECT TO ANY TECHNOLOGY, DATA OR
PRODUCTS.

13.      Indemnity.

         13.1       Collaboration. Each party (the "Indemnifying Party") shall 
defend the other party and such other party's Affiliates, officers, directors,
shareholders, employees and agents (collectively, the "Indemnified Parties" for
purposes of this Section 13.1) against any claims made against the Indemnified
Parties by third parties to the extent that such claims arise out of negligent,
reckless or intentionally wrongful acts or omissions of the Indemnifying Party
or its Affiliates in the course of performing its activities in the course of
the Feasibility Study or the Screening Program or out of breaches of this
Agreement by the Indemnifying Party, and the Indemnifying Party shall either
settle such claims or pay all damages and costs finally awarded against the
Indemnified Parties by a court of competent jurisdiction as a result of such
claims. The Indemnifying Party shall have no liability for any such claim if
the Indemnified Parties do not notify the Indemnifying party promptly in
writing of the claim, give the Indemnifying Party the exclusive control of the
defense and settlement thereof, and provide all reasonable assistance in
connection therewith, at the Indemnifying Party's expense.

         13.2       Additional Indemnity by Chiron for Products. Chiron shall 
defend RPI and RPI's Affiliates, officers, directors, shareholders and agents
(collectively, the "Indemnified Parties" for purposes of this Section 13.2)
against any claims made against the Indemnified Parties by third parties to the
extent that such claims arise out of the manufacture, use or sale of any
Product developed by Chiron; and shall either settle such claims or pay all
damages and costs finally awarded against the Indemnified Parties by a court of
competent jurisdiction as a result of such claims. Chiron shall have no
liability for any such claim (i) unless it receives prompt written notification
of such claim, is given exclusive control of the defense and settlement
thereof, and is provided with all reasonable assistance in connection therewith
by the Indemnified Parties, at Chiron's expense, or (ii) to the extent that
such claim arises out of RPI's breach of this Agreement or any Supply Agreement
entered into pursuant to Section 8.1, or RPI's negligence or willful
misconduct.

<PAGE>   18

         13.3       Additional Indemnity by RPI for Products. RPI shall defend 
Chiron and Chiron's affiliates, officers, directors, shareholders and agents
(collectively, the "Indemnified Parties" for purposes of this Section 13.3)
against any claims made against the Indemnified parties by third parties to the
extent that such claims arise out of the manufacture, use or sale of any
Product developed by RPI; and shall either settle such claims or pay all
damages and costs finally awarded against the indemnified Parties by a court of
competent jurisdiction as a result of such claims. RPI shall have no liability
for any such claim (i) unless it receives prompt written notification of such
claim, is given exclusive control of the defense and settlement thereof, and is
provided with all reasonable assistance in connection therewith by the
Indemnified Parties, at RPI's expense, or (ii) to the extent that such claim
arises out of Chiron's breach of this Agreement or any Supply Agreement entered
into pursuant to Section 8.2, or Chiron's negligence or willful misconduct.

         13.4       Right to Reimbursement. Without limiting the right of the 
parties under Sections 13.1, 13.2, and 13.3, a party which is entitled to
indemnification against a lawsuit under Sections 13.1, 13.2 or 13.3, and is not
provided such indemnification by the other party, shall have the right to
defend itself in such suit and obtain reimbursement from the other party for
its reasonable legal fees and other costs incurred in defending itself in such
suits, and for any payments or amounts which it pays as a result of settlements
made or judgments awarded in such suit. Such right of reimbursement shall be in
addition to all other remedies which the party defending itself under this
Section 13.4 possesses with respect to the other party.

         13.5       Insurance. Each party shall maintain product liability 
insurance with respect to its development, manufacture and sale of Products, in
such amount as it customarily maintains with respect to its development,
manufacture and sale of other comparable products, and shall name the other
party as an additional insured party. Each party shall maintain such insurance
while it develops, manufactures or sells Products, and thereafter shall
maintain such insurance in effect for a reasonable period after the cessation
of sale or other distribution of such Product. Each party shall provide a copy
of the policy providing such product liability insurance to the other party
promptly after such policy becomes effective, and shall thereafter notify such
other party promptly after any change in the terms of such policy.

14.      Limitation of Liability.

IN NO EVENT SHALL EITHER PARTY BE LIABLE TO THE OTHER PARTY FOR LOST PROFITS OR
ANY CONSEQUENTIAL, SPECIAL, INCIDENTAL, OR INDIRECT DAMAGES OF SUCH OTHER
PARTY, HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, ARISING OUT OF THIS
AGREEMENT. CHIRON AND RPI ACKNOWLEDGE THAT THE AMOUNTS PAYABLE AND THE
OBLIGATIONS INCURRED HEREUNDER BY EACH PARTY ARE BASED IN PART UPON THESE
LIMITATIONS, AND FURTHER ACKNOWLEDGE THAT THESE LIMITATIONS SHALL APPLY
NOTWITHSTANDING ANY FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY.

