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                                                                   EXHIBIT 10.25

DATED                                                                       1998

(1) IMPERIAL CANCER RESEARCH TECHNOLOGY
    LIMITED
(2) INTROGEN THERAPEUTICS, INC




OPTION AGREEMENT
FOR TUMOUR SUPPRESSOR GENES



                                [RICHARDS BUTLER
                          INTERNATIONAL LAW FIRM LOGO]


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CONTENTS

CLAUSE

1 INTRODUCTION .............................................................  1
2 INTERPRETATION ...........................................................  1
3 GRANT OF THE FIRST OPTION ................................................  5
4 EXERCISE OF THE FIRST OPTION .............................................  7
5 THE PROJECT ..............................................................  8
6 OWNERSHIP OF TECHNOLOGY AND INTELLECTUAL PROPERTY ........................ 11
7 CONFIDENTIALITY AND PUBLICATION .......................................... 16
8 TERMINATION .............................................................. 19
9 GENERAL .................................................................. 21
10 NOTICES AND SERVICE ..................................................... 25
11 MISCELLANEOUS............................................................ 26


SCHEDULES

SCHEDULE 1 ................................................................. 27
     THE EXISTING PATENTS .................................................. 27
SCHEDULE 2 ................................................................. 28
     THE TERMS OF THE FIRST LICENCE ........................................ 28
SCHEDULE 3 ................................................................. 34
     OBJECTIVES OF THE PROJECT ............................................. 34
SCHEDULE 4 ................................................................. 36
     THE TERMS OF THE SECOND LICENCE ....................................... 36


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AGREEMENT dated                                                             1998

BETWEEN:

(1)   IMPERIAL CANCER RESEARCH TECHNOLOGY LIMITED, incorporated in England and
      Wales with registered number 1662284, whose registered office is at
      Sardinia House, Sardinia Street, London WC2A 3NL, England ('ICRT')

(2)   INTROGEN THERAPEUTICS, INC, incorporated in the State of Delaware, whose
      principal office is at 301 Congress Avenue, Suite 1850, Austin, Texas
      78701, USA ('INTROGEN')

1     INTRODUCTION

1.1   Imperial Cancer Research Fund ('ICRF') and ICRT have identified and
      carried out a programme of research work relating to certain tumour
      suppressor genes which have potential therapeutic uses, and in respect of
      which certain patent applications have been or are to be made by ICRT,
      details of which are given in Schedule 1.

1.2   Introgen wishes to acquire rights in relation to the Genes in order to
      develop DNA based therapeutic products for the treatment of cancer, and is
      willing to fund a project in ICRT's laboratory to evaluate the potential
      of the Genes in cancer gene therapy.

1.3   ICRT is a company wholly owned by ICRF and, by arrangement with ICRF, owns
      and is responsible for the management and exploitation of ICRF technology.

2     INTERPRETATION

2.1   In this Agreement -

      'AFFILIATE' means, in relation to either party, a company which controls
      that party, or is controlled by that party or by a company which controls
      that party; and for these purposes a company controls another company if,
      either directly or indirectly through one or more other companies, it can
      exercise a majority of the votes attached to the


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      shares in the other company, or appoint or remove a majority of the board
      of directors of the other company;

      'THE EFFECTIVE DATE' means 1st January 1999;

      'THE EXISTING PATENTS' means the patent applications referred to in clause
      1.1, and any other patent application which relates to the Field and
      claims the composition, use and/or method of action of any of the Genes,
      as disclosed in any of the patent applications referred to in clause 1.1,
      and which is made by ICRT at any time during the period from the Effective
      Date until the expiration of the First Option Period, any extension,
      reissue, division, continuation or continuation-in-part of any such
      application or patent and any patent of addition, supplementary protection
      certificate or similar rights based on any such patent;

      'EXISTING TECHNOLOGY' means any Technology relating to any of the Genes
      which has been obtained, developed, found, produced or made by or for ICRF
      or ICRT at any time prior to the Effective Date;

      'THE FIELD' means the field of [*];

      'THE FIRST LICENCE' means the licence to be granted pursuant to clause
      4.1;

      'THE FIRST OPTION' means the option granted by ICRT under clause 3.1;

      'THE FIRST OPTION PERIOD' means the period of [*] from the Effective
      Date;

      'THE GENES' means the tumour suppressor genes referred to in clause 1.1
      (i.e. Rsk3, DBCCR1, 11q24 and 16q23) including, for the avoidance of
      doubt, any splice variants or other derivatives of any such gene and for
      the purposes of the foregoing, a


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      "derivative" means a nucleotide sequence derived from that gene (including
      fragments thereof) the product of which has tumour suppressor activity;

      'ICRF' means Imperial Cancer Research Fund;

      'INTELLECTUAL PROPERTY' means any patent application or patent (including
      any extension, reissue, division, continuation or continuation-in-part of
      any such application or patent and any patent of addition, supplementary
      protection certificate or similar rights based on any patent), copyright
      or other form of protection, the right to make any application for any
      such protection in any part of the world, and any right in respect of any
      trade secret or other confidential information;

      'THE INVENTIONS' means the inventions claimed or disclosed in the Existing
      Patents;

      'MATERIALS' means any model, prototype, material or substance (including,
      without limitation, any living organism or genetic material), and includes
      any progeny or derivative of any of the foregoing;

      'THE NEGOTIATION PERIOD' means the period of [*] from the date of exercise
      of the First Option or the Second Option, as the case may be, or such
      longer period as the parties may agree in either case;

      'THE PROJECT' means the programme of collaborative research referred to in
      clause 5.1;

      'PROJECT TECHNOLOGY' means any Technology obtained, developed, found,
      produced or made at any time on or after the Effective Date in the course
      of the Project;

      'PROJECT PATENTS' means any patent applications claiming any Project
      Technology, any patents issued in pursuance of any such application, any
      extension, reissue, division, continuation or continuation-in-part of any
      such application or patent and any patent of addition, supplementary
      protection certificate or similar rights based on any such patent;



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      'THE SECOND LICENCE' means the agreement to be entered into pursuant to
      clause 6.7;

      'THE SECOND OPTION' and 'THE SECOND OPTION PERIOD' have the meanings given
      in clause 6.6;

      'TECHNOLOGY' means any methods, techniques, processes, discoveries,
      inventions (whether patentable or not), formulae, results of
      experimentation, statistics, data, computer software or plans, any
      Materials and any records in any form relating to any of the foregoing;
      and

      'YEAR' means a period of 365 (or, in the case of a leap year, 366) days.

