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                                                                    EXHIBIT 10.2


                           INTROGEN THERAPEUTICS, INC.

                                 1995 STOCK PLAN
                                  (AS AMENDED)

               1. Purposes of the Plan. The purposes of this Stock Plan are to
attract and retain the best available personnel for positions of substantial
responsibility, to provide additional incentive to Employees and Consultants of
the Company and its Subsidiaries and to promote the success of the Company's
business. Options granted under the Plan may be incentive stock options (as
defined under Section 422 of the Code) or non-statutory stock options, as
determined by the Administrator at the time of grant of an option and subject to
the applicable provisions of Section 422 of the Code, as amended, and the
regulations promulgated thereunder. Stock purchase rights may also be granted
under the Plan.

               2. Definitions. As used herein, the following definitions shall
apply:

                   (a) "Administrator" means the Board or any of its Committees
appointed pursuant to Section 4 of the Plan.

                   (b) "Board" means the Board of Directors of the Company.

                   (c) "Code" means the Internal Revenue Code of 1986, as
amended.

                   (d) "Committee" means a Committee appointed by the Board of
Directors in accordance with Section 4 of the Plan.

                   (e) "Common Stock" means the Common Stock of the Company.

                   (f) "Company" means Introgen Therapeutics, Inc., a Delaware
corporation.

                   (g) "Consultant" means any person who is engaged by the
Company or any Parent or Subsidiary to render consulting or advisory services
and is compensated for such services, and any director of the Company whether
compensated for such services or not.

                   (h) "Continuous Status as an Employee or Consultant" means
that the employment or consulting relationship is not interrupted or terminated
by the Company, any Parent or Subsidiary. Continuous Status as an Employee or
Consultant shall not be considered interrupted in the case of: (i) any leave of
absence approved by the Company, including sick leave, military leave, or any
other personal leave; provided, however, that for purposes of Incentive Stock
Options, no such leave may exceed ninety (90) days, unless reemployment upon the
expiration of such leave is guaranteed by contract (including certain Company
policies) or statute; provided, further, that on the ninety-first (91st) day of
any such leave (where reemployment is not guaranteed by contract or statute) the
Optionee's Incentive Stock Option shall automatically convert to a Nonstatutory
Stock Option, or (ii) transfers between locations of the Company or between the
Company, its Parent, its Subsidiaries or its successor.

                   (i) "Disability" means total and permanent disability as
defined in Section 22(e)(3) of the Code.


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                   (j) "Employee" means any person, including officers and
directors, employed by the Company or any Parent or Subsidiary of the Company.
The payment of a director's fee by the Company shall not be sufficient to
constitute "employment" by the Company.

                   (k) "Exchange Act" means the Securities Exchange Act of 1934,
as amended.

                   (l) "Fair Market Value" means, as of any date, the value of
Common Stock determined as follows:

                                   (i) If the Common Stock is listed on any
established stock exchange or a national market system, including without
limitation the Nasdaq National Market or The Nasdaq SmallCap Market of The
Nasdaq Stock Market, its Fair Market Value shall be the closing sales price for
such stock (or the closing bid, if no sales were reported) as quoted on such
exchange or system for the last market trading day prior to the time of
determination, as reported in The Wall Street Journal or such other source as
the Administrator deems reliable;

                                   (ii) If the Common Stock is regularly quoted
by a recognized securities dealer but selling prices are not reported, the Fair
Market Value of a Share of Common Stock shall be the mean between the high bid
and low asked prices for the Common Stock on the last market trading day prior
to the day of determination, as reported in The Wall Street Journal or such
other source as the Administrator deems reliable;

                                   (iii) In the absence of an established market
for the Common Stock, the Fair Market Value shall be determined in good faith by
the Administrator.

                             (m) "Incentive Stock Option" means an Option
intended to qualify as an incentive stock option within the meaning of Section
422 of the Code.

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

                             (o) "Officer" means a person who is an officer of
the Company within the meaning of Section 16 of the Exchange Act and the rules
and regulations promulgated thereunder.

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

                             (q) "Optioned Stock" means the Common Stock subject
to an Option or a Stock Purchase Right.

                             (r) "Optionee" means an Employee or Consultant who
receives an Option or Stock Purchase Right.

                             (s) "Parent" means a "parent corporation", whether
now or hereafter existing, as defined in Section 424(e) of the Code.


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                             (t) "Plan" means this 1995 Stock Plan.

                             (u) "Restricted Stock" means shares of Common Stock
acquired pursuant to a grant of a Stock Purchase Right under Section 11 below.

                             (v) "Share" means a share of the Common Stock, as
adjusted in accordance with
Section 12 below.

                             (w) "Stock Purchase Right" means the right to
purchase Common Stock pursuant to Section 11 below.

                             (x) "Subsidiary" means a "subsidiary corporation",
whether now or hereafter existing, as defined in Section 424(f) of the Code.