15.      Confidentiality.

         15.1       Confidential Information. As used in this Agreement, the 
term "Confidential Information" shall mean any information disclosed by one
party to the other pursuant to this Agreement which the recipient knows or has
a reason to know is deemed confidential or proprietary by the disclosing party.

         15.2       Confidentiality. Each party shall treat as confidential all
Confidential Information of the other party, shall not use such Confidential
Information except as set forth herein, and shall use reasonable efforts not to
disclose such Confidential Information to any third party. Without limiting the
foregoing, each of the parties shall use at least the same degree of care which
it uses to prevent the disclosure of its own confidential information of like
importance to prevent the disclosure of Confidential Information disclosed to
it by the other party under this Agreement. Each party shall promptly notify
the other party of any actual or suspected misuse or unauthorized disclosure of
the other party's Confidential Information.

         15.3       Exceptions. Notwithstanding the above, neither party shall 
have liability to the other with regard to any Confidential Information of the
other which the receiving party can demonstrate:

<PAGE>   19

                    (i)       was in the public domain at the time it was  
disclosed or has entered the public domainthrough no fault of the receiving
party;

                    (ii)      was known to the receiving party, at the time of  
disclosure, as demonstrated by files in existence at the time of disclosure;

                    (iii)     is disclosed with the prior written approval of 
the disclosing party;

                    (iv)      was independently developed by the receiving party
without any use of the Confidential Information, as demonstrated by files
created at the time of such independent development;

                    (v)       became known to the receiving party, without
restriction, from a source other than the disclosing party without breach of
this Agreement by the receiving party and otherwise not in violation of the
disclosing party's rights;

                    (vi)      is disclosed generally to third parties by the  
disclosing party without restrictions similar to those contained in this
Agreement; or

                    (vii)     is disclosed pursuant to the order or requirement 
of a court, administrative agency, or other governmental body; provided,
however, that the receiving party shall provide prompt written notice thereof
to the disclosing party to enable the disclosing party to seek a protective
order or otherwise prevent or restrict such disclosure.

         15.4       Return of Confidential Information. Upon expiration or 
termination of this Agreement each party shall upon request return all tangible
Confidential Information received from the other party.

         15.5       Publication and Disclosure of Results and Data.

         (a) Chiron shall have the right to publish the Feasibility Study
Results, the Screening Results or other Chiron Proprietary Product Data in its
sole discretion, provided that it does not disclose RPI Confidential
Information.

         (b) RPI shall not have the right to receive, nor shall it have the
right to publish or disclose, results of the Feasibility Study without Chiron's
prior written consent.

          The parties acknowledge that RPI wishes to be able to receive and
utilize Feasibility Study results and data which may be helpful in improving
RPI's screening technology, and RPI wishes to be able to disclose Feasibility
Study results to third parties in order to attract additional customers for
gene function studies. Chiron shall have the right to determine, in its sole
discretion, whether such use by RPI of Feasibility Study results and/or
disclosure by RPI to third parties of the identity of Feasibility Study Targets
or Feasibility Study results or data would place Chiron at a competitive
disadvantage, for example by disclosing Chiron trade secrets or Chiron
proprietary information that may provide a competitive advantage to others. If
Chiron determines that no such competitive disadvantage would result, Chiron
will disclose such Feasibility Study Results to RPI for use in improving its
screening technology, and permit RPI to disclose such target identity, results
or data to other potential gene function collaborators of RPI subject to
confidentiality obligations no less restrictive than those contained in this
Article 15.

         (c) RPI shall not have the right to publish or disclose any Screening
Results, or Chiron Proprietary Product Data, or other data or information
arising from the Collaboration. Chiron may elect to provide Screening Results
to RPI for its internal use in improving RPI's screening technology, if Chiron
determines that no competitive disadvantage would result to Chiron, under the
same standards as are set forth in Section 15.5(b) above.

         (d)  Any publication shall appropriately acknowledge the scientific 
contributions of the other party.

<PAGE>   20

16.      Confidentiality of Agreement.

Chiron and RPI agree that the terms and conditions of this Agreement contained
in Section 2, 3 and 6 shall be treated as Confidential Information and shall
not be disclosed to any third party without the prior consent of the other
party. Notwithstanding the statements above in this Section 16, either party
may disclose any of the terms and conditions of this Agreement:

         (i)         as required by any court or other governmental body;

         (ii)        as otherwise required by law;

         (iii)       to legal counsel of the parties;

         (iv)        in confidence, to accountants, banks, and financing 
sources, and other advisors or consultants of the parties;

         (v)        in connection with the enforcement of this Agreement or 
rights under this Agreement;

         (vi)       in confidence, in connection with a merger, acquisition, or 
similar transaction;

         (vii)      which have been previously disclosed in a joint press 
release by the parties hereto; or

         (viii)     in confidence, to a third party to the extent reasonably
necessary to permit the consideration of a bona fide collaboration which would
involve rights, obligations or limitations arising under this Agreement,
provided that such collaboration is not prohibited under this Agreement.

