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                                                                   EXHIBIT 10.31

                          TARGET GENE LICENSE AGREEMENT

         This Target Gene License Agreement ("Agreement") is made as of January
1, 1999 (the "Effective Date") by and between Introgen Therapeutics, Inc., a
Delaware corporation ("Introgen"), and Gendux, Inc., a Delaware corporation
("Gendux").

                                   BACKGROUND

         A. Introgen and Gendux are parties to that certain Administrative
Services and Management Agreement of even date herewith (the "Services
Agreement"), pursuant to which Introgen will provide certain administrative and
management services, all as set forth therein;

         B. Introgen controls rights to certain genes;

         C. Gendux desires to obtain from Introgen a license to certain of such
genes, and an assignment of Introgen's rights in certain other of such genes,
all on the terms and conditions set forth below; and

         D. The parties desire that Gendux commercialize such genes for
applications within the Field (as defined below). In this connection, Introgen
and Gendux have entered into that certain Delivery Technology License Agreement
of even date herewith (the "DTLA Agreement"), pursuant to which Introgen
licensed certain gene therapy technologies and rights to Gendux, all on the
terms and conditions set forth therein, and that certain Research and
Development Agreement of even date herewith (the "Development Agreement"),
pursuant to which Introgen has agreed to assist Gendux in performing a certain
developmental research program within the Field, all as set forth therein.

         NOW, THEREFORE, in consideration of the mutual covenants, conditions
and undertakings herein contained, the parties hereto agree as follows:

                                    ARTICLE 1
                                   DEFINITIONS

         As used in this Agreement, the following terms shall have the meanings
indicated:

         1.1 "Affiliate" shall mean any entity which controls, is controlled by
or is under common control with Introgen or Gendux. For purposes of this
definition, "control" shall mean beneficial ownership (direct or indirect) of
more than fifty percent (50%) of the shares of the subject entity entitled to
vote in the election of directors (or, in the case of an entity that is not a
corporation, for the election of the corresponding managing authority).
Notwithstanding the foregoing, neither Introgen nor Gendux shall be deemed to be
an Affiliate of the other for purposes of this Agreement.



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         1.2 "Agreement Product" shall mean any product, composition or material
the development, manufacture, use or sale of which incorporates, utilizes, is
derived from, or is otherwise based upon the Subject Genes.

         1.3 "Assigned Rights" shall mean all rights and obligations of Introgen
in and to those agreements listed on Exhibit A hereto (collectively, the
"Assigned Agreements").

         1.4 "Completion" shall be deemed to occur, subject to the terms of
Section 5.3 with respect to a particular phase for an Agreement Product, upon
the earlier of: (i) when all patients called for in the protocol for such phase
clinical trials have been dosed and all patient follow-up as defined in such
protocol has been completed or (ii) initiation of a later phase clinical trial
for the same Agreement Product.

         1.6 "Control" shall mean, except only for the purposes of Section 1.1
above, possession of the ability to grant a license or sublicense under this
Agreement without violating the terms of any agreement or other arrangement with
a third party.

         1.7 "Field" shall mean [*].

         1.8 "First Financing" shall mean the closing of the sale and/or
issuance of equity and/or debt securities by Gendux, as a result of which the
cumulative total of cash proceeds from such financings received by Gendux
exceeds [*].

         1.9 "Licensed Patents" shall mean any and all rights in all worldwide
patents and patent applications that are Controlled by Introgen during the term
of this Agreement, to the extent the same claim and disclose the composition of
a Licensed Gene.

         1.10 "Major Country" shall mean [*] or a [*].

         1.11 "Manufacturing Costs" shall mean, with respect to an Agreement
Product, the costs that are incurred by Introgen, or its respective Affiliate,
associated with the manufacture, filling, packaging, labeling and/or other
preparation of such Agreement Product, as determined in accordance with
generally accepted accounting principles in the United States.

         1.12 "Net Sales" shall mean the total amount invoiced to non-Affiliate
third parties on sales of Agreement Products by Gendux, its Affiliates, or
Sublicensees, less the following reasonable and customary deductions: (i) all
trade, cash and quantity credits, discounts, refunds or rebates actually allowed
to the customer; (ii) amounts for claims, allowances or credits for returns, and
retroactive price reductions actually allowed to the customer; (iii) handling
fees and prepaid freight, sales taxes, duties and other governmental charges
(including value added tax), in each case to the

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extent stated separately on the invoice and paid by the customer; and (iv)
provisions for uncollectable accounts determined in accordance with reasonable
accounting practices, consistently applied to all products of the selling party.
For the removal of doubt, Net Sales shall not include sales by Gendux to its
Affiliates for resale, provided that if Gendux sells an Agreement Product to an
Affiliate for resale, Net Sales shall include the amounts invoiced by such
Affiliate to third parties on the resale of such Agreement Product.

         1.13 "Own" shall mean possession of the ability to assign, as provided
for herein, all of one's rights without violating the terms of an agreement with
a third party.

         1.14 "Related Materials" shall mean technical information, processes,
procedures, compositions, biological materials, data and know-how related to the
Licensed Genes that Introgen provides to Gendux in connection with this
Agreement, in each case to the extent the same are Controlled by Introgen.

         1.15 "Subject Genes" shall mean the Licensed Patents, the Assigned
Rights, and the Related Materials.

         1.16 "Sublicensee" shall mean any non-Affiliate third party to whom
Gendux has granted, directly or indirectly, a right or license to market, sell
or distribute Agreement Products.

