Document:

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                                                                        REDACTED
                                                                  EXHIBIT 10.307

                      **CONFIDENTIAL TREATMENT REQUESTED**

                           HCV PROBE LICENSE AGREEMENT

                                     BETWEEN

                               CHIRON CORPORATION

                            F. HOFFMANN-LA ROCHE LTD.

                                       AND

                          ROCHE MOLECULAR SYSTEMS, INC.

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                           HCV PROBE LICENSE AGREEMENT

                                TABLE OF CONTENTS
                                                                          PAGE
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RECITALS                                                                     3

ARTICLE 1: DEFINITIONS                                                       3

ARTICLE 2: LICENSE GRANTS                                                   12

ARTICLE 3: PAYMENTS, ROYALTIES                                              15

ARTICLE 4: RECORDS AND REPORTS                                              15

ARTICLE 5: OTHER ACTIONS                                                    17

ARTICLE 6: REPRESENTATIONS AND WARRANTIES                                   19

ARTICLE 7: TERM AND TERMINATION                                             21

ARTICLE 8: CONFIDENTIALITY                                                  24

ARTICLE 9: INDEMNITY                                                        25

ARTICLE 10: ALTERNATIVE DISPUTE RESOLUTION                                  26

ARTICLE 11: MISCELLANEOUS                                                   27

ARTICLE 12: FIELD RESTRICTIONS AND OTHER COVENANTS                          30

ARTICLE 13: INFRINGEMENT BY THIRD PARTIES                                   32

ARTICLE 14: EUROPEAN COMMUNITY PROVISIONS                                   34

EXHIBIT A: COMPENSATION TO CHIRON

EXHIBIT B: CHIRON PATENT LIST

EXHIBIT C: [CONFIDENTIAL TREATMENT REQUESTED] PATENT LIST

EXHIBIT D: CHIRON LICENSED PRODUCTS & UNIT SIZES

EXHIBIT E: FORM OF REPORT

EXHIBIT F: EXISTING LICENSES

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                     HCV PROBE LICENSE AND OPTION AGREEMENT

This agreement (hereinafter "Agreement") is made by and between CHIRON
CORPORATION, a Delaware corporation, of 4560 Horton Street, Emeryville,
California 94608 (hereinafter referred to as "CHIRON"), F. HOFFMANN-LA ROCHE
LTD., a Swiss corporation, of Grenzacherstrasse 124, Basel, Switzerland
(hereinafter referred to as "ROCHE PARENT"), and ROCHE MOLECULAR SYSTEMS,
INC., a Delaware corporation, of 1145 Atlantic Avenue, Suite 100, Alameda,
California 94501 (hereinafter referred to as "RMS" and collectively with
ROCHE PARENT, "ROCHE").

                                   BACKGROUND

WHEREAS, CHIRON and ROCHE currently own or control certain patent rights
relating to the hepatitis C virus ("HCV"), as defined below.

WHEREAS, CHIRON and ROCHE have as of the date hereof entered into that
certain Settlement Agreement (the "Settlement Agreement") pertaining to the
settlement of the certain litigation matters described therein.

WHEREAS, in consideration of and subject to the execution and delivery of the
Settlement Agreement, CHIRON is willing to grant licenses to ROCHE under
certain patent rights relating to HCV for use in assays for the detection of
nucleic acid sequences for use in IN VITRO diagnostics (excluding use in
Blood Screening, as defined below, but without limiting the effect of the
Blood Screening Agreement, as defined below), all on the terms and conditions
set forth herein.

WHEREAS, in consideration of and subject to the execution and delivery of the
Settlement Agreement, ROCHE is willing to grant licenses to CHIRON under
certain patent rights relating to HCV for use in assays for the detection of
nucleic acid sequences for use in Blood Screening and the Transplantation
Field, as defined below, all on the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the above provisions and the mutual
covenants contained herein, CHIRON and ROCHE hereby agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

In this Agreement the following words and phrases shall have the following
meanings:

         1.1  "ADR" means Alternative Dispute Resolution in accordance with
Article 10.

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         1.2  "Affiliate" means an entity that directly, or indirectly
through one or more intermediaries, controls or is controlled by or is under
common control with, a specified entity. For the purposes of this definition,
"control" (including with correlative meanings, the terms "controlling",
"controlled by" and "under common control with"), as applied to any entity,
means: (a) the possession, directly or indirectly, of the power to direct or
cause the direction of the management and policies of that entity, whether
through the ownership of voting securities or by contract or otherwise; or
(b) the ownership of at least fifty percent (50%) of the voting securities of
that entity. Notwithstanding anything to the contrary contained herein,
"Affiliate" shall not include, in the case of CHIRON, Novartis AG or any
Affiliate of Novartis AG, unless Novartis shall have acquired direct control
of a majority of the Board of Directors of CHIRON. Notwithstanding anything
to the contrary contained herein, "Affiliate" shall not include, in the case
of ROCHE, Genentech Inc. or any Affiliate of Genentech Inc., nor Laboratory
Corporation of America Holdings or any Affiliate of Laboratory Corporation of
America Holdings.

         1.3  "Authorized Distributor" means a BONA FIDE, unaffiliated
distributor, but excluding any entity which is a Major IVD Manufacturer (as
defined below) that is not licensed in the Field (as defined below) under one
or more of the CHIRON Licensed Patents (as defined below) or is affiliated
with, or directly or indirectly controlled by, such a Major IVD Manufacturer,
except to the extent that such unlicensed Major IVD Manufacturer or its
Affiliates distributes CHIRON Licensed Product for ROCHE or its Affiliates on
a local country basis and in the same manner in which it distributes other
diagnostic products for ROCHE or its Affiliates and ROCHE and its Affiliates
are not otherwise selling CHIRON Licensed Products in such country.

         1.4  "Average Unit Price" or "AUP" means with respect to CHIRON
Licensed Products sold by ROCHE or its Affiliates from and including the
first day of the Calendar Quarter commencing immediately prior to the
Effective Date, with respect to a Calendar Quarter (as defined below), Net
Sales of such future CHIRON Licensed Product by ROCHE or its Affiliates
calculated on a per Unit basis, in a country or Region, on a
product-by-product basis, using customary and reasonable methodologies for
determining average unit pricing generally consistent with the definition
herein of Net Sales, during the preceding two (2) Calendar Quarters.

         1.5  "Bayer Cross License" means the Cross-License Agreement by and
between Chiron Diagnostics Corporation and CHIRON dated November 30, 1998, as
amended from time to time.

         1.6  "Blood Screening" means the commercial use of products that
detect nucleic acid sequences(s) for: (a) the screening of blood, plasma or
blood components intended for transfusion or for use in blood products (e.g.,
without
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limitation, immunoglobulins); or (b) confirmatory or supplemental testing of
the same samples otherwise screened for purposes described in Section 1.6(a).

         1.7  "Blood Screening Agreement" means the Blood Screening HCV/HIV
Probe License Agreement by and between CHIRON and ROCHE dated as of the
Effective Date, as amended from time to time.

         1.8  "Calendar Quarter" means the three (3) month period beginning
January 1, April 1, July 1 or October 1. For Net Sales outside the United
States, the Calendar Quarter and Calendar Year (as defined below) shall be
consistent with ROCHE financial reporting practices.

         1.9  "Calendar Year" means January 1 through December 31.

         1.10 "CHIRON Future HCV Sequence Patent Rights" means any and all
Valid Claims Directed to HCV of United States and foreign patents and patent
applications: (a) which are based upon inventions conceived or rights
acquired [CONFIDENTIAL TREATMENT REQUESTED] (as defined below); (b) which
claim HCV nucleic acid sequence(s) or a method to use (other than in the
manufacture of peptides) or detect such sequences specifically; (c) which are
owned by, licensed to or otherwise controlled by CHIRON or its Affiliates,
with rights to license or sublicense; and (d) with respect to which CHIRON
has the right to grant the option provided for in Section 2.6 of this
Agreement. For purposes of this Agreement, an invention will be deemed to
have been conceived if there is a patent, patent application, written
invention disclosure statement or other tangible document (whether or not
witnessed) describing such invention.

         1.11 "CHIRON Licensed Patents" means Valid Claims Directed to HCV
which cover the manufacture, use, sale, offer for sale or importation of a
Product that are contained within any of the following: (a) the patents and
applications identified in Exhibit B and any continuation,
continuation-in-part and divisional applications therefrom; (b) any reissued
or reexamined patents obtained from such patents and applications; (c) all
foreign counterparts of such patents and applications; and (d) all future
patents and applications which are based on inventions conceived by CHIRON or
its Affiliates on or before the Effective Date.

         1.12 "CHIRON Licensed Products" means Products which are
manufactured, used, offered for sale, imported or sold under circumstances
which would, in the absence of the licenses granted under Sections 2.1 and
2.3 constitute an infringement of a Valid Claim of the CHIRON Licensed
Patents, including without limitation the Products identified in Exhibit D,
as modified from time to time by mutual agreement of the parties or as
determined in accordance with Section 5.2.

         1.13 "Directed to HCV" means that the claim or technology in
question is directed to methods, compositions, reagents or kits specifically
for use in nucleic

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acid-based diagnostic assays for the detection of HCV nucleic acid
sequence(s), or specifically for use in the manufacture of any compositions
or reagents for use in, or manufacture of nucleic acid-based diagnostic
assays for detection of HCV nucleic acid sequence(s) (excluding, for example,
PCR claims and technology and other methods for detection of nucleic acid
sequence(s) generally which involve nucleic acid amplification). The
terminology "specifically for use" as used in this Section 1.13, is intended
to exclude inventions suitable for use with viruses or analytes other than
HCV (including by way of example and not by way of limitation, inventions
relating to PCR, or assay formats, improved expression systems, detectable
labels, instrumentation, packaging and the like), which shall not be
considered "specifically for use" in HCV detection as contemplated by this
Section 1.13 and shall therefore not be considered as "Directed to HCV"
hereunder.

         1.14 "Earned Royalty" shall have the meaning specified in paragraph
2 of Exhibit A.

         1.15 "Effective Date" means the date of full execution of this
Agreement.

         1.16 "End User" means a person or entity who is a final purchaser of
a Product, and whose use of a Product results in the Product's consumption,
operation, destruction or loss of activity.

         1.17 "Field" means the commercial use of human IN VITRO diagnostic
products that detect nucleic acid sequences of HCV. Expressly excluded from
the Field are: (a) products in Blood Screening; (b) products specifically
labeled or promoted for use in the Transplantation Field (as defined below).

         1.18 "Foundational Patents" means the CHIRON Licensed Patents
identified in Exhibit B which are stated therein to be Foundational Patents.

         1.19 "HCV" means any viral isolate of the hepatitis C virus
described in the CHIRON Licensed Patents or classified as HCV by the
International Committee on the Taxonomy of Viruses (or any body that replaces
such Committee) or any subtype of such isolate and further includes any
isolate that is at least forty percent (40%) homologous to any such isolate
and of the same genomic type and substantially the same genomic organization,
any isolate that has a genome that either hybridizes to or is substantially
identical to any such isolate or its compliment, and any defective or
modified form of any of the above isolates.

         1.20 "HCV Qualitative Assay" means a Product which: (a) is an assay;
(b) detects or measures the presence of HCV in an analyzed sample; (c) does
not determine the quantity of HCV in the analyzed sample; and (d) is not by
itself, through a single use, capable of being used as an HCV Classification
Assay, an

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HCV Genotyping Assay or an HCV Resistance Assay (as each is defined herein).

         1.21 "HCV Quantitative Assay" means a Product which: (a) is an
assay; (b) measures the presence of HCV in an analyzed sample; (c) does
determine the quantity of HCV in the analyzed sample; and (d) is not by
itself, through a single use, capable of being used as an HCV Classification
Assay, an HCV Genotyping Assay or an HCV Resistance Assay.

         1.22 "HCV Genotyping Assay" means a Product which is an assay or
method (e.g., sequencing) that is labeled or promoted as being useful through
a single use to determine and differentiate individual genotypes of an HCV
virus that are present in an analyzed sample.

         1.23 An "[CONFIDENTIAL TREATMENT REQUESTED]" means
[CONFIDENTIAL TREATMENT REQUESTED].

         1.24 "HCV Resistance Assay" means a Product which is an assay or
method (e.g., sequencing) that is labeled or promoted as being useful to
detect through a single use the specific drug resistance mutation(s) present
in the HCV virus in an analyzed sample.

         1.25 "HCV Taqman Qualitative/Quantitative Assay" means a Product
which: (a) is an assay; (b) detects and measures the presence of HCV in an
analyzed sample by utilization of ROCHE's proprietary 5' nuclease detection
method; (c) does determine the quantity of HCV in an analyzed sample; and
(d) is not by itself, through a single use capable of being used as only an
HCV Qualitative Assay, HCV Classification Assay, HCV Genotyping Assay or HCV
Resistance Assay.

         1.26 "Infringing Third Party Sales" means sales by a Major IVD
Manufacturer of Products: (a) which infringe one or more of the CHIRON
Licensed Patents; or (b) as to which a license under one or more of the
CHIRON Licensed Patents has been granted, but as to which the licensee is not
paying royalties thereunder.

         1.27 "Licensed Patents" means the CHIRON Licensed Patents and the
ROCHE Optioned Patents.

         1.28 "Major IVD Manufacturer" means a commercial entity (and its
Affiliates) that manufactures, sells and engages in other commercial
activities with respect to IN VITRO diagnostic products, and has a
significant marketing presence in one or more Regions. Major IVD
Manufacturers include Abbott, Bayer, Johnson & Johnson, Pasteur, Sanofi, Dade
Behring, Organon Teknika, Becton Dickinson, bioMerieux, BioRad, Fujirebio,
Beckman Coulter, Visible Genetics, Innogenetics, and PE Corporation and each
of their successors and

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assigns and any other entity which commands in the future at least an
equivalent presence as measured by total product sales as do any of the
foregoing entities as of the Effective Date in such Region.

         1.29 "Minimum Royalty" and "Minimum Royalty Amount" shall have the
meanings specified in paragraph 3 of Exhibit A.

         1.30 "Net Sales" means the amount billed or invoiced for CHIRON
Licensed Products sold by ROCHE or its Affiliates, less:

         (a) Discounts actually allowed and taken;

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

         (c) To the extent separately stated on purchase orders, invoices or
         other documents of sale, taxes levied on and/or other governmental
         charges made as to production, transportation or insurance charges;

         (d) The reasonable value of the instrument, instrument financing,
         consumables other than the CHIRON Licensed Products in question
         (including without limitation sample preparation) and service
         components of an operating or capital lease for instrumentation on
         which the CHIRON Licensed Products are used (collectively, "Associated
         Goods and Equipment"), for which the charges are included in the price
         of the CHIRON Licensed Products purchased, provided that the methods
         for determining such value shall be proposed by ROCHE and subject to
         CHIRON's written consent, not to be unreasonably withheld;

         (e) Charges for freight, handling and transportation paid by the
         selling entity; and

         (f) Sales, use and value-added taxes and other similar taxes incurred
         and separately stated on invoices.

                  (1) Net Sales shall include all sales to non-Affiliate
third parties, including sales to Authorized Distributors in countries where,
due to regulatory constraints and/or market practice, substantially all sales
of the relevant CHIRON Licensed Product are made through distributors,
provided that ROCHE shall use reasonable efforts in connection with sales to
such Authorized Distributors to comply with clause (A) immediately below.
With respect to sales to all other Authorized Distributors, if Net Sales are
based on the transfer price to the Authorized Distributor rather than End
User sales, either: (A) Net Sales on which royalties shall be calculated
shall be deemed to be not less than the higher of the average selling price
for the applicable Product in the United States or the European Union; or
(B) the parties shall adopt another mechanism for preserving for CHIRON the
same economics as if such sales had been made to the End

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User by ROCHE or its Affiliate rather than the Authorized Distributor. Any
such mechanism shall be proposed by ROCHE and shall be subject to CHIRON's
prior written consent, which shall not be unreasonably withheld. CHIRON shall
not withhold its consent to a proposal by ROCHE to calculate Net Sales at
[CONFIDENTIAL TREATMENT REQUESTED] of the transfer price to an Authorized
Distributor or such lesser percentage as reflects reasonably the distributor
mark-ups prevailing generally in the relevant country.

                  (2) For clarity of understanding, Net Sales shall not
include any CHIRON Licensed Product furnished to third parties for which no
payment is received, such as, experimental, test market, promotional or other
free goods. On the other hand, Net Sales shall include any CHIRON Licensed
Product furnished in return for payment, whether or not such CHIRON Licensed
Product is for commercial, research or other use. For clarity of
understanding, Minimum Royalties shall apply to each Unit of CHIRON Licensed
Product Shipped to a customer for any purpose, except for Units Shipped to
third parties at no charge for: (A) use in ROCHE's preclinical or clinical
trials in the Field or the Transplantation Field; (B) testing, quality
control or evaluation purposes; or (C) replacement of rejected or defective
goods. Without limiting the foregoing, CHIRON Licensed Products furnished to
third parties at price discounts, including, without limitation, free goods
furnished as part of sales promotions, shall be subject to Minimum Royalties.

                  (3) A sale shall be deemed to have been made and Earned
Royalties or Minimum Royalties incurred (except as specifically set forth in
Section 1.30(2) and this Section 1.30(3)) when the CHIRON Licensed Product is
consumed, invoiced or shipped by ROCHE or its Affiliates to a non-Affiliate
third party ("Shipped"); provided that where an invoice is issued, the
obligations to pay Earned Royalties and Minimum Royalties hereunder shall
arise on the invoice date. Sales to or between Affiliates shall not be
included in Net Sales or Minimum Royalties until ROCHE or its Affiliate
consumes the CHIRON Licensed Product in providing a commercial service for a
non-Affiliate third party or Ships the CHIRON Licensed Product to a
non-Affiliate third party.

                  (4) In the event that a CHIRON Licensed Product subject to
royalties hereunder is sold in combination with another Product or assay,
other than the Associated Goods and Equipment covered under clause (d) above,
for a single price (a "Combination Product"), Net Sales from sales of a
Combination Product, for purposes of calculating royalties due under this
Agreement, shall be calculated by multiplying the Net Sales of that
Combination Product by the fraction A/(A+B), where A is the AUP in the
country of sale, during the applicable reporting period, of the CHIRON
Licensed Product subject to royalties hereunder if sold separately in the
country of sale, and B is the AUP in the country of sale, during the
applicable reporting period, of the other Product(s) or assay(s) 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

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Combination Products, shall be a reasonable apportionment of the gross amount
invoiced therefor based upon the relative contribution of the CHIRON Licensed
Product subject to royalties hereunder to the price of the Combination
Product. Such apportionment for Combination Products currently or previously
sold shall be a reasonable apportionment of the gross amount invoiced
therefor based upon the relative contribution of the CHIRON Licensed Product
subject to royalties hereunder to the price of the Combination Product. Such
apportionment shall be determined by ROCHE based upon its past practice and
experience subject to CHIRON's written consent, not to be unreasonably
withheld. The apportionment of future Combination Products will be handled in
this same fashion prior to the first Unit Shipped or consumed by ROCHE or an
Affiliate in providing a commercial service, or resolved in accordance with
Section 5.2. Notwithstanding the above, if a CHIRON Licensed Product is an
assay that is capable in a single use of being used in more than one fashion
(e.g., as both an HCV Quantitative Assay and as an HCV Qualitative Assay),
such CHIRON Licensed Product is not a Combination Product solely for that
reason, but shall be treated for purposes of calculating the applicable
Minimum Royalty Amounts in the same fashion as the HCV Taqman
Qualitative/Quantitative Assay, as set forth in Exhibit A.

                  (5) In the event a sale of a CHIRON Licensed Product is
conditioned upon the payment of an initial licensing fee, access fee or other
required fee the payment of which is a prerequisite to the Shipment,
consumption or use of a CHIRON Licensed Product, Net Sales, for the purpose
of determining royalty payments on such CHIRON Licensed Product, shall
include a reasonable apportionment of the amount invoiced for such fee, based
upon the relative value of the intellectual property contained within the
CHIRON Licensed Product subject to royalties hereunder to the intellectual
property contained within the other product or service components Shipped,
licensed, consumed or used. Such apportionment shall be determined by ROCHE
based upon its past practice and experience subject to CHIRON's written
consent, not to be unreasonably withheld, and shall not include any portion
of a licensing fee, access fee or other required fee reasonably allocated
with specificity to the access, license or use of the ROCHE PCR patents.

                  (6) In the event that ROCHE or its Affiliates perform
assays for commercial purposes utilizing CHIRON Licensed Products, Net Sales
means the invoiced amount for the patient result provided as a result of
performance of such assays, less a reasonable deduction for the value of the
services and or other products provided therewith, less the applicable
deductions pursuant to this Section 1.30. The allocation of value to services
or other products provided shall be determined by ROCHE based upon its past
practice and experience, and shall be subject to CHIRON's prior written
consent, which shall not be unreasonably withheld.

         1.31 "PCR" means polymerase chain reaction technology.

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         1.32 "Product(s)" means reagents, compositions or kits suitable for
use in the Field or the Transplantation Field.

         1.33 "Product Category" has the meaning set forth in paragraph 3 of
Exhibit A.

         1.34 "Region" shall mean one of the four (4) following regions:

         Region I:         North America (United States and possessions, Puerto
                           Rico, Canada and Mexico);
         Region II:        European Union;
         Region III:       Japan; or
         Region IV:        All other countries of the world.

         1.35 "ROCHE Future HCV Sequence Patent Rights" means any and all
Valid Claims Directed to HCV of United States and foreign patents and patent
applications: (a) which are based on inventions conceived or rights acquired
[CONFIDENTIAL TREATMENT REQUESTED]; (a) are not ROCHE Optioned Patents (as
defined below); (b) which claim HCV nucleic acid sequence(s) or a method to
use (other than in the manufacture of peptides) or detect such sequences
specifically; (c) which are owned by, licensed to or otherwise controlled by
ROCHE or its Affiliate, with rights to license or sublicense; and (d) with
respect to which ROCHE has the right to grant the option provided for in
Section 2.7 of this Agreement. For purposes of this Agreement, an invention
will be deemed to have been conceived if there is a patent, patent
application, written invention disclosure statement or other tangible
document (whether or not witnessed) describing such invention.

         1.36 "ROCHE Optioned Patents" means: (a) the patents and
applications identified in Exhibit C and any continuation,
continuation-in-part and divisional applications therefrom; (b) any reissued
or reexamined patents obtained from such patents and applications; (c) all
foreign counterparts of such patents and applications; and (d) all future
patents and applications which are based on inventions conceived by ROCHE or
its Affiliates on or before the Effective Date, to the extent the items
described in clauses (a) through (d) of this Section 1.36 contain a Valid
Claim Directed to HCV which covers the manufacture, use, sale, offer for sale
or importation of a Product.

         1.37 "ROCHE Optioned Product" means a Product which is manufactured,
used, offered for sale, imported or sold under circumstances which would, in
the absence of the licenses for which an option is granted under Section 2.5,
constitute an infringement of a Valid Claim of the ROCHE Optioned Patents.

