Exhibit 99.2

CONFIDENTIAL PORTIONS OF THIS EXHIBIT HAVE BEEN OMITTED PURSUANT TO REGULATION
240.24B-2B OF THE SECURITIES EXCHANGE ACT OF 1934.  [*] INDICATES OMITTED
MATERIAL THAT IS THE SUBJECT OF A CONFIDENTIAL TREATMENT REQUEST AND IS FILED
SEPARATELY WITH THE COMMISSSION.

                                   AMENDMENT
                                       TO
                          THE PARTICIPATION AGREEMENT
                               OF AUGUST 24, 1998

This Amendment to the Participation Agreement dated August 24, 1998
("Amendment"), is entered into by and between: Ribozyme Pharmaceuticals Inc., a
Delaware corporation ("Founder 1); Dr. Ralph E. Christoffersen ("Founder 2");
Mr. Lawrence Bullock ("Founder 3"); Dr. Nassim Usman ("Founder 4"); Dr. James
Thompson ("Founder 5"); Ms. Alene Holzman ("Founder 6"); Dr. Thomas H. Rossing
("Founder 7"); Dr. Jorg Potzsch ("Founder 8"); Dr. Thomas Walther ("Founder 9");
Atugen Biotechnology, GmbH, a German entity ("Company"); and BB Bioventures L.P.
and its affiliates, all of which are managed by MPM Asset Management, LLC.,
("Investor"), as of this 23 day of November, 1998 (Effective Date).  Founders
                         --        --------
1-9 may hereinafter be referred to as "Founders."

RECITALS:

A.  The Founders, Investor and Company are parties to a Participation Agreement
    dated August 24, 1998 ("Agreement").

B.  The Founders, Investor and Company desire to amend the Agreement as set
    forth below.

I.  AMENDMENTS:

A.  At all points in the document, DM12,696,246  shall be equivalent to
    US$7,000,000.

B.  PREAMBLE
    --------

    Replace the second paragraph with the following:

    "The Founders intend to increase the share capital of the Company in order
    to provide the Company with new operating funds. Within the framework of
    this capital increase, the Investor shall be given the opportunity to
    purchase a share in the nominal amount of up to 30,600 DM in total after
    the capital increase has been effected at a closing (the "Closing") as set
    out in Annex 26."

[*] Confidential treatment requested


B.  PART 1: PARTICIPATION
    ---------------------

    1.  Section 1: Increase of Capital

        a.  Paragraph 4 shall be replaced with the following:
            ------------------------------------------------

            "The Investor shall pay the original capital contribution of DM
            30,600 and Founder 1 shall pay to the Company the US $2,000,000
            financial support required by the Service Agreement, the form of
            which is attached hereto as Annex 25, both immediately upon the
            execution of this Amendment  by all parties hereto.  Immediately
            upon receipt by the Company of the US$2,000,000 from Founder 1,
            the Investor shall also transfer to the Company, its US$7,000,000
            surcharge.  All payments under this section shall be wired or made
            by check to the Company's bank account at the Commerzbank, Berlin
            with the [*] and such payments shall be net of any bank transaction
            fees."

        b.  Paragraph 5 shall be deleted in its entirety.
            ---------------------------------------------

        c.  Paragraph 6 shall be deleted in its entirety
            ----------------------------------------------

        d.  The following new Paragraph 7 shall be added:
            ---------------------------------------------

            "The Parties agree that a partial share of Founder 1 in the
            nominal amount of DM 8,500 shall be redeemed on or before
            December 31, 1998 for the compensation of DM 8,500. Such a
            redemption shall be contingent upon the receipt of License Fees
            by Founder 1 from the Company as provided and defined in the
            License Agreement (Annex 23)."