         1.17 "Target Genes" shall mean (i) the genes PTEN, C-CAM, DBCCR1,
RSK-3, and (ii) any other genes substituted or added to this Agreement upon the
written mutual agreement of the parties hereto. The Target Genes consist of both
Licensed Genes and Assigned Genes, where:

                  (i) "Assigned Genes" shall mean those Target Genes listed on
Exhibit A hereto, as amended from time to time; and

                  (ii) "Licensed Genes" shall mean those Target Genes listed on
Exhibit B hereto, as amended from time to time.

         1.18 "Third Party Agreements" shall mean collectively those agreements
between Introgen and a third party pursuant to which Introgen obtained rights to
the Subject Genes.

                                   ARTICLE 2
                                    LICENSE

         2.1 Grant. Introgen hereby grants to Gendux a worldwide, exclusive
(except as otherwise expressly provided in Section 2.4 below), royalty-bearing
license under the Licensed Patents and Related Materials to make, use, import
and sell Agreement Products, in each case for purposes solely within the Field.



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         2.2 Assignment. Promptly following the Effective Date, Introgen agrees
to assign to Gendux the Assigned Rights, to the extent that Introgen has the
right to do so. In the event that Introgen does not have the right to do so as
of the Effective Date, Introgen agrees to use commercially reasonable to obtain
such right, and upon obtaining such right, to assign the particular Assigned
Rights to Gendux.

         2.3 Sublicenses. Gendux may grant sublicenses within the scope of the
license granted to Gendux under Section 2.1 above to the extent necessary or
useful for exercising such license. Gendux agrees to provide to Introgen a copy
of any agreement pursuant to which a sublicense is granted to the Licensed
Patents or Related Materials or pursuant to which a sublicense is granted under
the Assigned Rights, promptly after the signing of such agreement.

         2.4 Restrictions. Notwithstanding Sections 2.1, 2.2 or 2.3 above,
Gendux covenants not to manufacture or have manufactured Agreement Products (or
to grant any third party the right to manufacture or have manufactured Agreement
Products) except to the extent expressly permitted in Section 4.3 below. In such
event, Introgen shall provide to Gendux copies of all documentation within
Introgen's Control that is reasonably necessary for Gendux to manufacture or
have manufactured Agreement Products in accordance with Section 4.3 below, and
shall reasonably cooperate with Gendux to establish supply thereof, including
sources of materials. Without limiting the foregoing, in the event that Gendux
has any Agreement Product manufactured by a third party, such third party shall
enter into a confidentiality agreement with Introgen to protect against the
unauthorized use and disclosure of Introgen's Confidential Information.

         2.5 Development License. It is understood that Introgen retains a
royalty-free license to the Subject Genes for purposes of performing its duties
under the Development Agreement.

         2.6 No Implied Licenses. Nothing herein shall be construed as granting
to either party, by implication, estoppel or otherwise, any license or other
right to any intellectual property of the other party other than those rights
expressly granted herein. Without limiting the foregoing provision of this
Section 2.6, nothing herein shall be deemed to grant to Gendux rights with
respect to any gene other than a Target Gene, or for any product that includes
any subject matter not expressly included within the Field.

                                   ARTICLE 3
                  PATENT EXPENSES, ROYALTY PAYMENTS AND REPORTS

         3.1 Royalty. In consideration of the rights and licenses granted by
Introgen to Gendux under this Agreement, except as otherwise provided in this
Article 3, Gendux shall pay to Introgen running royalties equal to [*] of Net
Sales by Gendux, its Affiliates or Sublicensees of Agreement Products.

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                  3.1.1 Royalty Term. The obligation of Gendux to pay royalties
under this Article 3 shall continue with respect to each Agreement Product, on a
country-by-country basis, until the later of (i) the expiration of the
last-to-expire patent within the Licensed Patents or Assigned Rights covering
such Agreement Product in such country; or (ii) the abandonment, cancellation or
withdrawal of the last pending application for a patent within the Licensed
Patents or Assigned Rights covering such Agreement Product in such country; or
(iii) [*] after the date of the first full commercial sale of such Agreement
Product in such country.

                  3.1.2 DTLA Royalties. It is understood and agreed that

Gendux's total royalty obligation under this Agreement and the DTLA shall not
exceed a cumulative total of [*] of Net Sales and [*].

                  3.1.3 Combination Products. In the event that an Agreement
Product is sold in combination with another product or pharmaceutically active
ingredient which is not an Agreement Product or a Licensed Product (as defined
in the DTLA), Net Sales for purposes of calculating the amounts due under
Section 3.1 above shall be allocated between said Agreement Product and such
other product or pharmaceutically active ingredient, as mutually agreed by
Introgen and Gendux.

         3.2 Sublicense Revenues.

                  3.2.1 General. In addition to the amounts due under Section
3.1 above, Gendux shall pay to Introgen [*] of all fees or other consideration
(other than running royalties calculated on Net Sales of an Agreement Product)
received by Gendux from its Sublicensees (including, without limitation,
up-front fees and milestone payments), [*]. Without limiting the foregoing, in
the event that Introgen and Gendux enter into an agreement such that Introgen
licenses certain genes from Gendux, the parties will negotiate in good faith
with respect to Sublicense revenues on terms substantially similar to those set
forth in this Section 3.2.

                  3.2.2 Coordination with DTLA. In the event that Gendux
receives sublicense fees as described in Section 3.2 of the DTLA in connection
with Sublicense under this Agreement, Introgen shall not be entitled to receive
more than [*] of the total amounts received for such a combined Sublicense of
the rights under this Agreement and under the DTLA.

                  3.2.3 Cap. It is understood that such Development Costs will
not exceed [*].

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         3.3 Third Party Payments.

