GPC Biotech AG

                        2006 INCENTIVE STOCK OPTION PLAN


                          EFFECTIVE AS OF MAY 24, 2006


1.       PURPOSES.

         (a)      The purpose of this Plan is to provide a means by which
                  selected Employees and Directors of GPC Biotech Inc. (the
                  "Subsidiary"), a wholly owned subsidiary of GPC Biotech AG,
                  Munich/Germany (the "Company") may be given an opportunity to
                  benefit from increases in value of the stock of the Company
                  through the granting of (i) Incentive Stock Options, and (ii)
                  Nonstatutory Stock Options, all as defined below. The Plan
                  does not provide for the granting of stock appreciation rights
                  or restricted stock.

         (b)      The Company, by means of this Plan, seeks to retain the
                  services of persons who are now Employees or Directors of its
                  Subsidiary, to secure and retain the services of such persons
                  and to provide incentives for such persons to exert maximum
                  efforts for the success of the Company and its Subsidiary.

         (c)      The Company  intends that the Stock Option Grants issued
                  under this Plan shall, in the discretion of the Board of
                  Directors ("Vorstand") and in coordination with the
                  Supervisory Board ("Aufsichtsrat") of the Company be Options
                  granted pursuant to Section 6 hereof, including Incentive
                  Stock Options and Nonstatutory Stock Options. All Options
                  shall be separately designated Incentive Stock Options or
                  Nonstatutory Stock Options at the time of grant, and in such
                  form as required pursuant to Section 6, and a separate
                  certificate or certificates will be issued for each option
                  grant.

2.       DEFINITIONS.

         (a)      "Affiliate" means any subsidiary corporation of the Company,
                  whether now or hereafter existing, as defined in Section
                  424(f) of the Code, including GPC Biotech, Inc., a Delaware
                  corporation with its offices in Waltham (Massachusetts) and
                  Princeton (New Jersey).

         (b)      "Aktiengesetz" (abbr.: AktG) means the German Stock
                  Corporation Act.





                                     - 2 -

         (c)      "Aufsichtsrat" means the Supervisory Board of the Company.

         (d)      "Code" means the United States Internal Revenue Code of 1986,
                  as amended.

         (e)      "Company" means GPC Biotech AG, a German  Aktiengesellschaft
                  (stock corporation) with its seat in Planegg/Martinsried
                  (Germany).

         (f)      "Continuous  Status as an Employee or Director" means the
                  employment or relationship as an Employee or a Director is not
                  interrupted or terminated. The Aufsichtsrat, in its sole
                  discretion, may determine whether Continuous Status as an
                  Employee or a Director shall be considered interrupted in the
                  case of: (i) any leave of absence approved by the Vorstand,
                  including sick leave, military leave, or any other personal
                  leave; or (ii) transfers between locations of the Company or
                  between the Company and the Affiliates or their successors.

         (g)      "Director" means a member of the board of directors of an
                  Affiliate of the Company.

         (h)      "Employee" means any person,  employed by the Company or any
                  Affiliate of the Company. Neither service as a Director nor
                  payment of a director's fee by the Company shall be sufficient
                  to constitute "employment" by the Company.

         (i)      "Exchange Act" means the U.S. Securities Exchange Act of 1934,
                  as amended.

         (j)      "Fair Market  Value" means,  as of any date,  the value of the
                  ordinary bearer shares of the Company determined as follows,
                  and in each case in a manner consistent with the Code, the
                  Fair Market Value of an ordinary bearer shall be equivalent to
                  the average price at which the Company's no-par shares are
                  traded at XETRA's final auction on the Frankfurt stock
                  exchange during the last five stock exchange trading days
                  prior to the granting of the Options, at least, however, to
                  the share in the capital stock (pro rata amount) attributed to
                  one share of GPC Biotech AG.

         (k)      "Incentive  Stock  Option"  means an Option  intended to
                  qualify as an incentive stock option within the meaning of
                  Section 422 of the Code and the regulations promulgated
                  thereunder.