         1.38 "Shipped" has the meaning set forth in Section 1.30(3).

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         1.39 "Transplantation Field" means the commercial use of products
that detect nucleic acid sequences for the screening of any biological
materials intended for transfusion or transplantation, in each case from any
donor, including autologous donors, other than the transfusion or
transplantation of blood or its derivatives, components or replacements.

         1.40 "Unit" means, for each CHIRON Licensed Product, the number of
individual patient results generated by the use of a CHIRON Licensed Product.
The number of patient results that each CHIRON Licensed Product generates
shall be mutually determined by the parties through good faith negotiation
and resolved if necessary through the ADR process in accordance with Article
10 of this Agreement. Following such determination, the number of Units
contained in each CHIRON Licensed Product will be set forth on a schedule to
be attached as Exhibit D to this Agreement. The determination of the number
of "Units" in future CHIRON Licensed Products developed by ROCHE shall be
handled in accordance with Section 5.2 and Exhibit D shall be modified
accordingly. If future CHIRON Licensed Products are developed by ROCHE or its
Affiliates that do not contain reagents or other single-use consumable
materials, a method for calculating the number of "Units" in such CHIRON
Licensed Product shall be determined in accordance with Section 5.2.

         1.41 "Valid Claim" means a claim in any issued, active, unexpired
patent which has not been withdrawn, cancelled, lapsed or disclaimed, or held
unpatentable, invalid or permanently unenforceable by a non-appealed or
nonappealable final decision by a court or other appropriate body of
competent jurisdiction. The scope of a Valid Claim shall be limited to its
terms as defined by any such court or decision-making body of competent
jurisdiction in a nonappealable or non-appealed final decision.

                                    ARTICLE 2
                                 LICENSE GRANTS

         2.1 CHIRON GRANTS. Subject to the terms and conditions of this
Agreement, CHIRON hereby grants to ROCHE and its Affiliates, so long as they
remain Affiliates of ROCHE, a worldwide, semi-exclusive license, without the
right to sublicense, under the CHIRON Licensed Patents to research, develop,
make, have made, import, use, offer for sale and sell CHIRON Licensed
Products for use in the Field. CHIRON covenants not to sue any End User of a
CHIRON Licensed Product (with respect to which ROCHE has performed all of its
material obligations under this Agreement) to the extent of activities in the
Field or otherwise permitted under this Agreement. Conversely no immunity
from suit shall apply to End User activities in Blood Screening, except as
provided in the Blood Screening Agreement, or otherwise outside of the Field.
CHIRON retains the right to conduct research in any field, including to
develop Products and, subject to Section 2.3 and the Blood Screening
Agreement, retains all rights

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outside of the Field, including the nonexclusive right to practice and to
grant licenses under the CHIRON Licensed Patents to make, have made, use,
import, offer for sale and sell any products in the Transplantation Field.

         2.2 EXCLUSION FROM CHIRON LICENSE. ROCHE acknowledges that neither
ROCHE nor its Affiliates are licensed under this Agreement to perform
research or to develop any product other than a CHIRON Licensed Product.

         2.3 CHIRON TRANSPLANTATION FIELD LICENSE. Subject to the terms and
conditions of this Agreement, CHIRON hereby grants to ROCHE and its
Affiliates, so long as they remain Affiliates of ROCHE, a worldwide,
non-exclusive license, without the right to sublicense, under CHIRON Licensed
Patents to research, develop, make, have made, import, use, offer for sale
and sell CHIRON Licensed Products for use in the Transplantation Field.
CHIRON covenants not to sue any End User of such CHIRON Licensed Products
(with respect to which ROCHE has performed all of its material obligations
under this Agreement) to the extent of activities in the Transplantation
Field or as otherwise permitted under this Agreement. Conversely, no immunity
from suit under this Section 2.3 shall apply to End User activities in Blood
Screening, except as provided in the Blood Screening Agreement, or otherwise
outside of the Transplantation Field.

         2.4 SEMI-EXCLUSIVE CHIRON LICENSE. The license granted under
Section 2.1 shall be semi-exclusive to ROCHE and its Affiliates.
Semi-exclusive means that, in addition to licenses to third parties under
existing agreements referenced in Exhibit F including, without limitation,
the [CONFIDENTIAL TREATMENT REQUESTED], and licenses that may be granted by
such licensees, including licenses that may be granted by [CONFIDENTIAL
TREATMENT REQUESTED], CHIRON retains only the right to practice under the
CHIRON Licensed Patents and/or to grant additional licenses under one or
more of the CHIRON Licensed Patents in the Field as follows:

         (a) In the event that a license referenced in Exhibit F is terminated,
         including without limitation the [CONFIDENTIAL TREATMENT REQUESTED],
         CHIRON shall have the right to replace such license with a new license,
         consistent with the limitations required hereby and the scope, field
         and territory of the license that is replaced. Notwithstanding anything
         herein to the contrary, the [CONFIDENTIAL TREATMENT REQUESTED] under
         the [CONFIDENTIAL TREATMENT REQUESTED] between CHIRON and [CONFIDENTIAL
         TREATMENT REQUESTED] if terminated, could be replaced by a new license
         to a new licensee and containing terms determined by CHIRON in its
         discretion without any restrictions imposed by this Agreement;
         provided, however, that if [CONFIDENTIAL TREATMENT REQUESTED] CHIRON
         enters into a license to replace the [CONFIDENTIAL TREATMENT REQUESTED]
         with a third party that is not [CONFIDENTIAL TREATMENT REQUESTED], as

                                                                             13

<PAGE>

         the case may be, or an Affiliate, successor, assignee or licensee of
         either of them, CHIRON shall promptly provide ROCHE a written summary
         of the applicable royalty terms thereof and true copies of extracts of
         the applicable contract terms (including definitions and methods of
         calculating royalty amounts), and [CONFIDENTIAL TREATMENT REQUESTED] of
         the receipt by ROCHE of notice from CHIRON, provided, further however,
         that [CONFIDENTIAL TREATMENT REQUESTED]. (For the avoidance of doubt,
         [CONFIDENTIAL TREATMENT REQUESTED] contained in this Section 2.4(a)
         [CONFIDENTIAL TREATMENT REQUESTED];

         (b) Following the last to expire of the Foundational Patents, the
         license hereunder shall be nonexclusive; and

         (c) Notwithstanding this Section 2.4, CHIRON retains the nonexclusive
         right under the CHIRON Licensed Patents to conduct research in any
         field, including to develop Products and, subject to the Blood
         Screening Agreement, all rights outside of the Field and in the
         Transplantation Field, including the nonexclusive right to practice and
         to grant licenses under the CHIRON Licensed Patents to make, have made,
         use, import, offer for sale and sell any products in the
         Transplantation Field.

         2.5 ROCHE OPTIONED PATENTS. Subject to the terms and conditions of
this Agreement, ROCHE hereby grants to CHIRON and its Affiliates, so long as
they remain Affiliates of CHIRON, an option to enter into a worldwide,
non-exclusive, [CONFIDENTIAL TREATMENT REQUESTED], [CONFIDENTIAL TREATMENT
REQUESTED] license, with no right to sublicense except to have made or to
conduct research, under ROCHE Optioned Patents to research, develop, make,
have made, import, use, offer for sale and sell ROCHE Optioned Products for
use in Blood Screening and in the Transplantation Field.

         2.6 CHIRON FUTURE HCV SEQUENCE PATENT RIGHTS. CHIRON grants to ROCHE
a non-exclusive option to obtain one or more non-exclusive, worldwide
licenses, or sublicenses, as the case may be, with a right to sublicense to
ROCHE Affiliates only, under the CHIRON Future HCV Sequence Patent Rights, to
make, have made, use, import, offer for sale and sell CHIRON Licensed
Products and/or products in the Field and/or the Transplantation Field.
[CONFIDENTIAL TREATMENT REQUESTED].

         2.7 ROCHE FUTURE HCV SEQUENCE PATENT RIGHTS. ROCHE grants to CHIRON
a non-exclusive option to obtain one or more non-exclusive, worldwide
licenses, or sublicenses, as the case may be, with a right to sublicense to
CHIRON Affiliates only, under the ROCHE Future HCV Sequence Patent Rights, to
make, have made, use, import, offer for sale and sell ROCHE Optioned Products
and/or products in Blood Screening and/or the Transplantation Field.
[CONFIDENTIAL TREATMENT REQUESTED].

                                                                             14

<PAGE>

                                    ARTICLE 3
                               PAYMENTS, ROYALTIES

         With respect both to CHIRON Licensed Products sold or Shipped, ROCHE
shall make payments to CHIRON as set forth in Exhibit A.

                                    ARTICLE 4
                               RECORDS AND REPORTS

         4.1 NET SALES REPORT. ROCHE shall, within sixty (60) days after the
last day of each Calendar Quarter commencing after [CONFIDENTIAL TREATMENT
REQUESTED], deliver to CHIRON a true and accurate report for the prior
Calendar Quarter, substantially in the form attached as Exhibit E to this
Agreement, which shall state the amount of monies due hereunder, if any, as
Earned Royalties and Minimum Royalties, and shall include all information
reasonably necessary to calculate such amount, including, but not limited to,
the following information, presented by country and Region and by product and
Product Category (as defined in paragraph 3 of Exhibit A):

         (a) the amount of Net Sales, expressed in United States Dollars (with
         applicable exchange rates to the extent specifically requested in
         writing by CHIRON), and the applicable Earned Royalty rate or rates,
         and all credits and adjustments thereto;

         (b) the number of Units Shipped and the applicable Minimum Royalty
         Amounts, and adjustments to Units Shipped (returns, replacements,
         etc.); and

         (c) a statement of the basis for any deviation from the Earned Royalty
         rates and Minimum Royalty Amounts as expressed in paragraphs 2 and 3 of
         Exhibit A.

         4.2 PAYMENT DATES. Not later than the date each report required
under Section 4.1 is due, ROCHE shall pay to CHIRON the royalty due under
this Agreement for the period covered by such report. If no royalties are
due, ROCHE shall so report, stating the reasons why no such royalty is due.

         4.3 PAYMENT PROCEDURES. ROCHE shall pay royalties and all other
payments due hereunder to CHIRON in immediately available funds on the due
date by wire transfer to:

         Bank of America-San Francisco
         San Francisco, California
         Account Name: Chiron Corporation
         Account Number: [CONFIDENTIAL TREATMENT REQUESTED]

                                                                             15

<PAGE>

         ABA #: [CONFIDENTIAL TREATMENT REQUESTED]
         Reference: ROCHE HCV Probe License Agreement

or at such place and in such other manner as CHIRON may designate in a notice
signed by CHIRON's Treasurer or Controller to ROCHE.

         4.4 TAXES ON ROYALTIES. ROCHE shall deduct from amounts payable
hereunder all taxes assessed or imposed against, or required to be withheld
from, royalty payments due and shall pay such amount to the appropriate
fiscal or tax authorities on behalf of CHIRON. ROCHE shall forward promptly
to CHIRON all tax receipts received by ROCHE evidencing payment of such taxes.

         4.5 AUDIT. ROCHE shall keep reasonably detailed and accurate records
and books of account to enable a determination of the amounts payable by
ROCHE and its Affiliates to CHIRON hereunder. Upon thirty (30) days written
notice by CHIRON, and not more frequently than once per Calendar Year, CHIRON
may have such records and books of account examined during reasonable
business hours by a mutually acceptable independent certified public
accountant selected by CHIRON and at CHIRON's expense, whose acceptance shall
not unreasonably be withheld by ROCHE, for the purpose of verifying the
amounts due hereunder; provided that such independent accountant agrees to
provide CHIRON only the information necessary to verify the calculation of
amounts due hereunder. A copy of any final written report provided by the
independent accountant to CHIRON shall be given concurrently to ROCHE. Such
examination shall not be permitted unless it is requested within three (3)
years following the end of the Calendar Year to which the books and records
pertain. Where such examination results in a finding that ROCHE underpaid
CHIRON by the greater of [CONFIDENTIAL TREATMENT REQUESTED], ROCHE shall
reimburse CHIRON for its reasonable costs and expenses in conducting such
examination. ROCHE and CHIRON shall promptly rectify any overpayments or
underpayments by repaying such amounts together with interest thereon at an
annual rate equal to the lesser of: (a) [CONFIDENTIAL TREATMENT REQUESTED] as
published in the Wall Street Journal, or (b) the maximum rates permitted by
applicable law, from the time such payment was originally due to the time it
is paid.

         4.6 CONFIDENTIALITY OF AUDIT. CHIRON agrees that all audited
information shall be confidential to ROCHE and its Affiliates, and that any
person or entity conducting an audit on behalf of CHIRON pursuant to Section
4.5 shall be required to protect the confidentiality of such information.

         4.7 PAYMENT IN UNITED STATES CURRENCY. All payments shall be made in
United States Dollars and shall be made on the dates set forth herein. The
Net Sales amount calculated hereunder for sales in countries other than the
United States shall be converted into equivalent United States Dollars in
accordance with the methods used for internal financial reporting purposes
within ROCHE.

                                                                             16

<PAGE>

         4.8 LATE PAYMENT FEE. Any payment, including, without limitation,
royalty payments, made by ROCHE hereunder after the date such payment is due,
as set forth in this Article 4 hereof, shall bear interest at the lesser of:
(a) [CONFIDENTIAL TREATMENT REQUESTED] as published in the Wall Street
Journal as of the date such payment was due, or (b) the maximum rate
permitted by applicable law.

                                    ARTICLE 5
                                  OTHER ACTIONS

         5.1 PATENT VALIDITY; ENFORCEABILITY. Immediately upon the Effective
Date, or as soon as possible thereafter, ROCHE shall discontinue any
opposition, challenge, compulsory license application or the like with
respect to the CHIRON Licensed Patents. Immediately after the Effective Date,
or as soon as possible thereafter, CHIRON shall discontinue any opposition,
challenge, interference or the like with respect to the ROCHE Optioned
Patents.

         5.2 FUTURE PRODUCTS DIRECTED TO HCV.

         (a) Promptly upon its determination to Ship, or to provide a commercial
         service utilizing, a Product Directed to HCV not then set forth as a
         CHIRON Licensed Product on Exhibit D, ROCHE shall provide CHIRON with
         written notice of such Product and the parties will engage in good
         faith negotiations to determine the existing or new Product Category
         for such Product as set forth on Exhibit A, the number of Units in such
         Product pursuant to Section 1.40, the reasonable value of Associated
         Goods and Equipment, if any, to be deducted from the Net Sales of such
         Product pursuant to Section 1.30(d), and, if such Product is a
         Combination Product, the apportionment of the gross amount to be
         invoiced for such Product pursuant to Section 1.30(4). As set forth in
         these Sections, [CONFIDENTIAL TREATMENT REQUESTED]. Promptly following
         such determinations, CHIRON will prepare a revised Exhibit D to include
         this Product and such revised Exhibit D shall be incorporated into and
         become part of this Agreement.

         (b) If ROCHE determines to Ship, or to provide a commercial service
         utilizing, a Product Directed to HCV not then set forth on Exhibit D
         as a CHIRON Licensed Product and ROCHE reasonably believes that the
         manufacture, use or sales of such Product would not, in the absence of
         the licenses granted pursuant to Sections 2.1 and 2.3, constitute an
         infringement of a Valid Claim of a CHIRON Licensed Patent, then ROCHE's
         written notice to CHIRON shall set forth the basis of ROCHE's
         reasonable belief in sufficient detail to permit CHIRON to evaluate the
         matter. [CONFIDENTIAL TREATMENT REQUESTED].

                                                                             17

<PAGE>

         (c) ROCHE may elect, in its reasonable discretion, to commence
         Shipping, or the provision of a commercial service utilizing, a Product
         Directed to HCV not then set forth on Exhibit D as a CHIRON Licensed
         Product [CONFIDENTIAL TREATMENT REQUESTED], PROVIDED ROCHE shall make a
         reasonable determination as to the applicable existing Product Category
         to determine the applicable Minimum Royalty Amount and shall utilize a
         reasonable determination of the number of Units in such Product and the
         deductions and apportionment for the calculation of Earned Royalty due
         on the Net Sales of such Product. [CONFIDENTIAL TREATMENT REQUESTED],
         any underpayment or overpayment of the Minimum Royalty or Earned
         Royalty shall be rectified in accordance with the provisions set forth
         in Section 4.8; [CONFIDENTIAL TREATMENT REQUESTED].

                                    ARTICLE 6
                         REPRESENTATIONS AND WARRANTIES

         6.1 CORPORATE AUTHORITY. Each party represents and warrants to the
other party that it has the necessary corporate authority to enter into this
Agreement.

         6.2 RIGHT TO GRANT. Each party represents and warrants that they
have the right to grant the licenses granted in Article 2 hereof and that
they are the sole owner of their respective Licensed Patents, subject to
licenses existing as of the Effective Date. CHIRON represents and warrants to
ROCHE that, to the best of its knowledge, neither CHIRON nor any of its
Affiliates have transferred to [CONFIDENTIAL TREATMENT REQUESTED] or any if
its Affiliates (a) before December 1, 1998, title to any patent or patent
application Directed to HCV in the Field existing on that date; or (b) on or
after that date, title to any patent, patent application or invention
Directed to HCV in the Field.

         6.3 CURRENT LICENSES. CHIRON represents and warrants that: (a) as of
the Effective Date the entities set forth in Exhibit F are the only parties
to which it has granted any licensed rights or other grants or immunities to
one or more of the CHIRON Licensed Patents in the Field; and (b) Exhibit F
contains a complete and accurate description of the effective scope, field
and territory of such grant as of the Effective Date. CHIRON also represents
and warrants that [CONFIDENTIAL TREATMENT REQUESTED] except as disclosed in
Exhibit F.

         6.4 COMPLETE PATENT LIST. CHIRON represents and warrants to ROCHE
that, to the best of its knowledge and belief, Exhibit B contains a complete
list, as of the Effective Date, of all patents and patent applications owned
by, licensed to (with a right to sublicense), or otherwise controlled by
CHIRON or its Affiliates containing claims Directed to HCV in the Field. To
the extent that any other patent or patent application owned by, licensed to
(with a right to sublicense) or otherwise controlled by CHIRON or its
Affiliates and filed on or before the

                                                                             18

<PAGE>

Effective Date contains a claim Directed to HCV in the Field, such patent or
patent application shall be automatically added to the CHIRON Licensed
Patents. Upon ROCHE's written request, not more frequently than annually,
CHIRON shall provide ROCHE with an updated Exhibit B and a report of the
prosecution status of applications within CHIRON Licensed Patents. ROCHE
represents and warrants to CHIRON that, to the best of its knowledge and
belief, Exhibit C contains a complete list, as of the Effective Date, of all
patents and patent applications owned by, licensed to (with a right to
sublicense), or otherwise controlled by ROCHE or its Affiliates containing
claims Directed to HCV in the Field. To the extent that any other patent or
patent application owned by, licensed to (with a right to sublicense) or
otherwise controlled by ROCHE or its Affiliates and filed on or before the
Effective Date contains a claim Directed to HCV in the Field, such patent or
patent application shall be automatically added to the ROCHE Optioned
Patents. Upon CHIRON's written request, not more frequently than annually,
ROCHE shall provide CHIRON with an updated Exhibit C and a report of the
prosecution status of applications within ROCHE Optioned Patents.

         6.5 EXCLUSIONS. Nothing contained in this Agreement shall be
construed as:

         (a) A representation or warranty by any party hereto as to the validity
         of any patent rights which are the subject of this Agreement;

         (b) A representation or warranty that anything made, used, imported,
         offered for sale, sold or otherwise disposed of under any of the patent
         rights which are the subject of this Agreement is or will be free from
         infringement of patents of third parties or of patents of either party
         that are not Directed to HCV;

         (c) An obligation to bring or prosecute actions or suits against third
         parties for infringement of any patent rights which are the subject of
         this Agreement;

         (d) A grant of any right to bring or prosecute actions or suits against
         third parties for infringement of any patent rights which are the
         subject of this Agreement; or

         (e) A grant, by implication, estoppel or otherwise, of any license,
         option, covenant or right other than those which are expressly stated
         herein, including without limitation (i) any license under any patent
         or patent application (or claim thereof) not within the Licensed
         Patents, or (ii) any covenant by CHIRON or ROCHE not to sue under any
         such patent or patent application (or claim thereof).

                                                                             19

<PAGE>

         6.6 FURTHER ROCHE ASSURANCE. ROCHE acknowledges that the inclusion
of ROCHE Affiliates within the license and option grants pursuant to Sections
2.1, 2.3 and 2.6 is intended to enable ROCHE to utilize the manufacturing and
sales capabilities of its Affiliates in connection with the manufacture and
sale of CHIRON Licensed Products in a manner substantially similar to the
involvement of such Affiliates in the manufacture and sale of ROCHE's
products generally. ROCHE shall not, directly or indirectly, take any action
having or intended to have the effect of sublicensing ROCHE's rights under
any of the CHIRON Licensed Patents, other than to a BONA FIDE Affiliate,
including, without limitation, by creating Affiliates specifically in
connection with CHIRON Licensed Products, or through other third party
arrangements such as joint ventures, collaborations, or distribution
arrangements with distributors. ROCHE and its Affiliates are licensed
hereunder to sell and distribute CHIRON Licensed Products only under the
label, name and trademark rights owned by, licensed to or otherwise
controlled by ROCHE or its Affiliates, and only through the sales force of
ROCHE or its Affiliates, or through Authorized Distributors. ROCHE and its
Affiliates are not licensed to perform OEM manufacturing of CHIRON Licensed
Products for a third party other than an Authorized Distributor; to supply
CHIRON Licensed Products for resale to any third party other than an
Authorized Distributor; to permit any Authorized Distributor or other third
party to sell any CHIRON Licensed Products under another third party label,
name or trademark or to permit any Authorized Distributor or other third
party to sell any CHIRON Licensed Products under the Authorized Distributor's
or any third party's own label, name or trademark for use on an instrument
bearing the label name or trademark of a party other than ROCHE or its
Affiliates; provided, however, that nothing in this Section 6.6 shall be
construed to limit the rights of ROCHE or its Affiliates to engage in
activities with such third parties, to the extent such third parties have
obtained rights under the CHIRON Licensed Patents permitting such activities.

         6.7 LIMITATION OF WARRANTY. EXCEPT AS SPECIFICALLY SET FORTH HEREIN,
NO PARTY MAKES ANY REPRESENTATION OR WARRANTY, EITHER EXPRESS OR IMPLIED,
ARISING BY LAW OR OTHERWISE, INCLUDING, BUT NOT LIMITED TO, IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

                                    ARTICLE 7
                              TERM AND TERMINATION

         7.1 TERM. This Agreement shall be in effect from the Effective Date
until the last to expire of the CHIRON Licensed Patents issued under the
authority of the Patent and Trademark Office of the United States (the
"Term"), unless earlier terminated pursuant to Sections 7.2 or 7.3 below.