2.2   Unless the context otherwise requires, each reference in this Agreement to

      (a) 'WRITING', and any cognate expression, includes a reference to any
          communication effected by facsimile transmission or similar means
          (but not electronic mail);

      (b) a licence includes a sub-licence; and 'LICENSE' (as a verb) and
          cognate expressions shall be construed accordingly;

      (c) a statute or a provision of a statute is a reference to that statute
          or provision as amended, re-enacted or extended at the relevant time,
          and includes any statute or a corresponding provision in a statute
          replacing that statute or provision;

      (d) 'THIS AGREEMENT' is a reference to this Agreement and each of the
          Schedules, as amended or supplemented at the relevant time;

      (e) a Schedule is a reference to a schedule to this Agreement;

      (f)  a clause or a paragraph is a reference to a clause of this Agreement
          (other than the Schedules) or a paragraph of the relevant Schedule;


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      (g) any reference to the parties includes a reference to their
          respective successors in title and permitted assignees;

      (h) any reference to a person includes any body corporate, unincorporated
          association, partnership or other legal entity;

      (i) the singular includes the plural and vice versa; and

      (j) words importing any gender include any other gender.

2.3   The headings in this Agreement are for convenience only and shall not
      affect its interpretation.

3     GRANT OF THE FIRST OPTION

3.1   ICRT hereby grants to Introgen, on and subject to the terms of this
      Agreement, the exclusive option to obtain an exclusive, world-wide licence
      (to the extent that ICRT is able to grant such a licence under any
      applicable law) in respect of the Existing Patents relating to any one
      or more of the Genes and any Materials or other Existing Technology
      referred to in clause 5.4, in respect of the Gene or Genes in question, on
      the terms referred to in clause 4.1.

3.2   The First Option shall be exercisable by Introgen, in respect of any
      one or more of the Genes, subject to payment of the sum referred to in
      clause 3.3, by giving written notice to ICRT at any time during the First
      Option Period, specifying the Gene or Genes in respect of which it is
      exercised. If Introgen so exercises the First Option in respect of one or
      more but not all of the Genes it may do so at any subsequent time within
      the First Option Period in respect of the remaining Gene or Genes.

3.3   In consideration of the grant of the First Option, Introgen shall pay to
      ICRT the sum of [*] on the Effective Date.

3.4   The sum referred to in clause 3.3 shall not be refunded in any
      circumstances.


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3.5   If Introgen does not duly exercise the First Option during the First
      Option Period in respect of one or more of the Genes, it shall forthwith
      lapse in respect of the Gene or Genes in question for which Introgen did
      not so exercise the First Option.

3.6   During the First Option period ICRT shall diligently prosecute and
      maintain the Existing Patents and keep Introgen fully informed as to the
      prosecution status of the Existing Patents (including, without limitation,
      furnishing to Introgen information relevant to such prosecution and
      maintenance) and shall give fair consideration to suggestions made by
      Introgen in respect of the prosecution strategy in so far as they relate
      to the Field, but if ICRT notifies Introgen in writing that -

      (a) it wishes to abandon any patent application or patent within the
          Existing Patents which relates to the Field, it shall give a prompt
          written notice Introgen offering to assign it to Introgen at the
          expense of Introgen but otherwise free of charge, and if Introgen does
          not accept the offer in writing within 30 days, ICRT shall have no
          further obligation with respect to the patent or patent application;
          or

      (b) it does not wish to elect to proceed from PCT stage to national stage
          with respect to any such application in any country, it shall give a
          prompt written notice to Introgen, and ICRT shall have no further
          obligation with respect to the application unless Introgen notifies
          ICRT in writing within thirty (30) days that it wishes ICRT so to
          proceed, in which event ICRT shall do so but at the sole expense of
          Introgen, and accordingly for the purposes of -

          (i)  clause 3.7(b), that application and any Existing Patent granted
               pursuant to it in the relevant country shall be treated as if
               they had been assigned to Introgen; and

          (ii) the provisions of the First Licence as to royalties summarised in
               paragraph 9 of Schedule 2, that application and any Existing
               Patent


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               granted pursuant to it shall be deemed not to exist in the
               relevant country.

3.7   During the First Option Period the out-of-pocket costs and expenses of
      prosecuting and maintaining the Existing Patents shall be borne -

      (a) in respect of any of the Existing Patents the claims of which relate
          exclusively to any matter outside the Field, [*];

      (b) in respect of any of the Existing Patents the claims of which relate
          exclusively to the Field, or which have been assigned to Introgen
          pursuant to clause 3.6(a) (or are treated as if they had been so
          assigned pursuant to clause 3.6(b)(i), [*];

      (c) in respect of any other of the Existing Patents, [*];

      and Introgen shall accordingly pay to ICRT the [*] of those costs and
      expenses incurred from time to time within 30 days after receipt from ICRT
      of an account setting out the relevant information to enable its share to
      be ascertained.

4     EXERCISE OF THE FIRST OPTION

4.1   If Introgen exercises the First Option in accordance with clause 3.2, in
      respect of one or more of the Genes, ICRT and Introgen shall forthwith use
      their best endeavours during the Negotiation Period to negotiate in good
      faith the terms and conditions for the grant to Introgen of the licence
      referred to in clause 3.1 ('THE FIRST LICENCE'), which shall include the
      terms and conditions set out in Schedule 2 and such other terms and
      conditions (consistent with those set out in Schedule 2) as are reasonable
      and customary in the biopharmaceutical industry for arrangements of the
      type contemplated by the First Licence. If Introgen subsequently exercises
      the First Option in respect of any of the Genes, the Gene or Genes in
      question shall be deemed as from the date of exercise to be covered by the
      terms of the First Licence.


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4.2   Upon agreement being reached between ICRT and Introgen as to the terms of
      the First Licence, the parties shall forthwith execute an agreement
      containing the terms so agreed between ICRT and Introgen.

4.3   If, notwithstanding their best endeavours, ICRT and Introgen do not agree
      upon the terms for the grant of the First Licence to Introgen during the
      Negotiation Period, Introgen shall have the right, exercisable by
      notifying ICRT in writing at any time within fifteen (15) days after the
      expiration of the Negotiation Period, to initiate a binding arbitration
      proceeding, pursuant to which the terms and conditions of the First
      Licence shall be established. Any arbitration under this provision shall
      be held in accordance with clause 9.12 by a single arbitrator and the sole
      issue before such arbitrator shall be to establish the terms and
      conditions of the First Licence in accordance with clause 4.1, to the
      extent that they have not been agreed. If Introgen does not exercise the
      foregoing right to initiate arbitration within the applicable fifteen (15)
      day period, the First Option shall lapse in respect of the Gene or Genes
      in question.

4.4   If the First Option lapses pursuant to clause 3.5 or 4.3 (and if Introgen
      has no further right to exercise the First Option in respect of any of the
      Genes) then, except to the extent that clauses 5, 6 and 7 continue to
      operate, this Agreement shall terminate automatically, in which case all
      rights and obligations of the parties shall terminate except as provided
      in clause 8.4.