               3. Stock Subject to the Plan. Subject to the provisions of
Section 12 of the Plan, the maximum aggregate number of shares which may be
optioned and sold under the Plan is 1,750,000 shares of Common Stock. The shares
may be authorized, but unissued, or reacquired Common Stock.

                             If an Option or Stock Purchase Right expires or
becomes unexercisable without having been exercised in full, or is surrendered
pursuant to an option exchange program, the unpurchased Shares which were
subject thereto shall become available for future grant or sale under the Plan
(unless the Plan has terminated); provided, however, that Shares that have
actually been issued under the Plan, whether upon exercise of an Option or Stock
Purchase Right, shall not be returned to the Plan and shall not become available
for future distribution under the Plan, except that if Shares of Restricted
Stock are repurchased by the Company at their original purchase price, such
Shares shall become available for future grant under the Plan.

               4. Administration of the Plan.

                             (a) Plan Procedure.

                                   (i) Administration With Respect to Directors
and Officers. With respect to grants of Options or Stock Purchase Rights to
Officers or directors of the Company, the Plan shall be administered by (A) the
Board if the Board may administer the Plan in compliance with Rule 16b-3
promulgated under the Exchange Act or any successor thereto ("Rule 16b-3") with
respect to a plan intended to qualify thereunder as a discretionary plan, or (B)
a committee designated by the Board to administer the Plan, which committee
shall be constituted in such a manner as to permit the Plan to comply with Rule
16b-3 with respect to a plan intended to qualify thereunder as a discretionary
plan. Once appointed, such Committee shall continue to serve in its designated
capacity until otherwise directed by the Board. From time to time the Board may
increase the size of the Committee and appoint additional members thereof,
remove members (with or without cause) and appoint new members in sub stitution
therefor, fill vacancies, however caused, and remove all members of the
Committee and thereafter directly administer the Plan, all to the extent
permitted by Rule 16b-3 with respect to a plan intended to qualify thereunder as
a discretionary plan.


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                                   (ii) Multiple Administrative Bodies. If
permitted by Rule 16b-3, the Plan may be administered by different bodies with
respect to directors, non-director Officers and Employees who are neither
directors nor Officers.

                                   (iii) Administration With Respect to
Consultants and Other Employees. With respect to grants of Options or Stock
Purchase Rights to Employees or Consultants who are neither directors nor
officers of the Company, the Plan shall be administered by (A) the Board or (B)
a committee designated by the Board, which committee shall be constituted in
such a manner as to satisfy the legal requirements relating to the
administration of incentive stock option plans, if any, of Delaware corporate
and securities laws, of the Code, and of any applicable stock exchange (the
"Applicable Laws"). Once appointed, such Committee shall continue to serve in
its designated capacity until otherwise directed by the Board. From time to time
the Board may increase the size of the Committee and appoint additional members
thereof, remove members (with or without cause) and appoint new members in
substitution therefor, fill vacancies, however caused, and remove all members of
the Committee and thereafter directly administer the Plan, all to the extent
permitted by the Applicable Laws.

                             (b) Powers of the Administrator. Subject to the
provisions of the Plan and, in the case of a Committee, the specific duties
delegated by the Board to such Committee, and subject to the approval of any
relevant authorities, including the approval, if required, of any stock exchange
upon which the Common Stock is listed, the Administrator shall have the
authority, in its discretion:

                                 (i) to determine the Fair Market Value of the
Common Stock, in accordance with Section 2(l) of the Plan;

                                 (ii) to select the Consultants and Employees to
whom Options and Stock Purchase Rights may from time to time be granted
hereunder;

                                 (iii) to determine whether and to what extent
Options and Stock Purchase Rights or any combination thereof are granted
hereunder;

                                 (iv) to determine the number of shares of
Common Stock to be covered by each such award granted hereunder;

                                 (v) to approve forms of agreement for use under
the Plan;

                                 (vi) to determine the terms and conditions, not
inconsistent with the terms of the Plan, of any award granted hereunder;

                                 (vii) to determine whether and under what
circumstances an Option may be settled in cash under subsection 9(f) instead of
Common Stock;

                                 (viii) to reduce the exercise price of any
Option to the then current Fair Market Value if the Fair Market Value of the
Common Stock covered by such Option shall have declined since the date the
Option was granted;


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                                 (ix) to determine the terms and restrictions
applicable to Stock Purchase Rights and the Restricted Stock purchased by
exercising such Stock Purchase Rights; and

                                 (x) to construe and interpret the terms of the
Plan and awards granted pursuant to the Plan.

                             (c) Effect of Administrator's Decision. All
decisions, determinations and interpretations of the Administrator shall be
final and binding on all Optionees and any other holders of any Options or Stock
Purchase Rights.

