As filed with the Securities and Exchange Commission
                                on May 18, 2005

                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                   FORM 20-F/A

         ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
                              EXCHANGE ACT OF 1934

                   For the fiscal year ended December 31, 2004

                       Commission file number: 001-117629

                                 GPC Biotech AG
             (Exact name of Registrant as specified in its charter)
                           Federal Republic of Germany
                 (Jurisdiction of incorporation or organization)
            Fraunhoferstrasse 20, D-82152 Martinsried/Munich, Germany
                    (Address of principal executive offices)

 Securities registered or to be registered pursuant to Section 12(b) of the Act:
                                      None.
 Securities registered or to be registered pursuant to Section 12(g) of the Act.
--------------------------------------------------------------------------------
Title:
Ordinary Bearer Shares, without par value
American Depository Shares (as evidenced
by American Depository Receipts), each
representing one Ordinary Bearer Share
--------------------------------------------------------------------------------


 Securities for which there is a reporting obligation pursuant to
                           Section 15(d) of the Act:
                                      None.

As of December 31, 2004, 28,741,194 ordinary shares, of no par value, of GPC
Biotech AG were outstanding.

     Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days.

                                                           X   Yes      No


     Indicate by check mark which financial statement item the registrant has
elected to follow.

                                                        Item 17   X Item 18



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                                TABLE OF CONTENTS

PART I
Item 6:  Directors, Senior Management & Employees. . . . . . . . . . . . . 2

PART III
Item 19:  Exhibits . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2




<PAGE>


                               CERTAIN DEFINITIONS

        In this Amendment No. 1 on Form 20-F/A ("Amendment No. 1") to the annual
report of GPC Biotech AG on Form 20-F for the fiscal year ended December 31,
2004 (the "annual report"), unless otherwise provided, references to "GPC
Biotech", "the company", "we", "us" and "our" refer to GPC Biotech AG and its
wholly owned subsidiary, GPC Biotech Inc.

                                EXPLANATORY NOTE

        This Amendment No. 1 is being filed solely for the purpose of including
additional disclosure in Item 6 regarding our exemptions from certain corporate
governance rules of Nasdaq. The disclosure in this Amendment No. 1 speaks as of
December 31, 2004. Except for the inclusion of such disclosure in Item 6, this
Amendment No. 1 does not purport to amend, update or restate the information in
our annual report as filed on March 31, 2005, or reflect any events that have
occurred after the date on which the annual report was filed. In connection with
this Amendment No. 1, we are including the certifications required by Rule
13a-14(a) under the Securities Exchange Act of 1934, as amended.

                                       1

<PAGE>


PART 1

Item 6.  Directors, Senior Management & Employees

        The following paragraphs are added to the disclosure under Item 6 of the
Annual Report on Form 20-F for the fiscal year ended December 31, 2004.

Marketplace Rules Exemptions Granted by Nasdaq

        In 2004, in connection with our listing of American Depository Shares
representing our ordinary shares on the Nasdaq National Market, Nasdaq granted
us two exemptions with respect its Marketplace Rules.

     Quorum

        Nasdaq granted us an exemption with respect to Marketplace Rule 4350(f),
which requires issuers' by-laws to establish a minimum quorum of 33 1/3 % for
any meeting of the holders of common stock. Neither German law nor the rules and
regulations promulgated by the Frankfurt Stock Exchange, the primary market for
our shares, require a specific quorum for annual general meetings; therefore,
our Articles of Association do not provide for a quorum. The absence of a quorum
requirement in the Company's Articles of Association is consistent with German
law and such a requirement would be contrary to generally accepted business
practice in Germany.

     Shareholder Approval of Stock Option Plans

        Nasdaq granted us an exemption with respect to Marketplace Rule
4350(i)(1)(A), which requires issuers to obtain shareholder approval prior to
the establishment of, or material amendment to, certain stock option or purchase
plans. The exact terms and conditions of our equity compensation plans are not
the subject of a shareholder vote at the annual general meeting. Instead, our
shareholders only vote on the creation of underlying capital to service the
equity awards and certain other general terms prescribed by German law and
authorize the Management Board or, in respect of awards to be made to the
members of our Management Board, the Supervisory Board, to determine the details
of our equity compensation plans. It is intended that all such plans be
established within the policies and programs approved by our Compensation
Committee.

PART III

Item 19.  Exhibits

Exhibit
Number                     Description
-------                    -----------

12.3              Certification of the Principal Executive Officer pursuant to
                  Section 302 of the Sarbanes-Oxley Act of 2002.

12.4              Certification of the Principal Financial Officer pursuant
                  to Section 302 of the Sarbanes-Oxley Act of 2002.

                                       2

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                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act, as amended, the
registrant certifies that it meets all of the requirements for filing on Form
20-F/A and has duly caused this Amendment No. 1 to its annual report to be
signed on its behalf by the undersigned, thereto duly authorized.

                                                 GPC BIOTECH AG

                                                 By: /s/ Bernd R. Seizinger
                                                     ---------------------------

                                                 Name:  Bernd R. Seizinger
                                                 Title: Chief Executive Officer

                                                 By: /s/ Mirko Scherer
                                                     ---------------------------
                                                 Name:  Mirko Scherer
                                                 Title: Chief Financial Officer

                                       3

May 18, 2005



<PAGE>


                                  EXHIBIT INDEX

Exhibit
Number                     Description
-------                    -----------

12.3              Certification of the Principal Executive Officer pursuant
                  to Section 302 of the Sarbanes-Oxley Act of 2002.

12.4              Certification of the Principal Financial Officer pursuant
                  to Section 302 of the Sarbanes-Oxley Act of 2002.





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