<PAGE>   1
   As filed with the Securities and Exchange Commission on September 18, 1998
                                                           Registration No. 333-

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               ------------------

                                 RiboGene, Inc.
             (Exact name of registrant as specified in its charter)

                               ------------------

       Delaware                                         94-3095154
(State of Incorporation)                    (I.R.S. Employer Identification No.)

                               ------------------

                                 RiboGene, Inc.
                               26118 Research Road
                                Hayward, CA 94595
                    (Address of principal executive offices)

                               ------------------

                           1997 Equity Incentive Plan
                       1997 Employee Stock Purchase Plan
                 1997 Non-Employee Directors' Stock Option Plan
                            (Full title of the plans)



                              Charles J. Casamento
                      President and Chief Executive Officer
                               26118 Research Road
                                Hayward, CA 94595
              -----------------------------------------------------
 (Name, address, including zip code, and telephone number, including area code,
                              of agent for service)


                               ------------------

                                   Copies to:
                             Robert J. Brigham, Esq.
                               Cooley Godward LLP
                              FIVE PALO ALTO SQUARE
                               3000 EL CAMINO REAL
                            PALO ALTO, CA 94306-2155
                                 (650) 843-5000

                               ------------------


<PAGE>   2
                         CALCULATION OF REGISTRATION FEE


<TABLE>
<CAPTION>
===========================================================================================================================
                                                      PROPOSED MAXIMUM          PROPOSED MAXIMUM
 TITLE OF SECURITIES TO        AMOUNT TO BE          OFFERING PRICE PER        AGGREGATE OFFERING             AMOUNT OF   
      BE REGISTERED             REGISTERED               SHARE (1)                 PRICE (1)              REGISTRATION FEE
===========================================================================================================================
<S>                            <C>                   <C>                       <C>                        <C>        
Stock  Options and Common
Stock (par value $.001)         1,480,000                  $3.03                   $4,484,400                  $1,323      
===========================================================================================================================
</TABLE>


(1)   Estimated solely for the purpose of calculating the amount of the
      registration fee pursuant to Rule 457(h) and 457(c). The price per share
      and aggregate offering price are based upon the average of the bid and ask
      prices of Registrant's Common Stock on September 11, 1998 as reported on
      the American Stock Exchange.





                                       2
<PAGE>   3
                 INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

      The following documents filed by RiboGene, Inc. (the "Company" or
"Registrant") with the Securities and Exchange Commission are incorporated by
reference into this Registration Statement:

      (a)   The Company's latest annual report on Form 10-K filed pursuant to
Sections 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), or either (1) the Company's latest prospectus filed pursuant to
Rule 424(b) under the Securities Act of 1933, as amended (the "Act"), that
contains audited financial statements for the Company's latest fiscal year for
which such statements have been filed, or (2) the Company's effective
registration statement on Form 10 or 20-F filed under the Exchange Act
containing audited financial statements for the Company's latest fiscal year.

      (b)   All other reports filed pursuant to Sections 13(a) or 15(d) of the
Exchange Act since the end of the fiscal year covered by the annual reports, the
prospectus or the registration statement referred to in (a) above. 

      (c)   The description of the Company's Common Stock which is contained in
a registration statement filed under the Exchange Act, including any amendment
or report filed for the purpose of updating such description.

      All reports and other documents subsequently filed by the Company pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing
of a post-effective amendment which indicates that all securities offered have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference herein and to be a part of this
registration statement from the date of the filing of such reports and
documents.