               5.            Eligibility.

                             (a) Nonstatutory Stock Options and Stock Purchase
Rights may be granted to Employees and Consultants. Incentive Stock Options may
be granted only to Employees. An Employee or Consultant who has been granted an
Option or Stock Purchase Right may, if otherwise eligible, be granted additional
Options or Stock Purchase Rights.

                             (b) Each Option shall be designated in the written
option agreement as either an Incentive Stock Option or a Nonstatutory Stock
Option. However, notwithstanding such designations, to the extent that the
aggregate Fair Market Value of the Shares with respect to which Options
designated as Incentive Stock Options are exercisable for the first time by any
Optionee during any calendar year (under all plans of the Company or any Parent
or Subsidiary) exceeds $100,000, such excess Options shall be treated as
Nonstatutory Stock Options.

                             (c) For purposes of Section 5(b), Incentive Stock
Options shall be taken into account in the order in which they were granted, and
the Fair Market Value of the Shares shall be determined as of the time the
Option with respect to such Shares is granted.

                             (d) The following limitations shall apply to grants
of Options:

                                   (i) No Employee shall be granted, in any
fiscal year of the Company, Options to purchase more than 500,000 Shares.

                                   (ii) In connection with his or her initial
service, a Service Provider may be granted Options to purchase up to an
additional 500,000 Shares which shall not count against the limit set forth in
subsection (i) above.

                                   (iii) The foregoing limitations shall be
adjusted proportionately in connection with any change in the Company's
capitalization as described in Section 12.

                                   (iv) If an Option is cancelled in the same
fiscal year of the Company in which it was granted (other than in connection
with a transaction described in Section 12), the cancelled Option will be
counted against the limits set forth in subsections (i) and (ii) above. For this
purpose, if the


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exercise price of an Option is reduced, the transaction will be treated as a
cancellation of the Option and the grant of a new Option.

                             (e) The Plan shall not confer upon any Optionee any
right with respect to continuation of employment relationship with the Company,
nor shall it interfere in any way with his or her right or the Company's right
to terminate his or her employment relationship at any time, with or without
cause.

               6. Term of Plan. The Plan shall become effective upon the earlier
to occur of its adoption by the Board of Directors or its approval by the
shareholders of the Company, as described in Section 18 of the Plan. It shall
continue in effect for a term of ten (10) years unless sooner terminated under
Section 14 of the Plan.

               7. Term of Option. The term of each Option shall be the term
stated in the Option Agreement; provided, however, that the term shall be no
more than ten (10) years from the date of grant thereof. However, in the case of
an Incentive Stock Option granted to an Optionee who, at the time the Option is
granted, owns stock representing more than ten percent (10%) of the voting power
of all classes of stock of the Company or any Parent or Subsidiary, the term of
the Option shall be five (5) years from the date of grant thereof or such
shorter term as may be provided in the Option Agreement.

               8. Option Exercise Price and Consideration.

                             (a) The per share exercise price for the Shares to
be issued pursuant to exercise of an Option shall be such price as is determined
by the Administrator, but shall be subject to the following:

                                   (i) In the case of an Incentive Stock Option

                                       (A) granted to an Employee who, at the
time of the grant of such Incentive Stock Option, owns stock representing more
than ten percent (10%) of the voting power of all classes of stock of the
Company or any Parent or Subsidiary, the per Share exercise price shall be no
less than 110% of the Fair Market Value per Share on the date of grant.

                                       (B) granted to any Employee, the per
Share exercise price shall be no less than 100% of the Fair Market Value per
Share on the date of grant.

                                   (ii) In the case of a Nonstatutory Stock
Option, the per Share exercise price shall be determined by the Administrator.


                             (b) The consideration to be paid for the Shares to
be issued upon exercise of an Option, including the method of payment, shall be
determined by the Administrator (and, in the case of an Incentive Stock Option,
shall be determined at the time of grant) and may consist entirely of (1) cash,
(2) check, (3) promissory note, (4) other Shares which (x) in the case of Shares
acquired upon exercise of an Option, have been owned by the Optionee for more
than six months on the date of surrender, and (y) have a Fair Market Value on
the date of surrender equal to the aggregate exercise price of the Shares


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as to which said Option shall be exercised, (5) delivery of a properly executed
exercise notice together with such other documentation as the Administrator and
the broker, if applicable, shall require to effect an exercise of the Option and
delivery to the Company of the sale or loan proceeds required to pay the
exercise price, or (6) any combination of the foregoing methods of payment. In
making its determination as to the type of consideration to accept, the
Administrator shall consider if acceptance of such consideration may be
reasonably expected to benefit the Company.

               9. Exercise of Option.

                  (a) Procedure for Exercise; Rights as a Shareholder. Any
Option granted hereunder shall be exercisable at such times and under such
conditions as determined by the Administrator, including performance criteria
with respect to the Company and/or the Optionee, and as shall be permissible
under the terms of the Plan.

                             An Option may not be exercised for a fraction of a
Share.