         (l)      "Nonstatutory Stock Option" means an Option not intended to
                  qualify as an Incentive Stock Option.




                                     - 3 -

         (m)      "Option" means a stock option granted pursuant to the Plan.

         (n)      "Optionee" means any Employee or Director who holds an
                  outstanding Option.

         (o)      "Plan" means the 2006 Incentive Stock Option Plan.

         (p)      "Redomociling"  shall  occur  only in the event  that (i) the
                  Company has a class of equity securities registered pursuant
                  to Section 12 of the Exchange Act, and (ii) the Company no
                  longer qualifies as a "foreign private issuer" under
                  applicable US securities laws.

         (q)      "Rule 16b-3"  means  Rule 16b-3 of the Exchange Act or any
                  successor to Rule 16b-3, as in effect when discretion is being
                  exercised with respect to the Plan.

         (r)      "share(s)"  means the Company's  ordinary  bearer shares and,
                  unless the context otherwise requires, its American Depositary
                  Receipts evidencing American Depositary Shares, each
                  representing one ordinary bearer share.

         (s)      "Stock Option Grant" means any Option right granted under the
                  Plan.

         (t)      "Stock  Option Agreement" means a written agreement between
                  the Company and a holder of a Stock Option Grant evidencing
                  the terms and conditions of an individual Stock Option Grant.
                  Each Stock Option Agreement shall be subject to the terms and
                  conditions of the Plan.

         (u)      "Subsidiary" means any affiliated corporation of the Company,
                  whether now or hereafter existing, as defined in Section
                  424(f) of the Code, including GPC Biotech Inc., a Delaware
                  corporation with offices in Waltham (Massachusetts) and
                  Princeton (New Jersey).

         (v)      "Vorstand" means the Management Board of the Company.

3.       ADMINISTRATION.

         (a)      The Plan shall be  administered  by the Vorstand in
                  accordance with the respective resolutions of the Company's
                  stockholders and, where applicable, in coordination with the
                  Aufsichtsrat and internal guidelines of the Company.

         (b)      Notwithstanding  subparagraph  (a) above,  the Vorstand shall
                  have the power subject to and within the limitations of the
                  express provisions of the Plan:




                                      - 4-

                  (1)       To determine  from time to time which of the persons
                            eligible under the Plan shall be granted Stock
                            Option Grants; when and how each Stock Option Grant
                            shall be granted; whether a Stock Option Grant will
                            be an Incentive Stock Option, a Nonstatutory Stock
                            Option or a combination of the foregoing; the
                            provisions of each Stock Option Grant granted (which
                            need not be identical), including the time or times
                            when a person shall be permitted to receive stock
                            pursuant to a Stock Option Grant, whether a person
                            shall receive ordinary bearer shares or American
                            Despositary Receipts and the number of shares with
                            respect to which a Stock Option Grant shall be
                            granted to each such person.

                  (2)       To construe and interpret the Plan and Stock Option
                            Grants granted under it, and to establish, amend and
                            revoke rules and regulations for its administration.
                            The Vorstand, in the exercise of this power, may
                            correct any defect, omission or inconsistency in the
                            Plan or in any Stock Option Agreement, in a manner
                            and to the extent it shall deem necessary or
                            expedient to make the Plan fully effective. All
                            decisions by the Vorstand shall be made in the
                            Vorstand's sole discretion and shall be final and
                            binding on all persons having or claiming any
                            interest in the Plan or in any Option. No Director
                            or person acting pursuant to the authority delegated
                            by the Vorstand shall be liable for any action or
                            determination relating to or under the Plan made in
                            good faith.

                  (3)       To amend the Plan or a Stock Option Grant as
                            provided in Section 11.