         In the event of any disclosure pursuant to (i) or (ii) above, the
disclosing party shall use all reasonable efforts to obtain confidential
treatment of materials so disclosed. The parties intend to issue a mutually
approved press release with respect to this Agreement. Neither party shall make
public disclosures of the terms and conditions, not previously disclosed,
except in accordance with this Article 16.

17.      General.

         17.1       Governing  Law. This Agreement shall be governed by and 
interpreted in accordance with the laws of the State of California, without
reference to conflict of laws provisions.

         17.2       Partial Invalidity. If any provision in this Agreement shall
be found or be held to be invalid or unenforceable in any jurisdiction in which
this Agreement is being performed, then the meaning of said provision shall be
construed, to the extent feasible, so as to render the provision enforceable,
and if no feasible interpretation would save such provision, it shall be
severed, solely in such jurisdiction, from the remainder of this Agreement,
which shall remain in full force and effect; provided that the remainder is
consistent with the intent of the parties as evidenced by this Agreement as a
whole. In such event, the parties shall negotiate, in good faith, a substitute,
valid and enforceable provision, effective solely in such jurisdiction, which
most nearly effects the parties' intent in entering into this Agreement.

         17.3       Relationship of the Parties. Both parties are independent
contractors under this Agreement, and nothing contained in this Agreement is
intended nor is it to be construed so as to constitute Chiron and RPI as
partners or joint venturers with respect to this Agreement. Employees of each
party remain employees of said party and shall be considered at no time agents
of or to be obligated to render a fiduciary duty to the other.

         17.4       Modification. No alteration, amendment, waiver, cancellation
or any other change in any term or condition of this Agreement shall be valid
or binding on either party unless the same shall have been mutually assented to
in writing by both parties.

<PAGE>   21

         17.5       Waiver. The failure of either party to enforce at any time 
any of the provisions of this Agreement, or the failure to require at any time
performance by the other party of any of the provisions of this Agreement,
shall in no way be construed to be a present or future waiver of such
provisions, nor in any way affect the right of either party to enforce each and
every such provision thereafter. The express waiver by either party of any
provision, condition or requirement of this Agreement shall not constitute a
waiver of any future obligation to comply with such provision, condition or
requirement.

         17.6       Assignment. This Agreement shall be binding upon and shall 
inure to the benefit of the parties hereto and their respective successors and
assigns. Neither party may assign any of its rights, obligations or privileges
(by operation of law or otherwise) hereunder without the prior written consent
of the other party, which shall not be unreasonably withheld, provided, that
either party shall have the right to assign its rights, obligations and
privileges hereunder to an Affiliate or a successor in business or an acquirer
of all or substantially all of its business or assets to which this Agreement
pertains without obtaining the consent of the other party.

         17.7       Notices. Any notice required or permitted to be given by 
either party under this Agreement shall be in writing, and shall be personally
delivered or sent by certified or registered letter, or by telecopy confirmed
by registered or certified letter, to the other party at the address set forth
below, or such new address as may from time to time be supplied hereunder by
the parties hereto. Notices will be deemed effective upon receipt.

         If to Chiron:        Chiron Corporation
                              4560 Horton Street
                              Emeryville, CA 94608-2916

                              Attention:  President, Chiron Technologies
                              Copy to:    General Counsel

         If to RPI: Ribozyme Pharmaceuticals, Inc.
                              2950 Wilderness Place
                              Boulder, CO 80301

                              Attention:  Chief Executive Officer
                              Copy to:    General Counsel

         17.8       Force Majeure. Notwithstanding anything else in this 
Agreement, no default, delay or failure to perform on the part of either party
shall be considered a breach of this Agreement if such default, delay or
failure to perform is shown to be due to causes beyond the reasonable control
of the party charged with a default, including, but not limited to, causes such
as strikes, lockouts or other labor disputes, riots, civil disturbances,
actions or inactions of governmental authorities or suppliers, epidemics, war,
embargoes, severe weather, fire, earthquakes, acts of God or other deities,
acts of the public enemy, nuclear disasters, or default of a common carrier;
provided, that for the duration of such force majeure the party charged with
such default must continue to use all reasonable efforts to overcome such force
majeure.