                             An Option shall be deemed to be exercised when
written notice of such exercise has been given to the Company in accordance with
the terms of the Option by the person entitled to exercise the Option and full
payment for the Shares with respect to which the Option is exercised has been
received by the Company. Full payment may, as authorized by the Administrator,
consist of any consideration and method of payment allowable under Section 8(b)
of the Plan. Until the issuance (as evidenced by the appropriate entry on the
books of the Company or of a duly authorized transfer agent of the Company) of
the stock certificate evidencing such Shares, no right to vote or receive
dividends or any other rights as a shareholder shall exist with respect to the
Optioned Stock, notwithstanding the exercise of the Option. The Company shall
issue (or cause to be issued) such stock certificate promptly upon exercise of
the Option. No adjustment will be made for a dividend or other right for which
the record date is prior to the date the stock certificate is issued, except as
provided in Section 12 of the Plan.

                             Exercise of an Option in any manner shall result in
a decrease in the number of Shares which thereafter may be available, both for
purposes of the Plan and for sale under the Option, by the number of Shares as
to which the Option is exercised.

                  (b) Termination of Employment or Consulting Relationship. In
the event of termination of an Optionee's Continuous Status as an Employee or
Consultant with the Company (but not in the event of an Optionee's change of
status from Employee to Consultant (in which case an Employee's Incentive Stock
Option shall automatically convert to a Nonstatutory Stock Option on the
ninety-first (91st) day following such change of status) or from Consultant to
Employee), such Optionee may, but only within such period of time as is
determined by the Administrator, of at least thirty (30) days, with such
determination in the case of an Incentive Stock Option not exceeding three (3)
months after the date of such termination (but in no event later than the
expiration date of the term of such Option as set forth in the Option
Agreement), exercise his or her Option to the extent that Optionee was entitled
to exercise it at the date of such termination. To the extent that Optionee was
not entitled to exercise the Option at the date of such termination, or if
Optionee does not exercise such Option to the extent so entitled within the time
specified herein, the Option shall terminate.


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                  (c) Disability of Optionee. In the event of termination of an
Optionee's consulting relationship or Continuous Status as an Employee as a
result of his or her Disability, Optionee may, but only within twelve (12)
months from the date of such termination (and in no event later than the
expiration date of the term of such Option as set forth in the Option
Agreement), exercise the Option to the extent otherwise entitled to exercise it
at the date of such termination. To the extent that Optionee was not entitled to
exercise the Option at the date of termination, or if Optionee does not exercise
such Option to the extent so entitled within the time specified herein, the
Option shall terminate, and the Shares covered by such Option shall revert to
the Plan.

                  (d) Death of Optionee. In the event of the death of an
Optionee, the Option may be exercised at any time within twelve (12) months
following the date of death (but in no event later than the expiration of the
term of such Option as set forth in the Notice of Grant), by the Optionee's
estate or by a person who acquired the right to exercise the Option by bequest
or inheritance, but only to the extent that the Optionee was entitled to
exercise the Option at the date of death. If, at the time of death, the Optionee
was not entitled to exercise his or her entire Option, the Shares covered by the
unexercisable portion of the Option shall immediately revert to the Plan. If,
after death, the Optionee's estate or a person who acquired the right to
exercise the Option by bequest or inheritance does not exercise the Option
within the time specified herein, the Option shall terminate, and the Shares
covered by such Option shall revert to the Plan.

                  (e) Rule 16b-3. Options granted to persons subject to Section
16(b) of the Exchange Act must comply with Rule 16b-3 and shall contain such
additional conditions or restrictions as may be required thereunder to qualify
for the maximum exemption from Section 16 of the Exchange Act with respect to
Plan transactions.

                  (f) Buyout Provisions. The Administrator may at any time offer
to buy out for a payment in cash or Shares, an Option previously granted, based
on such terms and conditions as the Administrator shall establish and
communicate to the Optionee at the time that such offer is made.

               10. Non-Transferability of Options and Stock Purchase Rights.
Options and Stock Purchase Rights may not be sold, pledged, hypothecated,
transferred or disposed of in any manner other than by will or by the laws of
descent or distribution and may be exercised, during the lifetime of the
Optionee, only by the Optionee; provided, however, that, with the written
approval of the Administrator, which may be granted or withheld in its absolute
discretion, Non-Statutory Stock Options may be sold, transferred, pledged or
assigned, and may be exercised by any such approved transferee.