4.       SHARES SUBJECT TO THE PLAN.

         (a)      Subject to the respective  resolutions of the Company's
                  stockholders as well as subject to the provisions of Section
                  10 relating to adjustments upon changes in stock, the maximum
                  number of shares that may be issued pursuant to Stock Option
                  Grants made under the Plan may not exceed 415,000, which is
                  the corresponding number of shares that can be issued
                  according to the existing conditional capital which, has been
                  be created by a resolution of the Company's stockholders
                  according to subparagraph (b). If any Stock Option Grant shall
                  for any reason expire or otherwise terminate, in whole or in
                  part, without having been exercised in full, the stock not
                  acquired under such Stock Option Grant shall revert to and
                  again become available for issuance under the Plan subject,
                  however, in the case of Incentive Stock Options, to any
                  limitation required under the Code.



                                      - 5-

         (b)      The stock subject to the Plan may be new shares which will be
                  issued by way of capital increase using up conditional capital
                  which has been created by a resolution of the Company's
                  stockholders on May 24, 2006 in order to satisfy the Company's
                  obligations under the Plan. The provisions of the
                  Aktiengesetz, in particular Sections 192 para. 2 cif. 3, 193
                  para. 2 cif. 4, AktG, have to be obeyed. However, an exercised
                  Option subject to the Plan may be satisfied with reacquired
                  shares, bought on the market or otherwise in accordance with
                  Section 71 AktG.

5.       ELIGIBILITY.

         (a)      Incentive Stock Options may be granted only to Employees and
                  shall be subject to and construed consistently with the
                  requirements of Section 422 of the Code. Stock Option Grants
                  other than Incentive Stock Options may be granted only to
                  Employees and Directors. The Company shall have no liability
                  to an Employee, or any other party, if an Option (or any part
                  thereof) that is intended to be an Incentive Stock Option is
                  not an Incentive Stock Option.

         (b)      No Employee shall be eligible for the grant of an Incentive
                  Stock Option if, at the time of grant, such person owns (or is
                  deemed to own pursuant to Section 424(d) of the Code) stock
                  possessing more than ten percent (10%) of the total combined
                  voting power of all classes of stock of the Company or of any
                  of its Affiliates (a "10% Stockholder") unless the exercise
                  price of such Option is at least one hundred ten percent
                  (110%) of the Fair Market Value of such stock at the date of
                  grant and the Option is not exercisable after the expiration
                  of five (5) years from the date of grant.

         (c)      Subject to the provisions of Section 10 relating to
                  adjustments upon changes in stock, no person shall be eligible
                  to be granted Options covering more than one hundred thousand
                  (100,000) of the Company's shares in any calendar year. This
                  Section 5(c) shall not apply until the Company is Redomiciled.

6.       OPTION PROVISIONS.

         Each Option shall be evidenced by a written instrument in such form as
         the Vorstand shall determine and shall contain such terms and
         conditions as the Vorstand in co-ordination with the Aufsichtsrat shall
         deem appropriate. The provisions of separate Options need not be
         identical, but each Option shall include (through incorporation of
         provisions hereof by reference in the Option or otherwise) the
         substance of each of the following provisions:

         (a)      Term.  The Options may be offered to the Optionees during the
                  last fifteen working days of each calendar month (acquisition
                  period pursuant to Section 193 Para. 2 No. 4 AktG).




                                     - 6 -

                  Each Option shall be exercisable at such times and subject to
                  such terms as the Vorstand may specify in the applicable Stock
                  Option Grant, provided, however, that no Option shall be
                  exercisable after the expiration of ten (10) years from the
                  date it was granted.

         (b)      Price.  The Vorstand shall establish the exercise price at
                  the time each Option is granted and shall specify it in the
                  applicable Stock Option Grant, provided however, that, except
                  as provided in Section 5(b), the exercise price of each
                  Incentive Stock Option shall be not less than one hundred
                  percent (100%) of the Fair Market Value.

         (c)      Consideration.  According to applicable German Law, the
                  exercise price of stock acquired pursuant to an Option can
                  only be paid to the Company, at the latest, when the Option is
                  exercised either (i) in cash (EURO), or (ii) by money transfer
                  onto an account of the Company with a (German or
                  international) bank residing in Germany. Any other means of
                  payment or payment in kind is prohibited according to Section
                  199 para. 1, 54 para. 3, 36 para. 2 AktG.