                  3.3.1 Generally. Gendux shall promptly reimburse Introgen for
any amounts paid or payable by Introgen to third parties pursuant to a Third
Party Agreement, including without limitation any royalties, patent expenses,
license fees or milestone payments due to such third parties. Without limiting
the foregoing, it is understood that all [*].

                  3.3.2 Payment; Reports. If Introgen is obligated to pay
amounts to a third party pursuant to a Third Party Agreement subject to
reimbursement pursuant to Section 3.3.1 above, Introgen shall notify Gendux
reasonably in advance, and Gendux shall reimburse its share of such payments by
the earlier of (i) ten (10) days before such amounts are payable to such third
party or (ii) thirty (30) days after receipt of notice therefor. In addition, to
the extent that Introgen is obligated to provide reports to a third party
pursuant to a Third Party Agreement, Gendux shall reasonably assist Introgen by
providing information in its possession or control and in sufficient detail to
complete and submit such reports as required.

         3.4 Royalty Reports and Payments. After the first sale of an Agreement
Product by Gendux, its Affiliates or Sublicensees, Gendux shall deliver to
Introgen within forty-five (45) days after the end of each calendar quarter, a
written report, certified by an officer of Gendux, setting forth in reasonable
detail the calculation of the royalties due to Introgen for such calendar
quarter, which calculation shall include, without limitation, the number,
description, and aggregate Net Sales of Agreement Products sold during such
calendar quarter. Simultaneously with the delivery of each such report, Gendux
shall pay to Introgen the total royalties, if any, due to Introgen for the
period of such report. If no royalties are due, Gendux shall so report. All
financial information contained in reports provided to Introgen pursuant to this
Section 3.4 shall be treated as Confidential Information of Gendux pursuant to
Article 11.

         3.5 Payment Method. All amounts payable under this Agreement shall be
made by bank wire transfer in immediately available funds to an account
designated by Introgen. All dollar amounts specified in this Agreement are
expressed, and all payments hereunder shall be made, in U.S. dollars. Any
payments or portions thereof due under this Agreement which are not paid on the
date such payments are due under this Agreement shall, to the extent permitted
by applicable law, bear interest at the U.S. prime rate per annum quoted in the
"Money Rates" column of The Wall Street Journal (U.S.), on the first business
day after such payment is due, calculated on the number of days such payment is
delinquent.

         3.6 Currency Conversion. If Gendux receives revenues from Net Sales of
Agreement Products in currency other than U.S. dollars, for purposes of
calculating royalties hereunder, such revenues shall be converted using the
selling exchange rate for conversion of the foreign currency into U.S. dollars,
quoted for current transactions reported in The Wall Street Journal (U.S.) for
the last business day of the applicable calendar quarter.


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         3.7 Records; Inspection. Gendux shall keep, and require its Affiliates
and Sublicensees to keep, complete, true and accurate books of account and
records for the purpose of determining the amounts payable pursuant to this
Agreement. Such books and records shall be kept for at least three (3) years
following the end of the calendar quarter to which they pertain. Such records
will be open for inspection during such three (3) year period by a
representative or agent of Introgen for the purpose of verifying the amounts
payable by Gendux hereunder. Such inspections may be made no more than once each
calendar year, at reasonable times and on reasonable notice. Introgen's
representative or agent will be obliged to execute a reasonable confidentiality
agreement prior to commencing any such inspection. Introgen shall bear the costs
and expenses of inspections conducted under this Section 3.7, unless a variation
or error producing an underpayment in amounts payable exceeding ten percent
(10%) of the amount paid for any period covered by the inspection is established
in the course of any such inspection, whereupon all costs relating to the
inspection and any unpaid amounts that are discovered shall be paid by Gendux,
together with interest on such unpaid amounts at the rate specified in Section
3.5 above.

         3.8 Taxes. All payments by Gendux specified hereunder are expressed as
net amounts and shall be made free and clear of, and without reduction for, any
taxes. Any such taxes (including, without limitation, foreign withholding taxes)
which are otherwise imposed on payments to Introgen shall be the sole
responsibility of Gendux. Gendux shall provide Introgen with official receipts
issued by the appropriate taxing authority or such other evidence as is
reasonably requested by Introgen to establish that such taxes have been paid. If
Introgen has the legal obligation to collect and/or pay any sales, use, excise
or value added taxes, the appropriate amount shall be added to Gendux's invoice
and paid by Gendux, unless Gendux provides Introgen with a valid tax exemption
certificate authorized by the appropriate taxing authority.

                                   ARTICLE 4
                              MANUFACTURING RIGHTS

         4.1 Manufacture and Supply. Subject to Section 4.3 below, Introgen
shall have the worldwide, exclusive right to manufacture, or have manufactured,
and supply to Gendux Agreement Products for use or sale in the Field, and except
as set forth below, Gendux shall purchase exclusively from Introgen all of
Gendux', its Affiliates' and Sublicensees' requirements of Agreement Products.
It is understood that Introgen may, at its election, engage subcontractors with
respect to the manufacture of Agreement Products for supply to Gendux.

         4.2 Transfer Price. Agreement Products to be supplied by Introgen to
Gendux for use or sale within the Field shall be supplied at a price equal to
Introgen's Manufacturing Costs therefor  [*]; provided, however, that with
respect to Agreement Products used for clinical research and regulatory affairs
necessary to obtain the government approvals required to market such Agreement
Products, the price will be equal to Introgen's Manufacturing Costs thereof [*].
Notwithstanding the foregoing, as long as Introgen owns [*] or more of the fully
diluted capitalization of Gendux, the


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price will be equal to Introgen's Manufacturing Costs therefor [*]. Without
limiting the foregoing, in the event that Introgen and Gendux enter into an
agreement such that Gendux supplies products similar to Agreement Products to
Introgen, the parties will negotiate in good faith with respect to the transfer
price of such Agreement Products on terms substantially similar to those set
forth in this Section 4.2.