               11. Stock Purchase Rights.

                   (a) Rights to Purchase. Stock Purchase Rights may be issued
either alone, in addition to, or in tandem with other awards granted under the
Plan and/or cash awards made outside of the Plan. After the Administrator
determines that it will offer Stock Purchase Rights under the Plan, it shall
advise the offeree in writing of the terms, conditions and restrictions related
to the offer, including the number of Shares that such person shall be entitled
to purchase, the price to be paid, and the time within which such person must
accept such offer, which shall in no event exceed thirty (30) days from the date
upon which the Administrator made the determination to grant the Stock Purchase
Right. The price to be paid


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shall be determined by the Administrator. The offer shall be accepted by
execution of a Restricted Stock Purchase Agreement in the form determined by the
Administrator. Shares purchased pursuant to the grant of a Stock Purchase Right
shall be referred to herein as "Restricted Stock."

                             (b) Repurchase Option. Unless the Administrator
determines otherwise, the Restricted Stock purchase agreement shall grant the
Company a repurchase option exercisable upon the voluntary or involuntary
termination of the purchaser's employment with the Company for any reason
(including death or Disability). The purchase price for Shares repurchased
pursuant to the Restricted Stock purchase agreement shall be the original price
paid by the purchaser and may be paid by cancellation of any indebtedness of the
purchaser to the Company. The repurchase option shall lapse at such rate as the
Administrator may determine.

                             (c) Other Provisions. The Restricted Stock purchase
agreement shall contain such other terms, provisions and conditions not
inconsistent with the Plan as may be determined by the Administrator in its sole
discretion. In addition, the provisions of Restricted Stock purchase agreements
need not be the same with respect to each purchaser.

                             (d) Rights as a Shareholder. Once the Stock
Purchase Right is exercised, the purchaser shall have the rights equivalent to
those of a shareholder, and shall be a shareholder when his or her purchase is
entered upon the records of the duly authorized transfer agent of the Company.
No adjustment will be made for a dividend or other right for which the record
date is prior to the date the Stock Purchase Right is exercised, except as
provided in Section 12 of the Plan.

               12.           Adjustments.

                             (a) Changes in Capitalization. Subject to any
required action by the shareholders of the Company, the number of shares of
Common Stock covered by each outstanding Option or Stock Purchase Right, and the
number of shares of Common Stock which have been authorized for issuance under
the Plan but as to which no Options or Stock Purchase Rights have yet been
granted or which have been returned to the Plan upon cancellation or expiration
of an Option or Stock Purchase Right, as well as the price per share of Common
Stock covered by each such outstanding Option or Stock Purchase Right, shall be
proportionately adjusted for any increase or decrease in the number of issued
shares of Common Stock resulting from a stock split, reverse stock split, stock
dividend, combination or reclas sification of the Common Stock, or any other
increase or decrease in the number of issued shares of Common Stock effected
without receipt of consideration by the Company; provided, however, that
conversion of any convertible securities of the Company shall not be deemed to
have been "effected without receipt of consideration." Such adjustment shall be
made by the Administrator, whose determination in that respect shall be final,
binding and conclusive. Except as expressly provided herein, no issuance by the
Company of shares of stock of any class, or securities convertible into shares
of stock of any class, shall affect, and no adjustment by reason thereof shall
be made with respect to, the number or price of shares of Common Stock subject
to an Option or Stock Purchase Right.

                             (b) Dissolution or Liquidation. In the event of the
proposed dissolution or liquidation of the Company, the Administrator shall
notify each Optionee as soon as practicable prior to the effective


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date of such proposed transaction. The Administrator in its discretion may
provide for an Optionee to have the right to exercise his or her Option until
ten (10) days prior to such transaction as to all of the Optioned Stock covered
thereby, including Shares as to which the Option would not otherwise be
exercisable. In addition, the Administrator may provide that any Company
repurchase option applicable to any Shares purchased upon exercise of an Option
or Stock Purchase Right shall lapse as to all such Shares, provided the proposed
dissolution or liquidation takes place at the time and in the manner
contemplated. To the extent it has not been previously exercised, an Option or
Stock Purchase Right will terminate immediately prior to the consummation of
such proposed action.

                             (c) Merger or Asset Sale. In the event of a merger
of the Company with or into another corporation, or the sale of substantially
all of the assets of the Company, each outstanding Option and Stock Purchase
Right shall be assumed or an equivalent option or right substituted by the
successor corporation or a Parent or Subsidiary of the successor corporation. In
the event that the successor corporation refuses to assume or substitute for the
Option or Stock Purchase Right, the Optionee shall fully vest in and have the
right to exercise the Option or Stock Purchase Right as to all of the Optioned
Stock, including Shares as to which it would not otherwise be vested or
exercisable. If an Option or Stock Purchase Right becomes fully vested and
exercisable in lieu of assumption or substitution in the event of a merger or
sale of assets, the Administrator shall notify the Optionee in writing or
electronically that the Option or Stock Purchase Right shall be fully vested and
exercisable for a period of fifteen (15) days from the date of such notice, and
the Option or Stock Purchase Right shall terminate upon the expiration of such
period. For the purposes of this paragraph, the Option or Stock Purchase Right
shall be considered assumed if, following the merger or sale of assets, the
option or right confers the right to purchase or receive, for each Share of
Optioned Stock subject to the Option or Stock Purchase Right immediately prior
to the merger or sale of assets, the consideration (whether stock, cash, or
other securities or property) received in the merger or sale of assets by
holders of Common Stock for each Share held on the effective date of the
transaction (and if holders were offered a choice of consideration, the type of
consideration chosen by the holders of a majority of the outstanding Shares);
provided, however, that if such consideration received in the merger or sale of
assets is not solely common stock of the successor corporation or its Parent,
the Administrator may, with the consent of the successor corporation, provide
for the consideration to be received upon the exercise of the Option or Stock
Purchase Right, for each Share of Optioned Stock subject to the Option or Stock
Purchase Right, to be solely common stock of the successor corporation or its
Parent equal in fair market value to the per share consideration received by
holders of Common Stock in the merger or sale of assets.