         (d)      Transferability.  An Incentive Stock Option shall not be
                  transferable except by will or by the laws of descent and
                  distribution, and shall be exercisable during the lifetime of
                  the person to whom the Option is granted only by such person.
                  Notwithstanding the foregoing, the person to whom an Incentive
                  Stock Option Agreement is granted may, by delivering written
                  notice to the Company, in a form satisfactory to the Company,
                  designate a third party who, in the event of the death of the
                  Optionee, shall thereafter be entitled to exercise the Option.

         (e)      Vesting.  The total number of shares of stock subject to an
                  Option may, but need not, be allotted in periodic installments
                  (which may, but need not, be equal). The Stock Option
                  Agreement may provide that from time to time during each of
                  such installment periods, the Option, notwithstanding Section
                  6(i), may become exercisable ("vest") with respect to some or
                  all of the shares allotted to that period, and may be
                  exercised with respect to some or all of the shares allotted
                  to such period and/or any prior period as to which the Option
                  became vested but was not fully exercised. The Option may be
                  subject to such other terms and conditions on the time or
                  times when it may be exercised (which may be based on
                  performance or other criteria according to the then applicable
                  resolution of the Company's stockholders) as the Vorstand in
                  co-ordination with the Aufsichtsrat may deem appropriate.

         (f)      Termination of Employment or Relationship as a Director.  In
                  the event an Optionee's Continuous Status as an Employee or
                  Director terminates (other than upon the Optionee's death or
                  disability, as defined below), the Optionee may exercise his
                  or her Option to the extent that the Optionee was entitled to
                  exercise it according




                                      - 7-

                  to Sections 6(e) and 6(i) at the date of termination but only
                  within such period of time ending on the earlier of (i) the
                  date three (3) months after the termination of the Optionee's
                  Continuous Status as an Employee or Director (or such longer
                  or shorter period as specified in the Stock Option Agreement)
                  or (ii) the expiration of the term of the Option as set forth
                  in the Stock Option Agreement. However, notwithstanding the
                  foregoing, should the date of termination be prior to that of
                  the expiration of the two-year waiting period mentioned in
                  Section 6(i), the Optionee may exercise his or her Option at
                  the date of expiration of such waiting period but only within
                  three (3) months after the expiration of the two-year waiting
                  period; provided, however, that, unless otherwise provided in
                  the Code or the Treasury regulations thereunder, any such
                  Option which was intended to be an Incentive Stock Option
                  which is exercised at any time after three (3) months of the
                  termination of the Optionee's Continuous Status as an Employee
                  shall no longer qualify as an Incentive Stock Option, but
                  shall be treated as, and have the consequences of, a
                  Nonstatutory Stock Option. If the Optionee does not exercise
                  his or her Option within the time required, the Option shall
                  terminate, and the shares covered by such Option shall revert
                  to and again become available for issuance under the Plan
                  subject, however, in the case of Incentive Stock Options to
                  any limitation required under the Code.