         4.3 Gendux Right to Supply. In the event that Introgen elects not to
supply quantities of Agreement Products within the Field, or fails to supply
such quantities under the terms and conditions established under Section 4.4
below, Gendux shall have the right to manufacture, or have manufactured, and
supply (and/or to authorize its Sublicensees to do so, subject to Section 2.4
above) the quantities that Introgen so elects not to or fails to supply, for use
or sale (as the case may be) within the Field.

         4.4 Supply Agreement. Upon request by Introgen or Gendux, the parties
shall enter into a supply agreement on reasonable and customary terms with
respect to the supply arrangements contemplated in this Article 4.

                                   ARTICLE 5
                                 DUE DILIGENCE

         5.1 Due Diligence. Gendux shall use its best efforts, itself or though
a Sublicensee on a worldwide basis, to develop for commercial sale, obtain
regulatory approval to market, and to market, promote and distribute Agreement
Products for each of the Target Genes, in each case as soon as practicable. Any
efforts of Gendux's Sublicensees shall be considered efforts of Gendux for the
sole purpose of determining Gendux's compliance with its obligation under this
Section 5.1.

         5.2 Progress Reports. Upon request by Introgen, Gendux shall provide
Introgen on each December 1 with written progress reports, summarizing in
reasonable detail the progress of the development, evaluation, testing and
commercialization of each Agreement Product.

         5.3 Milestones.

                  5.3.1 PTEN; C-CAM. With respect to each Agreement Product
based upon PTEN or C-CAM, Gendux shall accomplish each of the following
milestones on or before the times set forth below:

<TABLE>
<S>                                                           <C>
Initiation of [*] clinical trials
in a Major Country:                                           [*]


Initiation of [*] clinical trials
in a Major Country:                                           [*]
</TABLE>



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<TABLE>
<S>                                                           <C>
Initiation of [*] clinical trials
in a Major Country:                                           The earlier of [*]

Filing of [*] in a Major Country:                             The earlier of [*]

</TABLE>

                  5.3.2 DBCCR1; RSK-3. With respect to each Agreement Product
based upon DBCCR1 or RSK-3, Gendux shall accomplish each of the following
milestones on or before the times set forth below:

<TABLE>
<S>                                                           <C>
Initiation of [*] clinical trials
in a Major Country:                                           [*]

Initiation of [*] clinical trials                             [*]

Initiation of [*] clinical trials
in a Major Country:                                           [*]

Filing of [*] in a Major Country:                             [*]
</TABLE>

         5.4 Failure to Meet Milestones. In the event Gendux fails to meet the
milestones of Section 5.3 with respect to any Agreement Product, Gendux's rights
and license with respect to such Agreement Product shall terminate, Gendux shall
promptly re-assign to Introgen all of the Assigned Rights relating to such
Agreement Product, and Introgen shall have the exclusive right to manufacture,
market, sell and distribute such Agreement Product. Notwithstanding the
foregoing, Gendux's rights to any Agreement Product shall not terminate by
reason of a delay in meeting one or



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more of the foregoing milestones, to the extent that circumstances outside of
Gendux's reasonable control (i.e., legal requirements to suspend clinical trials
or the like) require such delay. However, it is understood that a decision not
to proceed or to delay proceeding based on lower than expected efficacy, or any
other factors that may affect the likelihood of approval or marketability of the
Agreement Product, shall not be deemed a circumstance beyond Gendux's reasonable
control.

                                   ARTICLE 6
                              TERM AND TERMINATION

         6.1 Term. Unless terminated earlier pursuant to this Article 6, the
term of this Agreement shall commence on the Effective Date and continue in full
force and effect until expiration, revocation or invalidation of the last patent
or the abandonment of the last patent application within the Licensed Patents or
Assigned Rights, whichever is later.

         6.2 Termination by Introgen. In the event the First Financing does not
occur on or before [*], Introgen may terminate this Agreement upon written
notice.

         6.3 Termination for Breach. Either Gendux or Introgen may terminate
this Agreement, in the event the other shall have materially breached or
defaulted in the performance of any of its obligations hereunder and such breach
shall have continued for thirty (30) days after written notice is given by the
nonbreaching party to the breaching party specifying the breach. For such
purposes, breach of the DTLA, the Development Agreement or the Services
Agreement shall be deemed a breach of this Agreement.

         6.4 Survival.

                  6.4.1 Termination of this Agreement for any reason shall not
release either party hereto from any liability which, at the time of such
termination, has already accrued to the other party or which is attributable to
a period prior to such termination, nor preclude either party from pursuing any
rights or remedies it may have hereunder or at law or in equity with respect to
any breach of this Agreement.

                  6.4.2 In the event this Agreement is terminated for any
reason, Gendux and its Affiliates shall have the right to sell or otherwise
dispose of the stock of any Agreement Products then on hand within one hundred
twenty (120) days of such termination, all subject to the payment to Introgen of
fees and royalties pursuant to Article 3 hereof.

                  6.4.3 Articles 1, 8, 9, 10, 11 and 12 and Sections 3.7 and 6.4
shall survive the expiration and any termination of this Agreement. Except as
otherwise provided in this Article 6, all rights and obligations of the parties
under this Agreement shall terminate upon the expiration or termination of this
Agreement.