5     THE PROJECT

5.1   As further consideration for the grant of the First Option, Introgen
      shall co-operate with ICRT on a programme of collaborative research on the
      following terms.

5.2   Subject to the following provisions, the Project shall be carried on for a
      period of [*] from the Effective Date.

5.3   The overall objectives of the Project shall be as set out in Schedule 3.
      Within those overall objectives, the detailed objectives and
      implementation of the Project, and the


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      work to be carried out by ICRT and Introgen respectively as part of the
      Project, shall be as agreed between Dr. David Snary of ICRT and Dr. Sunil
      Chada of Introgen from time to time, but initially as set out in Schedule
      3.

5.4   ICRT shall, as soon as practicable after the Effective Date -

      (a) supply to Introgen samples of such of the Materials relating to the
          Genes and in the possession or control of ICRT as are reasonably
          necessary to enable Introgen to carry its tasks in relation to the
          Project or as are otherwise requested by Introgen from time to time in
          connection with its evaluation of the Genes with a view to deciding
          whether or not to exercise the First Option or the Second Option; and

      (b) disclose to Introgen such other of the Existing Technology as is
          relevant to the Project or it exercise of the First Option or the
          Second Option;

      and Introgen shall be entitled to use and practice the Inventions, and to
      use any Materials so supplied and any Existing Technology so disclosed
      during the continuance of the Project, for the purposes only of carrying
      out its part of the Project and planning the development and exploitation
      in the Field of the Existing Technology and Project Technology or as
      otherwise reasonably necessary to evaluate the Genes with a view to
      deciding whether or not to exercise the First Option or the Second Option.

5.5   Subject as provided in clause 5.4, the resources to be applied to the
      Project by each of ICRT and Introgen shall be solely at its discretion.

5.6   Introgen shall pay to ICRT, as a contribution to the work to be carried
      out by ICRT as part of the Project, the sum of [*] on the
      Effective Date and [*].

5.7   For the avoidance of doubt, each sum payable pursuant to clause 5.6 shall
      not be refunded in any circumstances, and if Introgen exercises the First
      Option before the


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      end of the First Option Period, any such sum which is outstanding shall
      continue to be payable.

5.8   [*]

5.9   If within [*] from the Effective Date Introgen has not commenced good
      faith active steps with a view to carrying out its part of the Project for
      any reason, ICRT shall be entitled to terminate the Project by giving to
      Introgen not less than [*] written notice provided that Introgen does
      not commence such steps within such [*] which case the parties shall
      forthwith take such steps as may be necessary to terminate the Project,
      and subject to those steps being taken this Agreement shall terminate
      automatically.

5.10  For the purposes of the Project the principal points of contact between
      the parties will be as follows -

      for ICRT:     Dr David Snary

      for Introgen: Dr Sunil Chada.

5.11  ICRT and Introgen shall ensure that Dr Snary and Dr Chada respectively
      shall communicate and meet with one another as necessary to progress the
      work on the Project, and that each of them shall report their research
      data at semi-annual intervals in a short written report to Introgen and
      ICRT respectively.

5.12  If any employees or other representatives of ICRT are requested to visit
      the premises of Introgen for the purposes of the Project, Introgen shall -


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      (a) at its own cost give all reasonable assistance required by any of them
          for that purpose; and

      (b) reimburse ICRT for their reasonable travel, accommodation and other
          expenses incurred, within 30 days after receipt of an invoice for the
          sum in question.

5.13  If by agreement with ICRT any employees or other representatives of
      Introgen visit the premises of ICRT for the purposes of the Project -

      (a) ICRT shall at the cost of Introgen give all reasonable assistance
          required by any of them for that purpose, and Introgen shall reimburse
          to ICRT any out-of-pocket sum incurred by ICRT for that purpose
          within 30 days after receipt of an invoice for the sum in question;
          and

      (b) Introgen shall be responsible for their travel, accommodation and
          other expenses.

6     OWNERSHIP OF TECHNOLOGY AND INTELLECTUAL PROPERTY

6.1   Subject to provisions of this Agreement, the Inventions, the Existing
      Patents, the Existing Technology and all Intellectual Property in respect
      of any of the Existing Technology shall remain the exclusive property of
      ICRT.

6.2   Any Project Technology, and any Project Patents or other Intellectual
      Property in respect of any Project Technology, shall -

      (a) if made solely by ICRT staff working on the Project, belong
          exclusively to ICRT;

      (b) if made solely by Introgen staff working on the Project, belong
          exclusively to Introgen;


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      (c) if made jointly by ICRT staff and Introgen staff working on the
          Project, belong to ICRT and Introgen jointly in equal undivided
          shares.

6.3   Except as otherwise provided in this Agreement and subject to the rights
      and licences granted herein, neither party shall have any obligation to
      account to the other for profits, or to obtain any approval or consent of
      the other party to license or exploit any Intellectual Property, by reason
      of their joint ownership of such Intellectual Property.

6.4   ICRT and Introgen shall discuss and seek to agree upon the extent to
      which, and the countries in which, patent protection for any Project
      Technology owned by ICRT or jointly owned by ICRT and Introgen should be
      obtained and, except to the extent that they otherwise agree in writing -

      (a) the protection shall be applied for by ICRT in the name of ICRT, or
          jointly in the names of ICRT and Introgen, as the case may be;

      (b) ICRT shall diligently prosecute and maintain the Project Patents in
          question and keep Introgen fully informed as to the prosecution status
          of the Project Patents (including, without limitation, furnishing to
          Introgen information relevant to such prosecution and maintenance) and
          shall give fair consideration to suggestions made by Introgen in
          respect of the prosecution strategy in as far as they relate to the
          Field, but if ICRT notifies Introgen in writing that -

          (i)  it wishes to abandon any such patent application or patent, it
               shall give a prompt written notice to Introgen offering to assign
               it to Introgen at the expense of Introgen but otherwise free of
               charge, and if Introgen does not accept the offer in writing
               within 30 days, ICRT shall have no further obligation with
               respect to the patent or patent application in question; or


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          (ii) it does not wish to elect to proceed from PCT stage to national
               stage with respect to any such application in any country, it
               shall give a prompt written notice to Introgen;

      (c) where ICRT gives such a notice pursuant to clause 6.4(b)(ii) above,
          ICRT shall have no further obligation with respect to the application
          unless Introgen notifies ICRT in writing within 30 days that it wishes
          ICRT so to proceed, in which event ICRT shall do so but at the sole
          expense of Introgen, and accordingly for the purposes of -

          (i)  clause 6.4(d), that application and any Project Patent granted
               pursuant to it in the relevant country shall be treated as if
               they had been assigned to Introgen; and

          (ii) the provisions of the First Licence as to royalties summarised in
               paragraph 9 of Schedule 2 (as they apply to Project Patents
               pursuant to paragraph 3 of Schedule 4), that application and any
               Existing Patent granted pursuant to it shall be deemed not to
               exist in the relevant country;

      (d) the out of pocket costs and expenses of prosecuting and maintaining
          the Project Patents in question shall be borne, as if they were
          Existing Patents, in the manner provided in clause 3.7 which shall
          apply with the necessary changes (and so that the reference therein to
          clause 3.6(b)(i) shall be deemed to be a reference to clause
          6.4(c)(i));

      (e) Introgen shall keep ICRT informed as to the prosecution status of all
          patent applications within the Project Patents owned by Introgen; and

      (f) each of ICRT and Introgen shall give the other such assistance as the
          other may reasonably require and at the other party's expense in order
          to obtain and maintain such protection.