         (g)      Disability of Optionee.  In the event an Optionee's Continuous
                  Status as an Employee or Director terminates as a result of
                  the Optionee's disability (within the meaning of Section
                  22(e)(3) of the Code), the Optionee may exercise his or her
                  Option to the extent that the Optionee was entitled to
                  exercise it according to Sections 6(e) and 6(i) at the date of
                  termination, but only within such period of time ending on the
                  earlier of (i) the date three (3) months following such
                  termination (or such longer or shorter period as specified in
                  the Stock Option Agreement ) or (ii) the expiration of the
                  term of the Option as set forth in the Stock Option Agreement;
                  provided, however, should the date of termination be prior to
                  that of the expiration of the two-year waiting period
                  mentioned in Section 6(i), the Optionee may exercise his or
                  her Option at the date of expiration of such waiting period
                  but only within three (3) months after the expiration of the
                  two-year waiting period; provided further, however, that,
                  unless otherwise provided in the Code or the Treasury
                  regulations thereunder, any such Option which was intended to
                  be an Incentive Stock Option which is exercised at any time
                  after one year of the termination of the Optionee's Continuous
                  Status as an Employee shall no longer qualify as an Incentive
                  Stock Option but shall be treated as, and have the
                  consequences of, a Nonstatutory Stock Option. If, at the date
                  of termination, the Optionee is not entitled to exercise his
                  or her entire Option, the shares covered by the unexercisable
                  portion of the Option shall revert to and again become
                  available for issuance under the Plan subject, however, in the
                  case of Incentive Stock Options to any limitations under the
                  Code. If, after termination, the Optionee does not exercise
                  his or her Option within the time




                                     - 8 -

                  specified herein, the Option shall terminate, and the shares
                  covered by such Option shall revert to and again become
                  available for issuance under the Plan subject, however, in the
                  case of Incentive Stock Options to any limitations under the
                  Code.

         (h)      Death of Optionee.  In the event of the death of an Optionee
                  during, or within a period specified in the Option after the
                  termination of, the Optionee's Continuous Status as an
                  Employee or Director, the Option may be exercised to the
                  extent the Optionee was entitled to exercise it according to
                  Sections 6(e) and 6(i)at the date of death by the Optionee's
                  estate, by a person who acquired the right to exercise the
                  Option by bequest or inheritance or by a person designated to
                  exercise the Option upon the Optionee's death pursuant to
                  Section 6(d), but only within the period ending on the earlier
                  of (i) the date six (6) months following the date of death (or
                  such longer or shorter period as specified in the Stock Option
                  Agreement) or (ii) the expiration of the term of such Option
                  as set forth in the Stock Option Agreement. However, should
                  the date of termination be prior to that of the expiration of
                  the two-year waiting period mentioned in Section 6(i), the
                  Optionee may exercise his or her Option at the date of
                  expiration of such waiting period but only within the later of
                  six (6) months after the expiration of the two-year waiting
                  period; provided further, however, that, unless otherwise
                  provided in the Code or the Treasury regulations thereunder,
                  any such Option which was intended to be an Incentive Stock
                  Option which is exercised at any time after one year of the
                  termination of the Optionee's Continuous Status as an Employee
                  shall no longer qualify as an Incentive Stock Option but shall
                  be treated as, and have the consequences of, a Nonstatutory
                  Stock Option. If, at the time of death, the Optionee was not
                  entitled to exercise his or her entire Option, the shares
                  covered by the unexercisable portion of the Option shall
                  revert to and again become available for issuance under the
                  Plan subject, however, in the case of Incentive Stock Options
                  to any limitations under the Code. If, after death, the Option
                  is not exercised within the time specified herein, the Option
                  shall terminate, and the shares covered by such Option shall
                  revert to and again become available for issuance under the
                  Plan subject, however, in the case of Incentive Stock Options
                  to any limitations under the Code.

         (i)      Exercise.  Before any Option subject to the Plan may be
                  exercised according to Section 193 para. 2 cif. 4 AktG a
                  mandatory minimum waiting period of two years, counted as of
                  the date of the Stock Option Grant, has to be observed. No
                  shares shall be issued before the aforementioned waiting
                  period has expired.

                  The stock options may only be exercised if the Closing Price
                  develops better than a reference index (performance goal
                  pursuant to Section 193 Para. 2 No. 4 of the German Stock
                  Corporation Act).




                                     - 9 -

                  Closing Price is the price of one GPCB Share in the XETRA
                  closing auction on the Frankfurt Stock Exchange.

                  Reference index shall be the stock index TecDax of the
                  Frankfurt Stock Exchange (the "Price Index").