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                  6.4.4 In addition, upon any termination of this Agreement,
Gendux shall promptly re-assign to Introgen all of the Assigned Rights. In the
event that Gendux does not have the right to do so under the agreements
comprising the Assigned Rights, Gendux shall use its best efforts to obtain such
right as soon as possible, and upon obtaining such right, Gendux shall re-assign
the particular Assigned Rights to Introgen. Gendux hereby grants to Introgen a
worldwide right and sublicense, including the right to grant and authorize
further sublicenses, to practice and exercise for all purposes the Assigned
Rights; provided that Introgen agrees not to exercise such right and sublicense
during the term of this Agreement.

                  6.4.5 Following the re-assignment of the Assigned Rights by
Gendux to Introgen pursuant to Section 6.4.4 above, Introgen agrees to pay to
Gendux running royalties equal to [*] of Net Sales by Introgen, its Affiliates
or Sublicensees of Agreement Products covered by such Assigned Rights, under the
same principles set forth in Section 3.1 above (as applicable), [*].

                                   ARTICLE 7
                           INFRINGEMENT BY THIRD PARTY

         7.1 Enforcement. During the term of this Agreement, in the event that
Gendux reasonably believes that any Licensed Patent is being infringed or
otherwise misappropriated by a third party by reason of the manufacture or sale
of a product within the Field, Gendux shall promptly notify Introgen in writing.
In the event Introgen does not initiate an action to enforce such Licensed
Patent against a commercially significant infringement in the Field by a third
party within one hundred eighty (180) days of a written request by Gendux to do
so, Gendux may initiate such action with Introgen's prior written consent. Any
amount recovered in such action shall first be applied to reimburse the
out-of-pocket costs of such action and the remainder shall be [*].

         7.2 Defense. If Gendux, its Affiliate, Sublicensee, distributor or
other customer is sued by a third party charging infringement of patent rights
that dominate a claim of the Licensed Patents or that otherwise cover the
manufacture, use, distribution or sale of an Agreement Product, Gendux will
promptly notify Introgen in writing. As between the parties to this Agreement,
Gendux will be entitled to control the defense in any such action, provided that
Introgen shall have the right to participate in the defense or settlement
thereof at its own expense with counsel of its own choosing. Except as agreed in
writing by Introgen, Gendux shall not enter into any settlement of any such
action if such settlement admits the unpatentability, invalidity or
unenforceability of any Licensed Patent. Gendux agrees to keep Introgen
reasonably informed of all developments in connection with any such action.



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         7.3 Cooperation. In any suit, action or other proceeding in connection
with defense of the Licensed Patents, Introgen shall reasonably cooperate with
Gendux with respect to such proceeding, at Gendux's expense. In any suit, action
or other proceeding in connection with enforcement of the Licensed Patents,
Gendux shall reasonably cooperate with Introgen with respect to such proceeding,
at Introgen's expense.

         7.4 Patent Prosecution.

                  7.4.1 Prosecution by Introgen. Introgen shall have the right,
at its option, to control the filing for, prosecution and maintenance of the
Licensed Patents. Upon request by Gendux from time to time, Introgen shall
advise Gendux as to the status of any particular patent or patent application
within the Licensed Patents within the Field.

                  7.4.2 Prosecution by Gendux. If Introgen elects not to file,
prosecute or maintain any patent application or issued patent within the
Licensed Patents or pay any fee related thereto, in any country, Introgen shall
promptly notify Gendux of such election, but in no case later than sixty (60)
days prior to any required action relating to the filing, prosecution or
maintenance of such patent application or patent. In such event, upon notice to
Introgen, Gendux shall have the right, at its option, to control the filing,
prosecution and/or maintenance of any such patent applications or patents within
the Licensed Patents at its own expense. In the event that Gendux takes over the
filing, prosecution and/or maintenance of any such patent application or patent
within the Licensed Patents, Gendux shall keep Introgen reasonably informed on
matters regarding such filing, prosecution and maintenance. Without limiting the
foregoing, Gendux shall consult with Introgen in a timely manner concerning (i)
the scope and content of patent applications within the Licensed Patents prior
to filing such applications, and (ii) the content of and proposed responses to
official actions of the U.S. Patent and Trademark Offices and foreign patent
offices during the prosecution of such patent applications. For purposes of this
Section 7.4.2, "timely" shall mean sufficiently in advance of any decisions by
Gendux or any deadline imposed upon written response by Gendux so as to allow
Introgen to review such decision and/or written response and also provide
comments to Gendux in advance of such decision or deadline.

                  7.4.3 Other. If Gendux elects not to file, prosecute or
maintain any patent application or issued patent within the Licensed Patents or
pay any fee related thereto, in any country, Gendux shall promptly notify
Introgen of such election, but in no case later than sixty (60) days prior to
any required action relating to the filing, prosecuting or maintenance of such
patent application or patent. In such event, upon notice to Gendux, Introgen
shall have the right, at its option, to take over the filing, prosecution and/or
maintenance of any such patent application or patent within the Licensed Patents
at its own expense.

         In addition if during the exercise of its rights under Section 7.4.2
above, Gendux fails, in Introgen's judgment, to appropriately file, prosecute or
maintain any particular patent or patent application within the Licensed
Patents, then upon notice from Introgen, Gendux's right to file, prosecute
and/or maintain such patent or patent application shall terminate and Introgen
shall have



                                      -12-
<PAGE>   13

the right, at its option, to control the filing, prosecution and/or maintenance
of such patent or patent application within the Licensed Patents at its own
expense. In such event, Gendux shall cooperate and take all steps necessary to
transfer to Introgen the filing, prosecution and/or maintenance of such patent
or patent application within the Licensed Patents.