    2.      Section 2: Transformation into an AG (German Stock Corporation) and
            Employee Participation

        a.  Paragraph 1 shall be replaced with the following:
            -------------------------------------------------

            "The Parties will convert the Company into an Aktiengesellschaft
            (German Stock Corporation), changing its legal form within sixty
            (60) days from the date of Closing, provided that the terms of
            the restructuring, as set forth in the documents to be prepared
            in connection therewith, are acceptable to the Investor. In the
            course of the Company's conversion into an AG, the Investor's
            shares will be changed into preferred convertible stock

[*] Confidential treatment requested


            with voting rights and liquidation preference ("Vorzugsaktien") as
            outlined in annex 17 and the founders' shares will be changed into
            common stock. "


C.  PART 2: ASSURANCES AND WARRANTIES
    ---------------------------------

    1.   Section 3, Subsection I (2), paragraph 1 shall be replaced with the
         following:

         "On May 5, 1998,  Founder 1 acquired all capital shares of the
         Company, changed the Company's name to "Atugen Biotechnology GmbH",
         amended and restated the Articles of Association. On June 10, 1998,
         the Company moved the Company's seat to Berlin, shortly thereafter
         split its share with the nominal amount of DM 50,000 into one partial
         share with the nominal amount of DM 46,000 and four small partial
         shares  and sold the latter ones to the Founders 2, 8 and 9 as well as
         to the Founders 3 to 7 who are holding their share in the nominal
         amount of DM 1,600 jointly.  There are no other shares of capital
         stock of the Company issued or outstanding (see Annex 26)."

    2.   Section 3, Subsection I (5) shall be replaced with the following:

         "The excerpt from the Trade Register in Berlin as seen in annex 4
         correctly and completely shows the Company's current legal status,
         except that such excerpt does not reflect the appointment of Dr.
         Potzsch as general manager, which appointment was effected by the
         shareholders' meeting of July 10, 1998."

    3.   Section 3, Subsection I (6) shall be replaced with the following:
         The only persons entitled to represent the Company and to execute
         documents on its behalf are:

         Dr. Ralph Earl Christoffersen
         Dr. Jorg Potzsch
         Dr. Michael Steinmetz (upon Closing and shareholder action)

    4.   Section 3, subsection II: Declarations with of Assets and Financial
         Standing

         a.  Paragraph 1(a) shall be replaced with the following:

                 "The Company has no due  binding obligations with regard to
                 taxes or social insurance contributions or other contributions
                 for an employee's pension, and the

[*] Confidential treatment requested


                 Company is not obligated under any warranty or guarantee
                 contracts, bills of exchange or suretyships."

         b.  Paragraph 1(b) shall be replaced with the following:

             "Past due pension obligations do not exist. Promises for pensions
             have not been made."

         c.  Paragraph 2, line 4:
             --------------------

             "[A]nnex 14" shall be replaced with Annex 23 and Annex 24--

    5.   Section 3, subsection III: Other Declarations

         a.  Paragraph 2 shall be replaced with the following:
             -------------------------------------------------

             "The Founders each individually declare that they are not the
             owner of any intellectual property rights (patents, licenses,
             other intellectual property rights) on the basis of which any
             royalty payment could be demanded from the Company or the
             Company's business conduct could be impeded or  prohibited world-
             wide with the exception of the patents and patent applications of
             Founder 1 which are subject to licenses to the Company through
             the license agreements enclosed herein as Annex 23 and Annex 24
             and the Service Agreement enclosed herein as Annex 25.
             (i) To the extent set forth in Annex 27, the initial Licensed
             Technology List to be provided by Founder 1 to the Investor
             pursuant to Section 3.2.5(1) of the License Agreement attached
             hereto as Annex 23, the Cech Patents in the Annex 24, and the
             "Pending Trademark Applications list in Annex 21, (together
             "Founder 1 IP"), considered together, contain a complete and
             accurate list of all (a) patented or registered intellectual
             property rights owned by the Company or owned by Founder 1 and
             being transferred or licensed to the Company in connection with
             the transactions contemplated herein, (b) pending patent
             applications and applications for registrations of other
             intellectual property rights filed by Founder 1 which relate to
             the technology to be transferred or licensed to the Company, (c)
             material unregistered trade names and corporate names owned by
             the Company, (d) material unregistered trademarks, service marks,
             copyrights, mask works and computer software owned by the Company
             and (e) all other intellectual property rights owned by the