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6.5   ICRT hereby grants to Introgen the exclusive option to take an exclusive
      licence under any or all of the Project Patents and Project Technology
      owned exclusively by ICRT and the exclusive right to exploit any and all
      Project Patents owned jointly by ICRT and Introgen, in each case insofar
      as the Project Patents and Project Technology relate to any one or more of
      the Genes in respect of which Introgen has exercised the First Option.

6.6   The option granted under clause 6.5 ('THE SECOND OPTION') shall be
      exercisable by Introgen by giving written notice to ICRT at any time
      during the period ('THE SECOND OPTION PERIOD') of [*] after the
      termination of the Project (except where this Agreement is terminated by
      ICRT pursuant to clause 8.2 or 8.3).

6.7   If Introgen exercises the Second Option in accordance with clause 6.6, the
      First Licence shall be modified to include such Project Patents and
      Project Technology within the scope of the First Licence, in accordance
      with the provisions of Schedule 4, and ICRT and Introgen shall forthwith
      execute an agreement ('THE SECOND LICENCE') to effect such a modification.
      In the event of any disagreement as to the terms of the Second Licence,
      the provisions of clause 4.3 shall apply with the necessary changes.

6.8   Notwithstanding any licence or right granted by ICRT pursuant to this
      Agreement, ICRT (for itself and ICRF) shall retain -

      (a) the exclusive right to use any Existing Technology (and any Existing
          Patents or other Intellectual Property in respect thereof) for any
          purpose outside the Field;

      (b) the exclusive right to use any Project Technology which belongs
          exclusively to ICRT (and any Project Patents or other Intellectual
          Property in respect thereof), for any purpose outside the Field;

      (c) the exclusive right to use any Project Technology which belongs to
          ICRT and Introgen jointly (and any Project Patents or other
          Intellectual Property in respect thereof) for [*]; and


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      (d) the non-exclusive right to use any Project Technology which belongs to
          ICRT and Introgen jointly (and any Project Patents or other
          Intellectual Property in respect thereof) for research and all other
          applications (except [*]) outside the Field.

6.9   Introgen hereby grants to ICRT (for itself and ICRF) an irrevocable,
      perpetual, nonexclusive, worldwide, royalty-free licence, with the right
      to grant sublicences, in respect of any Introgen Improvement, and any
      Project Patents or other Intellectual Property in respect of any such
      Introgen Improvement, for the purposes of research and the manufacture,
      sale and use of products for [*] outside the Field.

      For the purpose of this Agreement 'INTROGEN IMPROVEMENT' means any Project
      Technology which belongs exclusively to Introgen and which is a derivative
      (as defined in clause 2.1) of any of the Genes or a method of using any of
      the Genes (including derivative thereof); provided, however, that an
      'Introgen Improvement' shall not include any vector, delivery system,
      method, composition or other subject matter which is proprietary to
      Introgen, or any such Project Technology which necessarily involves or
      includes the use of or combination of any such vector, delivery system,
      method, composition or other subject matter.

6.10  If Introgen does not duly exercise the Second Option during the Second
      Option Period in respect of any one or more of the Genes, the Second
      Option shall lapse in respect of the Gene or Genes in question, and ICRT
      shall have the option, exercisable within a further [*] by giving written
      notice to Introgen, to negotiate for the grant to ICRT of an exclusive
      licence in respect of any Introgen Improvement, a nonexclusive licence in
      respect of any other Project Technology which belongs to ICRT and Introgen
      jointly, and all Project Patents or other Intellectual Property in respect
      thereof relating to the Gene or Genes in question (but excluding any
      rights in respect of any vector, delivery system, method, composition or
      other technology which is proprietary to Introgen, or any such Project
      Technology which necessarily involves or includes the use of or
      combination of any such vector, delivery system, method,



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      composition or other technology), to use the same for any purpose, on a
      world-wide, royalty-bearing basis, to the extent that Introgen is able to
      grant such a licence or right.

6.11  If ICRT exercises the option referred to in clause 6.10, ICRT and Introgen
      shall forthwith use their best endeavours to negotiate in good faith the
      terms of an agreement for the grant of the licence or right within the
      period of [*] from the date of exercise of the option (provided that any
      such agreement shall contain the right for ICRT to grant licences (or
      sub-licences) under the Project Patents and Project Technology in question
      to any other person). In the event of any disagreement as to the terms of
      such agreement, the provisions of clause 4.3 shall apply with the
      necessary changes.

7     CONFIDENTIALITY AND PUBLICATION

7.1   Except as provided herein, each party shall maintain in confidence during
      the term of this Agreement and for seven (7) years thereafter, and shall
      not use for any purpose or disclose to any third party, any Technology or
      other information disclosed by the other party in writing and marked
      "Confidential" or that is disclosed orally and confirmed in writing as
      confidential within forty-five (45) days following such disclosure
      (collectively 'CONFIDENTIAL INFORMATION'), except to the extent that any
      such Confidential Information -

      (a) is at the time of being so provided or after that time through no
          fault of the party to whom it was so provided becomes public
          knowledge; or

      (b) was lawfully available on a non-confidential basis to the party to
          whom it was so provided before that time; or

      (c) can be shown by the party to whom it was so provided to have been
          independently produced by that party without any use of such
          confidential information provided to it by the other party; or


         [*]    Certain information on this page has been omitted and filed
                separately with the Commission. Confidential treatment has been
                requested with respect to the omitted portions.




                                                                  [CONFIDENTIAL]
                                     PAGE 16
<PAGE>   19

      (d) is made available to the party to whom it was so provided otherwise
          than in breach of an obligation of confidentiality owed to the other
          party.

7.2   The results of the Project may be made public by either party (or, in the
      case of ICRT, by ICRF) except to the extent that -

      (a) publication would include any Confidential Information of the other
          party; or

      (b) publication would prejudice the obtaining of patent protection for an
          invention constituting Project Technology, or the commercial
          exploitation of any unpatented or unpatentable Project Technology
          which remains unpublished.