                  The Price Index as well as the Closing Price on the date on
                  which the stock options are issued shall serve as the starting
                  point for the performance measurement. The stock options may
                  only be exercised if the Closing Price has developed better
                  than the Price Index. The relevant comparison date for this
                  shall be the date four weeks prior to the exercise of the
                  stock options.

                  Options may be exercised by submitting a written notice of
                  exercise to the Company signed by the proper person or by any
                  other form of notice approved by the Vorstand together with
                  payment in full as specified in Section 6(c) for the number of
                  shares for which the Option is exercised.

                  Options may not be exercised from the date on which the
                  Company submits an offer to its shareholders for the
                  subscription of new shares or convertible bonds with
                  conversion or option rights by written notice to all
                  shareholders or through an announcement in the publications
                  named in the Company's Articles of Association or in a
                  mandatory stock exchange publication of the Frankfurt Stock
                  Exchange until the end of the last day of the subscription
                  period.


                  Furthermore, the Options may, each time, only be exercised
                  within a period of six weeks after publication of the
                  quarterly reports or annual financial statements (exercise
                  period pursuant to Sect. 193 Para. 2 No. 4 AktG). As a matter
                  of principle, exercise of the Options shall be excluded from
                  December 24 to December 31 of each calendar year.

         (j)      Public Offering.  Each Optionee, for as long as any
                  shareholder of the Company who had previously been an
                  Optionee, may be restricted from selling shares in connection
                  with any public offering of shares by the Company, subject to
                  the same restrictions should he exercise his Options during
                  the period within which such former Optionee is so restricted.

         (k)      Vorstand Discretion.  Except as otherwise  provided in the
                  Plan, each Stock Option Grant may be made alone or in relation
                  to any other Stock Option Grant. The terms of each Stock
                  Option Grant need not be identical, and the Vorstand need not
                  treat Optionees uniformly.





                                     - 10 -

7.       COVENANTS OF THE COMPANY.

         The Company shall seek to obtain from each regulatory commission or
         agency having jurisdiction over the Plan such authority as may be
         required to issue and sell shares of stock upon exercise of the Stock
         Option Grant; provided, however, that this undertaking shall not
         require the Company to register under the Securities Act of 1933, as
         amended (the "Securities Act") either the Plan, any Stock Option Grant
         or any stock issued or issuable pursuant to any such Stock Option
         Grant. If, after reasonable efforts, the Company is unable to obtain
         from any such regulatory commission or agency the authority which
         counsel for the Company deems necessary for the lawful issuance and
         sale of stock under the Plan, the Company shall be relieved from any
         liability for failure to issue and sell stock upon exercise of such
         Stock Option Grants unless and until such authority is obtained.

8.       USE OF PROCEEDS FROM STOCK.

         Proceeds from the sale of stock pursuant to Stock Option Grants shall
         constitute capital reserves of the Company.

9.       MISCELLANEOUS.

         (a)      The Vorstand in coordination with the Aufsichtsrat shall have
                  the power to accelerate the time at which a Stock Option Grant
                  may first be exercised or the time during which a Stock Option
                  Grant or any part thereof will vest pursuant to Section 6(e),
                  notwithstanding the provisions in the Stock Option Grant
                  stating the time at which it may first be exercised or the
                  time during which it will vest.

         (b)      Neither an Employee or Director nor any person to whom a Stock
                  Option Grant is transferred under Section 6(d) shall be deemed
                  to be the holder of, or to have any of the rights of a holder
                  with respect to, any shares subject to such Stock Option Grant
                  unless and until such person has satisfied all requirements
                  for exercise of the Stock Option Grant pursuant to its terms.

         (c)      Nothing in the Plan or any instrument executed or Stock Option
                  Grant granted pursuant thereto shall confer upon any Employee
                  or Director any right to continue in the employment of the
                  Company or any Affiliate (or to continue acting as a Director)
                  or shall affect the right of the Company or any Affiliate to
                  terminate the employment of any such person with or without
                  cause.