[*] Confidential treatment requested


             Company that are material to the operation of the business of the
             Company as presently conducted and as presently proposed to be
             conducted. The items constituting the Founder 1 IP constitute all
             of the intellectual property and intellectual property rights
             necessary for the operation of the Company's business as
             contemplated by this Agreement and the other agreements
             contemplated hereby.
             (ii) Annex 22 also contains a complete and accurate list of (a)
             all material licenses and other rights granted by the Company to
             any third party with respect to any intellectual property rights,
             except with respect to rights granted to customers of the Company
             with respect to the Company's products in the ordinary course of
             business, (b) all material licenses and other rights granted by
             Founder 1 to any third party with respect to any intellectual
             property rights to be transferred to the Company, and (c) to the
             extent not disclosed pursuant to Paragraph 2(i), all licenses and
             other rights material to the operation of the businesses of the
             Company as presently conducted and as presently proposed to be
             conducted, free and clear or subordinated of all liens or
             encumbrances granted by any third party to the Company with
             respect to any intellectual property rights, in each identifying
             the subject intellectual property rights.
             (iii)  Except to the extent set forth in the schedule of
             exceptions provided to the Investor, (a) the Company and Founder
             1 collectively own all right, title and interest in and to all of
             the intellectual property rights listed or required to be listed
             in the Founder 1 IP pursuant to Section 2(i), free and clear or
             subordinated of all liens or encumbrances; (b) the Company will
             have pursuant to the license granted by Founder 1, a valid
             license to all intellectual property rights not owned by Founder
             1  that are material to the operation of the contemplated
             businesses of the Company as presently conducted and as presently
             proposed to be conducted (including but not limited to those
             intellectual property rights listed under Founder 1 IP pursuant
             to Sections 2(i), and (ii)), free and clear or subordinated of
             all liens or encumbrances, and such license or licenses will not
             be terminated as a result of or require any third party consent
             to effect an effective transfer via the license to the Company;
             (c) the conduct of the Founder 1's business as it relates to the
             technology being licensed to the Company, to the best of Founder
             1`s knowledge, and except as disclosed to the Investor, as of

[*] Confidential treatment requested


             the effective date of this Agreement, Founder 1 is not aware that
             it has infringed, misappropriated or conflicted with any
             intellectual property rights of other persons; (d) neither the
             Company nor Founder 1 has received any notices of, any
             infringement or misappropriation by, or conflict with, any third
             party with respect to such intellectual property rights
             (including, without limitation, any demand or request that the
             Company or Founder 1 license any rights from a third party) nor,
             to the Company's or Founder 1's  knowledge, are there valid
             grounds for any such assertion of infringement, misappropriation
             or conflict; (e) to the best of the Company's and Founder 1's
             knowledge, the intellectual property rights owned by or licensed
             to the Company have not been infringed, misappropriated or
             conflicted by other persons or entities; and (f) Founder 1 has
             taken all actions reasonably necessary to maintain and protect
             the Intellectual Property Rights which they own.

             Each service provider of Founder 1 has executed a proprietary
             information and inventions agreement that provides for the
             confidential treatment of the intellectual property rights of
             Founder 1 and the assignment to Founder 1 of inventions developed
             in connection with the performance of services for Founder 1, in
             the form previously furnished or made available to the Investors.
             To the Founder 1's best knowledge, no such service provider is in
             violation thereof.  To Founder 1's best knowledge, all relevant
             technology has been assigned to Founder 1 by all service
             providers. Each service provider of the Company will execute a
             proprietary information and inventions agreement that provides
             for the confidential treatment of the intellectual property
             rights to be held by the Company and the assignment to the
             Company of inventions to be developed in connection with services
             performed for the Company."