                            DESCRIPTION OF SECURITIES

Not Applicable


                     INTERESTS OF NAMED EXPERTS AND COUNSEL

Not Applicable

                    INDEMNIFICATION OF DIRECTORS AND OFFICERS

The Registrant's Certificate of Incorporation and By-laws include provisions to
(i) eliminate the personal liability of its directors for monetary damages
resulting from breaches of their fiduciary duty to the extent permitted by
Section 102(b)(7) of the General Corporation Law of Delaware (the "Delaware
Law") and (ii) require the Registrant to indemnify its directors and officers to
the fullest extent permitted by Section 145 of the Delaware Law, including
circumstances in which indemnification is otherwise discretionary. Pursuant to
Section 145 of the Delaware Law, a corporation generally has the power to
indemnify its present and former directors, officers, employees and agents
against expenses incurred by them in connection with any suit to which they are,
or are threatened to be made, a party by reason of their serving in such
positions so long as they acted in good faith and in a manner they reasonably
believed to be in, or not opposed to, the best interests of a corporation, and,
with respect to any criminal action, they had no reasonably cause to believe
their conduct was unlawful. The Registrant believes that these provisions are
necessary to attract and retain qualified persons as directors and officers.
These provisions do not eliminate liability for breach of a director's duty of
loyalty to the Registrant or its stockholders, for acts or omissions not in good
faith or involving intentional misconduct or knowing violations of law, for any
transaction from which the director derived an improper personal benefit or for
any willful or negligent payment of any unlawful dividend or any unlawful stock
purchase agreement or redemption.

The Registrant has entered into agreements with its directors and executive
officers that which provide for indemnification under certain circumstances for
acts and omissions which may not be covered by any directors' and officers'
liability 




                                       1
<PAGE>   4
insurance. The Registrant has purchased an insurance policy covering the
officers and directors of the Registrant with respect to certain liabilities
arising under the Securities Act or otherwise.

                       EXEMPTION FROM REGISTRATION CLAIMED

Not Applicable


                                    EXHIBITS


EXHIBIT
NUMBER

5.1         Opinion of Cooley Godward LLP

23.1        Consent of Ernst & Young LLP

23.2        Consent of Cooley Godward is contained in Exhibit 5.1 to this
            Registration Statement.

24.1        Power of Attorney is contained on the signature pages

99.1        1997 Equity Incentive Plan

99.2        Form of Stock Option Agreement used in connection with the 1997
            Equity Incentive Plan.

99.3        1997 Employee Stock Purchase Plan

99.4        1997 Non-Employee Directors' Stock Option Plan

99.5        Form of Stock Option Agreement used in connection with the 1997
            Non-Employee Directors' Stock Option Plan.


                                  UNDERTAKINGS

1.    The undersigned registrant hereby undertakes:

      (a)   To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

            (i)   To include any prospectus required by section 10(a)(3) of the
Securities Act;

            (ii)  To reflect in the prospectus any facts or events arising after
the effective date of the registration statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in the registration
statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) (Section 230.424(b) of this
chapter) if, in the aggregate, the 


                                       2
<PAGE>   5
changes in volume and price represent no more than a 20% change in the maximum
aggregate offering price set forth in the "Calculation of Registration Fee"
table in the effective registration statement. 

            (iii) To include any material information with respect to the plan
of distribution not previously disclosed in the registration statement or any
material change to such information in the registration statement; 

       Provided, however, that paragraphs (a)(i) and (a)(ii) do not apply if
the information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by the issuer pursuant to
section 13 or section 15(d) of the Exchange Act that are incorporated by
reference herein.

      (b)   That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered herein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

      (c)   To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering. 

2.    The undersigned registrant hereby undertakes that, for purposes of
      determining any liability under the Securities Act, each filing of the
      registrant's annual report pursuant to Section 13(a) or Section 15(d) of
      the Exchange Act (and, where applicable, each filing of an employee
      benefit plan's annual report pursuant to section 15(d) of the Exchange
      Act) that is incorporated by reference in the Registration Statement shall
      be deemed to be a new registration statement relating to the securities
      offered herein, and the offering of such securities at that time shall be
      deemed to be the initial bona fide offering thereof.