               13. Time of Granting Options and Stock Purchase Rights. The date
of grant of an Option or Stock Purchase Right shall, for all purposes, be the
date on which the Administrator makes the determination granting such Option or
Stock Purchase Right, or such other date as is determined by the Administrator.
Notice of the determination shall be given to each Employee or Consultant to
whom an Option or Stock Purchase Right is so granted within a reasonable time
after the date of such grant.

               14. Amendment and Termination of the Plan.

                   (a) Amendment and Termination. The Board may at any time
amend, alter, suspend or terminate the Plan.


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                   (b) Shareholder Approval. The Company shall obtain
shareholder approval of any Plan amendment to the extent necessary and desirable
to comply with Applicable Laws.

                   (c) Effect of Amendment or Termination. No amendment,
alteration, suspension or termination of the Plan shall impair the rights of any
Optionee, unless mutually agreed otherwise between the Optionee and the
Administrator, which agreement must be in writing and signed by the Optionee and
the Company.

               15. Conditions Upon Issuance of Shares. Shares shall not be
issued pursuant to the exercise of an Option or Stock Purchase Right unless the
exercise of such Option or Stock Purchase Right and the issuance and delivery of
such Shares pursuant thereto shall comply with all relevant provisions of law,
including, without limitation, the Securities Act of 1933, as amended, the
Exchange Act, the rules and regulations promulgated thereunder, and the
requirements of any stock exchange upon which the Shares may then be listed, and
shall be further subject to the approval of counsel for the Company with respect
to such compliance.

                   As a condition to the exercise of an Option or Stock Purchase
Right, the Company may require the person exercising such Option or Stock
Purchase Right to represent and warrant at the time of any such exercise that
the Shares are being purchased only for investment and without any present
intention to sell or distribute such Shares if, in the opinion of counsel for
the Company, such a representation is required by any of the aforementioned
relevant provisions of law.

               16. Reservation of Shares. The Company, during the term of this
Plan, will at all times reserve and keep available such number of Shares as
shall be sufficient to satisfy the requirements of the Plan.

                   The inability of the Company to obtain authority from any
regulatory body having jurisdiction, which authority is deemed by the Company's
counsel to be necessary to the lawful issuance and sale of any Shares hereunder,
shall relieve the Company of any liability in respect of the failure to issue or
sell such Shares as to which such requisite authority shall not have been
obtained.

               17. Agreements. Options and Stock Purchase Rights shall be
evidenced by written agreements in such form as the Administrator shall approve
from time to time.

               18. Shareholder Approval. Continuance of the Plan shall be
subject to approval by the shareholders of the Company within twelve (12) months
before or after the date the Plan is adopted. Such shareholder approval shall be
obtained in the degree and manner required under applicable state and federal
law and the rules of any stock exchange upon which the Common Stock is listed.



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                           INTROGEN THERAPEUTICS, INC.
                                 1995 STOCK PLAN
                                 NOTICE OF GRANT

               Unless otherwise defined herein, the terms defined in the Plan
shall have the same defined meanings in this Notice of Grant.

[Optionee's Name and Address]

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

               You have been granted an option to purchase Common Stock of the
Company, subject to the terms and conditions of the Plan and this Stock Option
Agreement, as follows:

               Grant Number                        ____________________

               Date of Grant                       ____________________

               Vesting Commencement Date           ____________________

               Exercise Price per Share            $___________________

               Total Number of Shares Granted      ____________________

               Total Exercise Price                $____________________

               Type of Option:                     ___ Incentive Stock Option
                                                   ___ Nonstatutory Stock Option

               Term Date:                          _____________________________

               Expiration Date:                    _____________________________

     Vesting Schedule:

               Twenty-five percent (25%) of the Shares subject to this Option
shall vest at the end of each twelve (12) month anniversary of the Vesting
Commencement Date in accordance with the following schedule:

<TABLE>
<CAPTION>
                                     $ OF SHARES        CUMULATIVE % OF SHARES
         DATE                         THAT VEST               VESTED
---------------------                -----------        -----------------------
<S>                                 <C>                <C>
12 month anniversary                     25%                    25%
24 month anniversary                     25%                    50%
36 month anniversary                     25%                    75%
48 month anniversary                     25%                   100%
</TABLE>


<PAGE>   13
               No vesting occurs at any date other than the anniversary dates
set forth above.