7.3   To allow time for review of any proposed disclosure of any subject matter
      which may be precluded from being made public under clause 7.2, each of
      ICRT and Introgen shall provide to the other -

      (a) a copy of any manuscript disclosing any results of the Project not
          less than 45 days notice before submitting the manuscript for
          publication; and

      (b) a copy of any slides to be used in an oral presentation disclosing any
          results of the Project together with an outline of the presentation
          not less than 20 working days before making any such oral
          presentation.

7.4   The party receiving any such material pursuant to clause 7.3 shall
      promptly and in any event prior to the proposed date of submission for
      publication review the proposed disclosure and notify the other party in
      writing of its conclusions, failing which the other party shall be free to
      make the proposed disclosure.

7.5   If in the reasonable opinion of the party receiving the material the
      proposed disclosure does not include subject matter which is precluded
      from being made public under clause 7.2, it shall promptly notify the
      other party which shall thereupon be free to make the proposed disclosure.


                                                                  [CONFIDENTIAL]
                                     PAGE 17
<PAGE>   20

7.6   If in the reasonable opinion of either party -

      (a) the proposed disclosure includes subject matter which is precluded
          from being made public under clause 7.2 and which is patentable,
          neither party shall publish or otherwise disclose the material in
          question for a period of three months from the date on which the
          relevant material was received by the party in question and, if a
          patent application is made within that period of three months, for a
          further period as agreed but in any event not exceeding a total of 18
          months from that date (including such period of three months),
          following which the other party shall be free to make the proposed
          disclosure; or

      (b) the proposed disclosure includes unpatented (or unpatentable) Project
          Technology which that party wishes to maintain as unpublished and
          which has been identified in Project reports pursuant to clause 5.11
          as being of potential commercial significance, neither party shall
          publish or otherwise disclose the material in question for a period of
          18 months from that date, following which either party shall be free
          to make the proposed disclosure; or

      (c) the proposed disclosure includes Confidential Information of the
          reviewing party, the disclosing party shall remove such Confidential
          Information prior to such disclosure.

7.7   Notwithstanding the foregoing provisions of this clause 7 above, the
      receiving party may use or disclose Confidential Information of the
      disclosing party -

      (a) to the extent necessary to exercise its rights hereunder (including
          providing such information to bona fide licensees or prospective
          licensees as contemplated by this Agreement or otherwise and to
          potential investors or partners on reasonable terms of
          confidentiality) or to fulfill its obligations and/or duties
          hereunder;

      (b) in filing for, prosecuting or maintaining any proprietary rights,
          prosecuting or defending litigation; and


                                                                  [CONFIDENTIAL]
                                     PAGE 18
<PAGE>   21

      (c) in complying with applicable governmental regulations and/or
          submitting information to tax or other governmental authorities; or as
          otherwise required by law;

      provided that if the receiving party is required by law to make any public
      disclosures of Confidential Information of the disclosing party then, to
      the extent it may legally do so, it shall give reasonable advance notice
      to the disclosing party of such disclosure and shall use its reasonable
      efforts to secure confidential treatment of Confidential Information prior
      to its disclosure (whether through protective orders or otherwise).

8     TERMINATION

8.1   This Agreement shall be deemed to have come into force on the Effective
      Date and, subject to the following provisions, shall continue in force for
      the respective periods of time provided for in this Agreement and
      otherwise without any time limit.

8.2   ICRT shall be entitled to terminate this Agreement forthwith by giving
      fifteen (15) days' prior written notice to Introgen if any sum payable
      under this Agreement is not paid in full within seven (7) days after the
      due date for payment and Introgen fails to make such payment within such
      fifteen (15) day period.

8.3   Either party shall be entitled to terminate this Agreement forthwith by
      giving written notice to the other party if -

      (a) the other party commits a breach of any of its obligations under this
          Agreement (other than, in the case of Introgen, a breach to which
          clause 8.2 applies) and fails to remedy to breach within thirty (30)
          days after receiving a written notice from the first mentioned party
          specifying the breach and requiring it to be remedied; or

      (b) the other party goes into liquidation, has a receiver appointed over
          any of its assets, has an administrator appointed, makes any voluntary
          arrangement with


                                                                  [CONFIDENTIAL]
                                     PAGE 19
<PAGE>   22

          any of its creditors, or ceases to carry on business, or any similar
          event under the law of any foreign jurisdiction occurs in relation to
          the other party.

8.4   On the termination of this Agreement for any reason (including, for the
      avoidance of doubt, any termination or partial termination pursuant to
      clause 4.4 or clause 5.9) -

      (a) the rights and obligations of Introgen under the First Licence (if it
          has been executed) and the Second Licence (if it has been executed) or
          of ICRT under any agreement entered into pursuant to clause 6.11 (if
          it has been executed) shall continue in force;

      (b) subject to paragraph (a), Introgen shall forthwith cease all use of
          the Genes, the Inventions, the Existing Technology and any Project
          Technology which belongs exclusively to ICRT, and destroy all
          Materials in the possession or control of Introgen which have been
          supplied by ICRT or produced or derived from any Materials so
          supplied;

      (c) except to the extent that paragraph (a) above applies (and that
          accordingly this paragraph (c) does not apply), ICRT shall be entitled
          to license the Existing Patents and the Existing Technology, any
          Project Patents (other than any of them which belong exclusively to
          Introgen) and any unpatented (or unpatentable) Project Technology
          (other than data which Introgen reasonably considers proprietary to
          itself) to any other person;

      (d) the provisions of clause 6.1, 6.2, 6.3, 6.8, 6.9, 6.10, 6.11, 7, 9.10,
          9.11 and 9.12 shall continue in force in accordance with their terms,

          but subject to the foregoing, and except for any accrued right or
          obligation of either ICRT or Introgen, neither of them shall be under
          any further obligation to the other.

8.5   Notwithstanding anything herein to the contrary, if either party disputes
      in good faith the other party's right to terminate this Agreement
      pursuant to the foregoing provisions of this clause 8 by reason of a
      breach by the other party, the other party's


                                                                  [CONFIDENTIAL]
                                     PAGE 20
<PAGE>   23

      right to terminate shall be stayed unless or until it has been determined
      in accordance with clause 9.12 that such party has such a right and, if it
      is so determined, the party in breach has failed to remedy the breach in
      question within thirty (30) days after such determination.

9     GENERAL

9.1   This Agreement and the rights granted under it are personal to each party,
      which may not assign, transfer or charge to any other person any of its
      rights under this Agreement, or subcontract or otherwise transfer to any
      other person any of its obligations under this Agreement.

9.2   Notwithstanding clause 9.1, either party may assign this Agreement and its
      obligations hereunder to a party that is an Affiliate of the assigning
      party at the time of the assignment or a party that succeeds to all or
      substantially all of its business or assets relating to this Agreement
      whether by sale, merger, operation of law or otherwise; provided that in
      either case such assignee promptly enters into an agreement in writing
      with the other party to be bound by the terms and conditions of this
      Agreement.