3.    Insofar as indemnification for liabilities arising under the Securities
      Act may be permitted to directors, officers and controlling persons of the
      registrant pursuant to the foregoing provisions, or otherwise, the
      registrant has been advised that in the opinion of the Securities and
      Exchange Commission such indemnification is against public policy as
      expressed in the Securities Act and is, therefore, unenforceable. In the
      event that a claim for indemnification against such liabilities (other
      than the payment by the registrant of expenses incurred or paid by a
      director, officer or controlling person of the registrant in the
      successful defense of any action, suit or proceeding) is asserted by such
      director, officer or controlling person in connection with the securities
      being registered, the registrant will, unless in the opinion of its
      counsel the matter has been settled by controlling precedent, submit to a
      court of appropriate jurisdiction the question whether such
      indemnification by it is against public policy as expressed in the
      Securities Act and will be governed by the final adjudication of such
      issue.


                                       3
<PAGE>   6
                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Hayward State of California on September 17, 
1998.


                                 RIBOGENE, INC.


                             By      /s/ Timothy E. Morris
                                     -------------------------------------------

                             Title   Vice President, Finance and Administration
                                     and Chief Financial Officer



                                POWER OF ATTORNEY


      KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Charles J. Casamento and Timothy E.
Morris and each or any one of them, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign any and all amendments
(including post-effective amendments) to this Registration Statement, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorneys-in-fact and agents, and each of them, full power and authority to do
and perform each and every act and thing requisite and necessary to be done in
connection therewith, as fully to all intents and purposes as he might or could
do in person, hereby ratifying and confirming all that said attorneys-in-fact
and agents, or any of them, or their or his substitutes or substitute, may
lawfully do or cause to be done by virtue hereof.


                                       4
<PAGE>   7
      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.


<TABLE>
<CAPTION>
SIGNATURE                                             TITLE                                        DATE
<S>                                                   <C>                                          <C>


/s/ Charles J. Casamento                              President, Chief Executive Officer           September 17, 1998
--------------------------------------------          And Director
         (Charles J. Casamento)                       



/s/ Timothy E. Morris                                 Vice President, Finance and                  September 17, 1998
--------------------------------------------          Administration, Chief Financial Officer
         (Timothy E. Morris)                          and Assistant Secretary (Principal
                                                      Financial and Accounting Officer)       
                                                      



/s/ Digby W. Barrios                                  Director                                     September 17, 1998
--------------------------------------------
          (Digby W. Barrios)



/s/ Frank J. Sasinowski                               Director                                     September 17, 1998
--------------------------------------------
         (Frank J. Sasinowski)



/s/ Jon S. Saxe                                       Director                                     September 17, 1998
--------------------------------------------
            (Jon S. Saxe)



/s/ Roger G. Stoll                                    Director                                     September 17, 1998
--------------------------------------------
         (Roger G. Stoll, Ph.D.)
</TABLE>


                                       5
<PAGE>   8
                                  EXHIBIT INDEX


EXHIBIT
NUMBER                        DESCRIPTION

5.1         Opinion of Cooley Godward LLP

23.1        Consent of Ernst & Young LLP

23.2        Consent of Cooley Godward is contained in Exhibit 5.1 to this
            Registration Statement.

24.1        Power of Attorney is contained on the signature pages

99.1        1997 Equity Incentive Plan

99.2        Form of Stock Option Agreement used in connection with the 1997
            Equity Incentive Plan.

99.3        1997 Employee Stock Purchase Plan

99.4        1997 Non-Employee Directors' Stock Option Plan

99.5        Form of Stock Option Agreement used in connection with the 1997
            Non-Employee Directors' Stock Option Plan.


                                       6
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 17758}]
{"company-data": {"conformed-name": "RIBOGENE INC / CA/", "cik": "0000924654", "assigned-sic": "8731", "irs-number": "943095154", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-63751", "film-number": "98711825"}, "business-address": {"street1": "21375 CABOT BLVD BLDG. B,", "city": "HAYWARD", "state": "CA", "zip": "94545", "phone": "5107325551"}, "mail-address": {"street1": "21375 CABOT BLVD", "city": "HAYWARD", "state": "CA", "zip": "94545"}, "former-company": {"former-conformed-name": "RIBOGENE INC  / CA/", "date-changed": "19971009"}}
1
   As filed with the Securities and Exchange Commission on September 18, 1998
                                                           Registration No. 333-

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933

                               ------------------

                                 RiboGene, Inc.
             (Exact name of registrant as specified in its charter)

                               ------------------

       Delaware                                         94-3095154
(State of Incorporation)                    (I.R.S. Employer Identification No.)