         7.5 No Implied Obligations. Neither party has any obligation to bring
or prosecute actions or suits against any third party for patent infringement.
Notwithstanding the foregoing, it is understood that the parties' rights and
obligations hereunder are subject to the Third Party Agreements.

                                   ARTICLE 8
                           INSURANCE; INDEMNIFICATION

         8.1 Insurance. Gendux shall secure and maintain in effect during the
term of this Agreement and for a period of three (3) years thereafter insurance
policy(ies) underwritten by a reputable insurance company and in a form and
having limits standard and customary for entities in the biotechnology industry
for exposures related to Gendux's indemnification obligations pursuant to this
Article 8 below. Such insurance shall include general liability, clinical trial
liability and product liability coverage with respect to the development and
commercialization of Agreement Products and shall name the Indemnitees (as
defined below) as additional insureds thereunder. Upon request by Introgen,
Gendux shall provide to Introgen certificates of insurance evidencing the
coverage required above.

         8.2 Indemnification. Gendux shall indemnify each of Introgen and its
directors, officers and employees and the successors and assigns of the
foregoing (collectively, the "Indemnitees"), and hold each Indemnitee harmless
from and against any and all liabilities, damages, settlements, claims, actions,
suits, penalties, fines, costs or expenses (including, without limitation,
reasonable attorneys' fees and other expenses of litigation) incurred by any
Indemnitee arising from or occurring as a result any claim, action, suit, or
other proceeding brought by third parties against an Indemnitee arising from or
occurring as a result of (i) the exercise of the rights granted to Gendux under
Section 2.1, including without limitation product liability claims relating to
any Agreement Product used, sold or otherwise distributed by or on behalf of
Gendux or its Affiliates or (ii) Introgen's performance of its responsibilities
with respect to the R&D Program (as defined in the Development Agreement) or the
manufacture and supply of Agreement Products hereunder or (iii) the gross
negligence or willful tortious misconduct of Gendux or any of its directors,
officers or employees or the successors or assigns of any of the foregoing.
Notwithstanding the foregoing, Gendux shall have no obligation under this
Section 8.2 with respect to liabilities, damages, settlements, claims, actions,
suits, penalties, fines, costs or expenses to the extent the same is caused by
the gross negligence or willful tortious misconduct of an Indemnitee.

         8.3 Procedure. An Indemnitee that intends to claim indemnification
under this Article 8 shall: (i) promptly notify Gendux in writing of any claim,
action, suit, or other proceeding brought



                                      -13-
<PAGE>   14

by third parties in respect of which the Indemnitee intends to claim such
indemnification; (ii) provide Gendux sole control of the defense and/or
settlement thereof, and (iii) provide Gendux, at Gendux's request and expense,
with reasonable assistance and full information with respect thereto.
Notwithstanding the foregoing, the indemnity obligation in this Article 8 shall
not apply to amounts paid in settlement of any loss, claim, damage, liability or
action if such settlement is effected without the consent of Gendux, to the
extent such consent is not withheld unreasonably or delayed. Without limiting
the foregoing provisions of this Section 8.3, Gendux shall keep Introgen
reasonably informed of the progress of any claim, suit or proceeding under this
Section 8.3 and Introgen shall have the right to participate in any such claim,
suit or proceeding with counsel of its choosing at its own expense.

                                   ARTICLE 9
                                  USE OF NAMES


         Except as required by law or in the normal course of business
identification and description, neither party shall issue any press release or
other public statements in connection with this Agreement intended for use in
the public media in a manner suggesting any endorsement by the other party,
without the prior written approval of such other party, which approval shall not
be unreasonably withheld.

                                   ARTICLE 10
                         REPRESENTATIONS AND WARRANTIES

         10.1 Introgen. Introgen hereby represents and warrants to Gendux that
(i) it has the full right and authority to enter into this Agreement and grant
the rights and licenses granted herein; (ii) it has not previously granted and
will not grant during the term of this Agreement any rights in the Subject Genes
in the Field that are inconsistent with the rights and licenses granted to
Gendux herein; and (iii) to its knowledge, there are no claims of any third
parties pending against it that would call into question its right to grant to
Gendux the rights and licenses contemplated hereunder.

         10.2 Gendux. Gendux hereby represents and warrants to Introgen that (i)
it has the full right and authority to enter into this Agreement and grant the
rights and licenses granted herein; (ii) it has not previously granted and will
not grant during the term of this Agreement any rights in conflict with the
rights and licenses granted herein; and (iii) to its knowledge, there are no
claims of any third parties pending against it that would call into question its
right to enter into and perform its obligations under this Agreement.

         10.3 Disclaimer. EXCEPT AS EXPRESSLY PROVIDED IN THIS ARTICLE 10,
NEITHER PARTY MAKES ANY WARRANTIES OR CONDITIONS (EXPRESS, IMPLIED, STATUTORY,
OR OTHERWISE) WITH RESPECT TO THE SUBJECT MATTER HEREOF, INCLUDING WITHOUT
LIMITATION, THE SUPPLY AND DEVELOPMENT OF



                                      -14-
<PAGE>   15

AGREEMENT PRODUCTS, THE AGREEMENT PRODUCTS THEMSELVES AND THE SUBJECT GENES,
AND INTROGEN SPECIFICALLY DISCLAIMS ANY AND ALL IMPLIED WARRANTIES OR CONDITIONS
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, AND ALL WARRANTIES AND
CONDITIONS OF THE VALIDITY OF THE PATENT RIGHTS OR NONINFRINGEMENT OF THIRD
PARTY INTELLECTUAL PROPERTY RIGHTS.