               Termination Period:

               This Option may be exercised for three (3) months after
termination of employment or consulting relationship, or such longer period as
may be applicable upon death or Disability of Optionee as provided in the Plan,
but in no event later than the Term/Expiration Date as provided above.


                                       -2-
<PAGE>   14
                           INTROGEN THERAPEUTICS, INC.
                             1995 STOCK OPTION PLAN
                                OPTION AGREEMENT


               1. Grant of Option. Introgen Therapeutics, Inc. (the "Company"),
hereby grants to the Optionee (the "Optionee") named in the Notice of Grant, an
option (the "Option") to purchase the total number of shares of Common Stock
(the "Shares") set forth in the Notice of Grant, at the exercise price per share
set forth in the Notice of Grant (the "Exercise Price") subject to the terms,
definitions and provisions of the 1995 Stock Option Plan (the "Plan") adopted by
the Company, which is incorporated herein by reference. Unless otherwise defined
herein, the terms defined in the Plan shall have the same defined meanings in
this Option Agreement.

                             If designated in the Notice of Grant as an
Incentive Stock Option ("ISO"), this Option is intended to qualify as an
Incentive Stock Option as defined in Section 422 of the Code. However, if this
Option is intended to be an Incentive Stock Option, to the extent that it
exceeds the $100,000 rule of Code Section 422(d) it shall be treated as a
Nonstatutory Stock Option ("NSO").

               2. Exercise of Option. This Option shall be exercisable during
its term in accordance with the Vesting Schedule set out in the Notice of Grant
and with the provisions of Section 9 of the Plan as follows:

                             (i)            Right to Exercise.

                                            (a) This Option may not be exercised
for a fraction of a Share.

                                            (b) In the event of Optionee's
death, disability or other termination of the Optionee's Continuous Status as an
Employee or Consultant, the exercisability of the Option is governed by Sections
6, 7 and 8 below, subject to the limitation contained in subsection 2(i)(c).

                                            (c) In no event may this Option be
exercised after the date of expiration of the term of this Option as set forth
in the Notice of Grant.

                             (ii) Method of Exercise. This Option shall be
exercisable by written notice (in the form attached as Exhibit A) which shall
state the election to exercise the Option, the number of Shares in respect of
which the Option is being exercised, and such other representations and
agreements as to the holder's investment intent with respect to such shares of
Common Stock as may be required by the Company pursuant to the provisions of the
Plan. Such written notice shall be signed by the Optionee and shall be delivered
in person or by certified mail to the Secretary of the Company. The written
notice shall be accompanied by payment of the Exercise Price. This Option shall
be deemed to be exercised upon receipt by the Company of such written notice
accompanied by the Exercise Price.

                             No Shares will be issued pursuant to the exercise
of an Option unless such issuance and such exercise shall comply with all
relevant provisions of law and the requirements of any stock exchange or
national market system upon which the Common Stock is then listed. Assuming such
<PAGE>   15
compliance, for income tax purposes the Shares shall be considered transferred
to the Optionee on the date on which the Option is exercised with respect to
such Shares.

               3. Optionee's Representations. In the event the Shares
purchasable pursuant to the exercise of this Option have not been registered
under the Securities Act of 1933, as amended, at the time this Option is
exercised, Optionee shall, if required by the Company, concurrently with the
exercise of all or any portion of this Option, deliver to the Company his or her
Investment Representation Statement in the form attached hereto as Exhibit B.

               4. Lock-Up Period. Optionee hereby agrees that if so requested by
the Company or any representative of the underwriters (the "Managing
Underwriter") in connection with any registration of the offering of any
securities of the Company under the Securities Act, Optionee shall not sell or
otherwise transfer any Shares or other securities of the Company during the
180-day period (or such longer period as may be requested in writing by the
Managing Underwriter and agreed to in writing by the Company) (the "Market
Standoff Period") following the effective date of a registration statement of
the Company filed under the Securities Act; provided, however, that such
restriction shall apply only to the first registration statement of the Company
to become effective under the Securities Act that includes securities to be sold
on behalf of the Company to the public in an underwritten public offering under
the Securities Act. The Company may impose stop-transfer instructions with
respect to securities subject to the foregoing restrictions until the end of
such Market Standoff Period.