                               ------------------

                                 RiboGene, Inc.
                               26118 Research Road
                                Hayward, CA 94595
                    (Address of principal executive offices)

                               ------------------

                           1997 Equity Incentive Plan
                       1997 Employee Stock Purchase Plan
                 1997 Non-Employee Directors' Stock Option Plan
                            (Full title of the plans)

                              Charles J. Casamento
                      President and Chief Executive Officer
                               26118 Research Road
                                Hayward, CA 94595
              -----------------------------------------------------
 (Name, address, including zip code, and telephone number, including area code,
                              of agent for service)

                               ------------------

                                   Copies to:
                             Robert J. Brigham, Esq.
                               Cooley Godward LLP
                              FIVE PALO ALTO SQUARE
                               3000 EL CAMINO REAL
                            PALO ALTO, CA 94306-2155
                                 (650) 843-5000

                               ------------------
2
                         CALCULATION OF REGISTRATION FEE
===========================================================================================================================
                                                      PROPOSED MAXIMUM          PROPOSED MAXIMUM
 TITLE OF SECURITIES TO        AMOUNT TO BE          OFFERING PRICE PER        AGGREGATE OFFERING             AMOUNT OF   
      BE REGISTERED             REGISTERED               SHARE (1)                 PRICE (1)              REGISTRATION FEE
===========================================================================================================================
Stock  Options and Common
Stock (par value $.001)         1,480,000                  $3.03                   $4,484,400                  $1,323      
===========================================================================================================================
(1)   Estimated solely for the purpose of calculating the amount of the
      registration fee pursuant to Rule 457(h) and 457(c). The price per share
      and aggregate offering price are based upon the average of the bid and ask
      prices of Registrant's Common Stock on September 11, 1998 as reported on
      the American Stock Exchange.

                                       2
3
                 INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

      The following documents filed by RiboGene, Inc. (the "Company" or
"Registrant") with the Securities and Exchange Commission are incorporated by
reference into this Registration Statement:

      (a)   The Company's latest annual report on Form 10-K filed pursuant to
Sections 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), or either (1) the Company's latest prospectus filed pursuant to
Rule 424(b) under the Securities Act of 1933, as amended (the "Act"), that
contains audited financial statements for the Company's latest fiscal year for
which such statements have been filed, or (2) the Company's effective
registration statement on Form 10 or 20-F filed under the Exchange Act
containing audited financial statements for the Company's latest fiscal year.

      (b)   All other reports filed pursuant to Sections 13(a) or 15(d) of the
Exchange Act since the end of the fiscal year covered by the annual reports, the
prospectus or the registration statement referred to in (a) above. 

      (c)   The description of the Company's Common Stock which is contained in
a registration statement filed under the Exchange Act, including any amendment
or report filed for the purpose of updating such description.

      All reports and other documents subsequently filed by the Company pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing
of a post-effective amendment which indicates that all securities offered have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference herein and to be a part of this
registration statement from the date of the filing of such reports and
documents.