         7.2 VOLUNTARY TERMINATION. ROCHE shall have the right to voluntarily
terminate all, but not less than all, licenses granted to ROCHE and its
affiliates

                                                                             20

<PAGE>

under this Agreement on not less than six (6) months prior written notice to
CHIRON. Notwithstanding the above, ROCHE may voluntarily terminate all, but
not less than all, licenses granted to ROCHE and its Affiliates under this
Agreement on a country-by-country basis, on not less than six (6) months
prior written notice to CHIRON, after the [CONFIDENTIAL TREATMENT REQUESTED]
anniversary of the Effective Date.

         7.3 TERMINATION BY CHIRON. CHIRON may terminate this Agreement only
upon any of the following grounds:

         (a) ROCHE's or its Affiliate's material breach of this Agreement,
         including, without limitation, a breach resulting from ROCHE's or its
         Affiliate's failure to pay any sums due hereunder, where such breach
         shall not have been remedied within thirty (30) days of the receipt of
         a written notification from CHIRON identifying the breach and requiring
         its remedy; whereupon termination under this Section 7.3(a) shall be
         effective upon the expiration of such thirty (30) day cure period,
         subject to Section 7.6; or

         (b) [CONFIDENTIAL TREATMENT REQUESTED]

         7.4 ENFORCEMENT AFTER TERMINATION. Upon valid termination of this
Agreement under Section 7.2 or 7.3, ROCHE and its Affiliates shall have no
further rights under CHIRON Licensed Patents and CHIRON shall not be limited
to its remedies under this Agreement, to the extent of such termination.

         7.5 ACCRUED RIGHTS. Termination of this Agreement for whatever
reason shall not affect any rights which have accrued prior to termination,
including without limitation royalty obligations occurring during the Term,
calculated in accordance with Article 3 and Exhibit A.

         7.6 ROCHE CHALLENGE TO SECTION 7.3(a) TERMINATION. In the event
ROCHE provides written notification to CHIRON prior to expiration of the
thirty (30) day notice/cure period referenced in Section 7.3(a) that ROCHE
disputes whether the grounds for termination under Section 7.3(a) are
present, such dispute shall be submitted to ADR pursuant to Article 10. The
thirty (30) day notice/cure period shall be suspended during the pendancy of
such ADR, provided that during the pendancy of the ADR, ROCHE shall continue
to make any disputed payments to CHIRON, on the condition that CHIRON shall
repay ROCHE the amounts of such disputed payments if ROCHE prevails in the
ADR, plus interest at the rate described in Section 4.8. Notwithstanding
anything in this Section 7.6 to the contrary, ROCHE may submit a dispute
concerning a method by which amounts payable by ROCHE and its Affiliates to
CHIRON hereunder are calculated only one time, and any resolution from the
ADR shall bind the parties as to such calculation method thereafter.

                                                                             21

<PAGE>

         7.7 ROCHE CHALLENGE TO SECTION 7.3(b) TERMINATION. In the event that
ROCHE, within thirty (30) days of receiving notice of termination by CHIRON
for the grounds set forth in Section 7.3(b) above, provides written notice to
CHIRON that ROCHE disputes whether such grounds are present, such dispute
shall be submitted to ADR pursuant to Article 10 and termination of this
Agreement shall be suspended during the pendancy of the ADR, provided that
ROCHE suspends its action, suit or proceeding (other than in an ADR
proceeding between the parties as permitted by Section 7.3(b) and Article
10) [CONFIDENTIAL TREATMENT REQUESTED], and continues to perform all of its
material obligations hereunder.

         7.8 AUDIT RESULTS NOT GROUNDS FOR TERMINATION. CHIRON's request for
an audit under Section 4.5 shall not be treated as a notice of breach under
Section 7.3(a). In the event such audit determines there has been an
underpayment by ROCHE, such underpayment shall not constitute grounds for
termination by CHIRON under Section 7.3(a) unless: (a) ROCHE has failed to
rectify such underpayment in accordance with Section 4.5; (b) ROCHE has
failed to rectify such underpayment after notification and opportunity to
cure under Section 7.3(a); and (c) any ADR requested by ROCHE, pursuant to
Section 7.6, and directed to any dispute concerning such underpayment,
results in a determination favorable to CHIRON and ROCHE has failed to
rectify such underpayment. Notwithstanding the foregoing, ROCHE shall
continue to make the disputed payments to CHIRON, on the condition that
CHIRON shall repay ROCHE the amounts of such disputed payments with respect
to which ROCHE prevails in the ADR, plus interest at the rate described in
Section 4.8.

         7.9 SURVIVAL. The following provisions of this Agreement shall
survive termination or expiration of this Agreement, in accordance with their
respective terms: Article 1; Sections 4.5, 4.6, 4.7, 4.8, 6.7, 7.4, 7.5 and
7.9; Articles 8, 9, and 10; Sections 11.9 through 11.14; and Section 14.1.

                                    ARTICLE 8
                                 CONFIDENTIALITY

         8.1 OBLIGATION. From time to time during the Term, CHIRON and ROCHE
may provide to each other information concerning patents, patent
applications, license agreements and other confidential or proprietary
information related to this Agreement (the "Information"). Each party
receiving the Information (the "Receiving Party") shall during the Term and
for a period of three (3) years after termination hereof: (a) maintain the
Information in confidence; (b) not disclose the Information to any third
party, other than employees, agents or consultants of the Receiving Party,
its Affiliates or permitted sublicensees who have a need to know the
Information and who are bound by confidentiality obligations to the Receiving
Party no less restrictive than those contained herein; and (c) not use the
Information for any purpose not directly related to performance hereunder or
otherwise authorized under this Agreement.

                                                                             22

<PAGE>

         8.2 EXCLUSIONS. The obligations of this Article 8 shall not apply to
any Information which: (a) is or which becomes generally known to the public
by publication or by means other than a breach of a duty by the Receiving
Party; (b) is otherwise known by the Receiving Party at the time of
disclosure by the other party; (c) otherwise becomes available to the
Receiving Party from a third party not in breach of confidentiality
obligations to the other party; or (d) is developed by or for the Receiving
Party independent of any disclosure from the other party. The Receiving Party
also shall be permitted to make disclosures of Information which are
reasonably necessary in connection with a possible grant of a permitted
sublicense by the Receiving Party or in due diligence related to a possible
acquisition, merger, consolidation, substantial asset transfer or similar
transaction of the Receiving Party, provided that the recipient is bound to
the Receiving Party by confidentiality obligations with respect to the
Information no less restrictive than those contained herein. Nothing herein
shall prevent the Receiving Party from making such disclosures of Information
as are reasonably required by law, regulation (including 37 C.F.R. Section
1.56), or order of any court or governmental agency; provided that the
Receiving Party has provided reasonable advance notice to allow the
disclosing party the opportunity to seek a protective order or otherwise
contest, prevent or limit such disclosure.

         8.3 RETURN OF INFORMATION. Upon termination of this Agreement for
any reason, the Receiving Party shall return, or at the option of the
disclosing party, certify destruction of, all Information and copies thereof;
provided that the Receiving Party may retain one copy thereof in its law
department files solely for evidentiary and regulatory purposes.

         8.4 DISCLOSURE OF AGREEMENTS AND TERMS. The parties shall issue a
joint press release disclosing the existence and certain financial terms of
this Agreement. CHIRON may disclose any of the terms in the Agreement to any
Affiliate of CHIRON or to Abbott or Bayer or a permitted sublicensee;
provided that the recipient of such disclosure is obligated to
confidentiality terms no less restrictive that those contained in this
Article 8. CHIRON and ROCHE may each disclose the amounts of the Prior Sales
Royalty, the Pre-Paid Minimum Royalty (as defined in Exhibit A) individually
and/or in the aggregate and the amounts thereof that will be recognized from
time-to-time in its respective financial statements. Each party may disclose
any information contained in or regarding this Agreement to the extent
required in its respective reasonable judgment by applicable law, regulation
or order of any court or governmental agency. Further, each party may
determine in its respective discretion to file this Agreement under the
Securities and Exchange Act of 1934 or otherwise with any United States or
foreign governmental agency, even if that filing may result in this Agreement
becoming available to the public generally. The filing party shall seek
confidential treatment for at least the essential financial terms hereof in
connection with any such filing, subject to applicable law and regulation,
and shall notify the other party in advance of any such filing and consider
such

                                                                             23

<PAGE>

suggestions as the other party may make as to the terms herein as to which
the filing party should seek confidential treatment.

                                    ARTICLE 9
                                    INDEMNITY

         9.1 ROCHE INDEMNITY. ROCHE shall indemnify, defend and hold harmless
CHIRON and its Affiliates and their officers, directors, shareholders,
employees, representatives and agents, against any claim, demand, loss,
damage or injury, including reasonable attorneys' fees, asserted by a third
party, arising from, relating to, or otherwise in respect of, (a) the
manufacture, use or sale of CHIRON Licensed Products, or (b) any breach by
ROCHE or its Affiliates of any representation, warranty or covenant under
this Agreement; provided, however, that such indemnity shall not extend to
damages arising directly from any breach or willful or negligent act of
CHIRON or its Affiliates.

         9.2 CHIRON INDEMNITY. CHIRON shall indemnify, defend and hold
harmless ROCHE and its Affiliates and their officers, directors,
shareholders, employees, representatives and agents, against any claim,
demand, loss, damage or injury, including reasonable attorneys' fees,
asserted by a third party, arising from, relating to, or otherwise in respect
of, (a) the manufacture, use or sale of ROCHE Licensed Products, if Chiron
exercises the options granted in Sections 2.5 or 2.7,or (b) any breach by
CHIRON or its Affiliates of any representation, warranty or covenant under
this Agreement; provided, however, that such indemnity shall not extend to
damages arising directly from any breach or willful or negligent act of ROCHE
or its Affiliates.

         9.3 INDEMNIFICATION PROCEDURES. In the event either party claims
indemnification pursuant to this Article 9, the indemnified party shall
promptly notify the indemnifying party in writing upon becoming aware of any
claim to which such indemnification may apply. Delay in providing such notice
shall constitute a waiver of the indemnifying party's indemnity obligations
hereunder only if the indemnifying party's ability to defend such claim is
materially impaired thereby. The indemnifying party shall have the right to
assume and solely control the defense of the claim at its own expense. If the
right to assume and solely control the defense is exercised, the indemnified
party shall have the right to participate in, but not to control, such
defense at its own expense, and the indemnifying party's indemnity
obligations shall be deemed not to include attorneys' fees and litigation
expenses incurred by the indemnified party after the assumption of the
defense by the indemnifying party. If the indemnifying party does not assume
the defense of the claim, the indemnified party may defend the claim at the
indemnifying party's expense. The indemnified party shall not settle or
compromise the claim without the prior written consent of the indemnifying
party, and the indemnifying party shall not settle or compromise the claim in
any manner which would have an adverse effect on the indemnified party
without the consent of the indemnified party, which consent, in each case,
shall not be

                                                                             24

<PAGE>

unreasonably withheld. The indemnified party shall reasonably cooperate with
the indemnifying party and shall make available to the indemnifying party all
pertinent information under the control of the indemnified party, all at the
expense of the indemnifying party.

         9.4 SUNSET. The provisions of Sections 9.1 and 9.2 shall continue in
effect on a claim-by-claim basis, after the termination of this Agreement,
only until the expiration of the last to expire statute of limitations
applicable to such claim.

         9.5 LIMITATION OF LIABILITY. Neither party shall be liable to the
other for any consequential, special, indirect or exemplary damages or for
the loss of profits arising from the performance or nonperformance of this
Agreement or any acts or omissions associated herewith.

                                   ARTICLE 10
                         ALTERNATIVE DISPUTE RESOLUTION

         The parties recognize that BONA-FIDE disputes may from time to time
arise which relate to any aspect of this Agreement, including, without
limitation, any of the parties' rights and/or obligations hereunder, and
including, without limitation, disputes relating to the interpretation, form,
validity, performance and/or termination of this Agreement or relating to
infringement, scope, claims construction, or (without limiting the effect of
Section 7.3(b)) validity or enforceability of the Licensed Patents. In the
event of the occurrence of any dispute, a party may, by notice to the other
party, have such dispute referred to their respective employees designated
below or their successors, for attempted resolution by good faith
negotiations within ninety (90) days after such notice is received. Said
designated officers are as follows:

         For ROCHE:
         PRESIDENT
         ROCHE MOLECULAR SYSTEMS, INC.

         For CHIRON:
         PRESIDENT
         BLOOD TESTING

         In the event the designated officers, after such good faith
negotiations, are not able to resolve such dispute within such ninety (90)
day period, or any agreed extension thereof, a party may invoke the
provisions for binding ADR as set forth in Paragraph 9 of the Settlement
Agreement. Neither party shall seek recourse against the other hereunder in
any court or other forum, except as permitted by Paragraph 9 of the
Settlement Agreement or as may be necessary to enforce a

                                                                             25

<PAGE>

determination made in ADR pursuant to this Article 10 and Paragraph 9 of the
Settlement Agreement.

                                   ARTICLE 11
                                  MISCELLANEOUS

         11.1 ASSIGNMENT.

                  (a) ROCHE and its Affiliates may not assign or transfer any
         rights under this Agreement without the prior written consent of
         CHIRON, except to an ROCHE Affiliate, and then only for so long as the
         assignee remains an ROCHE Affiliate, or as part of the sale or transfer
         of all or substantially all of ROCHE's and all of its Affiliates'
         assets and businesses to which this Agreement relates. In the case of a
         permitted assignment or transfer, the performance of the assignee shall
         be guaranteed by ROCHE.

                  (b) CHIRON and its Affiliates may not assign or transfer any
         rights under this Agreement without the prior written consent of ROCHE,
         except to a CHIRON Affiliate, and then only for so long as the assignee
         remains a CHIRON Affiliate, or as part of the sale or transfer of all
         or substantially all of CHIRON's and all of its Affiliates' assets and
         businesses to which this Agreement relates. In the case of a permitted
         assignment or transfer, the performance of the assignee shall be
         guaranteed by CHIRON.

         11.2 FORCE MAJEURE. A party hereto shall not be liable for, nor
shall this Agreement be terminable or cancelable by reason of, any delay or
default in any such party's performance hereunder, to the extent that such
default or delay is caused by events beyond such party's reasonable control
including, but not limited to: acts of God; regulation, law or action of any
government or agency thereof; war or insurrection; civil commotion; labor
disturbances; epidemic; or failure of suppliers, public utilities or common
carriers. Each party shall give prompt notice to the other party of such
cause, and shall take whatever reasonable steps are necessary to relieve the
effect of such cause as rapidly as possible.

         11.3 SEVERABILITY. In the event that any one or more of the
provisions of this Agreement should for any reason be held by any court or
authority having jurisdiction over this Agreement or over the parties hereto
to be invalid, illegal or unenforceable, such provision or provisions shall
be reformed to approximate as nearly as possible the intent of the parties,
in such jurisdiction; elsewhere, this Agreement shall not be affected.

         11.4 ENTIRE AGREEMENT. This Agreement together with the Exhibits,
Attachments and Schedules constitutes the entire agreement among the parties

                                                                             26

<PAGE>

relating to the subject matter of this Agreement. There are no other
understandings, representations or warranties of any kind.

         11.5 AMENDMENT. This Agreement shall not be altered, extended or
modified except by written agreement of the parties.

         11.6 WAIVER. Failure by a party hereunder to enforce any right under
this Agreement shall not be construed as a waiver of such right or any other
rights under this Agreement; nor shall a waiver by a party hereunder in one
or more instances be construed as constituting a continuing waiver or as a
waiver in other instances.

         11.7 COSTS. Each of the parties hereto shall be responsible for its
respective legal and other costs incurred in relation to the preparation of
this Agreement.

         11.8 COUNTERPARTS. This Agreement may be executed in two (2) or more
counterparts, each of which shall be deemed to be an original, but all of
which, taken together, shall constitute one and the same instrument.
Facsimile copies of signatures for a party shall be deemed to be originals
for purposes of execution of the Agreement and for determining the Effective
Date.

         11.9 NOTICES.

         (a) Any notice or other document to be given under this Agreement
shall be in writing and shall be deemed to have been duly given if personally
delivered or sent by first class mail, or express or air mail or other postal
service, or by certified mail, return receipt requested.

         (b) Any notice required by this Agreement shall be forwarded to the
respective addresses and marked for the attention of the persons set forth
below unless such addresses subsequently change by written notice to the
other party:

ROCHE:            F. Hoffmann-La Roche Ltd.
                  Grenzacherstrasse 124
                  Basel
                  Bale 4002
                  Switzerland
                  Attn: Head of Diagnostics Division

Copy to:          General Counsel
                  Roche Molecular Systems, Inc.
                  1145 Atlantic Avenue
                  Alameda, CA  94501

                                                                             27

<PAGE>

CHIRON:           Chiron Corporation
                  4560 Horton Street
                  Emeryville, California 94608
                  Attn.: President, Blood Testing

Copy to:          General Counsel
                  Chiron Corporation
                  4560 Horton Street
                  Emeryville, CA 94608

         (c) Any such notice or other document shall be deemed to have been
effective when received by the addressee. To prove the giving of a notice or
other document it shall be sufficient to show that it was received.

         11.10 GOVERNING LAW. All matters affecting the interpretation, form,
validity, performance and termination of this Agreement shall be decided and
interpreted under the laws of the State of New York, excluding any choice of
law rules which may direct application of the laws of any other jurisdiction.

         11.11 RELATIONSHIP OF THE PARTIES. The relationship of the parties
under this Agreement is that of independent contractors. Nothing contained in
this Agreement is intended or is to be construed so as to constitute the
parties as partners, joint venturers or agents of the other. Neither party or
its Affiliates has any express or implied right or authority under this
Agreement to assume or create any obligations or make any representations or
warranties on behalf of or in the name of the other party or its Affiliates.

         11.12 HEADINGS. The headings of the Articles and Sections in this
Agreement have been inserted for convenience only and do not constitute part
of this Agreement.

         11.13 NO TRADEMARK RIGHTS. No right, express or implied, is granted by
this Agreement to either party to use in any manner the name, trade name or
trademark of the other party in connection with the performance of this
Agreement.

         11.14 NO IMPLIED LICENSES. No license, express or implied, is
granted by this Agreement to either party, other than the licenses or options
granted under Sections 2.1, 2.3 and Sections 2.5 through 2.7.

                                   ARTICLE 12
                     FIELD RESTRICTIONS AND OTHER COVENANTS

         12.1 ROCHE COVENANT REGARDING BLOOD SCREENING.

                                                                             28

<PAGE>

         (a) ROCHE and its Affiliates shall not label or promote any CHIRON
Licensed Product labeled or promoted for use in the Field or the
Transplantation Field in any respect for use in Blood Screening; and ROCHE
shall use commercially reasonable efforts to prevent its Authorized
Distributors from labeling or promoting any CHIRON Licensed Products labeled
or promoted for use in the Field or the Transplantation Field in any respect
for use in Blood Screening.

         (b) Further, ROCHE and its Affiliates and Authorized Distributors
shall include on or with each CHIRON Licensed Product labeled or promoted for
use in the Field or the Transplantation Field a statement to the effect that
the CHIRON Licensed Product is not for use for testing or screening pooled
samples containing specimens from more than one individual, or otherwise in
blood or plasma screening, using language to be determined by ROCHE and
approved in advance in writing by CHIRON, which approval shall not be
unreasonably withheld. The location of such notice shall be the product
insert of such CHIRON Licensed Products or such other reasonably prominent
location to be determined by ROCHE.

         (c) In the event that ROCHE or CHIRON becomes aware of any material
use in Blood Screening of CHIRON Licensed Products labeled or promoted for
use in the Field or the Transplantation Field, such party will promptly
notify the other in writing of the relevant facts and, if so requested by
CHIRON, ROCHE will (i) meet and confer with CHIRON in good faith to determine
what steps either or both should take to abate such infringing use and (ii)
notify in writing any of its customers that engages in such infringing use
that use of the relevant CHIRON Licensed Product in Blood Screening may
infringe one or more of the CHIRON Licensed Patents.

         (d) Without limiting the labeling and promoting obligations under
this Section 12.1, CHIRON shall not sue ROCHE, its Affiliates, its Authorized
Distributors or its End User customers for the sale or use as a confirmatory
or supplemental test in conjunction with the screening of blood, plasma or
blood products (a "Confirmatory Test") of a CHIRON Licensed Product that is
labeled or promoted for use in the Field or the Transplantation Field, if the
End User customer has substantial non-infringing uses for such CHIRON
Licensed Product in the Field or the Transplantation Field. Further, ROCHE
shall not be obligated to notify such customers pursuant to Section
12.1(c)(ii) with respect to such CHIRON Licensed Product.

         (e) Nothing in this Section 12.1 shall apply to any product to the
extent that ROCHE's activity and that of its Affiliates with respect to such
product is either for or through an entity licensed in Blood Screening under
the CHIRON Licensed Patents.

                                                                             29

<PAGE>

         12.2 ROCHE COVENANT REGARDING PRODUCT LABELING. ROCHE and its
Affiliates shall include on or with each CHIRON Licensed Product a statement
as to the number of Units contained within each such CHIRON Licensed Product,
using such language to be determined by ROCHE and approved in advance in
writing by CHIRON, which approval shall not be unreasonably withheld. The
location of such statement shall be in the product insert of such CHIRON
Licensed Products or such other reasonably prominent location to be
determined by ROCHE.

         12.3 PATENT MARKING. ROCHE and its Affiliates shall include a patent
notice on each CHIRON Licensed Product to identify the CHIRON Licensed
Patents which such CHIRON Licensed Product, but for the licenses granted
herein, would infringe one or more Valid Claims (or for which royalties are
being paid); provided, however, identification of CHIRON Licensed Patents on
a CHIRON Licensed Product shall in no way be deemed to be an admission by
ROCHE or its Affiliates, or raise a presumption, that such CHIRON Licensed
Product is in fact covered by such CHIRON Licensed Patent.

         12.4 CHIRON COVENANT REGARDING FIELD.

         (a) CHIRON and its Affiliates shall not, and CHIRON shall require
any of its future licensees under the CHIRON Licensed Patents that are
licensed in Blood Screening to agree not to, label or promote, in any respect
for use in the Field, any product sold in, labeled or promoted for use in
Blood Screening [CONFIDENTIAL TREATMENT REQUESTED], which product detects
nucleic acid sequences of HCV.

         (b) Further, CHIRON and its Affiliates shall, and CHIRON shall
require its future licensees in Blood Screening to, include with each such
HCV product sold by CHIRON or its Affiliates or licensees in Blood Screening
a statement to the effect that such product is not for use in the Field,
using language to be determined by CHIRON and approved by ROCHE, which
approval shall not be unreasonably withheld. The location of such notice
shall be in the product insert for such product or such other reasonably
prominent location to be determined by CHIRON.

         (c) In the event that CHIRON or ROCHE becomes aware of any material
use of any such product in the Field, such party will promptly notify the
other in writing of the relevant facts and, if so requested by ROCHE, CHIRON
will (i) meet and confer with ROCHE in good-faith to determine what steps
either or both of them should take to abate such use and (ii) notify in
writing any of its customers that engage in such use that use of the relevant
product in the Field may infringe one or more of the CHIRON Licensed Patents.