         (d)      For so long as the Code provides, to the extent that the
                  aggregate Fair Market Value (determined at the time of grant)
                  of stock with respect to which Incentive Stock Options are
                  exercisable for the first time by any Option holder during any
                  calendar




                                     - 11 -

                  year under all stock plans of the Company and its Affiliates
                  exceeds one hundred thousand dollars ($100,000), the Options
                  or portions thereof which exceed such limit (according to the
                  order in which they were granted) shall be treated as
                  Nonstatutory Stock Options.

         (e)      The Company may require any person to whom an Option is
                  granted, or any person to whom an Option is transferred
                  pursuant to Section 6(d), as a condition of exercising or
                  acquiring stock under any Stock Option Grant,(i) to give
                  written assurances satisfactory to the Company as to such
                  person's knowledge and experience in financial and business
                  matters and/or to employ a purchaser representative reasonably
                  satisfactory to the Company who is knowledgeable and
                  experienced in financial and business matters, and that he or
                  she is capable of evaluating, alone or together with the
                  purchaser representative, the merits and risks of exercising
                  the Stock Option Grant; and (ii) to give written assurances
                  satisfactory to the Company stating that such person is
                  acquiring the stock subject to the Stock Option Grant for such
                  person's own account and not with any present intention of
                  selling or otherwise distributing the stock. The foregoing
                  requirements, and any assurances given pursuant to such
                  requirements, shall be inoperative if (i) the issuance of the
                  shares upon the exercise or acquisition of stock under the
                  Stock Option Grant has been registered under a then currently
                  effective registration statement under the Securities Act, or
                  (ii) as to any particular requirement, a determination is made
                  by counsel for the Company that such requirement need not be
                  met in the circumstances under the then applicable securities
                  laws. The Company may, upon advice of counsel to the Company,
                  place legends on stock certificates issued under the Plan as
                  such counsel deems necessary or appropriate in order to comply
                  with applicable securities laws, including, but not limited
                  to, legends restricting the transfer of the stock.

         (f)      To the extent provided by the terms of a Stock Option
                  Agreement, the person to whom an Option is granted must
                  satisfy any federal, state or local tax withholding obligation
                  relating to the exercise or acquisition of stock under the
                  Plan by any of the following means or by a combination of such
                  means: (i) tendering a cash payment; (ii) authorizing the
                  Company or Subsidiary to withhold shares from the shares
                  otherwise issuable to the participant as a result of the
                  exercise or acquisition of stock under the Plan; or (iii)
                  delivering to the Company or Subsidiary owned and unencumbered
                  shares of the Company. Payment of such withholding obligation
                  shall be made no later than the date of the event creating the
                  tax liability.

10.      ADJUSTMENTS UPON CHANGES IN STOCK.




                                     - 12 -

         (a)      In the event of a merger of the Company with and into another
                  entity where the Company is not the surviving entity
                  (Verschmelzung durch Aufnahme), a change in the legal form of
                  the Company (Umwandlung), a change in the notional nominal
                  value of the shares of stock in the Company and similar
                  measures leading to the cancellation or conversion of the
                  shares of stock underlying the Options, each outstanding
                  Option shall be substituted by the right to purchase at the
                  exercise price a specific number of shares of stock or other
                  interests in the Company or its successor entity (calculated
                  on the basis of the Fair Market Value at the time of any such
                  change) substituting the shares of stock in the Company. The
                  remaining provisions of this Plan shall remain unaffected.

         (b)      In the event of a capital decrease by means of amalgamating
                  the ordinary shares in the Company (Kapitalherabsetzung durch
                  Zusammenlegung, ss. 222(4) AktG) or by means of cancellation
                  (Einziehung) of ordinary shares (ss. 237 AktG), the
                  subscription ratio (as specified in the applicable Stock
                  Option Grant) shall be adjusted by multiplying it with the
                  coefficient resulting from the division of the number of
                  shares of stock after such capital decrease by the number of
                  shares of stock prior to such capital decrease. Fractional
                  shares of stock resulting from any such capital decrease will
                  not be delivered upon exercise of the Options.