         17.9       Dispute Resolution. In the event of any disagreement arising
hereunder, the matter shall be referred to the Chief Executive Officers
("CEOs") of each company. The CEOs shall negotiate in good faith to resolve
such dispute for 30 days, or for such longer period of time as may be specified
herein or to which the CEOs may agree. If such negotiations do not result in a
mutually satisfactory resolution of the issue in question (an "Impasse"), then
the matter shall be resolved by any procedure agreed to by the CEOs or, in the
absence of such an agreed procedure, through such remedies as may be available
at law or equity.

         17.10      Representations. It is the mutual desire and intent of the
parties to provide certainty as to their future rights and remedies against
each other by defining the extent of their mutual undertakings as provided
herein. Each of the parties hereto acknowledges and agrees (i) that no
representation or promise not expressly contained in this Agreement has been
made by the other party hereto or by any of its agents, employees,
representatives or 

<PAGE>   22

attorneys; (ii) that this Agreement is not being entered into on the basis of,
or in reliance on, any promise or representation, expressed or implied,
covering the subject matter hereof, other than those which are set forth
expressly in this Agreement; and (iii) that each party has had the opportunity
to be represented by counsel of its own choice in this matter, including the
negotiations which preceded the execution of this Agreement.

         17.11      Entire Agreement. The terms and conditions herein contained
constitute the entire agreement between the parties and supersede all previous
agreements and understandings, whether oral or written, between the parties
hereto with respect to the subject matter hereof.

         17.12      License of Intellectual Property. All rights and licenses
granted under this Agreement by one party ("Licensor") to the other party
("Licensee") are, and shall be deemed to be, for purposes of Section 365(n) of
the U.S. Bankruptcy Code, licenses of rights to "intellectual property" as
defined under Section 101 of the U.S. Bankruptcy Code. The parties agree that
Licensee, as the licensee of such rights under this Agreement, may fully
exercise all of its rights and elections under the Bankruptcy Code. The parties
further agree that, in the event a Licensee elects to retain its rights as a
licensee in Licensor's bankruptcy proceedings, such Licensee shall be entitled
to a complete duplicate of (or complete access to, as appropriate) any
technology licensed to Licensee by Licensor hereunder, and all embodiments of
such technology, and such embodiments of such technology, if not already in its
possession, shall be promptly delivered to Licensee (i) upon any such
commencement of a bankruptcy proceeding upon written request therefor by
Licensee unless Licensor elects to continue to perform all of its obligations
under this Agreement, or (ii) if not delivered under (i) above, upon the
rejection of this Agreement by or on behalf of Licensor upon written request
for such embodiments by Licensee.

         17.13      No Fiduciary Duty. The provisions contained in this 
Agreement are not intended to create and shall not create any fiduciary duty on
either party and shall not require either party to expend funds or efforts or
commit resources in excess of that expressly provided herein.

         17.14      [ ]


<PAGE>   23




IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be signed
by duly authorized officers or representatives as of the date first above
written.

CHIRON CORPORATION                       RIBOZYME PHARMACEUTICALS, INC.



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

Exhibits

         Exhibit A - Excluded Targets
         Exhibit B - RPI Licenses and Patents
         Exhibit C - Example of Transfer Price Structure



<PAGE>   24



                                   EXHIBIT A
                                Excluded Targets


[                                                                              ]



<PAGE>   25



                                   EXHIBIT B


<TABLE>
<CAPTION>
=================================================================================================================
               TITLE                      ISSUE DATE         U.S. PATENT NO.              FOREIGN STATUS
-----------------------------------------------------------------------------------------------------------------
   <S>                                     <C>              <C>                  <C>

     RNA Ribozyme Polymerases,             01/22/91             4,987,071        Europe - Allowed broad claims;
   Dephosphorylases, Restriction                                                 interviewed with the Japanese
   Endoribonucleases and Methods                                                 patent office in April
-----------------------------------------------------------------------------------------------------------------

   RNA Ribozyme Polymerases, and           08/06/91             5,037,746
              Methods
-----------------------------------------------------------------------------------------------------------------

     RNA Ribozyme Polymerases,             03/03/92             5,093,246;
   Dephosphorylases, Restriction
   Endoribonucleases and Methods
-----------------------------------------------------------------------------------------------------------------

      RNA Ribozyme Restriction             05/26/92             5,116,742
   Endoribonucleases and Methods
-----------------------------------------------------------------------------------------------------------------

     RNA Ribozyme Polymerases,               N/A            Alllowed-no patent
   Dephosphorylases, Restriction                                number yet
   Endoribonucleases and Methods
=================================================================================================================
</TABLE>






<PAGE>   26



                                   EXHIBIT C
                      EXAMPLE OF TRANSFER PRICE STRUCTURE


[                                                                              ]