9.3   ICRT warrants to Introgen that -

      (a) except as disclosed in writing to Introgen, ICRT owns all right, title
          and interest in and to the Existing Technology, the Existing Patents
          and all other Intellectual Property of ICRT in respect of the Existing
          Technology and, subject to clause 9.4, it has the authority to enter
          into this Agreement and to grant the rights granted by it under this
          Agreement;

      (b) the execution by ICRT of, and the performance of its obligations
          under, this Agreement require no governmental or other approvals or,
          if required, all such approvals have been obtained;

      (c) it has not granted and, except as otherwise provided in this
          Agreement, will not during the continuance of this Agreement grant to
          any third party any rights


                                                                  [CONFIDENTIAL]
                                     PAGE 21
<PAGE>   24

          which are inconsistent with the rights granted by it under or
          pursuant to this Agreement;

      (d) except as disclosed in writing to Introgen, it is not aware of any
          third party claims or governmental restrictions (other than legal
          provisions of general application) which would restrict its ability to
          grant the rights agreed to be granted by it under this Agreement; and

      (e) except for the Existing Patents, as at the Effective Date ICRT does
          not own or control any patents or patent applications the claims of
          which would dominate the practice of the rights to be granted to
          Introgen pursuant to this Agreement.

9.4   Without limiting clause 9.3, ICRT does not warrant -

      (a) the efficacy or usefulness of the Existing Technology or any Project
          Technology; or

      (b) that the exercise of the rights granted under this Agreement will not
          infringe the patent or other Intellectual Property rights of any third
          party; or

      (c) that any of the Existing Patents or Project Patents is or will be
          valid or enforceable, or (in the case of an application) will proceed
          to grant.

9.5   Introgen warrants to ICRT that -

      (a) it has the authority to enter into this Agreement and to grant the
          rights granted by it under this Agreement;

      (b) the execution by Introgen of, and the performance of its obligations
          under, this Agreement require no governmental or other approvals or,
          if required, all such approvals have been obtained;

      (c) it has not granted and, except as otherwise provided in this
          Agreement, will not during the continuance of this Agreement grant to
          any third party any rights


                                                                  [CONFIDENTIAL]
                                     PAGE 22
<PAGE>   25

          which are inconsistent with the rights granted by it under or
          pursuant to this Agreement; and

      (d) it is not aware of any third party claims or governmental restrictions
          (other than legal provisions of general application) which would
          restrict its ability to grant the rights agreed to be granted by it
          under this Agreement.

9.6   Subject to the terms of the First Licence (if executed), the Second
      Licence (if executed) or any agreement entered into pursuant to clause
      6.11, if either party becomes aware of any infringement of any of the
      Existing Patents or the Project Patents, or any claim is made or
      threatened against either party that the exercise of any rights granted
      under this Agreement infringes the patent or other Intellectual Property
      rights of any third party, it shall forthwith notify the other party,
      whereupon the parties shall consult and seek to decide what steps if any
      to take, and each of them shall give the other party (at the other party's
      expense) such assistance as the other party may reasonably request in
      connection therewith.

9.7   Neither party nor its representatives or employees (or, in the case of
      ICRT, those of ICRF) shall be deemed in any circumstances to be the
      employees or representatives of the other party (or, in the case of ICRT,
      to be those of ICRF), or shall have any authority or power to bind the
      other party or to contract in its name.

9.8   This Agreement contains the entire agreement between the parties with
      respect to its subject matter and may not be modified except by an
      instrument in writing signed by the duly authorised representatives of the
      parties, and each party acknowledges that, in entering into this
      Agreement, it does not do so in reliance on any representation, warranty
      or other provision, except as expressly provided herein, and any implied
      warranties are hereby excluded to the fullest extent permitted by law, but
      nothing in this provision shall affect the liability of either party for
      any fraudulent misrepresentation.


                                                                  [CONFIDENTIAL]
                                     PAGE 23
<PAGE>   26

9.9   Except with regard to the exercise of the First Option and the Second
      Option, no failure or delay by either party in exercising any of its
      rights under this Agreement shall be deemed to be a waiver of that right,
      and no waiver by either party of a breach of any provision of this
      Agreement shall be deemed to be a waiver of any subsequent breach of the
      same or any other provision.

9.10  If any provision of this Agreement is held by any court or other competent
      authority to be invalid or unenforceable in whole or in part, the other
      provisions of this Agreement and the remainder of the affected provision
      shall continue to be valid.

9.11  This Agreement (and any licence to be entered into pursuant to this
      Agreement) shall be governed and construed in all respects in accordance
      with the laws of England, and the parties agree to submit to the
      non-exclusive jurisdiction of the English Courts.

9.12  Any dispute or arising out of, in relation to, or in connection with this
      Agreement, or the validity, enforceability, construction, performance or
      breach hereof, shall be settled by binding arbitration in London, England,
      under the then-current Rules of Arbitration of the International Chamber
      of Commerce Court of Arbitration by a single arbitrator appointed in
      accordance with such rules, provided that if either party so requests (and
      unless otherwise provided hereunder) the arbitration shall be conducted by
      a panel of three (3) arbitrators appointed in accordance with the Rules.
      The decision and/or award rendered by the arbitrator(s) shall be written,
      final and non-appealable and may be entered in any court of competent
      jurisdiction. Accordingly, the parties hereby waive any and all rights of
      appeal to the Court under the Arbitration Act 1996. The parties agree
      that, any provision of applicable law notwithstanding, they will not
      request, and the arbitrator shall have no authority to award, punitive or
      exemplary damages against any party. The costs of any arbitration,
      including administrative fees and fees of the arbitrator(s), shall be
      shared equally by the parties, unless otherwise determined by the
      arbitrator(s). Each party shall bear the cost of its own legal and expert
      fees; provided that the arbitrator(s) may in his or their discretion
      award to the prevailing party the costs and expenses incurred by the
      prevailing party in connection with the arbitration proceeding.


                                                                  [CONFIDENTIAL]
                                     PAGE 24
<PAGE>   27

10    NOTICES AND SERVICE

10.1  Any notice or other information required or authorised by this Agreement
      to be given by either party to the other shall be given by -

      (a) delivering it by hand;

      (b) sending it by pre-paid registered post; or

      (c) sending it by facsimile transmission or similar means of communication
          (but not electronic mail);

      to the other party at the address given in clause 10.4.

10.2  Any notice or information sent by post in the manner provided by clause
      10.1(b) which is not returned to the sender as undelivered shall be deemed
      to have been given on the seventh day after the envelope containing it was
      so posted; and proof that the envelope containing any such notice or
      information was properly addressed, pre-paid, registered and posted, and
      that it has not been so returned to the sender, shall be sufficient
      evidence that the notice or information has been duly given.