         (c)      In case of a capital increase out of retained  earnings by the
                  Company, any existing conditional capital will be increased
                  according to Section 218 AktG in the same ratio as the
                  Company's share capital, instead of a deduction of the
                  exercise price. The right of an Option holder to purchase
                  stock of the Company, at the point in time of exercise, will
                  increase in the same ratio as the Company's share capital
                  increase.

11.      AMENDMENT OF THE PLAN AND STOCK OPTION GRANTS.

         (a)      The Vorstand in coordination with the Aufsichtsrat at any
                  time, and from time to time, may amend the Plan and/or some or
                  all outstanding Stock Option Grants granted under the Plan.
                  However, except as provided in Section 10 relating to
                  adjustments upon changes in stock, no amendment shall be
                  effective unless approved by the stockholders of the Company
                  to the extent stockholder approval is necessary for the Plan
                  to satisfy the requirements of the Aktiengesetz as well as of
                  Section 422 of the Code, or any security laws or any Nasdaq or
                  securities exchange listing requirements.

         (b)      The Vorstand in coordination with the Aufsichtsrat may in its
                  discretion submit any other amendment to the Plan for
                  stockholder approval, including, but not limited to,
                  amendments to the Plan intended to satisfy the requirements of
                  the Aktiengesetz and/or Section 162(m) of the Code and the
                  regulations promulgated thereunder




                                     - 13 -

                  regarding the exclusion of performance-based compensation from
                  the limit on corporate deductibility of compensation paid to
                  certain executive officers.

         (c)      It is expressly contemplated that the Vorstand in coordination
                  with the Aufsichtsrat may amend the Plan in any respect the
                  Vorstand deems necessary or advisable to provide eligible
                  Employees or Directors with the maximum benefits provided or
                  to be provided under the provisions of the Code and the
                  regulations promulgated thereunder relating to Incentive Stock
                  Options and/or to bring the Plan and/or Incentive Stock
                  Options granted under it into compliance therewith.

         (d)      Rights and obligations under any Option granted before
                  amendment of the Plan shall not be impaired by any Plan
                  amendment unless the Company requests the consent of the
                  person to whom the Stock Option Grant was granted and such
                  person consents in writing.

         (e)      The Vorstand in coordination with the Aufsichtsrat at any
                  time, and from time to time, may amend the terms of any one or
                  more Stock Option Grant; provided, however, that the rights
                  and obligations under any Stock Option Grant shall not be
                  impaired by any such amendment unless (i) the Company requests
                  the consent of the person to whom the Stock Option Grant was
                  granted and (ii) such person consents in writing.

12.      TERMINATION OR SUSPENSION OF THE PLAN.

         (a)      The Vorstand in coordination with the Aufsichtsrat may suspend
                  or terminate the Plan at any time. Unless sooner terminated,
                  the Plan shall terminate on the last business day of May 31,
                  2010. No Options may be granted under the Plan while the Plan
                  is suspended or after it is terminated but any outstanding
                  option may be exercised ten (10) years from the grant date.

         (b)      Rights and obligations under any Option granted while the Plan
                  is in effect shall not be impaired by suspension or
                  termination of the Plan, except with the consent of the person
                  to whom the Stock Option Grant was granted.

13.      EFFECTIVE DATE OF PLAN.

         The Plan is effective as of the approval of the shareholders on June 8,
         2005; provided, however, that, following a Redomociling, no Stock
         Option Grant granted to an Optionee designated by the Vorstand as
         subject to Section 162(m) of the Code shall become exercisable, vested
         or realizable, as applicable to such Stock Option Grant, unless and
         until the Plan has been approved by the Company's stockholders to the
         extent stockholder




                                     - 14 -

         approval is required by Section 162(m) in the manner required under
         Section 162(m) (including the vote required under Section 162(m)).

Martinsried/Planegg, May 24, 2006

                                                      GPC Biotech AG
                                                       Der Vorstand