                                   ARTICLE 11
                                 CONFIDENTIALITY

         11.1 Confidential Information. Except as expressly provided herein,
each party shall maintain in confidence, and shall not use for any purpose or
disclose to any third party, information disclosed by the other party in writing
and marked "confidential" or that is disclosed orally and confirmed in writing
as confidential within a reasonable time following such disclosure
(collectively, "Confidential Information"). Notwithstanding the foregoing,
Confidential Information shall not include any information that, in each case as
demonstrated by contemporaneous written documentation: (i) was already known to
the receiving party, other than under an obligation of confidentiality, at the
time of disclosure hereunder, or (ii) was generally available to the public or
otherwise part of the public domain at the time of its disclosure to the
receiving party, or (iii) became generally available to the public or otherwise
part of the public domain after its disclosure, other than through any act or
omission of the receiving party, or (iv) was subsequently lawfully disclosed to
the receiving party by a person other than a party hereto or (v) was
independently developed by the receiving party without reference to any
information or materials disclosed by the disclosing party.

         11.2 Permitted Usage. Notwithstanding the provisions of Section 11.1
above, each party may use or disclose the other party's Confidential Information
to the extent such use and disclosure is reasonably necessary in filing or
prosecuting patent applications, prosecuting or defending litigation, complying
with applicable governmental regulations, submitting information to tax or other
governmental authorities conducting clinical trials or exercising its rights
hereunder (including granting any permitted sublicenses); provided that if a
party is legally required to make any public disclosures of the other party's
Confidential Information, to the extent it may legally do so, it will give
reasonable advance notice to the other party of such disclosure and will use its
reasonable efforts to secure confidential treatment of such Confidential
Information prior to its disclosure (whether through protective orders or
otherwise).

                                   ARTICLE 12
                                     GENERAL

         12.1 Improvements. Gendux hereby grants to Introgen a [*],
license for all purposes, with the right to grant and
authorize sublicenses, under any and all improvements to the Subject Genes
(including, without limitation, improvements to any subject


         [*]    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.




                                      -15-
<PAGE>   16

matter covered by the Assigned Rights), which improvements are made by Gendux or
by third parties on behalf or under the authority of Gendux. As used herein,
"improvements" to the Subject Genes shall mean any invention, biological
material or other subject matter that is made using, or derived in whole or in
part from, the Subject Genes and shall in any event be deemed to include
(without limiting the foregoing) any invention, material and subject matter
useful in connection with a Target Gene or gene therapy; it being further
understood that the license granted in this Section 12.1 shall extend to all
patent and other rights in such improvements. Gendux agrees to (i) promptly
notify Introgen of any such improvements, (ii) provide with such notice samples
in reasonable quantities of any tangible materials within such improvements, and
(iii) keep Introgen fully informed of the status of any patents and patent
applications with respect to such improvements. Introgen agrees not to exercise
such license during the term of this Agreement with respect to any improvement
that consists of a modification of a Target Gene for so long as Gendux retains
its exclusive rights under the Licensed Patents or Assigned Rights with respect
to such Target Gene. It is understood that the license granted herein shall be
exclusive, but to the extent and during such period that Introgen agrees not to
exercise such license, this license shall be deemed to be nonexclusive.

         12.2 Independent Contractors. The relationship of Gendux and Introgen
established by this Agreement is that of independent contractors. Nothing in
this Agreement shall be construed to create any other relationship between the
parties. Neither party shall have any express or implied right, power or
authority to assume, create or incur any expense, liability or obligation on
behalf of or in the name of the other party.

         12.3 Confidential Terms. Except as expressly provided herein, each
party agrees not to disclose any terms of this Agreement to any third party
without the prior written consent of the other party, except as required by
securities or other applicable laws and (subject to reasonable conditions of
confidentiality) to prospective and other investors and such party's
accountants, attorneys and other professional advisors.

         12.4 Assignment. This Agreement shall not be assignable by either party
to any third party without the prior written consent of the other party hereto,
except that either party may assign this Agreement without the other party's
consent to an entity that acquires all or substantially all of the business or
assets of the assigning party, in each case whether by sale, merger, transfer of
assets, operation of law or otherwise; provided that in either case, such
assignee or transferee promptly agrees in writing to be bound by the terms and
conditions of this Agreement. Without limiting the foregoing, in the event of
such merger or transfer or acquisition of assets, no intellectual property
rights of the assignee or its affiliate shall be included in the Licensed
Patents, Related Materials, Assigned Rights or Subject Genes, to the extent that
such intellectual property rights were owned or Controlled by the assignee or
its affiliate prior to such merger or transfer or acquisition of assets, or are
created outside the Development Agreement or by personnel who were not employees
of assigning party prior to the merger or transfer or acquisition of assets.
Upon a permitted assignment of this Agreement, all references herein to the
assigning party shall be deemed references to the assignee. Any assignment not
permitted under this Section 12.4 shall be null and void.



                                      -16-
<PAGE>   17

         12.5 Force Majeure. Nonperformance of either party (except for payment
of amounts due hereunder) shall be excused to the extent that performance is
rendered impossible by strike, fire, earthquake, flood, governmental acts or
orders or restrictions, or any other reason, including failure of suppliers,
where failure to perform is beyond the reasonable control of the nonperforming
party. Without limiting the foregoing, the party subject to such inability shall
use reasonable efforts to minimize the duration of any force majeure event.

         12.6 Patent Marking. Gendux agrees to mark, and have its Affiliates and
Sublicensees mark, all Agreement Products sold or otherwise distributed pursuant
to this Agreement in accordance with the applicable patent statutes or
regulations in the country or countries of manufacture and sale thereof.