         (d) Nothing in this Section 12.4 shall apply to any product to the
extent that CHIRON's activity and that of its Affiliates or licensees with
respect to such

                                                                             30

<PAGE>

product either (i) is for or through an entity that is licensed under the
CHIRON Licensed Patents in the Field or (ii) is within CHIRON's rights to
practice in the Field, pursuant to its rights retained under, and subject to
the limitations of, Section 2.1.

                                   ARTICLE 13
                          INFRINGEMENT BY THIRD PARTIES

         13.1 NOTICE OF INFRINGEMENT. Each party shall notify the other if it
becomes aware of Infringing Third Party Sales. CHIRON shall have the
exclusive right to take action against any infringement of any of the CHIRON
Licensed Patents, in its sole discretion, subject to this Article 13.

         13.2 INFRINGEMENT LITIGATION.

         (a) In the event that "substantial" Infringing Third Party Sales are
occurring in a country in which ROCHE or its Affiliates or an Authorized
Distributor is selling a CHIRON Licensed Product (in each such country, the
"Impacted Product"), and ROCHE has notified CHIRON pursuant to Section 13.1
of the existence of such infringement in [CONFIDENTIAL TREATMENT REQUESTED]
(an "Infringement Notice"), then the provisions of this Section 13.2 shall
apply. For purposes of this Section 13.2, an Infringing Third Party Sale
shall be considered substantial in a country if the infringing third party
achieves market share of at least [CONFIDENTIAL TREATMENT REQUESTED] of the
Aggregated Products in such country as determined by an Independent Auditor
paid for by ROCHE. For purposes of this Section 13.2, "Major Country" shall
mean the United States, Germany, United Kingdom or Japan. For purposes of
this Section 13.2, "Aggregated Products" means the number of CHIRON Licensed
Products of the Applicable Product Category and Competitive Products sold in
a country, and "Competitive Products" means Products which are sold in the
Field and which compete with a CHIRON Licensed Product sold by ROCHE or its
Affiliates in a country.

         (b) If either (i) the Infringement Notice identified an Impacted
Product in the United States and CHIRON fails to institute legal action in
the United States [CONFIDENTIAL TREATMENT REQUESTED] following receipt by
CHIRON of the Infringement Notice and infringement is not otherwise abated,
or (ii) the Infringement Notice identified an Impacted Product in a Major
Country other than the United States and CHIRON fails to institute legal
action against the infringing party in at least one of the United States, the
Netherlands, Germany, United Kingdom or Japan, [CONFIDENTIAL TREATMENT
REQUESTED] following receipt by CHIRON of the Infringement Notice and
infringement is not otherwise abated; then ROCHE shall be relieved of the
obligation to pay the portion of Earned Royalties set forth in Section
13.2(c) and [CONFIDENTIAL TREATMENT REQUESTED], with respect to the Impacted
Product until such time as CHIRON institutes such legal action as described
in this Section 13.2(b); provided,

                                                                             31

<PAGE>

however, that CHIRON need not initiate or continue any such legal action, if,
after reasonably diligent effort (including reasonably diligent effort by
ROCHE if requested by CHIRON), CHIRON is unable to acquire admissible
evidence sufficient to establish a prima facia case of infringement under the
law of the applicable country.

         (c) If CHIRON has not instituted such legal action at the end of
such [CONFIDENTIAL TREATMENT REQUESTED], to the extent required under
Section 13.2(b), and such infringement is not otherwise abated, the Earned
Royalty with respect to an Impacted Product shall be reduced by [CONFIDENTIAL
TREATMENT REQUESTED]. If, at the end of each [CONFIDENTIAL TREATMENT REQUESTED]
thereafter, CHIRON has not instituted such legal action, to the extent so
required, and infringement is not otherwise abated, such Earned Royalties
shall be reduced by an [CONFIDENTIAL TREATMENT REQUESTED] of the original
Earned Royalties, such that if legal action required under Section 13.2(b)
has not commenced and the infringement is not otherwise abated by the end of
the [CONFIDENTIAL TREATMENT REQUESTED] following receipt by CHIRON of the
Infringement Notice, [CONFIDENTIAL TREATMENT REQUESTED] shall be payable
hereunder with respect to the Impacted Product.

         (d) The obligations to pay Earned Royalties and Minimum Royalties
shall be reinstated on a prospective basis at such time as ROCHE receives
written notice of the institution of legal action in accordance with Section
13.2(b) or the infringement is otherwise abated, all subject to Section
13.2(e).

         (e) If legal action required under Section 13.2(b) has not been
instituted and the infringement is not otherwise abated for more than
[CONFIDENTIAL TREATMENT REQUESTED] following receipt by CHIRON of the
Infringement Notice, and if, as a result of the infringement, sales of the
Impacted Product in a Major Country by ROCHE, its Affiliates or an Authorized
Distributor have declined by [CONFIDENTIAL TREATMENT REQUESTED] or more
during the preceding [CONFIDENTIAL TREATMENT REQUESTED], then upon
reinstatement of Earned Royalties and Minimum pursuant to Section 13.2(d),
the parties shall meet and confer regarding possible adjustments to the
Earned Royalties and Minimum Royalties for the Impacted Product in view of
such degradation of the market. The parties will discuss possible rate
reductions, as well as a plan for reinstating the original economic
expectations of the parties. It is expected that any agreement for reduction
of Earned Royalties and Minimum Royalties will be phased out over time, so as
to return to the Earned Royalties and Minimum Royalties set forth in Exhibit
A. If the parties fail to reach agreement on any such adjustment, the matter
shall be submitted for resolution by ADR, except that in the event of ADR,
each party shall submit to the neutral a proposal with respect to adjustments
pursuant to this Section 13.2(e). The neutral shall be empowered to choose
one proposal or the other,

                                                                             32

<PAGE>

but shall not be empowered to order any such adjustment other than as
proposed by one of the parties.

         13.3. COOPERATION. ROCHE and its Affiliates shall cooperate with
CHIRON in connection with any legal action referred to in this Article 13.

                                   ARTICLE 14
                          EUROPEAN COMMUNITY PROVISIONS

         14.1 TERMINATION IN EUROPEAN COMMUNITY. Notwithstanding the
provisions of Article 7, this Agreement, with respect to the European
Community, shall terminate in each member country seventeen (17) years from
the Effective Date or on the expiration of the last to expire of the patents
within the CHIRON Licensed Patents in such member country based upon a patent
existing or a patent application pending as of the Effective Date, whichever
is later; provided, however, that prior to the termination of this Agreement
in the first member country in which it would otherwise terminate pursuant to
the foregoing, ROCHE may, in its discretion, elect by written notice to
CHIRON to extend this Agreement as to all such member countries for an
additional term which shall expire on a country-by-country basis on the
expiration date of the last to expire patent within the CHIRON Licensed
Patents existing in such member country as of the date of such extension.

         14.2 COMPETITION NOTIFICATION. If either party (the "Notifying
Party") elects to file a notification with respect to this Agreement (a
"Notification") with the Competition Directorate of Commission of European
Community (the "Commission") in accordance with regulations established by
the Commission, the Notifying Party shall provide a non-confidential version
of the final draft to the other party for comment at least thirty (30) days
before making the filing and shall consider in good faith the modification
thereto, if any, that the other party may propose. The other party shall
execute all documents reasonably required by the Notifying Party and shall
otherwise reasonably cooperate in connection with the Notification. The
Notifying Party shall bear all costs incurred by it relating to the
Notification.

         14.3 REFORMATION. If, at any time during the Term, either party
receives a request or other communication from the Commission with respect to
the Notification (a "Request"), such party shall promptly inform the other of
the nature of the Request. In the event that the Commission indicates in a
Statement of Objection(s) that this Agreement will violate the provisions of
Article 81 or 82 of the Treaty of Rome, then the parties shall amend this
Agreement by making those minimal modifications necessary to satisfy the
concerns of the Commission as set forth in the Statement of Objection(s).
Notwithstanding the foregoing, the parties agree that ROCHE shall retain
substantially the same license rights at substantially the same royalties as
specified under this Agreement.

                                                                             33

<PAGE>

IN WITNESS WHEREOF this Agreement has been executed by duly authorized
officers of CHIRON and ROCHE as of the Effective Date.

CHIRON CORPORATION

By:      /s/ SEAN P. LANCE
         -----------------
         Sean P. Lance

Title:    Chairman and Chief Executive Officer

Date:  October 10, 2000

F. HOFFMANN-LA ROCHE LTD

By:     /s/ HEINO VON PRONDZYNSKI
        -------------------------

Title:   Head of Diagnostics

Date:   10/10/2000

By:      /s/ S. SCHWAN
         -------------

Title:   Head of Diagnostics Finance

Date:    10/10/2000

ROCHE MOLECULAR SYSTEMS, INC.

By:   /s/ KATHY ORDONEZ
      -----------------

Title: President & CEO

Date:   October 10, 2000

                                                                             34

<PAGE>

                                    EXHIBIT A
                       COMPENSATION TO CHIRON CORPORATION

1. PRIOR SALES ROYALTY. In consideration of the licenses granted pursuant to
Sections 2.1 and 2.3, within ten (10) days of the Effective Date ROCHE shall
pay [CONFIDENTIAL TREATMENT REQUESTED], for all sales of CHIRON Licensed
Products [CONFIDENTIAL TREATMENT REQUESTED], and [CONFIDENTIAL TREATMENT
REQUESTED] for all sales of Chiron Licensed Products [CONFIDENTIAL TREATMENT
REQUESTED], that would have, in the absence of the licenses granted pursuant
to Section 2.1 and 2.3 and under the Blood Screening Agreement, constituted
an infringement of a Valid Claim of a CHIRON Licensed Patent (the "Prior
Sales Royalty"). The Prior Sales Royalty shall be nonrefundable and fully
earned when paid.

2. EARNED ROYALTY. In consideration of the licenses granted pursuant to
Sections 2.1 and 2.3, ROCHE shall pay earned royalties equal to [CONFIDENTIAL
TREATMENT REQUESTED] of Net Sales of CHIRON Licensed Products, that would,
[CONFIDENTIAL TREATMENT REQUESTED].

         Earned Royalties shall be payable quarterly, commencing with the
Calendar Quarter ending [CONFIDENTIAL TREATMENT REQUESTED], within sixty (60)
days following the end of each Calendar Quarter, and shall be accompanied by
a report pursuant to Article 4 of this Agreement.

3. MINIMUM ROYALTY. Notwithstanding the Earned Royalties due pursuant to
Paragraph 2 of this Exhibit A, and subject to the adjustments referenced in
Paragraphs 2 and 3(b) of this Exhibit A, royalties paid to CHIRON under this
Agreement in any Calendar Quarter shall not be less than a minimum royalty in
such quarter (the "Minimum Royalty") calculated as follows:

The Minimum Royalty for each Calendar Quarter shall be the sum of the
products obtained by multiplying (x) [CONFIDENTIAL TREATMENT REQUESTED] in
each category within the CHIRON Licensed Products (a "Product Category") and
in each Region times (y) the applicable minimum amount (the "Minimum Royalty
Amount"), each of which Minimum Royalty Amounts shall be calculated by the
following equation:

                       [CONFIDENTIAL TREATMENT REQUESTED]

Where:

         A equals [CONFIDENTIAL TREATMENT REQUESTED](the "Minimum Amount/Test");

         B equals [CONFIDENTIAL TREATMENT REQUESTED]

         C equals [CONFIDENTIAL TREATMENT REQUESTED].

<TABLE>
<CAPTION>
                                                        Minimum Amount/Test

         FIELD:                             REGION I          REGION II         REGION III       REGION IV
<S>                                                           <C>

         [CONFIDENTIAL TREATMENT REQUESTED]
</TABLE>

<PAGE>

<TABLE>

<S>                                                           <C>
         [CONFIDENTIAL TREATMENT REQUESTED]
</TABLE>

<TABLE>

         FIELD:                             REGION I          REGION II         REGION III       REGION IV
<S>                                                           <C>

         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]
</TABLE>

<TABLE>

         TRANSPLANTATION FIELD:             REGION I          REGION II         REGION III       REGION IV
<S>                                                           <C>

         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]
</TABLE>

         (a) Within ten (10) days of the Effective Date, ROCHE shall pre-pay
[CONFIDENTIAL TREATMENT REQUESTED], for all sales of CHIRON Licensed Products
made [CONFIDENTIAL TREATMENT REQUESTED], that would, in the absence of the
licenses granted pursuant to Sections 2.1 and 2.3, constitute an infringement
of a Valid Claim of a CHIRON Licensed Patent (the "Pre-Paid Minimum
Royalty"). The Pre-Paid Minimum Royalty shall be nonrefundable except as
provided below. The unamortized balance from time-to-time of the Pre-Paid
Minimum Royalty, [CONFIDENTIAL TREATMENT REQUESTED], shall be applied to
reduce the Minimum Amount/Test for each Product Category by the following
amounts:

<TABLE>
<CAPTION>
                                                        Minimum Amount/Test

         FIELD:                             REGION I          REGION II         REGION III       REGION IV
<S>                                                           <C>

         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]
</TABLE>

<TABLE>
<CAPTION>

         TRANSPLANTATION FIELD:             REGION I          REGION II         REGION III       REGION IV
<S>                                                           <C>

         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]
         [CONFIDENTIAL TREATMENT REQUESTED]

</TABLE>
                                                                             2

<PAGE>

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         (b) Minimum Royalty shall be determined on a [CONFIDENTIAL TREATMENT
REQUESTED], except to the extent [CONFIDENTIAL TREATMENT REQUESTED].

         (c) In the event that action by governmental pricing or
reimbursement authority or other governmental agency in a country results in
a requirement that ROCHE or its Affiliates sell a CHIRON Licensed Product
[CONFIDENTIAL TREATMENT REQUESTED] (after adjustment as provided in Paragraph
3(a) of Exhibit A), excluding for the purpose of calculating the impact of
such price reduction any currency exchange rate fluctuations from the
Effective Date (i.e., the calculation shall be made using the exchange rate
in effect as of the Effective Date), [CONFIDENTIAL TREATMENT REQUESTED]. If
any such action or series of actions results in a requirement that ROCHE or
its Affiliates sell a CHIRON Licensed Product [CONFIDENTIAL TREATMENT
REQUESTED], then at the request of ROCHE, the parties shall meet and
reasonably consider greater adjustment to the Minimum Amount/Test with
respect to the CHIRON Licensed Product in that country. No adjustment shall
be made to the Minimum Amount/Test unless mutually agreed or determined
pursuant to ADR as provided in this subparagraph 3(c).

[CONFIDENTIAL TREATMENT REQUESTED]

         (d) Within sixty (60) days of the third anniversary of the Effective
Date and every third anniversary thereafter during the Term of this Agreement
the parties shall meet and reasonably consider adjustment to the Minimum
Amount/Test with respect to each CHIRON Licensed Product based on the average
price increase if any for diagnostics products on an industry-wide basis in
each Region over the prior three-year period; provided that no adjustment
shall be made to any Minimum Amount/Test unless mutually agreed or determined
pursuant to ADR as provided in this subparagraph 3(d), and provided further
that [CONFIDENTIAL TREATMENT REQUESTED].

        (e) Minimum Royalties shall be payable quarterly, net of the
applicable portion of the Pre-Paid Minimum Royalty pursuant to paragraph 3(a)
of Exhibit A, commencing with the Calendar Quarter ending
[CONFIDENTIAL TREATMENT REQUESTED], within sixty (60) days following the end
of each Calendar Quarter. Such payment shall be accompanied by a report
pursuant to Article 4 and shall be fully creditable against Earned Royalties
payable pursuant to paragraph 2 of Exhibit A for the same Calendar Quarter.

         (f) [CONFIDENTIAL TREATMENT REQUESTED]

         ROCHE shall only be entitled to a single adjustment by reason of
this Paragraph 3(f) with respect to [CONFIDENTIAL TREATMENT REQUESTED]
                                                                             3

<PAGE>

4. SINGLE ROYALTY PER CHIRON LICENSED PRODUCT. Only one payment of Earned
Royalty shall be due with respect to any Net Sales or only one payment of
Minimum Royalty Amount shall be due with respect to any Unit of CHIRON
Licensed Product Shipped, irrespective of the number of patents or Valid
Claims in the CHIRON Licensed Patents covering such CHIRON Licensed Product.

5. DISPUTE RESOLUTION. Any dispute between CHIRON and ROCHE regarding whether
any adjustment to or credits against Earned Royalties or Minimum Royalties
under this Exhibit A is appropriate, and which the parties fail to resolve
themselves may only be resolved by resort to the ADR provisions of Article
10. Until such dispute is resolved, ROCHE shall pay CHIRON the Earned Royalty
or Minimum Royalty provided for herein without benefit of the applicable
disputed adjustment on the condition that CHIRON shall repay ROCHE the
amounts of such disputed payments if ROCHE prevails in the ADR, plus interest
at the rate described in Section 4.8.
                                                                             4

<PAGE>

                                 EXHIBIT B - HCV
                                   PAGE 1 OF 3

                                CHIRON HCV PATENTS

                               FOUNDATIONAL PATENTS

[CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

                                 EXHIBIT B - HCV
                                   PAGE 2 OF 3

                             NON-FOUNDATIONAL PATENTS

[CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

                                 EXHIBIT B - HCV
                                   PAGE 3 OF 3

[CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

                                 EXHIBIT C - HCV
                                   PAGE 1 OF 1

                                ROCHE HCV PATENTS

[CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

<TABLE>
<CAPTION>

                                   Exhibit D

PRODUCT CODES, HCV KITS:                                      MAX

                                                            LABELED
DESCRIPTION                           SAP/ PART NO.         CAPACITY        UNITS      CONTROLS
-----------------------------------------------------------------------------------------------
<S>                                                                         <C>

</TABLE>

[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED]

[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED]

CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN
CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED    [CONFIDEN

[CONFIDENTIAL TREATMENT REQUESTED]

[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN

[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN

[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN

<PAGE>

<TABLE>
<CAPTION>

                                   Exhibit D-1

PRODUCT CODES, HCV KITS*:                                    MAX

                                                            LABELED
DESCRIPTION                           SAP/ PART NO.         CAPACITY        UNITS      CONTROLS
-----------------------------------------------------------------------------------------------
<S>                                                                         <C>

CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

*CONFIDENTIAL TREATMENT REQUESTED
</TABLE>

<PAGE>

                                 [EXHIBIT E - PAGE 1]

                               HCV PROBES ROYALTY REPORT
                           REGION_: ______________________
                          FOR THE QUARTER ENDING____________

<TABLE>
<CAPTION>

                                                                                               Adjusted for Pre-Paid Royalty
                                                                                               -----------------------------
                  Number                                  Maximum  Minimum         Pre-Paid               Minimum          Pre-Paid
               of Product  Units per          Minimum     Labeled  Royalty Minimum  Minimum     Minimum   Royalty  Minimum  Minimum
Product            Sold     Product   Units  Amount/Test  Capacity  Amount Royalty Amount/Test Amount/Test Amount  Royalty  Royalty
-------            ----     -------   -----  -----------  --------  ------ ------- ----------- ----------- ------  -------  -------
<S>               <C>      <C>       <C>    <C>          <C>        <C>    <C>    <C>         <C>         <C>     <C>      <C>

HCV Quantitative
  [SKU#1]
  [SKU#2]
  [SKU#3]
  [SKU#4]

HCV Qualitative
  [SKU#1]
  [SKU#2]
  [SKU#3]
  [SKU#4]
                                     [CONFIDENTIAL TREATMENT REQUESTED]
HCV Genotyping
  [SKU#1]
  [SKU#2]
  [SKU#3]
  [SKU#4]

HCV Resistance
  [SKU#1]
  [SKU#2]
  [SKU#3]
  [SKU#4]

Total
                                                                                                                         -------
                                                                                                                              $0
                                                                                                                         =======

</TABLE>

Example                              [CONFIDENTIAL TREATMENT REQUESTED]

[CONFIDENTIAL TREATMENT REQUESTED]

*FOR PURPOSES OF CALCULATING NUMBER OF UNITS, TO AVOID DOUBLE COUNTING FOR
AMPLIFICATION AND DETECTION UNITS, THE NUMBER OF UNITS IN THE DETECTION KIT
WILL BE USED.

<PAGE>

                                    [EXHIBIT E - PAGE 2]

                                 HCV PROBES ROYALTY REPORT
                               REGION_: __________________
                          FOR THE QUARTER ENDING _________

<TABLE>
<CAPTION>                                                  Earned
                                                           Royalty    Earned        Royalty
Product            Sales      Deductions     Net Sales      Rate      Royalty     Payment Date
-------            -----      ----------     ---------     -------    -------     ------------

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

HCV Quantitative
  [SKU #1]
  [SKU #2]
  [SKU #3]
  [SKU #4]

HCV Qualitative
  [SKU #1]
  [SKU #2]
  [SKU #3]
  [SKU #4]
                              [CONFIDENTIAL TREATMENT REQUESTED]
HCV Genotyping
  [SKU #1]
  [SKU #2]
  [SKU #3]
  [SKU #4]

HCV Resistance
  [SKU #1]
  [SKU #2]
  [SKU #3]
  [SKU #4]
                                                                                  ------------
Total                                                                                       $0
                                                                                  ============

</TABLE>

Example             [CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

                                  HCV EXHIBIT F

   EXISTING LICENSES OR RIGHTS GRANTED IN THE FIELD UNDER THE LICENSED PATENTS
                            AS OF THE EFFECTIVE DATE

1.       [CONFIDENTIAL TREATMENT REQUESTED]

2.       [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

3.       [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

4.       [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

5.       [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

6.       [CONFIDENTIAL TREATMENT REQUESTED]

         [CONFIDENTIAL TREATMENT REQUESTED]

  [CONFIDENTIAL TREATMENT REQUESTED]<PAGE>

                                                                REDACTED
                                                                Exhibit 10.308

                      **CONFIDENTIAL TREATMENT REQUESTED**

                           HIV PROBE LICENSE AGREEMENT

                                     BETWEEN

                               CHIRON CORPORATION

                           F. HOFFMANN-LA ROCHE LTD.

                                       AND

                          ROCHE MOLECULAR SYSTEMS, INC.