10.3  Any notice or information sent by facsimile transmission or similar means
      of communication (but not electronic mail) shall be deemed to have been
      duly given on the date of transmission, provided that a confirming copy is
      sent as provided in clause 10.1(b) to the other party at the address given
      in clause 10.4 within 24 hours after transmission.

10.4  The address of either party for service of any legal proceedings
      concerning or arising out of this Agreement, or for the purposes of clause
      10.1, shall be that of its registered or principal office, or such other
      address as it may last have notified to the other party in writing from
      time to time.


                                                                  [CONFIDENTIAL]
                                     PAGE 25
<PAGE>   28

11    MISCELLANEOUS

11.1  Each sum payable pursuant to this Agreement is exclusive of any applicable
      Value Added Tax or other taxes or duties (other than taxes on profits or
      income), which shall be additionally payable by Introgen together with the
      relevant sum.

11.2  Each party shall from time to time do all such acts and execute all such
      documents as may be reasonably necessary in order to give effect to the
      provisions of this Agreement.

11.3  The parties shall bear their own costs of and incidental to the
      preparation, execution and implementation of this Agreement.

11.4  Except as required by law, neither party shall make any press or other
      public announcement concerning any aspect of this Agreement or use the
      name of the other (including, in the case of ICRT, that of ICRF) without
      first obtaining the agreement in writing of an authorised representative
      of the other party.

11.5  This Agreement may be executed in more than one counterpart and shall come
      into force once each party has executed such a counterpart in identical
      form and exchanged it with the other party.


                                                                  [CONFIDENTIAL]
                                     PAGE 26
<PAGE>   29

                                   SCHEDULE 1

                              THE EXISTING PATENTS

<TABLE>
<CAPTION>
GENE             ORIGINATING                    PATENT            DATE
                 SCIENTIST                      APPLICATION
<S>              <C>                            <C>               <C>

[*]

</TABLE>


         [*]    Certain information on this page has been omitted and filed
                separately with the Commission. Confidential treatment has been
                requested with respect to the omitted portions.





                                                                  [CONFIDENTIAL]
                                    PAGE 27
<PAGE>   30


                                   SCHEDULE 2

                         THE TERMS OF THE FIRST LICENCE

1 Parties:          ICRT (the Licensor) and Introgen (the Licensee).

2 Definitions:      'LICENSED PRODUCT' will mean any product (i) which
                    incorporates any of the Genes, in respect of which the First
                    Option is exercised by Introgen, or (ii) the manufacture,
                    use or sale of which would in the absence of the licence
                    granted to Introgen infringe a valid claim within any of
                    the Existing Patents in respect of the Gene or Genes in
                    question in the country for which the product is sold.

                    A 'VALID CLAIM' will include the claims of issued patents
                    (including patents of addition, supplementary protection
                    certificates or similar rights based on any such patent) and
                    patent applications; provided that in the case of a patent
                    application which has not been issued, not more than [*]
                    have elapsed from the earliest priority filing date to,
                    which the claim is entitled.

                    'LICENSED SUBJECT MATTER' will mean the Existing Technology,
                    the Existing Patents and any other Intellectual Property of
                    ICRT in respect of the Existing Technology, relating to the
                    Gene or Genes in question.

                    Subject as provided above, the provisions of clause 2 shall
                    apply.

3 Licence:          ICRT will grant to Introgen an exclusive, worldwide licence,
                    with the right to grant and authorise sublicences, under the
                    Licensed Subject Matter to make, have made, use and sell
                    Licensed Products, practice any method, process or procedure
                    and otherwise exploit the Licensed Subject Matter, in each
                    case within the Field. For the avoidance of


                                                                  [CONFIDENTIAL]
                                     PAGE 28

      [*] Certain information on this page has been omitted and filed
          separately with the Commission. Confidential treatment has been
          requested with respect to the omitted portions.

<PAGE>   31

                    doubt, Introgen will not have any rights in respect of any
                    [*] or in respect of any
                    [*] outside the Field.

4 Retained Rights:  Notwithstanding the foregoing, ICRT (for itself and ICRF)
                    will retain the rights under the Licensed Subject Matter
                    referred to in clause 6.8.

5 Clinical          Introgen will be responsible for conducting, directly or
  Development:      through third parties, clinical development with respect to
                    Licensed Products. Such clinical development shall include
                    carrying out clinical trials sufficient to market a Licensed
                    Product in all Major Markets. Without limiting the
                    foregoing, Introgen will use the same diligent efforts to
                    initiate and complete such clinical trials as it expends for
                    its other products being developed with similar market
                    potential. The detailed plans and budgets for clinical
                    development will be determined by Introgen in consultation
                    with ICRT (and in default of agreement settled by
                    arbitration pursuant to clause 4.3) and set forth in the
                    Agreement. Introgen will consult with and keep ICRT
                    reasonably informed relating to the scope and progress of
                    such clinical development and will provide semi-annual
                    reports to ICRT on each stage of product development.

                    'MAJOR MARKET' will mean the [*], [*] and
                    the [*].

6 Data Access:      During the term of the Agreement, Introgen will have access
                    to copies of data, reports, analyses and other information
                    in ICRT's possession or control, which are reasonably
                    necessary for Introgen's exercise of its rights under the
                    Licensed Subject Matter. In addition, ICRT will provide
                    Introgen with reasonable quantities of the Gene or Genes in
                    question from time to time.

7 Licence Fee:      Introgen shall pay to ICRT on the execution of the First
                    Licence (and on any subsequent exercise of the First Option)
                    a licence fee, in respect


                                                                  [CONFIDENTIAL]
                                     PAGE 29

      [*] Certain information on this page has been omitted and filed
          separately with the Commission. Confidential treatment has been
          requested with respect to the omitted portions.

<PAGE>   32
                    of each of the Genes in respect of which the First Licence
                    is granted, of [*], which shall be non-refundable and
                    non-creditable against royalties.

8 Milestone         Upon the occurrence of the events set forth below for the
  Payments:         first Licensed Product relating to each of the Genes in
                    respect of which the First Licence is granted, Introgen will
                    make the corresponding payment below to ICRT -


<TABLE>
<CAPTION>
                     Milestone                        Amount
                     ---------                        ------

          <S>                                       <C>
          Completion of [*] trials                   [*]

          Completion of [*] trials                   [*]

          First approval for [*]                     [*]

          First approval for [*]                     [*]

          First year where Net Sales of a            [*]
          Licensed Product exceeds [*]

          TOTAL IN RESPECT OF EACH GENE              [*]
</TABLE>


                                                                  [CONFIDENTIAL]
                                     PAGE 30

      [*] Certain information on this page has been omitted and filed
          separately with the Commission. Confidential treatment has been
          requested with respect to the omitted portions.
<PAGE>   33

9 Royalties:        Introgen will pay to ICRT as royalties the following
                    percentages of Net Sales by Introgen and its sublicensees,
                    based upon the aggregate Net Sales of all Licensed
                    Products in respect of each of the Genes -


<TABLE>
<CAPTION>
                                             ROYALTIES ON INCREMENTAL
          ANNUAL NET SALES                             AMOUNT
          ----------------                   ------------------------
         <S>                                 <C>
         [*]                                           [*]

         [*]                                           [*]
</TABLE>

                    The foregoing royalties will be reduced by [*] in countries
                    where no valid claim of any of the Existing Patents covers a
                    Licensed Product in respect of the Gene in question.