         b.  Paragraph 7 shall be replaced with the following:

             "Annex 28 of this Amendment contains a complete and correct list
             of all bank accounts of the Company and all powers granted to
             employees for the respective bank accounts."

         c.  Paragraph 11 shall be replaced with the following:
             --------------------------------------------------


[*] Confidential treatment requested


             "Other than obligations to employees, obligations to make
             ---------------------------------------------------------
             payments upon a line of credit in the amount of DM 1,000,000 and
             ----------------------------------------------------------------
             those obligations listed on Annex 8, the Company is not a party
             ---------------------------------------------------------------
             to any contract or other agreement or obligation pursuant to
             ------------------------------------------------------------
             which it is committed or would become committed upon the
             --------------------------------------------------------
             fulfillment of contingencies to pay to any party an amount
             ----------------------------------------------------------
             greater than DM 50,000 per annum."
             ----------------------------------

D.  PART 4: NEW PROVISIONS
    ----------------------

    1.   Section 3(vi) shall be replaced with the following:

         "maintain such insurance, including if determined by the Advisory
         Council, key person insurance"

    2.   Section 6: The title shall be replaced with the following:

         "License, Sub-License and Service Agreements"

         a.  Paragraph 1 shall be replaced with the following:

             "The Company has concluded an employment agreement for the
             position of general manager with Dr. Potzsch in accordance with
             annex 11."

         b.  Paragraph 2 shall be replaced with the following:
             -------------------------------------------------

             "The Company has concluded individual employment contracts with
             the employees listed in the Annex 29."

         c.  Paragraph 3 shall be replaced with the following:
             -------------------------------------------------

             "The Company has concluded a License Agreement and a Sub-License
             Agreement with the Founder 1 in the forms attached hereto as
             Annex 23 and Annex 24, respectively."

         b.  Paragraph 4 shall be replaced with the following:
             -------------------------------------------------

             "The Company has concluded a Service Agreement with the Founder 1
             in the form attached hereto as Annex 25."

         c.  Paragraph 5 shall be deleted in its entirety
             --------------------------------------------


E.  TABLE: LIST OF ANNEXES TO THE PARTICIPATION AGREEMENT shall be replaced with
    ----------------------------------------------------------------------------
    the following:
    --------------


[*] Confidential treatment requested


                                List of Annexes
                                ---------------
                                    to the
                                    ------
                            Participation Agreement
                            -----------------------


                                       
- --------------------------------------------------------------------------------------------------
                Annex 1                   Signed Term Sheet of June 16,1998
- --------------------------------------------------------------------------------------------------
                Annex 2                   Business Plan in the version of July 30, 1998
- --------------------------------------------------------------------------------------------------
                Annex 3                   Minutes from the shareholders' meeting of June 10, 1998
                                          including the Articles of Association
- --------------------------------------------------------------------------------------------------
                Annex 4                   Excerpt from the Trade Register
- --------------------------------------------------------------------------------------------------
                Annex 5                   List of Shareholders
- --------------------------------------------------------------------------------------------------
                Annex 6                   Shareholdings in other Companies Which Are Active in
                                          the Field of the Company or a Related Field or Are in a
                                          Business Relationship with the Company
- --------------------------------------------------------------------------------------------------
                Annex 7
- --------------------------------------------------------------------------------------------------
                Annex 8                   Obligations of the Company Exceeding  DM 50,000
- --------------------------------------------------------------------------------------------------
                Annex 9
- --------------------------------------------------------------------------------------------------
                Annex 10                  Draft of the New Articles of Association
- --------------------------------------------------------------------------------------------------
                Annex 11                  Employment Contracts for the General Manager(s)
- --------------------------------------------------------------------------------------------------
                Annex 12                  Employment Contract
- --------------------------------------------------------------------------------------------------
                Annex 13                  Void
- --------------------------------------------------------------------------------------------------
                Annex 14                  Void
- --------------------------------------------------------------------------------------------------
                Annex 15                  Void
- --------------------------------------------------------------------------------------------------
                Annex 16                  Void
- --------------------------------------------------------------------------------------------------
                Annex 17                  Rights of Preferred Stock
- --------------------------------------------------------------------------------------------------