<PAGE>

                           HIV PROBE LICENSE AGREEMENT

                                TABLE OF CONTENTS

                                                                          PAGE

RECITALS                                                                     3

ARTICLE 1: DEFINITIONS                                                       3

ARTICLE 2: LICENSE GRANTS                                                   13

ARTICLE 3: PAYMENTS, ROYALTIES                                              15

ARTICLE 4: RECORDS AND REPORTS                                              15

ARTICLE 5: OTHER ACTIONS                                                    18

ARTICLE 6: REPRESENTATIONS AND WARRANTIES                                   19

ARTICLE 7: TERM AND TERMINATION                                             22

ARTICLE 8: CONFIDENTIALITY                                                  24

ARTICLE 9: INDEMNITY                                                        25

ARTICLE 10: ALTERNATIVE DISPUTE RESOLUTION                                  27

ARTICLE 11: MISCELLANEOUS                                                   27

ARTICLE 12: FIELD RESTRICTIONS AND OTHER COVENANTS                          30

ARTICLE 13: INFRINGEMENT BY THIRD PARTIES                                   32

ARTICLE 14: EUROPEAN COMMUNITY PROVISIONS                                   34

EXHIBIT A: COMPENSATION TO CHIRON

EXHIBIT B: CHIRON PATENT LIST

EXHIBIT C: [CONFIDENTIAL TREATMENT REQUESTED] PATENT LIST

EXHIBIT D: CHIRON LICENSED PRODUCTS & UNIT SIZES

EXHIBIT E: FORM OF REPORT

EXHIBIT F: EXISTING LICENSES

                                                                               2
<PAGE>

                     HIV PROBE LICENSE AND OPTION AGREEMENT

This agreement (hereinafter "Agreement") is made by and between CHIRON
CORPORATION, a Delaware corporation, of 4560 Horton Street, Emeryville,
California 94608 (hereinafter referred to as "CHIRON"), F. HOFFMANN-LA ROCHE
LTD., a Swiss corporation, of Grenzacherstrasse 124, Basel, Switzerland
(hereinafter referred to as "ROCHE PARENT"), and ROCHE MOLECULAR SYSTEMS, INC.,
a Delaware corporation, of 1145 Atlantic Avenue, Suite 100, Alameda, California
94501 (hereinafter referred to as "RMS" and collectively with ROCHE PARENT,
"ROCHE").

                                   BACKGROUND

WHEREAS, CHIRON and ROCHE currently own or control certain patent rights
relating to the human immunodeficiency virus ("HIV"), as defined below.

WHEREAS, CHIRON and ROCHE have as of the date hereof entered into that certain
Settlement Agreement (the "Settlement Agreement") pertaining to the settlement
of the certain litigation matters described therein.

WHEREAS, in consideration of and subject to the execution and delivery of the
Settlement Agreement, CHIRON is willing to grant licenses to ROCHE under certain
patent rights relating to HIV for use in assays for the detection of nucleic
acid sequences for use in IN VITRO diagnostics (excusing use in Blood Screening,
as defined below, but without limiting the effect of the Blood Screening
Agreement, as defined below), all on the terms and conditions set forth herein.

WHEREAS, in consideration of and subject to the execution and delivery of the
Settlement Agreement, ROCHE is willing to grant to CHIRON an option to license
certain patent rights relating to HIV for use in assays for the detection of
nucleic acid sequences for use in Blood Screening and the Transplantation Field
(as defined below), all on the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the above provisions and the mutual
covenants contained herein, CHIRON and ROCHE hereby agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

In this Agreement the following words and phrases shall have the following
meanings:

1.1 "ADR" means Alternative Dispute Resolution in accordance with Article 10.

                                                                               3
<PAGE>

     1.2 "Affiliate" means an entity that directly, or indirectly through one or
more intermediaries, controls or is controlled by or is under common control
with, a specified entity. For the purposes of this definition, "control"
(including with correlative meanings, the terms "controlling", "controlled by"
and "under common control with"), as applied to any entity, means: (a) the
possession, directly or indirectly, of the power to direct or cause the
direction of the management and policies of that entity, whether through the
ownership of voting securities or by contract or otherwise; or (b) the ownership
of at least fifty percent (50%) of the voting securities of that entity.
Notwithstanding anything to the contrary contained herein, "Affiliate" shall not
include, in the case of CHIRON, Novartis AG or any Affiliate of Novartis AG,
unless Novartis shall have acquired direct control of a majority of the Board of
Directors of CHIRON. Notwithstanding anything to the contrary contained herein,
"Affiliate" shall not include, in the case of ROCHE, Genentech Inc. or any
Affiliate of Genentech Inc., nor Laboratory Corporation of America Holdings or
any Affiliate of Laboratory Corporation of America Holdings.

     1.3 "Authorized Distributor" means a BONA FIDE, unaffiliated distributor,
but excluding any entity which is a Major IVD Manufacturer (as defined below)
that is not licensed in the Field (as defined below) under one or more of the
CHIRON Licensed Patents (as defined below) or is affiliated with, or directly or
indirectly controlled by, such a Major IVD Manufacturer, except to the extent
that such unlicensed Major IVD Manufacturer or its Affiliates distributes CHIRON
Licensed Product for ROCHE or its Affiliates on a local country basis and in the
same manner in which it distributes other diagnostic products for ROCHE or its
Affiliates and ROCHE and its Affiliates are not otherwise selling CHIRON
Licensed Products in such country.

     1.4 "Average Unit Price" or "AUP" means with respect to CHIRON Licensed
Products sold by ROCHE or its Affiliates from and including the first day of the
Calendar Quarter commencing immediately prior to the Effective Date, with
respect to a Calendar Quarter (as defined below), Net Sales of such future
CHIRON Licensed Product by ROCHE or its Affiliates calculated on a per Unit
basis, in a country or Region, on a product-by-product basis, using customary
and reasonable methodologies for determining average unit pricing generally
consistent with the definition herein of Net Sales, during the preceding two (2)
Calendar Quarters.

     1.5 "Bayer Cross License" means the Cross-License Agreement by and between
Chiron Diagnostics Corporation and CHIRON dated November 30, 1998, as amended
from time to time.

     1.6 "Blood Screening" means the commercial use of products that detect
nucleic acid sequences(s) for: (a) the screening of blood, plasma or blood
components intended for transfusion or for use in blood products (e.g., without

                                                                               4
<PAGE>

limitation, immunoglobulins); or (b) confirmatory or supplemental testing of the
same samples otherwise screened for purposes described in Section 1.6(a).

     1.7 "Blood Screening Agreement" means the Blood Screening HCV/HIV Probe
License Agreement by and between CHIRON and ROCHE dated as of the Effective
Date, as amended from time to time.

     1.8 "Calendar Quarter" means the three (3) month period beginning January
1, April 1, July 1 or October 1. For Net Sales outside the United States, the
Calendar Quarter and Calendar Year (as defined below) shall be consistent with
ROCHE financial reporting practices.

     1.9 "Calendar Year" means January 1 through December 31.

     1.10 "CHIRON Future HIV Sequence Patent Rights" means any and all Valid
Claims Directed to HIV of United States and foreign patents and patent
applications: (a) which are based upon inventions conceived or rights acquired
[CONFIDENTIAL TREATMENT REQUESTED] (as defined below); (b) which claim HIV
nucleic acid sequence(s) or a method to use (other than in the manufacture of
peptides) or detect such sequences specifically; (c) which are owned by,
licensed to or otherwise controlled by CHIRON or its Affiliates, with rights to
license or sublicense; and (d) with respect to which CHIRON has the right to
grant the option provided for in Section 2.5 of this Agreement. For purposes of
this Agreement, an invention will be deemed to have been conceived if there is a
patent, patent application, written invention disclosure statement or other
tangible document (whether or not witnessed) describing such invention.

     1.11 "CHIRON Licensed Patents" means Valid Claims Directed to HIV which
cover the manufacture, use, sale, offer for sale or importation of a Product
that are contained within any of the following: (a) the patents and applications
identified in Exhibit B and any continuation, continuation-in-part and
divisional applications therefrom; (b) any reissued or reexamined patents
obtained from such patents and applications; (c) all foreign counterparts of
such patents and applications; and (d) all future patents and applications which
are based on inventions conceived by CHIRON or its Affiliates on or before the
Effective Date.

     1.12 "CHIRON Licensed Products" means Products which are used by or sold to
an End User under circumstances and in jurisdictions, such that in the absence
of the licenses granted under Sections 2.1 and 2.3, such use or sale would
constitute an infringement of a Valid Claim of the CHIRON Licensed Patents,
including without limitation the Products identified in Exhibit D, as modified
from time to time by mutual agreement of the parties or as determined in
accordance with Section 5.2.

     1.13 "Directed to HIV" means that the claim or technology in question is
directed to methods, compositions, reagents or kits specifically for use in
nucleic

                                                                               5
<PAGE>

acid-based diagnostic assays for the detection of HIV nucleic acid
sequence(s), or specifically for use in the manufacture of any compositions or
reagents for use in, or manufacture of nucleic acid-based diagnostic assays for
detection of HIV nucleic acid sequence(s) (excluding, for example, PCR claims
and technology and other methods for detection of nucleic acid sequence(s)
generally which involve nucleic acid amplification). The terminology
"specifically for use" as used in this Section 1.13, is intended to exclude
inventions suitable for use with viruses or analytes other than HIV (including
by way of example and not by way of limitation, inventions relating to PCR, or
assay formats, improved expression systems, detectable labels, instrumentation,
packaging and the like), which shall not be considered "specifically for use" in
HIV detection as contemplated by this Section 1.13 and shall therefore not be
considered as "Directed to HIV" hereunder.

     1.14 "Earned Royalty" shall have the meaning specified in Paragraph 2 of
Exhibit A.

     1.15 "Effective Date" means the date of full execution of this Agreement.

     1.16 "Eligible Third Party License" means a license agreement in the Field
entered into by CHIRON or Bayer or their respective Affiliates with a Licensed
Third Party (as defined below) after the Effective Date and includes any
material amendment made after the Effective Date to a license existing on the
Effective Date, other than the Bayer Cross License, which: (a) grants such
Licensed Third Party the license under one or more of the CHIRON Licensed
Patents to make, have made, use, import, offer for sale or sell Product which
ROCHE is licensed to make, have made, use, import, offer for sale or sell under
this Agreement; and (b) imposes payment obligations which would have the effect
of providing more favorable license payment terms to such Licensed Third Party
than the terms to ROCHE under this Agreement.

     1.17 "End User" means a person or entity who is a final purchaser of a
Product, and whose use of a Product results in the Product's consumption,
operation, destruction or loss of activity.

     1.18 [CONFIDENTIAL TREATMENT REQUESTED].

     1.19 "Field" means the commercial use of human IN VITRO diagnostic products
that detect nucleic acid sequences of HIV. Expressly excluded from the Field
are: (a) products in Blood Screening; and (b) products specifically labeled or
promoted for use in the Transplantation Field (as defined below).

     1.20 "Foundational Patents" means the CHIRON Licensed Patents identified in
Exhibit B which are stated therein to be Foundational Patents.

                                                                               6
<PAGE>

     1.21 "HIV" means any viral isolate of the human immunodeficiency virus
classified as HIV by the International Committee on the Taxonomy of Viruses (or
any body that replaces such Committee) or any subtype of such isolate and
further includes any isolate that is at least forty percent (40%) homologous to
any such isolate and of the same genomic type and substantially the same genomic
organization, any isolate that has a genome that either hybridizes to or is
substantially identical to any such isolate or its compliment, and any defective
or modified form of any of the above isolates.

     1.22 "HIV Qualitative Assay" means a Product which: (a) is an assay; (b)
detects or measures the presence of HIV in an analyzed sample; (c) does not
determine the quantity of HIV in the analyzed sample; and (d) is not by itself,
through a single use, capable of being used as an HIV Genotyping Assay or an HIV
Resistance Assay (as each is defined herein).

     1.23 "HIV Quantitative Assay," means a Product which: (a) is an assay; (b)
measures the presence of HIV in an analyzed sample; (c) does determine the
quantity of HIV in the analyzed sample; and (d) is not by itself, through a
single use, capable of being used as an HIV Genotyping Assay or an HIV
Resistance Assay.

     1.24 "HIV Genotyping Assay" means a Product which is an assay or method
(e.g., sequencing) that is labeled or promoted as being useful through a single
use to determine and differentiate individual genotypes of an HIV virus that are
present in an analyzed.

     1.25 "HIV Resistance Assay" means a Product which is an assay or method
(e.g., sequencing) that is labeled or promoted as being useful to detect through
a single use the specific drug resistance mutation(s) present in the HIV virus
in an analyzed sample.

     1.26 "HIV Taqman Qualitative/Quantitative Assay" means a Product which: (a)
is an assay; (b) detects and measures the presence of HIV in an analyzed sample
by utilization of ROCHE's proprietary 5' nuclease detection method; (c) does
determine the quantity of HIV in an analyzed same; and (d) is not by itself,
through a single use capable of being used as only an HIV Qualitative Assay, HIV
Classification Assay, HIV Genotyping Assay or HIV Resistance Assay.

     1.27 "Infringing Third Party Sales" means sales by a major IVD Manufacturer
of Products: (a) which infringe one or more of the CHIRON Licensed Patents; or
(b) as to which a license under one or more of the CHIRON Licensed Patents has
been granted, but as to which the licensee is not paying royalties thereunder.

                                                                               7
<PAGE>

     1.28 "Licensed Patents" means the CHIRON Licensed Patents and the ROCHE
Optioned Patents.

     1.29 "Licensed Third Party" means an unaffiliated third party to whom
CHIRON or Bayer or their respective Affiliates grants a license or a covenant
not to sue after the Effective Date, under which license or covenant not to sue
such third party is allowed to make, have made, use, import, offer for sale or
sell any Product, directly or indirectly, under one or more of the CHIRON
Licensed Patents. Expressly excluded from Licensed Third Party are: (a) any
Affiliate of CHIRON; (b) Bayer or any of its Affiliates (to the extent operating
under the Bayer Cross License); or (c) any entity which receives a judicially,
or other governmental agency, imposed license or freedom from suit under any one
or more of the CHIRON Licensed Patents and does not otherwise have a Voluntary
License (as defined below).

     1.30 "Major IVD Manufacturer" means a commercial entity (and its
Affiliates) that manufactures, sells and engages in other commercial activities
with respect to IN VITRO diagnostic products, and has a significant marketing
presence in one or more Regions. Major IVD Manufacturers include Abbott, Bayer,
Johnson & Johnson, Pasteur, Sanofi, Dade Behring, Organon Teknika, Becton
Dickinson, bioMerieux, BioRad, Fujirebio, Beckman Coulter, Visible Genetics,
Innogenetics and PE Corporation and each of their successors and assigns and any
other entity which commands in the future at least an equivalent presence as
measured by total product sales as do any of the foregoing entities as of the
Effective Date in such Region.

     1.31 "Minimum Royalty" and "Minimum Royalty Amount" shall have the meanings
specified in Paragraph 4 of Exhibit A.

     1.32 "Net Sales" means the amount billed or invoiced for CHIRON Licensed
Products sold by ROCHE or its Affiliates, less:

     (a)   Discounts actually allowed and taken;

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

     (c)   To the extent separately stated on purchase orders, invoices or
           other documents of sale, taxes levied on and/or other governmental
           charges made as to production, transportation or insurance charges;

     (d)   The reasonable value of the instrument, instrument financing,
           consumables other than the CHIRON Licensed Products in question
           (including without limitation sample preparation) and service
           components of an operating or capital lease for instrumentation on
           which the CHIRON Licensed Products are used (collectively,
           "Associated Goods and Equipment"), for which the charges are
           included in the price of the

                                                                               8
<PAGE>

         CHIRON Licensed Products purchased, provided that the methods
         for determining such value shall be proposed by ROCHE and subject to
         CHIRON's written consent, not to be unreasonably withheld;

     (e) Charges for freight, handling and transportation paid by the selling
         entity; and

     (f) Sales, use and value-added taxes and other similar taxes incurred and
         separately stated on invoices.

         (1) Net Sales shall include all sales to non-Affiliate third parties,
including sales to Authorized Distributors in countries where, due to regulatory
constraints and/or market practice, substantially all sales of the relevant
CHIRON Licensed Product are made through distributors, provided that ROCHE shall
use reasonable efforts in connection with sales to such Authorized Distributors
to comply with clause (A) immediately below. With respect to sales to all other
Authorized Distributors, if Net Sales are based on the transfer price to the
Authorized Distributor rather than End User sales, either: (A) Net Sales on
which royalties shall be calculated shall be deemed to be not less than the
higher of the average selling price for the applicable Product in the United
States or the European Union; or (B) the parties shall adopt another mechanism
for preserving for CHIRON the same economics as if such sales had been made to
the End User by ROCHE or its Affiliate rather than the Authorized Distributor.
Any such mechanism shall be proposed by ROCHE and shall be subject to CHIRON's
prior written consent, which shall not be unreasonably withheld. CHIRON shall
not withhold its consent to a proposal by ROCHE to calculate Net Sales at
[CONFIDENTIAL TREATMENT REQUESTED] of the transfer price to an Authorized
Distributor or such lesser percentage as reflects reasonably the distributor
mark-ups prevailing generally in the relevant country.

         (2) For clarity of understanding, Net Sales shall not include any
CHIRON Licensed Product furnished to third parties for which no payment is
received, such as, experimental, test market, promotional or other free goods.
On the other hand, Net Sales shall include any CHIRON Licensed Product furnished
in return for payment, whether or not such CHIRON Licensed Product is for
commercial, research or other use. For clarity of understanding, Minimum
Royalties shall apply to each Unit of CHIRON Licensed Product Shipped to a
customer for any purpose, except for Units Shipped to third parties at no charge
for: (A) use in ROCHE's preclinical or clinical trials in the Field or the
Transplantation Field; (B) testing, quality control or evaluation purposes; or
(C) replacement of rejected or defective goods. Without limiting the foregoing,
CHIRON Licensed Products furnished to third parties at price discounts,
including, without limitation, free goods furnished as part of sales promotions,
shall be subject to Minimum Royalties.

                                                                               9
<PAGE>

         (3) A sale shall be deemed to have been made and Earned Royalties or
Minimum Royalties incurred (except as specifically set forth in Section 1.32(2)
and this Section 1.32(3)) when the CHIRON Licensed Product is consumed, invoiced
or shipped by ROCHE or its Affiliates to a non-Affiliate third party
("Shipped"); provided that where an invoice is issued, the obligations to pay
Earned Royalties and Minimum Royalties hereunder shall arise on the invoice
date. Sales to or between Affiliates shall not be included in Net Sales or
Minimum Royalties until ROCHE or its Affiliate consumes the CHIRON Licensed
Product in providing a commercial service for a non-Affiliate third party or
Ships the CHIRON Licensed Product to a non-Affiliate third party.

         (4) In the event that a CHIRON Licensed Product subject to royalties
hereunder is sold in combination with another Product or assay, other than the
Associated Goods and Equipment covered by Clause (d) above, for a single price
(a "Combination Product"), Net Sales from sales of a Combination Product, for
purposes of calculating royalties due under this Agreement, shall be calculated
by multiplying the Net Sales of that Combination Product by the fraction
A/(A+B), where A is the AUP in the country of sale, during the applicable
reporting period, of the CHIRON Licensed Product subject to royalties hereunder
if sold separately in the country of sale, and B is the AUP in the country of
sale, during the applicable reporting period, of the other Product(s) or assays
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 apportionment of the gross amount
invoiced therefor based upon the relative contribution of the CHIRON Licensed
Product subject to royalties hereunder to the price of the Combination Product.
Such apportionment for Combination Products currently or previously sold shall
be a reasonable apportionment of the gross amount invoiced therefor based upon
the relative contribution of the CHIRON Licensed Product subject to royalties
hereunder to the price of the Combination Product. Such apportionment shall be
determined by ROCHE based upon its past practice and experience subject to
CHIRON's written consent, not to be unreasonably withheld. The apportionment of
future Combination Products will be handled in this same fashion prior to the
first Unit Shipped or consumed by ROCHE or an Affiliate in providing a
commercial service, or resolved in accordance with Section 5.2. Notwithstanding
the above, if a CHIRON Licensed Product is an assay that is capable in a single
use of being used in more than one fashion (e.g., as both an HIV Quantitative
Assay and as an HIV Qualitative Assay), such CHIRON Licensed Product is not a
Combination Product solely for that reason, but shall be treated for purposes of
calculating Minimum Royalties in the same fashion as the HCV Taqman
Qualitative/Quantitative Assay, as set forth in Exhibit A.

         (5) In the event a sale of a CHIRON Licensed Product is conditioned
upon the payment of an initial licensing fee, access fee or other required fee
the payment of which is a prerequisite to the Shipment, consumption or use of a
CHIRON Licensed Product, Net Sales, for the purpose of determining royalty
payments on such CHIRON Licensed Product, shall include a reasonable

                                                                              10
<PAGE>

apportionment of the amount invoiced for such fee, based upon the relative value
of the intellectual property contained within the CHIRON Licensed Product
subject to royalties hereunder to the intellectual property contained within the
other product or service components Shipped, licensed, consumed or used. Such
apportionment shall be determined by ROCHE based upon its past practice and
experience subject to CHIRON's written consent, not to be unreasonably withheld,
and Net Sales shall not include any portion of a licensing fee, access fee or
other required fee reasonably allocated with specificity to the access, license
or use of the ROCHE PCR patents.

                  (6) In the event that ROCHE or its Affiliates perform assays
for commercial purposes utilizing CHIRON Licensed Products, Net Sales means the
invoiced amount for the patient result provided as a result of performance of
such assays, less a reasonable deduction for the value of the services and or
other products provided therewith, less the applicable deductions pursuant to
this Section 1.32. The allocation of value to services or other products
provided shall be determined by ROCHE based upon its past practice and
experience, and shall be subject to CHIRON's prior written consent, which shall
not be unreasonably withheld.

     1.33 "PCR" means polymerase chain reaction technology.

     1.34 "Product(s)" means reagents, compositions or kits suitable for use in
the Field or the Transplantation Field.

     1.35 "Product Category" has the meaning set forth in Paragraph 4 of Exhibit
A.

     1.36 "Region" shall mean one of the four (4) following regions:

     Region I:    North America (United States and possessions, Puerto Rico,
                  Canada and Mexico);
     Region II:   European Union;
     Region III:  Japan; or
     Region IV:   All other countries of the world.

     1.37 "ROCHE Future HIV Sequence Patent Rights" means any and all Valid
Claims Directed to HIV of United States and foreign patents and patent
applications: (a) which are based upon inventions conceived or rights acquired
[CONFIDENTIAL TREATMENT REQUESTED]; (b) which claim HIV nucleic acid sequence(s)
or a method to use (other than in the manufacture of peptides) or detect such
sequences specifically; (c) which are owned by, licensed to or otherwise
controlled by ROCHE or its Affiliate, with rights to license or sublicense; and
(d) with respect to which ROCHE has the right to grant the option provided for
in Section 2.6 of this Agreement. For purposes of this Agreement, an invention
will be deemed to have been conceived if there is a

                                                                              11
<PAGE>

patent, patent application, written invention disclosure statement or other
tangible document (whether or not witnessed) describing such invention.

     1.38 "ROCHE Optioned Patents" means: (a) the patents and applications
identified in Exhibit C and any continuation, continuation-in-part and
divisional applications therefrom; (b) any reissued or reexamined patents
obtained from such patents and applications; (c) all foreign counterparts of
such patents and applications; and (d) all future patents and applications which
are based on inventions conceived by ROCHE or its Affiliates on or before the
Effective Date, to the extent the items described in clauses (a) through (d) of
this Section 1.38 contain a Valid Claim Directed to HIV which covers the
manufacture, use, sale, offer for sale or importation of a Product.