                    In the event that Licensed Products are sold in combination
                    with one or more other registered products for which a
                    royalty would not otherwise be due, it is understood that
                    Net Sales from the combination product will be reasonably
                    allocated as to be set forth in the First Licence.

                    In the event that Introgen or any of its Affiliates or
                    sublicensees becomes obligated to pay a royalty to a third
                    party in respect of patent rights covering the Gene or the
                    use thereof such that the total royalty burden on the Gene
                    or use thereof (prior to reductions) is in excess of [*]
                    Net Sales, Introgen may deduct [*] of such excess royalty
                    from the royalty owing to ICRT on the applicable Net Sales;
                    provided, however, that the royalty rate payable on
                    applicable Net Sales to such third party after adjustments
                    will not exceed the royalty rate payable (after adjustments)
                    to ICRT on such Net Sales (except with the consent of ICRT,
                    which consent will not be unreasonably withheld) and in no
                    case will the amount paid to ICRT be so reduced to less than
                    [*] of the amount that would otherwise be due to ICRT on
                    such Net Sales.


                                                                  [CONFIDENTIAL]
                                     PAGE 31

      [*] Certain information on this page has been omitted and filed
          separately with the Commission. Confidential treatment has been
          requested with respect to the omitted portions.
<PAGE>   34


                    Each royalty payment will be accompanied by a proper
                    statement and will be made without deduction. Introgen will
                    keep proper accounts to enable the accuracy of royalty
                    payments to be confirmed, and will allow ICRT access to
                    inspect and take copies.

10 Marketing:       Introgen will be responsible for the establishment, control
                    and implementation of the promotion and marketing strategy,
                    plans and budgets for Licensed Products. Introgen will use
                    the same diligent efforts with respect to the marketing,
                    sale and promotion of Licensed Products for each Major
                    Market as Introgen expends for its own products being
                    developed with similar market potential.

11 Patent           The provisions of clauses 3.6 and 3.7 above will apply
   Prosecution:     throughout the term of the First Licence as they apply
                    during the First Option Period.

12 Miscellaneous:   Each party will keep Confidential Information of the other
                    confidential on the same terms as under clause 7 above.

                    The First Licence will be subject to termination on the same
                    terms as under clause 8 above. On termination all rights
                    will revert to ICRT.

                    Introgen will assume responsibility for the exploitation of
                    the Licensed Subject Matter and will indemnify ICRT (and
                    ICRF) accordingly. ICRT (or ICRF) will have no liability
                    howsoever arising under or in connection with the First
                    Licence for loss of profit or indirect or consequential loss
                    or for sums exceeding the amount of royalties paid by
                    Introgen.

                    Clauses 9,10 and 11 above will apply to the First Licence.

                    The First Licence will include other reasonable and
                    customary terms and conditions contained in similar
                    agreements of this type, in so far as


                                                                  [CONFIDENTIAL]
                                     PAGE 32
<PAGE>   35

                    they are consistent with the above.




                                                                  [CONFIDENTIAL]
                                     PAGE 33
<PAGE>   36

                                   SCHEDULE 3

                            OBJECTIVES OF THE PROJECT

                                      [*]

                                                                  [CONFIDENTIAL]
                                     PAGE 34

      [*] Certain information on this page has been omitted and filed
          separately with the Commission. Confidential treatment has been
          requested with respect to the omitted portions.
<PAGE>   37

                                      [*]
                                                                [CONFIDENTIAL]

                                     PAGE 35

      [*] Certain information on this page has been omitted and filed
          separately with the Commission. Confidential treatment has been
          requested with respect to the omitted portions.
<PAGE>   38

                                   SCHEDULE 4

                         THE TERMS OF THE SECOND LICENCE

1     'LICENSED SUBJECT MATTER' will include, in addition to the Existing
      Patents and Existing Technology, any Project Technology and Project Patent
      owned exclusively by ICRT or owned jointly by ICRT and Introgen.

2     'LICENSED PRODUCT' will mean any product (i) which incorporates any of the
      Genes, or (d) the manufacture, use or sale of which would in the absence
      of the licence granted to Introgen infringe a valid claim within any of
      the Existing Patents or the Project Patents in respect of the Gene or
      Genes in question owned exclusively by ICRT or owned jointly by ICRT and
      Introgen (or, in the latter case, would do so if the Project Patent in
      question was owned exclusively by ICRT) in the country for which the
      product is sold.

3     Royalties will be payable, at the rates specified in Schedule 2, on Net
      Sales of Licensed Products (as defined above), where the product (i)
      incorporates any of the Genes or (ii) is covered by a valid claim of an
      Existing Patent or a Project Patent owned exclusively by ICRT in respect
      of the Gene or Genes in question. The foregoing royalties will be reduced
      by [*] in countries where no valid claim of an Existing Patent or a
      Project Patent owned exclusively by ICRT covers a Licensed Product.

4     Clauses 6.3, 6.4, 6.8, and 6.9 shall apply throughout the term of the
      Second Licence.

5     Subject to paragraphs 1 to 4 above, the provisions of Schedule 2 shall
      apply with the necessary changes (and so that references to Existing
      Technology and Existing Patents shall be construed as references to
      Existing Technology and Existing Patents and/or Project Technology and
      Project Patents owned exclusively by ICRT or owned jointly by ICRT and
      Introgen).



                                                                  [CONFIDENTIAL]

      [*] Certain information on this page has been omitted and filed
          separately with the Commission. Confidential treatment has been
          requested with respect to the omitted portions.

                                 PAGE 36
<PAGE>   39
                                   SCHEDULE 1

                              THE EXISTING PATENTS


<TABLE>
<S>                  <C>                             <C>                   <C>
GENE                 ORIGINATING SCIENTIST           PATENT APPLICATION       DATE

                                      [*]
</TABLE>

          [*] Certain information on this page has been omitted and filed
              separately with the Commission. Confidential treatment has been
              requested with respect to the omitted portions.


<PAGE>   40
For IMPERIAL CANCER RESEARCH TECHNOLOGY LIMITED


/s/ JOHN C. WALL
-----------------------------------
Director



For INTROGEN THERAPEUTICS, INC.



/s/ MAHENDRA G. SHAH                       11/24/98
-----------------------------------
Director


                                                                  [CONFIDENTIAL]

                                    PAGE 37