                            DESCRIPTION OF SECURITIES

Not Applicable

                     INTERESTS OF NAMED EXPERTS AND COUNSEL

Not Applicable

                    INDEMNIFICATION OF DIRECTORS AND OFFICERS

The Registrant's Certificate of Incorporation and By-laws include provisions to
(i) eliminate the personal liability of its directors for monetary damages
resulting from breaches of their fiduciary duty to the extent permitted by
Section 102(b)(7) of the General Corporation Law of Delaware (the "Delaware
Law") and (ii) require the Registrant to indemnify its directors and officers to
the fullest extent permitted by Section 145 of the Delaware Law, including
circumstances in which indemnification is otherwise discretionary. Pursuant to
Section 145 of the Delaware Law, a corporation generally has the power to
indemnify its present and former directors, officers, employees and agents
against expenses incurred by them in connection with any suit to which they are,
or are threatened to be made, a party by reason of their serving in such
positions so long as they acted in good faith and in a manner they reasonably
believed to be in, or not opposed to, the best interests of a corporation, and,
with respect to any criminal action, they had no reasonably cause to believe
their conduct was unlawful. The Registrant believes that these provisions are
necessary to attract and retain qualified persons as directors and officers.
These provisions do not eliminate liability for breach of a director's duty of
loyalty to the Registrant or its stockholders, for acts or omissions not in good
faith or involving intentional misconduct or knowing violations of law, for any
transaction from which the director derived an improper personal benefit or for
any willful or negligent payment of any unlawful dividend or any unlawful stock
purchase agreement or redemption.

The Registrant has entered into agreements with its directors and executive
officers that which provide for indemnification under certain circumstances for
acts and omissions which may not be covered by any directors' and officers'
liability 

                                       1
4
insurance. The Registrant has purchased an insurance policy covering the
officers and directors of the Registrant with respect to certain liabilities
arising under the Securities Act or otherwise.

                       EXEMPTION FROM REGISTRATION CLAIMED

Not Applicable

                                    EXHIBITS

EXHIBIT
NUMBER

5.1         Opinion of Cooley Godward LLP

23.1        Consent of Ernst & Young LLP

23.2        Consent of Cooley Godward is contained in Exhibit 5.1 to this
            Registration Statement.

24.1        Power of Attorney is contained on the signature pages

99.1        1997 Equity Incentive Plan

99.2        Form of Stock Option Agreement used in connection with the 1997
            Equity Incentive Plan.

99.3        1997 Employee Stock Purchase Plan

99.4        1997 Non-Employee Directors' Stock Option Plan

99.5        Form of Stock Option Agreement used in connection with the 1997
            Non-Employee Directors' Stock Option Plan.

                                  UNDERTAKINGS

1.    The undersigned registrant hereby undertakes:

      (a)   To file, during any period in which offers or sales are being made,
a post-effective amendment to this registration statement:

            (i)   To include any prospectus required by section 10(a)(3) of the
Securities Act;

            (ii)  To reflect in the prospectus any facts or events arising after
the effective date of the registration statement (or the most recent
post-effective amendment thereof) which, individually or in the aggregate,
represent a fundamental change in the information set forth in the registration
statement. Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) (Section 230.424(b) of this
chapter) if, in the aggregate, the 

                                       2
5
changes in volume and price represent no more than a 20% change in the maximum
aggregate offering price set forth in the "Calculation of Registration Fee"
table in the effective registration statement. 

            (iii) To include any material information with respect to the plan
of distribution not previously disclosed in the registration statement or any
material change to such information in the registration statement; 

       Provided, however, that paragraphs (a)(i) and (a)(ii) do not apply if
the information required to be included in a post-effective amendment by those
paragraphs is contained in periodic reports filed by the issuer pursuant to
section 13 or section 15(d) of the Exchange Act that are incorporated by
reference herein.

      (b)   That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered herein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

      (c)   To remove from registration by means of a post-effective amendment
any of the securities being registered which remain unsold at the termination of
the offering. 

2.    The undersigned registrant hereby undertakes that, for purposes of
      determining any liability under the Securities Act, each filing of the
      registrant's annual report pursuant to Section 13(a) or Section 15(d) of
      the Exchange Act (and, where applicable, each filing of an employee
      benefit plan's annual report pursuant to section 15(d) of the Exchange
      Act) that is incorporated by reference in the Registration Statement shall
      be deemed to be a new registration statement relating to the securities
      offered herein, and the offering of such securities at that time shall be
      deemed to be the initial bona fide offering thereof.