         12.7 Notices. All notices, requests and other communications hereunder
shall be made in writing and shall be sent by registered or certified mail,
return receipt requested, postage prepaid; facsimile transmission (receipt
verified); or express courier service (signature required), in each case to the
respective address or fax number specified below, or such other address or fax
number as may be specified in writing to the other party:

                  Gendux:                   Gendux, Inc.
                                            301 Congress Avenue, Suite 1850
                                            Austin, Texas 78701
                                            Attn: President
                                            Fax: (512) 708-9311

                  with a copy to:           Wilson Sonsini Goodrich & Rosati
                                            650 Page Mill Road
                                            Palo Alto, California 94304-1050
                                            Attn: Kenneth A. Clark
                                            Fax: (650) 493-6811

                  Introgen:                 Introgen Therapeutics, Inc.
                                            301 Congress Avenue, Suite 1850
                                            Austin, Texas 78701
                                            Attn: President
                                            Fax: (512) 708-9311

                  with a copy to:           Wilson Sonsini Goodrich & Rosati
                                            650 Page Mill Road
                                            Palo Alto, California 94304-1050
                                            Attn: Kenneth A. Clark
                                            Fax: (650) 493-6811



                                      -17-
<PAGE>   18

         12.8 Governing Law. This Agreement shall be governed by, and construed
and interpreted in accordance with, the laws of the State of Texas, without
regard to conflicts of laws principles. Exclusive venue and jurisdiction of any
disputes governed by this Agreement shall be in the federal courts for the State
of Texas. The parties hereby consent to the jurisdiction of such courts.

         12.9 Compliance with Law. Gendux shall comply with all applicable laws
and regulations in connection with its activities pursuant to this Agreement.

         12.10 Modification; Waiver. No amendment or modification of any
provision of this Agreement shall be effective unless in writing signed by the
party to be charged. No provision of this Agreement shall be varied,
contradicted or explained by any oral agreement, course of dealing or
performance, or any other matter not set forth in an agreement in writing and
signed by both parties hereto. No failure on the part of either party to
exercise, and no delay in exercising any right under this Agreement or provided
by statute or at law or in equity or otherwise, shall impair, prejudice or
constitute a waiver of any such right, nor shall any partial exercise of any
such right preclude any other or further exercise thereof or the exercise of any
other right.

         12.11 Headings. Headings included herein are for convenience only, do
not form a part of this Agreement and shall not be used in any way to construe
or interpret this Agreement.

         12.12 Severability. If any provision hereof should be held invalid,
illegal or unenforceable in any jurisdiction, the parties shall negotiate in
good faith a valid, legal and enforceable substitute provision that most nearly
reflects the original intent of the parties (or shall strike such provision in
the absence of such substitute provision) and all other provisions hereof shall
remain in full force and effect in such jurisdiction and shall be liberally
construed in order to carry out the intentions of the parties hereto as nearly
as may be possible. Such invalidity, illegality or unenforceability shall not
affect the validity, legality or enforceability of such provision in any other
jurisdiction.

         12.13 Entire Agreement. This Agreement (including the Exhibits hereto)
together with the DTLA, the Development Agreement and the Services Agreement
(including the respective Exhibits thereto), each entered into by the parties of
even date, constitute the entire understanding and agreement between the parties
with respect to the subject matter hereof and supersede any and all prior
negotiations, representations, agreements, and understandings, whether written
or oral, between the parties with respect to such subject matter.

         12.14 Counterparts. This Agreement may be executed in two counterparts,
each of which shall be deemed an original, but both of which together shall
constitute one and the same instrument.





            (The remainder of this page is intentionally left blank.)



                                      -18-
<PAGE>   19

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly
executed and delivered in duplicate originals.


INTROGEN THERAPEUTICS, INC.

By: /s/ JAMES W. ALBRECHT, JR.
   ----------------------------------
Name:   James W. Albrecht, Jr.
     --------------------------------
Title:  Chief Financial Officer
      -------------------------------

GENDUX, INC.

By: /s/ DAVID G. NANCE
   ----------------------------------
Name:   David G. Nance
     --------------------------------
Title:  President & CEO
      -------------------------------



                                      -19-
<PAGE>   20

                                    EXHIBIT A

                                 ASSIGNED GENES


<TABLE>
<CAPTION>
       ASSIGNED GENE                      CORRESPONDING ASSIGNED AGREEMENT
       -------------                      --------------------------------
<S>                                 <C>
           PTEN                     Option Agreement, dated May 21, 1998, by and
                                    between Imperial Cancer Research Technology
                                    Limited and Introgen Therapeutics, Inc.
</TABLE>





<PAGE>   21



                                    EXHIBIT B

                                 LICENSED GENES


<TABLE>
<CAPTION>
       LICENSED GENE                    CORRESPONDING THIRD PARTY RIGHTS
       -------------                    --------------------------------

<S>                                 <C>
            C-CAM                   Patent and Delivery Technology License
                                    Agreement, dated July 20, 1994 by and
                                    between The University of Texas, M.D.
                                    Anderson Cancer Center and Introgen
                                    Therapeutics, Inc., as amended

            DBCCRI                  Option Agreement for Tumor Suppressor Genes,
                                    effective January 1, 1999, by and between
                                    Imperial Cancer Research Technology Limited
                                    and Introgen Therapeutics, Inc.

            RSK-3                   Option Agreement for Tumor Suppressor Genes,
                                    effective January 1, 1999, by and between
                                    Imperial Cancer Research Technology Limited
                                    and Introgen Therapeutics, Inc.
</TABLE>