     1.39 "ROCHE Optioned Products" means Products which are manufactured, used,
offered for sale, imported or sold under circumstances which would, in the
absence of the licenses for which an option is granted under Section 2.6,
constitute an infringement of a Valid Claim of the ROCHE Optioned Patents.

     1.40 "Shipped" has the meaning set forth in Section 1.32(3).

     1.41 "Transplantation Field" means the commercial use of products that
detect nucleic acid sequences for the screening of any biological materials
intended for transfusion or transplantation, in each case from any donor,
including autologous donors, other than the transfusion or transplantation of
blood or its derivatives, components or replacements.

     1.42 "Unit" means, for each CHIRON Licensed Product, the number of
individual patient results generated by the use of a CHIRON Licensed Product.
The number of patient results that each CHIRON Licensed Product currently or
previously sold generates shall be mutually determined by the parties through
good faith negotiation and resolved if necessary through the ADR process in
accordance with Article 10 of this Agreement. Following such determination, the
number of Units contained in each CHIRON Licensed Product will be set forth on a
schedule to be attached as Exhibit E to this Agreement. The determination of the
number of "Units" in future CHIRON Licensed Products developed by ROCHE shall be
handled in accordance with Section 5.2, and Exhibit D shall be modified
accordingly. If future CHIRON Licensed Products are developed by ROCHE or its
Affiliates that do not contain reagents or other single-use consumable
materials, a method for calculating the number of "Units" in such CHIRON
Licensed Product shall be determined in accordance with Section 5.2.

     1.43 "Valid Claim" means a claim in any issued, active, unexpired patent
which has not been withdrawn, cancelled, lapsed or disclaimed, or held
unpatentable, invalid or permanently unenforceable by a non-appealed or
nonappealable final decision by a court or other appropriate body of competent
jurisdiction. The scope of a Valid Claim shall be limited to its terms as
defined by any such court or decision-making body of competent

                                                                              12
<PAGE>

jurisdiction in a non-appealable or non-appealed final decision.

     1.44 "Voluntary License" means a license or covenant not to sue granted by
contract under any one or more of the CHIRON Licensed Patents to make, use,
offer for sale, import or sell Products in the Field or the Transplantation
Field, except to the extent granted by compulsion of law, such as a compulsory
license, whether by court order or action of other governmental authority.

                                    ARTICLE 2
                                 LICENSE GRANTS

     2.1 CHIRON GRANTS. Subject to the terms and conditions of this Agreement,
CHIRON hereby grants to ROCHE and its Affiliates, so long as they remain
Affiliates of ROCHE, a worldwide, semi-exclusive license, without the right to
sublicense, under the CHIRON Licensed Patents to research, develop, make, have
made, import, use, offer for sale and sell CHIRON Licensed Products for use in
the Field. CHIRON covenants not to sue any End User of a CHIRON Licensed Product
(with respect to which ROCHE has performed all of its material obligations under
this Agreement) to the extent of activities in the Field or otherwise permitted
under this Agreement. Conversely, no immunity from suit shall apply to End User
activities in Blood Screening, except as provided in the Blood Screening
Agreement, or otherwise outside of the Field. CHIRON retains the right to
conduct research in any field, including to develop Products and, subject to
Section 2.3 and the Blood Screening Agreement, retains all rights outside of the
Field, including the nonexclusive right to practice and to grant licenses under
the CHIRON Licensed Patents to make, have made, use, import, offer for sale and
sell any products in the Transplantation Field.

     2.2 EXCLUSION FROM CHIRON LICENSE. ROCHE acknowledges that neither ROCHE
nor its Affiliates are licensed under this Agreement to perform research or to
develop any product other than a CHIRON Licensed Product.

     2.3 CHIRON TRANSPLANTATION FIELD LICENSE. Subject to the terms and
conditions of this Agreement, CHIRON hereby grants to ROCHE and its Affiliates,
so long as they remain Affiliates of ROCHE, a worldwide, non-exclusive license,
without the right to sublicense, under CHIRON Licensed Patents to research,
develop, make, have made, import, use, offer for sale and sell CHIRON Licensed
Products for use in the Transplantation Field. CHIRON covenants not to sue any
End User of such CHIRON Licensed Products (with respect to which ROCHE has
performed all of its material obligations under this Agreement) to the extent of
activities in the Transplantation Field or as otherwise permitted under this
Agreement. Conversely, no immunity from suit under this Section 2.3 shall apply
to End User activities in Blood Screening, except as

                                                                              13
<PAGE>

provided in the Blood Screening Agreement, or otherwise outside of the
Transplantation Field.

     2.4 SEMI-EXCLUSIVE CHIRON LICENSE. The license granted under Section 2.1
shall be semi-exclusive to ROCHE and its Affiliates. Semi-exclusive means that,
in addition to licenses to third parties under existing agreements referenced in
Exhibit G including, without limitation, the [CONFIDENTIAL TREATMENT REQUESTED],
and licenses that may be granted by such licensees, including licenses that may
be granted by [CONFIDENTIAL TREATMENT REQUESTED], CHIRON retains only the right
to practice in the field under the CHIRON Licensed Patents and/or to grant
additional licenses under one or more of the CHIRON Licensed Patents in the
Field as follows:

     (a) CHIRON may grant up to [CONFIDENTIAL TREATMENT REQUESTED] in the Field,
     if CHIRON is not engaged in the sale of Products;

     (b) If CHIRON has not granted [CONFIDENTIAL TREATMENT REQUESTED] under
     Section 2.4(a) and CHIRON is not then engaged in the sale of Products,
     CHIRON shall have the right, in its sole discretion, in lieu of such
     worldwide license, to grant [CONFIDENTIAL TREATMENT REQUESTED] under the
     Licensed Patents in the Field in each Region;

     (c) If CHIRON chooses to engage in the sale of Products, such activities
     shall replace [CONFIDENTIAL TREATMENT REQUESTED] CHIRON is permitted to
     grant under Section 2.4(a) if CHIRON's sales are worldwide; or, if
     CHIRON's sales are regional, such activities shall replace [CONFIDENTIAL
     TREATMENT REQUESTED] CHIRON is permitted to grant under Section 2.4(b) in
     each Region in which CHIRON sells such Products;

     (d) Licenses granted under Section 2.4(a) or 2.4(b) shall not include the
     right to grant sublicenses, except to Affiliates for so long as they remain
     Affiliates of the licensee;

     (e) In the event that a license referenced in Exhibit F is terminated,
     including without limitation the [CONFIDENTIAL TREATMENT REQUESTED], CHIRON
     shall have the right to replace such license with a new license, consistent
     with the limitations required hereby and the scope, field and territory of
     the license that is replaced. Notwithstanding anything herein to the
     contrary, the [CONFIDENTIAL TREATMENT REQUESTED] under the [CONFIDENTIAL
     TREATMENT REQUESTED], if terminated, could be replaced by a new license to
     a new licensee and containing terms determined by CHIRON in its discretion
     without any restrictions imposed by this Agreement; provided, however,
     that if [CONFIDENTIAL TREATMENT REQUESTED] CHIRON enters into a

                                                                              14
<PAGE>

     license to replace the [CONFIDENTIAL TREATMENT REQUESTED] with a third
     party that is not [CONFIDENTIAL TREATMENT REQUESTED], or an Affiliate,
     successor, assignee or licensee of [CONFIDENTIAL TREATMENT REQUESTED],
     ROCHE shall have the rights provided by Paragraph 6 of Exhibit A with
     respect thereto;

     (f) Following the last to expire of the Foundational Patents, the license
     hereunder shall be nonexclusive; and

     (g) Notwithstanding this Section 2.4, CHIRON retains the nonexclusive right
     under the CHIRON Licensed Patents to conduct research in any field,
     including to develop Products and, subject to the Blood Screening
     Agreement, all rights outside of the Field and in the Transplantation
     Field, including the nonexclusive right to practice and to grant licenses
     under the CHIRON Licensed Patents to make, have made, use, import, offer
     for sale and sell any products in the Transplantation Field.

     2.5 CHIRON FUTURE HIV SEQUENCE PATENT RIGHTS. CHIRON grants to ROCHE a
non-exclusive option to obtain one or more non-exclusive, worldwide licenses, or
sublicenses, as the case may be, with a right to sublicense to ROCHE Affiliates
only, under the CHIRON Future HIV Sequence Patent Rights, to make, have made,
use, import, offer for sale and sell CHIRON Licensed Products and/or products in
the Field and/or the Transplantation Field. [CONFIDENTIAL TREATMENT REQUESTED].

     2.6 ROCHE OPTIONED PATENTS AND ROCHE FUTURE HIV SEQUENCE PATENT RIGHTS.
ROCHE grants to CHIRON a non-exclusive option to obtain one or more
non-exclusive, worldwide licenses, or sublicenses, as the case may be, with a
right to sublicense solely to CHIRON Affiliates only, under the ROCHE Optioned
Patents and ROCHE Future HIV Sequence Patent Rights, to make, have made, use,
import, offer for sale and sell ROCHE Optioned Products and/or products in Blood
Screening and/or the Transplantation Field. [CONFIDENTIAL TREATMENT REQUESTED].

                                    ARTICLE 3
                               PAYMENTS, ROYALTIES

     With respect both to CHIRON Licensed Products sold or Shipped, ROCHE shall
make payments to CHIRON as set forth in Exhibit A.

                                    ARTICLE 4
                               RECORDS AND REPORTS

     4.1 NET SALES REPORT. ROCHE shall, within sixty (60) days after the last
day of each Calendar Quarter commencing after [CONFIDENTIAL TREATMENT
REQUESTED], deliver to CHIRON a true and accurate report for

                                                                              15
<PAGE>

the prior Calendar Quarter, substantially in the form attached as Exhibit E
to this Agreement, which shall state the amount of monies due hereunder, if any,
as Earned Royalties and Minimum Royalties, and shall include all information
reasonably necessary to calculate such amount, including, but not limited to,
the following information, presented by country and Region and by product and
Product Category (as defined in Paragraph 4 of Exhibit A):

     (a) the amount of Net Sales, expressed in United States Dollars (with
     applicable exchange rates to the extent specifically requested in writing
     by CHIRON), and the applicable Earned Royalty rate or rates, and all
     credits and adjustments thereto;

     (b) the number of Units Shipped and the applicable Minimum Royalty
     Amounts, and adjustments to Units Shipped (returns, replacements,
     etc.); and

     (c) a statement of the basis for any deviation from the Earned Royalty
     rates and Minimum Royalty Amounts as expressed in Paragraphs 3 and 4 of
     Exhibit A.

     4.2 PAYMENT DATES. Not later than the date each report required under
Section 4.1 is due, ROCHE shall pay to CHIRON the royalty due under this
Agreement for the period covered by such report. If no royalties are due, ROCHE
shall so report, stating the reasons why no such royalty is due.

     4.3 PAYMENT PROCEDURES. ROCHE shall pay royalties and all other payments
due hereunder to CHIRON in immediately available funds on the due date by wire
transfer to:

         Bank of America-San Francisco
         San Francisco, California
         Account Name: Chiron Corporation
         Account Number: [CONFIDENTIAL TREATMENT REQUESTED]
         ABA #: [CONFIDENTIAL TREATMENT REQUESTED]
         Reference: ROCHE HIV Probe License Agreement

or at such place and in such other manner as CHIRON may designate in a notice
signed by CHIRON's Treasurer or Controller to ROCHE.

     4.4 TAXES ON ROYALTIES. ROCHE shall deduct from amounts payable hereunder
all taxes assessed or imposed against, or required to be withheld from, royalty
payments due and shall pay such amount to the appropriate fiscal or tax
authorities on behalf of CHIRON. ROCHE shall forward promptly to CHIRON all tax
receipts received by ROCHE evidencing payment of such taxes.

                                                                              16
<PAGE>

     4.5 AUDIT. ROCHE shall keep reasonably detailed and accurate records and
books of account to enable a determination of the amounts payable by ROCHE and
its Affiliates to CHIRON hereunder. Upon thirty (30) days written notice by
CHIRON, and not more frequently than once per Calendar Year, CHIRON may have
such records and books of account examined during reasonable business hours by a
mutually acceptable independent certified public accountant selected by CHIRON
and at CHIRON's expense, whose acceptance shall not unreasonably be withheld by
ROCHE, for the purpose of verifying the amounts due hereunder; provided that
such independent accountant agrees to provide CHIRON only the information
necessary to verify the calculation of amounts due hereunder. A copy of any
final written report provided by the independent accountant to CHIRON shall be
given concurrently to ROCHE. Such examination shall not be permitted unless it
is requested within three (3) years following the end of the Calendar Year to
which the books and records pertain. Where such examination results in a finding
that ROCHE underpaid CHIRON by the greater of [CONFIDENTIAL TREATMENT
REQUESTED], ROCHE shall reimburse CHIRON for its reasonable costs and expenses
in conducting such examination. ROCHE and CHIRON shall promptly rectify any
overpayments or underpayments by repaying such amounts together with interest
thereon at an annual rate equal to the lesser of: (a) [CONFIDENTIAL TREATMENT
REQUESTED] as published in the Wall Street Journal, or (b) the maximum rates
permitted by applicable law, from the time such payment was originally due to
the time it is paid.

     4.6 CONFIDENTIALITY OF AUDIT. CHIRON agrees that all audited information
shall be confidential to ROCHE and its Affiliates, and that any person or entity
conducting an audit on behalf of CHIRON pursuant to Section 4.5 shall be
required to protect the confidentiality of such information.

     4.7 PAYMENT IN UNITED STATES CURRENCY. All payments shall be made in United
States Dollars and shall be made on the dates set forth herein. The Net Sales
amount calculated hereunder for sales in countries other than the United States
shall be converted into equivalent United States Dollars in accordance with the
methods used for internal financial reporting purposes within ROCHE.

     4.8 LATE PAYMENT FEE. Any payment, including, without limitation, royalty
payments, made by ROCHE hereunder after the date such payment is due, as set
forth in this Article 4 hereof, shall bear interest at the lesser of: (a)
[CONFIDENTIAL TREATMENT REQUESTED] as published in the Wall Street Journal as of
the date such payment was due, or (b) the maximum rate permitted by applicable
law.

                                                                              17
<PAGE>

                                    ARTICLE 5
                                  OTHER ACTIONS

     5.1 PATENT VALIDITY; ENFORCEABILITY. Immediately upon the Effective Date,
or as soon as possible thereafter, ROCHE shall discontinue any opposition,
challenge, compulsory license application or the like with respect to the CHIRON
Licensed Patents, [CONFIDENTIAL TREATMENT REQUESTED]. Immediately after the
Effective Date, or as soon as possible thereafter, CHIRON shall discontinue any
opposition, challenge, interference or the like with respect to the ROCHE
Optioned Patents.

     5.2 FUTURE PRODUCTS DIRECTED TO HIV.

     (a) Promptly upon its determination to Ship, or to provide a commercial
     service utilizing, a Product Directed to HIV not then set forth as a CHIRON
     Licensed Product on Exhibit D, ROCHE shall provide CHIRON with written
     notice of such Product and the parties will engage in good faith
     negotiations to determine the existing or new Product Category for such
     Product as set forth on Exhibit A, the number of Units in such Product
     pursuant to Section 1.42, the reasonable value of Associated Goods and
     Equipment, if any, to be deducted from the Net Sales of such Product
     pursuant to Section 1.32(d), and, if such Product is a Combination Product,
     the apportionment of the gross amount to be invoiced for such Product
     pursuant to Section 1.32(4). As set forth in these Sections, [CONFIDENTIAL
     TREATMENT REQUESTED]. Promptly following such determinations, CHIRON will
     prepare a revised Exhibit D to include this Product and such revised
     Exhibit D shall be incorporated into and become part of this Agreement.

     (b) If ROCHE determines to Ship, or to provide a commercial service
     utilizing, a Product Directed to HIV not then set forth on Exhibit D as a
     CHIRON Licensed Product and ROCHE reasonably believes that the sales of
     such Product would not, in the absence of the licenses granted pursuant to
     Sections 2.1 and 2.3, constitute an infringement of a Valid Claim of a
     CHIRON Licensed Patent, then ROCHE's written notice to CHIRON shall set
     forth the basis of ROCHE's reasonable belief in sufficient detail to permit
     CHIRON to evaluate the matter. [CONFIDENTIAL TREATMENT REQUESTED].

     (c) ROCHE may elect, in its reasonable discretion, to commence Shipping, or
     the provision of a commercial service utilizing, a Product Directed to HIV
     not then set forth on Exhibit D as a CHIRON Licensed Product [CONFIDENTIAL
     TREATMENT REQUESTED], PROVIDED ROCHE shall make a reasonable determination
     as to the applicable existing Product Category to determine the applicable
     Minimum Royalty Amount and shall utilize a reasonable determination of the
     number of Units in such

                                                                              18
<PAGE>

     Product and the deductions and apportionment for the calculation of Earned
     Royalty due on the Net Sales of such Product. [CONFIDENTIAL TREATMENT
     REQUESTED], any underpayment or overpayment of the Minimum Royalty or
     Earned Royalty shall be rectified in accordance with the provisions set
     forth in Section 4.8; [CONFIDENTIAL TREATMENT REQUESTED].

                                    ARTICLE 6
                         REPRESENTATIONS AND WARRANTIES

     6.1 CORPORATE AUTHORITY. Each party represents and warrants to the other
party that it has the necessary corporate authority to enter into this
Agreement.

     6.2 RIGHT TO GRANT. Each party represents and warrants that they have the
right to grant the licenses or options granted in Article 2 hereof and that they
are the sole owner of their respective Licensed Patents, subject to licenses
existing as of the Effective Date. CHIRON represents and warrants to ROCHE that,
to the best of its knowledge, neither CHIRON nor any of its Affiliates have
transferred to [CONFIDENTIAL TREATMENT REQUESTED] or any if its Affiliates (a)
before December 1, 1998, title to any patent or patent application Directed to
HIV in the Field existing on that date; or (b) on or after that date, title to
any patent, patent application or invention Directed to HIV in the Field.

     6.3 CURRENT LICENSES. CHIRON represents and warrants that: (a) as of the
Effective Date the entities set forth in Exhibit F are the only parties to which
it has granted any licensed rights or other grants or immunities to one or more
of the CHIRON Licensed Patents in the Field; and (b) Exhibit F contains a
complete and accurate description of the effective scope, field and territory of
such grant as of the Effective Date. CHIRON also represents and warrants that
[CONFIDENTIAL TREATMENT REQUESTED] except as disclosed in Exhibit F.

     6.4 COMPLETE PATENT LIST. CHIRON represents and warrants to ROCHE that, to
the best of its knowledge and belief, Exhibit B contains a complete list, as of
the Effective Date, of all patents and patent applications owned by, licensed to
(with a right to sublicense), or otherwise controlled by CHIRON or its
Affiliates containing claims Directed to HIV in the Field. To the extent that
any other patent or patent application owned by, licensed to (with a right to
sublicense), or otherwise controlled by CHIRON or its Affiliates and filed on or
before the Effective Date contains a claim Directed to HIV in the Field, such
patent or patent application shall be automatically added to the CHIRON Licensed
Patents. Upon ROCHE's written request, not more frequently than annually, CHIRON
shall provide ROCHE with an updated Exhibit B and a report of the prosecution
status of applications within CHIRON Licensed Patents. ROCHE represents and
warrants to CHIRON that, to the best of its knowledge and belief, Exhibit C
contains a complete list, as of the Effective Date, of all

                                                                              19
<PAGE>

patents and patent applications owned by, licensed to (with a right to
sublicense), or otherwise controlled by ROCHE or its Affiliates containing
claims Directed to HIV in the Field. To the extent that any other patent or
patent application owned by, licensed to (with a right to sublicense), or
otherwise controlled by ROCHE or its Affiliates and filed on or before the
Effective Date contains a claim Directed to HIV in the Field, such patent or
patent application shall be automatically added to the ROCHE Optioned Patents.
Upon CHIRON's written request, not more frequently than annually, ROCHE shall
provide CHIRON with an updated Exhibit C and a report of the prosecution status
of applications within ROCHE Optioned Patents.

     6.5 EXCLUSIONS. Nothing contained in this Agreement shall be construed as:

     (a) A representation or warranty by any party hereto as to the validity of
     any patent rights which are the subject of this Agreement;

     (b) A representation or warranty that anything made, used, imported,
     offered for sale, sold or otherwise disposed of under any of the patent
     rights which are the subject of this Agreement is or will be free from
     infringement of patents of third parties or of patents of either party that
     are not Directed to HIV;

     (c) An obligation to bring or prosecute actions or suits against third
     parties for infringement of any patent rights which are the subject of this
     Agreement;

     (d) A grant of any right to bring or prosecute actions or suits against
     third parties for infringement of any patent rights which are the subject
     of this Agreement; or

     (e) A grant, by implication, estoppel or otherwise, of any license, option,
     covenant or right other than those which are expressly stated herein,
     including without limitation (i) any license under any patent or patent
     application (or claim thereof) not within the Licensed Patents, or (ii) any
     covenant by CHIRON or ROCHE not to sue under any such patent or patent
     application (or claim thereof).

     6.6 FURTHER ROCHE ASSURANCE. ROCHE acknowledges that the inclusion of ROCHE
Affiliates within the license and option grants pursuant to Sections 2.1, 2.3
and 2.5 is intended to enable ROCHE to utilize the manufacturing and sales
capabilities of its Affiliates in connection with the manufacture and sale of
CHIRON Licensed Products in a manner substantially similar to the involvement of
such Affiliates in the manufacture and sale of ROCHE's products generally. ROCHE
shall not, directly or indirectly, take any action having or intended to have
the effect of sublicensing ROCHE's rights

                                                                              20
<PAGE>

under any of the CHIRON Licensed Patents, other than to a BONA FIDE
Affiliate, including, without limitation, by creating Affiliates specifically in
connection with CHIRON Licensed Products, or through other third party
arrangements such as joint ventures, collaborations, or distribution
arrangements with distributors. ROCHE and its Affiliates are licensed hereunder
to sell and distribute CHIRON Licensed Products only under the label, name and
trademark rights owned by, licensed to or otherwise controlled by ROCHE or its
Affiliates, and only through the sales force of ROCHE or its Affiliates, or
through Authorized Distributors. ROCHE and its Affiliates are not licensed to
perform OEM manufacturing of CHIRON Licensed Products for a third party other
than an Authorized Distributor; to supply CHIRON Licensed Products for resale to
any third party other than an Authorized Distributor; to permit any Authorized
Distributor or other third party to sell any CHIRON Licensed Products under
another third party label, name or trademark or to permit any Authorized
Distributor or other third party to sell any CHIRON Licensed Products under the
Authorized Distributor's or any third party's own label, name or trademark for
use on an instrument bearing the label name or trademark of a party other than
ROCHE or its Affiliates; provided, however, that nothing in this Section 6.6
shall be construed to limit the rights of ROCHE or its Affiliates to engage in
activities with such third parties, to the extent such third parties have
obtained rights under the CHIRON Licensed Patents permitting such activities.

