
<PAGE>   1

                                            ***TEXT OMITTED AND FILED SEPARATELY
                                                CONFIDENTIAL TREATMENT REQUESTED
                                            UNDER 17 C.F.R. SECTIONS 200.80(B)4,
                                                            200.83 AND 240.24B-2


                                  AMENDMENT TO
                           DEVELOPMENT, MANUFACTURING
                             AND MARKETING AGREEMENT


            THIS AMENDMENT amends that certain AGREEMENT, dated as of April 1,
1996 (the "Agreement") between BAXTER HEALTHCARE CORPORATION, a Delaware
corporation with principal offices at One Baxter Parkway, Deerfield, Illinois
60015, and CERUS CORPORATION, a Delaware corporation, successor in interest to
STERITECH, INC., a California corporation, with principal offices at 2525
Stanwell Drive, Concord, California 94520, such amendment being effective as of
March 6, 1998.

            1. AMENDMENT TO SECTION 3.3(A). Section 3.3(a) is amended to read in
            full as follows:

                        (a) THE RED CELL PROJECT. The approved budget for 1998
            for the Red Cell Project is attached hereto as Schedule A. The
            parties agree to establish a reasonable budget for subsequent
            periods for the Red Cell Project, unless the Management Board
            determines to discontinue such Project. Each party shall perform the
            respective tasks set forth on Schedule A, except as the Management
            Board shall otherwise determine.

                                    (i) All funding of the Red Cell Project was
            provided by Cerus, until Regulatory Approval to commence Phase III
            clinical trials in the United States or Europe under the Platelet
            Agreement (the "Platelet Milestone"). Baxter shall participate in
            the Red Cell Project in accordance with this Agreement, including
            without limitation, the obligation to share fifty percent (50%) of
            the costs and expenses of the Cooperative Development Work incurred
            on or after January 1, 1997, and to market and sell the Systems for
            Red Cells developed under this Agreement. Subject to Section
            3.3.(a)(iii) hereof, Baxter shall pay to Cerus on the date of
            achievement of the Platelet Milestone fifty percent (50%) of the
            amount expended by Cerus under the Project budget from January 1,
            1997 to the date of payment.

                                    (ii) The parties acknowledge that the
            Platelet Milestone was achieved on September 30, 1997.

                                    (iii) Notwithstanding the foregoing
            provisions of this Section 3.3.(a), to the extent the approved
            budget for 1998 for the Red Cell Project exceeds Seven Million Three
            Hundred Thousand Dollars ($7,300,000), Cerus will fund all expenses
            for the Red Cell Project in 1998 in excess of such amount, up to the
            amount of the approved budget





                                       2.
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            ("Cerus 1998 Excess Expenditures"). To compensate for the Cerus 1998
            Excess Expenditures, Baxter will fully fund the first expenditures
            under the approved budget for the Red Cell Project for 1999 in an
            amount equal to the Cerus 1998 Excess Expenditures, after which the
            parties shall equally share the expenses of the Red Cell Project. If
            there is for any reason not an approved budget for the Red Cell
            Project for 1999, Baxter will fully fund the first expenditures for
            1999 under the approved budget for such other Cerus-Baxter program
            or programs as Cerus shall designate in an amount equal to the Cerus
            1998 Excess Expenditures. If by July 1, 1999, however, there is not
            an approved budget for such other Cerus-Baxter program or programs
            that is at least equal to such Excess Expenditures, Baxter will
            promptly pay to Cerus one-half of the amount by which the Excess
            Expenditures exceed the amount of expenditures to be funded by
            Baxter under the preceding sentence.

            2. AMENDMENT TO SECTION 3.7(B). Section 3.7(b) is amended to read in
            full as follows:

                        (b) RECONCILIATION OF EXPENDITURES. Unless otherwise
            agreed, the Management Board shall reconcile actual cash outlays and
            expenses approved by the Management Board with respect to a Project
            on a semi-annual basis for the Red Cell Project and on an annual
            basis for other Projects such that costs have been incurred in the
            proportion of fifty percent (50%) by Baxter and fifty (50%) by
            Cerus, or such other ratio as is established pursuant to Section
            3.7(a). If they are not in such proportion, Cerus will make a cash
            payment to Baxter, or Baxter will make a cash payment to Cerus, in
            order to achieve such proportion. The payment shall be made in cash
            within thirty (30) days following the determination by the
            Management Board based upon the reports made pursuant to Section
            3.5(a) of this Agreement.

            3. SCHEDULE A. The Schedule A referred to in such amended Section
            3.3(a) is attached to this Amendment.

            IN WITNESS WHEREOF, this Agreement is signed by duly authorized
            representatives of each party as of March 6, 1998.

BAXTER HEALTHCARE CORPORATION                 CERUS CORPORATION



By:      /s/ Roberto Perez                    By:    /s/ Stephen T. Isaacs
   ------------------------------                ------------------------------
         Roberto Perez                               Stephen T. Isaacs

Title:   President, Fenwal Division           Title: President







                                       2.
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                                   SCHEDULE A



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*CONFIDENTIAL TREATMENT REQUESTED




                                       3.