[*] Confidential treatment requested



                                       
- --------------------------------------------------------------------------------------------------
                Annex 18                  Letter of Intent (BMBF)
- --------------------------------------------------------------------------------------------------
                Annex 19                  Letter of Intent (Senate of Berlin)
- --------------------------------------------------------------------------------------------------
                Annex 20                  Void
- --------------------------------------------------------------------------------------------------
                Annex 21                  Void
- --------------------------------------------------------------------------------------------------
                Annex 22                  List of Existing Licensees
- --------------------------------------------------------------------------------------------------
                Annex 23                  License Agreement
- --------------------------------------------------------------------------------------------------
                Annex 24                  Manufacturing and Supply Agreement and  Sub-License
                                          Agreement
- --------------------------------------------------------------------------------------------------
                Annex 25                  Service Agreement
- --------------------------------------------------------------------------------------------------
                Annex 26                  Cap Table
- --------------------------------------------------------------------------------------------------
                Annex 27                  Liens
- --------------------------------------------------------------------------------------------------
                Annex 28                  Bank Accounts of the Company
- --------------------------------------------------------------------------------------------------
                Annex 29                  List of Employees
- --------------------------------------------------------------------------------------------------



II.    ENTIRE AMENDMENT:

       This Amendment, to the extent set forth herein, amends and
       modifies and supplements the Agreement.  Except as expressly amended
       herein, all of the terms and provisions of the Agreement remain in full
       force and effect and cannot be amended, modified or changed in any way
       except in writing witnessed and signed by duly authorized representatives
       of each Company, Founders and the Investor.

III.   GENERAL PROVISION:

       While both a German and an English version of this Amendment exist, only
       the English version of this Amendment shall be binding, and the German
       version of this Amendment shall not be used for any legal purpose,
       interpretive or otherwise.

[*] Confidential treatment requested


IN WITNESS WHEREOF, the Parties have caused this Amendment to be executed by
their duly authorized representatives.


November  23, 1998
          --

                                 Larry Bullock
                 ---------------------------------------------
                         RIBOZYME PHARMACEUTICALS INC.
                                   Founder 1


                          /s/ Ralph E. Christoffersen
                 ---------------------------------------------
                         Dr. Ralph Earl Christoffersen
                                   Founder 2


                               /s/ Larry Bullock
                 ---------------------------------------------
                               Mr. Larry Bullock
                                   Founder 3


                               /s/ Nassim Usman
                 ---------------------------------------------
                               Dr. Nassim Usman
                                   Founder 4


                              /s/ James  Thompson
                 ---------------------------------------------
                              Dr. James Thompson
                                   Founder 5


                               /s/ Alene Holzman
                 ---------------------------------------------
                               Ms. Alene Holzman
                                   Founder 6


                              /s/s Thomas Rossing
                 ---------------------------------------------
                              Dr. Thomas Rossing
                                   Founder 7


November __, 1998

        BB BIOVENTURES L.P.

By: /s/ Ansbert S. Gadicke
    ----------------------


[*] Confidential treatment requested


Name: Ansbert S. Gadicke
      ------------------
Title: Managing Director
       -----------------

November 23, 1998
         --

                               /s/ Jorg Potzsch
                 ---------------------------------------------
                               Dr. Jorg Potzsch
                                   Founder 8


                              /s/ Thomas  Walther
                 ---------------------------------------------
                              Dr. Thomas Walther
                                   Founder 9


                          /s/ Ralph E. Christoffersen
                 ---------------------------------------------
                           Atugen Biotechnology GmbH
                                    Company

[*] Confidential treatment requested