     6.7 LIMITATION OF WARRANTY. EXCEPT AS SPECIFICALLY SET FORTH HEREIN, NO
PARTY MAKES ANY REPRESENTATION OR WARRANTY, EITHER EXPRESS OR IMPLIED, ARISING
BY LAW OR OTHERWISE, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

                                    ARTICLE 7
                              TERM AND TERMINATION

     7.1 TERM. This Agreement shall be in effect from the Effective Date until
the last to expire of the CHIRON Licensed Patents issued under the authority of
the Patent and Trademark Office of the United States (the "Term"), unless
earlier terminated pursuant to Sections 7.2 or 7.3 below.

     7.2 VOLUNTARY TERMINATION. ROCHE shall have the right to voluntarily
terminate all, but not less than all, licenses granted to ROCHE and its
Affiliates under this Agreement on not less than six (6) months prior written
notice to CHIRON. Notwithstanding the above, ROCHE may voluntarily terminate
all, but not less than all, licenses granted to ROCHE and its Affiliates under
this Agreement on a country-by-country basis, on not less than six (6) months
prior written notice to CHIRON, after the [CONFIDENTIAL TREATMENT REQUESTED]
anniversary of the Effective Date.

                                                                              21
<PAGE>

     7.3 TERMINATION BY CHIRON. CHIRON may terminate this Agreement only upon
any of the following grounds:

     (a) ROCHE's or its Affiliate's material breach of this Agreement,
     including, without limitation, a breach resulting from ROCHE's or its
     Affiliate's failure to pay any sums due hereunder, where such breach
     shall not have been remedied within thirty (30) days of the receipt of
     a written notification from CHIRON identifying the breach and requiring
     its remedy; whereupon termination under this Section 7.3(a) shall be
     effective upon the expiration of such thirty (30) day cure period,
     subject to Section 7.6; or

     (b) [CONFIDENTIAL TREATMENT REQUESTED]

     7.4 ENFORCEMENT AFTER TERMINATION. Upon valid termination of this Agreement
under Section 7.2 or 7.3, ROCHE and its Affiliates shall have no further rights
under CHIRON Licensed Patents and CHIRON shall not be limited to its remedies
under this Agreement, to the extent of such termination.

     7.5 ACCRUED RIGHTS. Termination of this Agreement for whatever reason shall
not affect any rights which have accrued prior to termination, including without
limitation royalty obligations occurring during the Term, calculated in
accordance with Article 3 and Exhibit A.

     7.6 ROCHE CHALLENGE TO SECTION 7.3(a) TERMINATION. In the event ROCHE
provides written notification to CHIRON prior to expiration of the thirty (30)
day notice/cure period referenced in Section 7.3(a) that ROCHE disputes whether
the grounds for termination under Section 7.3(a) are present, such dispute shall
be submitted to ADR pursuant to Article 10. The thirty (30) day notice/cure
period shall be suspended during the pendancy of such ADR, provided that during
the pendancy of the ADR, ROCHE shall continue to make any disputed payments to
CHIRON, on the condition that CHIRON shall repay ROCHE the amounts of such
disputed payments if ROCHE prevails in the ADR, plus interest at the rate
described in Section 4.8. Notwithstanding anything in this Section 7.6 to the
contrary, ROCHE may submit a dispute concerning a method by which amounts
payable by ROCHE and its Affiliates to CHIRON hereunder are calculated only one
time, and any resolution from the ADR shall bind the parties as to such
calculation method thereafter.

     7.7 ROCHE CHALLENGE TO SECTION 7.3(b) TERMINATION. In the event that ROCHE,
within thirty (30) days of receiving notice of termination by CHIRON for the
grounds set forth in Section 7.3(b) above, provides written notice to CHIRON
that ROCHE disputes whether such grounds are present, such dispute shall be
submitted to ADR pursuant to Article 10 and termination of this Agreement shall
be suspended during the pendancy of the ADR, provided that ROCHE suspends its
action, suit or proceeding (other than an ADR proceeding between the parties

                                                                              22
<PAGE>

as permitted by Section 7.3 (b) and Article 10) [CONFIDENTIAL TREATMENT
REQUESTED] and continues to perform all of its material obligations hereunder.

     7.8 AUDIT RESULTS NOT GROUNDS FOR TERMINATION. CHIRON's request for an
audit under Section 4.5 shall not be treated as a notice of breach under Section
7.3(a). In the event such audit determines there has been an underpayment by
ROCHE, such underpayment shall not constitute grounds for termination by CHIRON
under Section 7.3(a) unless: (a) ROCHE has failed to rectify such underpayment
in accordance with Section 4.5; (b) ROCHE has failed to rectify such
underpayment after notification and opportunity to cure under Section 7.3(a);
and (c) any ADR requested by ROCHE, pursuant to Section 7.6, and directed to any
dispute concerning such underpayment, results in a determination favorable to
CHIRON and ROCHE has failed to rectify such underpayment. Notwithstanding the
foregoing, ROCHE shall continue to make the disputed payments to CHIRON, on the
condition that CHIRON shall repay ROCHE the amounts of such disputed payments
with respect to which ROCHE prevails in the ADR, plus interest at the rate
described in Section 4.8.

     7.9 SURVIVAL. The following provisions of this Agreement shall survive
termination or expiration of this Agreement, in accordance with their respective
terms: Article 1; Sections 4.5, 4.6, 4.7, 4.8, 6.7, 7.4, 7.5 and 7.9; Articles
8, 9, and 10; Sections 11.9 through 11.14; and Section 14.1.

                                    ARTICLE 8
                                 CONFIDENTIALITY

     8.1 OBLIGATION. From time to time during the Term, CHIRON and ROCHE may
provide to each other information concerning patents, patent applications,
license agreements and other confidential or proprietary information related to
this Agreement (the "Information"). Each party receiving the Information (the
"Receiving Party") shall during the Term and for a period of three (3) years
after termination hereof: (a) maintain the Information in confidence; (b) not
disclose the Information to any third party, other than employees, agents or
consultants of the Receiving Party, its Affiliates or permitted sublicensees who
have a need to know the Information and who are bound by confidentiality
obligations to the Receiving Party no less restrictive than those contained
herein; and (c) not use the Information for any purpose not directly related to
performance hereunder or otherwise authorized under this Agreement.

     8.2 EXCLUSIONS. The obligations of this Article 8 shall not apply to any
Information which: (a) is or which becomes generally known to the public by
publication or by means other than a breach of a duty by the Receiving Party;
(b) is otherwise known by the Receiving Party at the time of disclosure by the
other party; (c) otherwise becomes available to the Receiving Party from a third
party not in breach of confidentiality obligations to the other party; or (d) is
developed by or for the Receiving Party independent of any disclosure from the
other party.

                                                                              23
<PAGE>

The Receiving Party also shall be permitted to make disclosures of
Information which are reasonably necessary in connection with a possible
grant of a permitted sublicense by the Receiving Party or in due diligence
related to a possible acquisition, merger, consolidation, substantial asset
transfer or similar transaction of the Receiving Party, provided that the
recipient is bound to the Receiving Party by confidentiality obligations with
respect to the Information no less restrictive than those contained herein.
Nothing herein shall prevent the Receiving Party from making such disclosures
of Information as are reasonably required by law, regulation (including 37
C.F.R. Section 1.56), or order of any court or governmental agency; provided
that the Receiving Party has provided reasonable advance notice to allow the
disclosing party the opportunity to seek a protective order or otherwise
contest, prevent or limit such disclosure.

     8.3 RETURN OF INFORMATION. Upon termination of this Agreement for any
reason, the Receiving Party shall return, or at the option of the disclosing
party, certify destruction of, all Information and copies thereof; provided that
the Receiving Party may retain one copy thereof in its law department files
solely for evidentiary and regulatory purposes.

     8.4 DISCLOSURE OF AGREEMENTS AND TERMS. The parties shall issue a joint
press release disclosing the existence and certain financial terms of this
Agreement. CHIRON may disclose any of the terms in the Agreement to any
Affiliate of CHIRON or to Abbott or Bayer or a permitted sublicensee; provided
that the recipient of such disclosure is obligated to confidentiality terms no
less restrictive that those contained in this Article 8. CHIRON and ROCHE may
each disclose the amounts of the Prior Sales Royalty, the European License Fee
and the U.S. License Fee (as these terms are defined in Exhibit A) individually
and/or in the aggregate and the amounts thereof that will be recognized from
time-to-time in its respective financial statements. Each party may disclose any
information contained in or regarding this Agreement to the extent required in
its respective reasonable judgment by applicable law, regulation or order of any
court or governmental agency. Further, each party may determine in its
respective discretion to file this Agreement under the Securities and Exchange
Act of 1934 or otherwise with any United States or foreign governmental agency,
even if that filing may result in this Agreement becoming available to the
public generally. The filing party shall seek confidential treatment for at
least the essential financial terms hereof in connection with any such filing,
subject to applicable law and regulation, and shall notify the other party in
advance of any such filing and consider such suggestions as the other party may
make as to the terms herein as to which the filing party should seek
confidential treatment.

                                    ARTICLE 9
                                    INDEMNITY

     9.1 ROCHE INDEMNITY. ROCHE shall indemnify, defend and hold harmless CHIRON
and its Affiliates and their officers, directors, shareholders,

                                                                              24
<PAGE>

employees, representatives and agents, against any claim, demand, loss,
damage or injury, including reasonable attorneys' fees, asserted by a third
party, arising from, relating to, or otherwise in respect of, (a) the
manufacture, use or sale of CHIRON Licensed Products, or (b) any breach by ROCHE
or its Affiliates of any representation, warranty or covenant under this
Agreement; provided, however, that such indemnity shall not extend to damages
arising directly from any breach or willful or negligent act of CHIRON or its
Affiliates.

     9.2 CHIRON INDEMNITY. CHIRON shall indemnify, defend and hold harmless
ROCHE and its Affiliates and their officers, directors, shareholders, employees,
representatives and agents, against any claim, demand, loss, damage or injury,
including reasonable attorneys' fees, asserted by a third party, arising from,
relating to, or otherwise in respect of, (a) the manufacture, use or sale of
ROCHE Licensed Products, if CHIRON exercises the options granted in Section 2.6,
or (b) any breach by CHIRON or its Affiliates of any representation, warranty or
covenant under this Agreement; provided, however, that such indemnity shall not
extend to damages arising directly from any breach or willful or negligent act
of ROCHE or its Affiliates.

     9.3 INDEMNIFICATION PROCEDURES. In the event either party claims
indemnification pursuant to this Article 9, the indemnified party shall promptly
notify the indemnifying party in writing upon becoming aware of any claim to
which such indemnification may apply. Delay in providing such notice shall
constitute a waiver of the indemnifying party's indemnity obligations hereunder
only if the indemnifying party's ability to defend such claim is materially
impaired thereby. The indemnifying party shall have the right to assume and
solely control the defense of the claim at its own expense. If the right to
assume and solely control the defense is exercised, the indemnified party shall
have the right to participate in, but not to control, such defense at its own
expense, and the indemnifying party's indemnity obligations shall be deemed not
to include attorneys' fees and litigation expenses incurred by the indemnified
party after the assumption of the defense by the indemnifying party. If the
indemnifying party does not assume the defense of the claim, the indemnified
party may defend the claim at the indemnifying party's expense. The indemnified
party shall not settle or compromise the claim without the prior written consent
of the indemnifying party, and the indemnifying party shall not settle or
compromise the claim in any manner which would have an adverse effect on the
indemnified party without the consent of the indemnified party, which consent,
in each case, shall not be unreasonably withheld. The indemnified party shall
reasonably cooperate with the indemnifying party and shall make available to the
indemnifying party all pertinent information under the control of the
indemnified party, all at the expense of the indemnifying party.

     9.4 SUNSET. The provisions of Sections 9.1 and 9.2 shall continue in effect
on a claim-by-claim basis, after the termination of this Agreement, only

                                                                              25
<PAGE>

until the expiration of the last to expire statute of limitations applicable
to such claim.

     9.5 LIMITATION OF LIABILITY. Neither party shall be liable to the other for
any consequential, special, indirect or exemplary damages or for the loss of
profits arising from the performance or nonperformance of this Agreement or any
acts or omissions associated herewith.

                                   ARTICLE 10
                         ALTERNATIVE DISPUTE RESOLUTION

     The parties recognize that BONA-FIDE disputes may from time to time arise
which relate to any aspect of this Agreement, including, without limitation, any
of the parties' rights and/or obligations hereunder, and including, without
limitation, disputes relating to the interpretation, form, validity, performance
and/or termination of this Agreement or relating to infringement, scope, claims
construction, or (without limiting the effect of Section 7.3(b)) validity or
enforceability of the Licensed Patents. In the event of the occurrence of any
dispute, a party may, by notice to the other party, have such dispute referred
to their respective employees designated below or their successors, for
attempted resolution by good faith negotiations within ninety (90) days after
such notice is received. Said designated officers are as follows:

     For ROCHE:
     PRESIDENT
     ROCHE MOLECULAR SYSTEMS, INC.

     For CHIRON:
     PRESIDENT
     BLOOD TESTING

     In the event the designated officers, after such good faith negotiations,
are not able to resolve such dispute within such ninety (90) day period, or any
agreed extension thereof, a party may invoke the provisions for binding ADR as
set forth in Paragraph 9 of the Settlement Agreement. Neither party shall seek
recourse against the other hereunder in any court or other forum, except as
permitted by Paragraph 9 of the Settlement Agreement or as may be necessary to
enforce a determination made in ADR pursuant to this Article 10 and Paragraph 9
of the Settlement Agreement.

                                   ARTICLE 11
                                  MISCELLANEOUS

11.1     ASSIGNMENT.

                                                                              26
<PAGE>

         (a) ROCHE and its Affiliates may not assign or transfer any
     rights under this Agreement without the prior written consent of
     CHIRON, except to an ROCHE Affiliate, and then only for so long as the
     assignee remains an ROCHE Affiliate, or as part of the sale or transfer
     of all or substantially all of ROCHE's and all of its Affiliates'
     assets and businesses to which this Agreement relates. In the case of a
     permitted assignment or transfer, the performance of the assignee shall
     be guaranteed by ROCHE.

         (b) CHIRON and its Affiliates may not assign or transfer any
     rights under this Agreement without the prior written consent of ROCHE,
     except to a CHIRON Affiliate, and then only for so long as the assignee
     remains a CHIRON Affiliate, or as part of the sale or transfer of all
     or substantially all of CHIRON's and all of its Affiliates' assets and
     businesses to which this Agreement relates. In the case of a permitted
     assignment or transfer, the performance of the assignee shall be
     guaranteed by CHIRON.

     11.2 FORCE MAJEURE. A party hereto shall not be liable for, nor shall this
Agreement be terminable or cancelable by reason of, any delay or default in any
such party's performance hereunder, to the extent that such default or delay is
caused by events beyond such party's reasonable control including, but not
limited to: acts of God; regulation, law or action of any government or agency
thereof; war or insurrection; civil commotion; labor disturbances; epidemic; or
failure of suppliers, public utilities or common carriers. Each party shall give
prompt notice to the other party of such cause, and shall take whatever
reasonable steps are necessary to relieve the effect of such cause as rapidly as
possible.

     11.3 SEVERABILITY. In the event that any one or more of the provisions of
this Agreement should for any reason be held by any court or authority having
jurisdiction over this Agreement or over the parties hereto to be invalid,
illegal or unenforceable, such provision or provisions shall be reformed to
approximate as nearly as possible the intent of the parties, in such
jurisdiction; elsewhere, this Agreement shall not be affected.

     11.4 ENTIRE AGREEMENT. This Agreement together with the Exhibits,
Attachments and Schedules constitutes the entire agreement among the parties
relating to the subject matter of this Agreement. There are no other
understandings, representations or warranties of any kind.

     11.5 AMENDMENT. This Agreement shall not be altered, extended or modified
except by written agreement of the parties.

     11.6 WAIVER. Failure by a party hereunder to enforce any right under this
Agreement shall not be construed as a waiver of such right or any other rights
under this Agreement; nor shall a waiver by a party hereunder in one or

                                                                              27
<PAGE>

more instances be construed as constituting a continuing waiver or as a waiver
in other instances.

     11.7 COSTS. Each of the parties hereto shall be responsible for its
respective legal and other costs incurred in relation to the preparation of this
Agreement.

     11.8 COUNTERPARTS. This Agreement may be executed in two (2) or more
counterparts, each of which shall be deemed to be an original, but all of which,
taken together, shall constitute one and the same instrument. Facsimile copies
of signatures for a party shall be deemed to be originals for purposes of
execution of the Agreement and for determining the Effective Date.

     11.9 NOTICES.

     (a) Any notice or other document to be given under this Agreement shall
be in writing and shall be deemed to have been duly given if personally
delivered or sent by first class mail, or express or air mail or other postal
service, or by certified mail, return receipt requested.

     (b) Any notice required by this Agreement shall be forwarded to the
respective addresses and marked for the attention of the persons set forth below
unless such addresses subsequently change by written notice to the other party:

ROCHE:   F. Hoffmann-La Roche Ltd.
         Grenzacherstrasse 124
         Basel
         Bale 4002
         Switzerland
         Attn.: Head of Diagnostics Division

Copy to: General Counsel
         Roche Molecular systems, Inc.
         1145 Atlantic Avenue
         Alameda, CA  94501

CHIRON:  Chiron Corporation
         4560 Horton Street
         Emeryville, California 94608
         Attn.: President, Blood Testing

Copy to: General Counsel
         Chiron Corporation
         4560 Horton Street
         Emeryville, CA 94608

                                                                              28
<PAGE>

     (c) Any such notice or other document shall be deemed to have been
effective when received by the addressee. To prove the giving of a notice or
other document it shall be sufficient to show that it was received.

     11.10 GOVERNING LAW. All matters affecting the interpretation, form,
validity, performance and termination of this Agreement shall be decided and
interpreted under the laws of the State of New York, excluding any choice of law
rules which may direct application of the laws of any other jurisdiction.

     11.11 RELATIONSHIP OF THE PARTIES. The relationship of the parties under
this Agreement is that of independent contractors. Nothing contained in this
Agreement is intended or is to be construed so as to constitute the parties as
partners, joint venturers or agents of the other. Neither party or its
Affiliates has any express or implied right or authority under this Agreement to
assume or create any obligations or make any representations or warranties on
behalf of or in the name of the other party or its Affiliates.

     11.12 HEADINGS. The headings of the Articles and Sections in this Agreement
have been inserted for convenience only and do not constitute part of this
Agreement.

     11.13 NO TRADEMARK RIGHTS. No right, express or implied, is granted by this
Agreement to either party to use in any manner the name, trade name or trademark
of the other party in connection with the performance of this Agreement.

     11.14 NO IMPLIED LICENSES. No license, express or implied, is granted by
this Agreement to either party, other than the licenses or options granted under
Sections 2.1, 2.3, 2.5 and 2.6.

                                   ARTICLE 12
                     FIELD RESTRICTIONS AND OTHER COVENANTS

     12.1 ROCHE COVENANT REGARDING BLOOD SCREENING.

     (a) ROCHE and its Affiliates shall not label or promote any CHIRON Licensed
Product labeled or promoted for use in the Field or the Transplantation Field in
any respect for use in Blood Screening; and ROCHE shall use commercially
reasonable efforts to prevent its Authorized Distributors from labeling or
promoting any CHIRON Licensed Products labeled or promoted for use in the Field
or the Transplantation Field in any respect for use in Blood Screening.

     (b) Further, ROCHE and its Affiliates and Authorized Distributors shall
include on or with each CHIRON Licensed Product labeled or promoted for use in
the Field or the Transplantation Field a statement to the effect that the

                                                                              29
<PAGE>

CHIRON Licensed Product is not for use for testing or screening pooled
samples containing specimens from more than one individual, or otherwise in
blood or plasma screening, using language to be determined by ROCHE and approved
in advance in writing by CHIRON, which approval shall not be unreasonably
withheld. The location of such notice shall be the product insert of such CHIRON
Licensed Products or such other reasonably prominent location to be determined
by ROCHE.

     (c) In the event that ROCHE or CHIRON becomes aware of any material use in
Blood Screening of CHIRON Licensed Products labeled or promoted for use in the
Field or the Transplantation Field, such party will promptly notify the other in
writing of the relevant facts and, if so requested by CHIRON, ROCHE will (i)
meet and confer with CHIRON in good faith to determine what steps either or both
should take to abate such infringing use and (ii) notify in writing any of its
customers that engages in such infringing use that use of the relevant CHIRON
Licensed Product in Blood Screening may infringe one or more of the CHIRON
Licensed Patents.

     (d) Without limiting the labeling and promoting obligations under this
Section 12.1, CHIRON shall not sue ROCHE, its Affiliates, its Authorized
Distributors or its End User customers for the sale or use as a confirmatory or
supplemental test in conjunction with the screening of blood, plasma or blood
products (a "Confirmatory Test") of a CHIRON Licensed Product that is labeled or
promoted for use in the Field or the Transplantation Field, if the End User
customer has substantial noninfringing uses for such CHIRON Licensed Product in
the Field or the Transplantation Field. Further, ROCHE shall not be obligated to
notify such customers pursuant to Section 12.1(c)(ii) with respect to such
CHIRON Licensed Product.

     (e) Nothing in this Section 12.1 shall apply to any product to the extent
that ROCHE's activity and that of its Affiliates with respect to such product is
either for or through an entity licensed in Blood Screening under the CHIRON
Licensed Patents.

     12.2 ROCHE COVENANT REGARDING PRODUCT LABELING. ROCHE and its Affiliates
shall include on or with each CHIRON Licensed Product a statement as to the
number of Units contained within each such CHIRON Licensed Product, using such
language to be determined by ROCHE and approved in advance in writing by CHIRON,
which approval shall not be unreasonably withheld. The location of such
statement shall be product insert of such CHIRON Licensed Products or such other
reasonably prominent location to be determined by ROCHE.

     12.3 PATENT MARKING. ROCHE and its Affiliates shall include a patent notice
on each CHIRON Licensed Product to identify the CHIRON Licensed Patents which
such CHIRON Licensed Product, but for the licenses granted

                                                                              30
<PAGE>

herein, would infringe one or more Valid Claims (or for which royalties are
being paid); provided, however, identification of CHIRON Licensed Patents on a
CHIRON Licensed Product shall in no way be deemed to be an admission by ROCHE or
its Affiliates, or raise a presumption, that such CHIRON Licensed Product is in
fact covered by such CHIRON Licensed Patent.

     12.4 CHIRON COVENANT REGARDING FIELD.

     (a) CHIRON and its Affiliates shall not, and CHIRON shall require any of
its future licensees under the CHIRON Licensed Patents that are licensed in
Blood Screening to agree not to, label or promote, in any respect for use in the
Field, any product sold in, labeled or promoted for use in Blood Screening
[CONFIDENTIAL TREATMENT REQUESTED], which product detects nucleic acid sequences
of HIV.