3.    Insofar as indemnification for liabilities arising under the Securities
      Act may be permitted to directors, officers and controlling persons of the
      registrant pursuant to the foregoing provisions, or otherwise, the
      registrant has been advised that in the opinion of the Securities and
      Exchange Commission such indemnification is against public policy as
      expressed in the Securities Act and is, therefore, unenforceable. In the
      event that a claim for indemnification against such liabilities (other
      than the payment by the registrant of expenses incurred or paid by a
      director, officer or controlling person of the registrant in the
      successful defense of any action, suit or proceeding) is asserted by such
      director, officer or controlling person in connection with the securities
      being registered, the registrant will, unless in the opinion of its
      counsel the matter has been settled by controlling precedent, submit to a
      court of appropriate jurisdiction the question whether such
      indemnification by it is against public policy as expressed in the
      Securities Act and will be governed by the final adjudication of such
      issue.

                                       3
6
                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, as amended,
the Registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Hayward State of California on September 17, 
1998.

                                 RIBOGENE, INC.

                             By      /s/ Timothy E. Morris
                                     -------------------------------------------

                             Title   Vice President, Finance and Administration
                                     and Chief Financial Officer

                                POWER OF ATTORNEY

      KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints Charles J. Casamento and Timothy E.
Morris and each or any one of them, his true and lawful attorney-in-fact and
agent, with full power of substitution and resubstitution, for him and in his
name, place and stead, in any and all capacities, to sign any and all amendments
(including post-effective amendments) to this Registration Statement, and to
file the same, with all exhibits thereto, and other documents in connection
therewith, with the Securities and Exchange Commission, granting unto said
attorneys-in-fact and agents, and each of them, full power and authority to do
and perform each and every act and thing requisite and necessary to be done in
connection therewith, as fully to all intents and purposes as he might or could
do in person, hereby ratifying and confirming all that said attorneys-in-fact
and agents, or any of them, or their or his substitutes or substitute, may
lawfully do or cause to be done by virtue hereof.

                                       4
7
      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed by the following persons in the
capacities and on the dates indicated.
SIGNATURE                                             TITLE                                        DATE
/s/ Charles J. Casamento                              President, Chief Executive Officer           September 17, 1998
--------------------------------------------          And Director
         (Charles J. Casamento)                       

/s/ Timothy E. Morris                                 Vice President, Finance and                  September 17, 1998
--------------------------------------------          Administration, Chief Financial Officer
         (Timothy E. Morris)                          and Assistant Secretary (Principal
                                                      Financial and Accounting Officer)       
                                                      

/s/ Digby W. Barrios                                  Director                                     September 17, 1998
--------------------------------------------
          (Digby W. Barrios)

/s/ Frank J. Sasinowski                               Director                                     September 17, 1998
--------------------------------------------
         (Frank J. Sasinowski)

/s/ Jon S. Saxe                                       Director                                     September 17, 1998
--------------------------------------------
            (Jon S. Saxe)

/s/ Roger G. Stoll                                    Director                                     September 17, 1998
--------------------------------------------
         (Roger G. Stoll, Ph.D.)
5
8
                                  EXHIBIT INDEX

EXHIBIT
NUMBER                        DESCRIPTION

5.1         Opinion of Cooley Godward LLP

23.1        Consent of Ernst & Young LLP

23.2        Consent of Cooley Godward is contained in Exhibit 5.1 to this
            Registration Statement.

24.1        Power of Attorney is contained on the signature pages

99.1        1997 Equity Incentive Plan

99.2        Form of Stock Option Agreement used in connection with the 1997
            Equity Incentive Plan.

99.3        1997 Employee Stock Purchase Plan

99.4        1997 Non-Employee Directors' Stock Option Plan

99.5        Form of Stock Option Agreement used in connection with the 1997
            Non-Employee Directors' Stock Option Plan.

                                       6