     (b) Further, CHIRON and its Affiliates shall, and CHIRON shall require its
future licensees in Blood Screening to, include with each such HIV product sold
by CHIRON or its Affiliates or licensees in Blood Screening a statement to the
effect that such product is not for use in the Field, using language to be
determined by CHIRON and approved by ROCHE, which approval shall not be
unreasonably withheld. The location of such notice shall be in the product
insert for such product or such other reasonably prominent location to be
determined by CHIRON.

     (c) In the event that CHIRON or ROCHE becomes aware of any material use of
any such product in the Field, such party will promptly notify the other in
writing of the relevant facts and, if so requested by ROCHE, CHIRON will (i)
meet and confer with ROCHE in good-faith to determine what steps either or both
of them should take to abate such use and (ii) notify in writing any of its
customers that engage in such use that use of the relevant product in the Field
may infringe one or more of the CHIRON Licensed Patents.

     (d) Nothing in this Section 12.4 shall apply to any product to the extent
that CHIRON's activity and that of its Affiliates or licensees with respect to
such product either (i) is for or through an entity that is licensed under the
CHIRON Licensed Patents in the Field or (ii) is within CHIRON's rights to
practice in the Field, pursuant to its rights retained under, and subject to the
limitations of, Section 2.1.

                                   ARTICLE 13
                          INFRINGEMENT BY THIRD PARTIES

     13.1 NOTICE OF INFRINGEMENT. Each party shall notify the other if it
becomes aware of Infringing Third Party Sales. CHIRON shall have the exclusive
right to take action against any infringement of any of the CHIRON Licensed
Patents, in its sole discretion, subject to this Article 13.

                                                                              31
<PAGE>

     13.2 INFRINGEMENT LITIGATION.

     (a) In the event that "substantial" Infringing Third Party Sales are
occurring in a country in which ROCHE or its Affiliates or an Authorized
Distributor is selling a CHIRON Licensed Product (in each such country, the
"Impacted Product"), and ROCHE has notified CHIRON pursuant to Section 13.1 of
the existence of such infringement in [CONFIDENTIAL TREATMENT REQUESTED] (an
"Infringement Notice"), then the provisions of this Section 13.2 shall apply.
For purposes of this Section 13.2, an Infringing Third Party Sale shall be
considered substantial in a country if the infringing third party achieves
market share of at least [CONFIDENTIAL TREATMENT REQUESTED] of the Aggregated
Products in such country as determined by an Independent Auditor paid for by
ROCHE. For purposes of this Section 13.2, "Major Country" shall mean the United
States, Germany, United Kingdom or Japan. For purposes of this Section 13.2,
"Aggregated Products" means the number of CHIRON Licensed Products of the
applicable Product Category and Competitive Products sold in a country, and
"Competitive Products" means Products which are sold in the Field and which
compete with a CHIRON Licensed Product sold by ROCHE or its Affiliates in a
country.

     (b) If either (i) the Infringement Notice identified an Impacted Product in
the United States and CHIRON fails to institute legal action in the United
States [CONFIDENTIAL TREATMENT REQUESTED] following receipt by CHIRON of the
Infringement Notice and infringement is not otherwise abated, or (ii) the
Infringement Notice identified an Impacted Product in a Major Country other than
the United States and CHIRON fails to institute legal action against the
infringing party in at least one of the United States, the Netherlands, Germany,
United Kingdom or Japan, [CONFIDENTIAL TREATMENT REQUESTED] following receipt by
CHIRON of the Infringement Notice and infringement is not otherwise abated; then
ROCHE shall be relieved of the obligation to pay the portion of Earned Royalties
set forth in Section 13.2(c) and [CONFIDENTIAL TREATMENT REQUESTED], with
respect to the Impacted Product until such time as CHIRON institutes such legal
action as described in this Section 13.2(b); provided, however, that CHIRON need
not initiate or continue any such legal action, if, after reasonably diligent
effort (including reasonably diligent effort by ROCHE if requested by CHIRON),
CHIRON is unable to acquire admissible evidence sufficient to establish a prima
facia case of infringement under the law of the applicable country.

     (c) If CHIRON has not instituted such legal action at the end of such
[CONFIDENTIAL TREATMENT REQUESTED], to the extent required under Section
13.2(b), and such infringement is not otherwise abated, the Earned Royalty with
respect to an Impacted Product shall be reduced by [CONFIDENTIAL TREATMENT
REQUESTED]. If, at the end of each [CONFIDENTIAL TREATMENT REQUESTED]
thereafter, CHIRON has not

                                                                              32
<PAGE>

instituted such legal action, to the extent so required, and infringement
is not otherwise abated, such Earned Royalties shall be reduced by an
[CONFIDENTIAL TREATMENT REQUESTED] of the original Earned Royalties, such that
if legal action required under Section 13.2(b) has not commenced and the
infringement is not otherwise abated by the end of the [CONFIDENTIAL TREATMENT
REQUESTED] following receipt by CHIRON of the Infringement Notice, [CONFIDENTIAL
TREATMENT REQUESTED] shall be payable hereunder with respect to the Impacted
Product.

     (d) The obligations to pay Earned Royalties and Minimum Royalties shall be
reinstated on a prospective basis at such time as ROCHE receives written notice
of the institution of legal action in accordance with Section 13.2(b) or the
infringement is otherwise abated, all subject to Section 13.2(e).

     (e) If legal action required under Section 13.2(b) has not been instituted
and the infringement is not otherwise abated for more than [CONFIDENTIAL
TREATMENT REQUESTED] following receipt by CHIRON of the Infringement Notice, and
if, as a result of the infringement, sales of the Impacted Product in a Major
Country by ROCHE, its Affiliates or an Authorized Distributor have declined by
[CONFIDENTIAL TREATMENT REQUESTED] or more during the preceding [CONFIDENTIAL
TREATMENT REQUESTED], then upon reinstatement of Earned Royalties and Minimum
pursuant to Section 13.2(d), the parties shall meet and confer regarding
possible adjustments to the Earned Royalties and Minimum Royalties for the
Impacted Product in view of such degradation of the market. The parties will
discuss possible rate reductions, as well as a plan for reinstating the original
economic expectations of the parties. It is expected that any agreement for
reduction of Earned Royalties and Minimum Royalties will be phased out over
time, so as to return to the Earned Royalties and Minimum Royalties set forth in
Exhibit A. If the parties fail to reach agreement on any such adjustment, the
matter shall be submitted for resolution by ADR, except that in the event of
ADR, each party shall submit to the neutral a proposal with respect to
adjustments pursuant to this Section 13.2(e). The neutral shall be empowered to
choose one proposal or the other, but shall not be empowered to order any such
adjustment other than as proposed by one of the parties.

     13.3 COOPERATION. ROCHE and its Affiliates shall cooperate with CHIRON in
connection with any legal action referred to in this Article 13.

                                   ARTICLE 14
                          EUROPEAN COMMUNITY PROVISIONS

     14.1 TERMINATION IN EUROPEAN COMMUNITY. Notwithstanding the provisions of
Article 7, this Agreement, with respect to the European Community, shall
terminate in each member country seventeen (17) years from the Effective Date or
on the expiration of the last to expire of the patents within the CHIRON

                                                                              33
<PAGE>

Licensed Patents in such member country based upon a patent existing or a patent
application pending as of the Effective Date, whichever is later; provided,
however, that prior to the termination of this Agreement in the first member
country in which it would otherwise terminate pursuant to the foregoing, ROCHE
may, in its discretion, elect by written notice to CHIRON to extend this
Agreement as to all such member countries for an additional term which shall
expire on a country-by-country basis on the expiration date of the last to
expire patent within the CHIRON Licensed Patents existing in such member country
as of the date of such extension.

     14.2 COMPETITION NOTIFICATION. If either party (the "Notifying Party")
elects to file a notification with respect to this Agreement (a "Notification")
with the Competition Directorate of Commission of European Community (the
"Commission") in accordance with regulations established by the Commission, the
Notifying Party shall provide a non-confidential version of the final draft to
the other party for comment at least thirty (30) days before making the filing
and shall consider in good faith the modification thereto, if any, that the
other party may propose. The other party shall execute all documents reasonably
required by the Notifying Party and shall otherwise reasonably cooperate in
connection with the Notification. The Notifying Party shall bear all costs
incurred by it relating to the Notification.

     14.3 REFORMATION. If, at any time during the Term, either party receives a
request or other communication from the Commission with respect to the
Notification (a "Request"), such party shall promptly inform the other of the
nature of the Request. In the event that the Commission indicates in a Statement
of Objection(s) that this Agreement will violate the provisions of Article 81 or
82 of the Treaty of Rome, then the parties shall amend this Agreement by making
those minimal modifications necessary to satisfy the concerns of the Commission
as set forth in the Statement of Objection(s). Notwithstanding the foregoing,
the parties agree that ROCHE shall retain substantially the same license rights
at substantially the same royalties as specified under this Agreement.

                                                                              34
<PAGE>

IN WITNESS WHEREOF this Agreement has been executed by duly authorized officers
of CHIRON and ROCHE as of the Effective Date.

CHIRON CORPORATION

By:     /s/ SEAN P. LANCE
        -----------------
        Sean P. Lance

Title:  Chairman and Chief Executive Officer

Date:   October 10, 2000

F. HOFFMANN-LA ROCHE LTD

By:      /s/ HEINO VON PRONDZYNSKI
         -------------------------
Title:   Head of Diagnostics

Date:    10/10/2000

By:      /s/ S. SCHWAN
         -------------
Title:   Head of Diagnostics Finance

Date:    10/10/2000

ROCHE MOLECULAR SYSTEMS, INC.

By:      /s/ KATHY ORDONEZ
         -----------------
Title:   President & CEO

Date:    October 10, 2000

                                                                               2
<PAGE>

                                  HIV EXHIBIT A
                             COMPENSATION TO CHIRON

1. PRIOR SALES ROYALTY. In consideration of the licenses granted pursuant to
Sections 2.1 and 2.3, within 10 (ten) days of the Effective Date ROCHE shall pay
[CONFIDENTIAL TREATMENT REQUESTED], for all sales of CHIRON Licensed Products
[CONFIDENTIAL TREATMENT REQUESTED], that would have, in the absence of the
licenses granted pursuant to Sections 2.1 and 2.3 and under the Blood Screening
Agreement, constituted an infringement of a Valid Claim of a CHIRON Licensed
Patent (the "Prior Sales Royalty"). The Prior Sales Royalty shall be refundable
in full within thirty (30) days, with interest calculated from the date of
payment in accordance with Section 4.8, in the event [CONFIDENTIAL TREATMENT
REQUESTED].

2. LICENSING FEES. Within thirty (30) days of [CONFIDENTIAL TREATMENT
REQUESTED], ROCHE shall pay to CHIRON a licensing fee of [CONFIDENTIAL TREATMENT
REQUESTED] (the "European Licensing Fee"). In addition, within thirty (30) days
of the date [CONFIDENTIAL TREATMENT REQUESTED] that, in the absence of the
licenses granted under Sections 2.1 and 2.3, would result in sales of Products
by ROCHE or its Affiliates constituting an infringement of such claims, ROCHE
shall pay to CHIRON a licensing fee of [CONFIDENTIAL TREATMENT REQUESTED]. The
European Licensing Fee and the U.S. Licensing Fee shall be nonrefundable and
fully earned when paid.

3. EARNED ROYALTY. In consideration of the licenses granted pursuant to Sections
2.1 and 2.3, ROCHE shall pay earned royalties equal to [CONFIDENTIAL TREATMENT
REQUESTED] of Net Sales of CHIRON Licensed Products, that would, in the absence
of the licenses granted pursuant to Sections 2.1 and 2.3, constitute an
infringement of a Valid Claim of a CHIRON Licensed Patent (the "Earned
Royalty"); [CONFIDENTIAL TREATMENT REQUESTED].

         Earned Royalties shall be payable quarterly, commencing with the
Calendar Quarter ending [CONFIDENTIAL TREATMENT REQUESTED], and shall be
initially due upon the [CONFIDENTIAL TREATMENT REQUESTED] and thereafter within
sixty (60) days following the end of each Calendar Quarter, and shall be
accompanied by a report pursuant to Article 4 of this Agreement.

4. MINIMUM ROYALTY. Notwithstanding the Earned Royalties due pursuant to
paragraph 3 of Exhibit A, and subject to the adjustments referenced in
paragraphs 3 and 4(b) of Exhibit A, royalties paid to CHIRON under this
Agreement in any Calendar Quarter shall not be less than a minimum royalty in
such quarter (the "Minimum Royalty"), calculated as follows:

The Minimum Royalty for each Calendar Quarter shall be the sum of the products
obtained by multiplying (x) [CONFIDENTIAL TREATMENT REQUESTED] in each

                                                                           1
<PAGE>

category within the CHIRON Licensed Products (a "Product Category") and in
each Region times (y) the applicable minimum amount (the "Minimum Royalty
Amount"), each of which Minimum Royalty Amounts shall be calculated by the
following equation:

                       [CONFIDENTIAL TREATMENT REQUESTED]

Where:

     A equals [CONFIDENTIAL TREATMENT REQUESTED] (the "Minimum Amount/Test");

     B equals [CONFIDENTIAL TREATMENT REQUESTED] and

     C equals [CONFIDENTIAL TREATMENT REQUESTED].

<TABLE>
<CAPTION>
                                                             Minimum Amount/Test
FIELD:                                   REGION I         REGION II      REGION III       REGION IV
<S>                                      <C>              <C>            <C>              <C>

                       [CONFIDENTIAL TREATMENT REQUESTED]
                       [CONFIDENTIAL TREATMENT REQUESTED]
                       [CONFIDENTIAL TREATMENT REQUESTED]

                       [CONFIDENTIAL TREATMENT REQUESTED]

TRANSPLANTATION FIELD:

                       [CONFIDENTIAL TREATMENT REQUESTED]
                       [CONFIDENTIAL TREATMENT REQUESTED]

                       [CONFIDENTIAL TREATMENT REQUESTED]
                       [CONFIDENTIAL TREATMENT REQUESTED]

</TABLE>

[CONFIDENTIAL TREATMENT REQUESTED]

     (a) The Minimum Royalty shall be determined on a [CONFIDENTIAL
TREATMENT REQUESTED], except to the extent adjusted [CONFIDENTIAL TREATMENT
REQUESTED].

     (b) In the event that action by governmental pricing or reimbursement
authority or other governmental agency in a country results in a requirement
that

                                                                           2
<PAGE>

ROCHE or its Affiliates sell a CHIRON Licensed Product [CONFIDENTIAL
TREATMENT REQUESTED], excluding for the purpose of calculating the impact of
such price reduction any currency exchange rate fluctuations from the Effective
Date (i.e., the calculation shall be made using the exchange rate in effect as
of the Effective Date), [CONFIDENTIAL TREATMENT REQUESTED]. If any such action
or series of actions results in a requirement that ROCHE or its Affiliates sell
a CHIRON Licensed Product [CONFIDENTIAL TREATMENT REQUESTED], then at the
request of ROCHE, the parties shall meet and reasonably consider greater
adjustment to the Minimum Amount/Test amount with respect to the CHIRON Licensed
Product in that country. No adjustment shall be made to the Minimum Amount/Test
unless mutually agreed or determined pursuant to ADR as provided in this
subparagraph 4(b).

         [CONFIDENTIAL TREATMENT REQUESTED]

     (c) Within sixty (60) days of the third anniversary of the Effective Date
and every third anniversary thereafter during the Term of this Agreement the
parties shall meet and reasonably consider adjustment to the Minimum Amount/Test
with respect to each CHIRON Licensed Product based on the average price increase
for diagnostics products on an industry-wide basis in each Region over the prior
three-year period; provided that no adjustment shall be made to any Minimum
Amount/Test unless mutually agreed or determined pursuant to ADR as provided in
this subparagraph 4(c), and provided further that [CONFIDENTIAL TREATMENT
REQUESTED].

     (d) Minimum Royalties shall be payable quarterly commencing with the
Calendar Quarter ending [CONFIDENTIAL TREATMENT REQUESTED], and shall be
initially due upon [CONFIDENTIAL TREATMENT REQUESTED] and thereafter within
sixty (60) days following the end of each Calendar Quarter. Such payment shall
be accompanied by a report pursuant to Article 4 and shall be fully creditable
against Earned Royalties payable pursuant to paragraph 3 of Exhibit A for the
same Calendar Quarter.

5. SINGLE ROYALTY PER CHIRON LICENSED PRODUCT. Only one payment of Earned
Royalty shall be due with respect to any Net Sales or only one payment of
Minimum Royalty shall be due with respect to any Unit of CHIRON Licensed Product
Shipped, whatever is higher, irrespective of the number of patents or Valid
Claims in the CHIRON Licensed Patents covering such CHIRON Licensed Product.

6. MOST FAVORED LICENSE ADJUSTMENT. In the event after the Effective Date that
CHIRON enters into an [CONFIDENTIAL TREATMENT REQUESTED], CHIRON shall promptly
provide ROCHE a written summary of the applicable royalty terms thereof and,
upon request, true copies of the applicable contract terms (including
definitions and methods of calculating royalty amounts). ROCHE shall have the
[CONFIDENTIAL TREATMENT REQUESTED], only by giving written notice of such
election to CHIRON written sixty (60) days of the receipt by ROCHE of notice
from CHIRON; provided, however, that [CONFIDENTIAL TREATMENT REQUESTED]. For the
avoidance of doubt, [CONFIDENTIAL TREATMENT REQUESTED], but would otherwise
retain all

                                                                          3
<PAGE>

rights to most favored licensee status contained in this Agreement with respect
to other Product Categories and countries.

7. ROYALTY STACKING. If ROCHE's Aggregate Royalty Percentage exceeds
[CONFIDENTIAL TREATMENT REQUESTED] of Net Sales for a CHIRON Licensed Product,
then:

     (a) [CONFIDENTIAL TREATMENT REQUESTED]

     (b) [CONFIDENTIAL TREATMENT REQUESTED]:

     (i) [CONFIDENTIAL TREATMENT REQUESTED]

     (ii) [CONFIDENTIAL TREATMENT REQUESTED]

     (c) [CONFIDENTIAL TREATMENT REQUESTED].

     (d) As utilized herein, "Aggregate Royalty Percentage" shall mean the
[CONFIDENTIAL TREATMENT REQUESTED] as per paragraph 3 of this Exhibit A and the
[CONFIDENTIAL TREATMENT REQUESTED] in [CONFIDENTIAL TREATMENT REQUESTED]

8. DISPUTE RESOLUTION. Any dispute between CHIRON and ROCHE regarding whether
any adjustment to or credits against Earned Royalties or Minimum Royalties under
this Exhibit A is appropriate, and which the parties fail to resolve themselves
may only be resolved by resort to the ADR provisions of Article 10. Until such
dispute is resolved, ROCHE shall pay CHIRON the Earned Royalty or Minimum
Royalty provided for herein without benefit of the applicable disputed
adjustment on the condition that CHIRON shall repay ROCHE the amounts of such
disputed payments if ROCHE prevails in the ADR, plus interest at the rate
described in Section 4.8.

                                                                           4

<PAGE>

                                 EXHIBIT B - HIV
                                   PAGE 1 OF 1

                       [CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

                                 EXHIBIT C - HIV
                                   PAGE 1 OF 1

                       [CONFIDENTIAL TREATMENT REQUESTED]

<PAGE>

                                     EXHIBIT D

PRODUCT CODES, HIV KITS

<TABLE>
<CAPTION>

                                              MAX
                                            LABELED
DESCRIPTION            SAP/PART NO.         CAPACITY         UNITS       CONTROLS
---------------------------------------------------------------------------------

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

[CONFIDENTIAL TREATMENT REQUESTED]

[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED]  [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED[CONFIDENTIAL TREATMENT REQUESTED]  [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN

[CONFIDENTIAL TREATMENT REQUESTED]

[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN
[CONFIDENTIAL TREATMENT REQUESTED]
[CONFIDENTIAL TREATMENT REQUESTED][CONFIDENTIAL TREATMENT REQUESTED] [CONFIDEN

</TABLE>

<PAGE>

                           Exhibit D-1

PRODUCT CODES, HIV KITS*:

<TABLE>
<CAPTION>
                                              MAX
                                            LABELED
DESCRIPTION            SAP/PART NO.         CAPACITY         UNITS       CONTROLS
---------------------------------------------------------------------------------

<S>                    <C>                  <C>         <C>            <C>
CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREACONFIDENTCONFIDENTCONFIDENT

CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED CONFIDENTIAL TREACONFIDENTCONFIDENTCONFIDENT

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED
CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

CONFIDENTIAL TREATMENT REQUESTED

</TABLE>

*CONFIDENTIAL TREATMENT REQUESTED

<PAGE>

                              [EXHIBIT E - PAGE 1]

                           HIV PROBES ROYALTY REPORT
                        REGION _:  ___________________
                      FOR THE QUARTER ENDING ____________

<TABLE>
<CAPTION>
                               Number                                                            Maximum      Minimum
                             of Product        Units per                        Minimum          Labeled      Royalty      Minimum
Product                         Sold            Product          Units         Amount/Test       Capacity     Amount       Royalty
-------                         ----            -------          -----         -----------      ---------     -------      -------
<S>                             <C>             <C>              <C>           <C>              <C>           <C>          <C>
HIV Quantitative
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]

HIV Qualitative
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]
                                       [CONFIDENTIAL TREATMENT REQUESTED]
HIV Genotyping
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]

HIV Resistance
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]

Total
</TABLE>

<PAGE>

                              [EXHIBIT E - PAGE 2]

                           HIV PROBES ROYALTY REPORT
                        REGION _:  ___________________
                      FOR THE QUARTER ENDING ____________

<TABLE>
<CAPTION>

                                                                                     Earned
                                                                                     Royalty     Earned         Royalty
Product                                Sales         Deductions       Net Sales       Rate       Royalty      Payment Due
-------                                -----         ----------       ---------       ----       -------      -----------
<S>                                    <C>           <C>              <C>            <C>         <C>          <C>
HIV Quantitative
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]

HIV Qualitative
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]
                            [CONFIDENTIAL TREATMENT REQUESTED]
HIV Genotyping
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]

HIV Resistance
 [SKU #1]
 [SKU #2]
 [SKU #3]
 [SKU #4]
                                                                                      ---------
Total                                                                                      $0
                                                                                      ---------
                                                                                      ---------

</TABLE>

<PAGE>

                                     HIV EXHIBIT F

   EXISTING LICENSES OR RIGHTS GRANTED IN THE FIELD UNDER THE LICENSED PATENTS
                              AS OF THE EFFECTIVE DATE

1.  [CONFIDENTIAL TREATMENT REQUESTED]

2.  [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

3.  [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

4.  [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

5.  [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

6.  [CONFIDENTIAL TREATMENT REQUESTED]

    [CONFIDENTIAL TREATMENT REQUESTED]

[CONFIDENTIAL TREATMENT REQUESTED]

1

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