              5. Method of Payment. Payment of the Exercise Price shall be by
any of the following, or a combination thereof, at the election of the Optionee:

                             (i) cash; or

                             (ii) check; or

                             (iii) surrender of other shares of Common Stock of
the Company which (A) in the case of Shares acquired pursuant to the exercise of
a Company option, have been owned by the Optionee for more than six (6) months
on the date of surrender, and (B) have a Fair Market Value on the date of
surrender equal to the Exercise Price of the Shares as to which the Option is
being exercised; or

                             (iv) to the extent authorized by the Company,
delivery of a properly executed exercise notice together with such other
documentation as the Administrator and the broker, if applicable, shall require
to effect an exercise of the Option and delivery to the Company of the sale or
loan proceeds required to pay the Exercise Price.

               6. Restrictions on Exercise. This Option may not be exercised if
the issuance of such Shares upon such exercise or the method of payment of
consideration for such shares would constitute a violation of any applicable
federal or state securities or other law or regulation, including any rule under
Part 207 of Title 12 of the Code of Federal Regulations as promulgated by the
Federal


                                       -2-
<PAGE>   16
Reserve Board. As a condition to the exercise of this Option, the Company may
require Optionee to make any representation and warranty to the Company as may
be required by any applicable law or regulation.

               7. Termination of Relationship. In the event an Optionee's
Continuous Status as an Employee or Consultant terminates, Optionee may, to the
extent otherwise so entitled at the date of such termination (the "Termination
Date"), exercise this Option during the Termination Period set out in the Notice
of Grant. To the extent that Optionee was not entitled to exercise this Option
at the date of such termination, or if Optionee does not exercise this Option
within the time specified herein, the Option shall terminate.

               8. Disability of Optionee. Notwithstanding the provisions of
Section 6 above, in the event of termination of an Optionee's Continuous Status
as an Employee or Consultant as a result of his or her Disability, Optionee may,
but only within twelve (12) months from the date of such termination (and in no
event later than the expiration date of the term of such Option as set forth in
the Notice of Grant) exercise the Option to the extent otherwise entitled to
exercise it at the date of such termination. To the extent that Optionee is not
entitled to exercise the Option at the date of termination, or if Optionee does
not exercise such Option to the extent so entitled within the time specified
herein, the Option shall terminate, and the Shares covered by such Option shall
revert to the Plan.

               9. Death of Optionee. In the event of termination of Optionee's
Continuous Status as an Employee or Consultant as a result of the death of
Optionee, the Option may be exercised at any time within twelve (12) months
following the date of death (but in no event later than the date of expiration
of the term of this Option as set forth in Section 10 below), by Optionee's
estate or by a person who acquired the right to exercise the Option by bequest
or inheritance, but only to the extent the Optionee could exercise the Option at
the date of death.

               10. Non-Transferability of Option. This Option may not be
transferred in any manner otherwise than by will or by the laws of descent or
distribution and may be exercised during the lifetime of Optionee only by
Optionee. The terms of this Option shall be binding upon the executors,
administrators, heirs, successors and assigns of the Optionee.

               11. Term of Option. This Option may be exercised only within the
term set out in the Notice of Grant, and may be exercised during such term only
in accordance with the Plan and the terms of this Option. The limitations set
out in Section 7 of the Plan regarding Options designated as Incentive Stock
Options and Options granted to more than ten percent (10%) shareholders shall
apply to this Option.

               12. Tax Consequences. Set forth below is a brief summary as of
the date of this Option of some of the federal tax consequences of exercise of
this Option and disposition of the Shares. THIS SUMMARY IS NECESSARILY
INCOMPLETE, AND THE TAX LAWS AND REGULATIONS ARE SUBJECT TO CHANGE. OPTIONEE
SHOULD CONSULT A TAX ADVISER BEFORE EXERCISING THIS OPTION OR DISPOSING OF THE
SHARES.


                                       -3-
<PAGE>   17
                   (i) Exercise of an ISO. If this Option qualifies as an ISO,
there will be no regular federal income tax liability upon the exercise of the
Option, although the excess, if any, of the Fair Market Value of the Shares on
the date of exercise over the Exercise Price will be treated as an adjustment to
the alternative minimum tax for federal tax purposes and may subject the
Optionee to the alternative minimum tax in the year of exercise.

                   (ii) Exercise of an NSO. There may be a regular federal
income tax liability upon the exercise of an NSO. The Optionee will be treated
as having received compensation income (taxable at ordinary income tax rates)
equal to the excess, if any, of the Fair Market Value of the Shares on the date
of exercise over the Exercise Price. If Optionee is an Employee, the Company
will be required to withhold from Optionee's compensation or collect from
Optionee and pay to the applicable taxing authorities an amount equal to a
percentage of this compensation income at the time of exercise.

                   (iii) Disposition of Shares. In the case of an NSO, if Shares
are held for at least one year, any gain realized on disposition of the Shares
will be treated as long-term capital gain for federal income tax purposes. In
the case of an ISO, if Shares transferred pursuant to the Option are held for at
least one year after exercise and are disposed of at least two years after the
Date of Grant, any gain realized on disposition of the Shares will also be
treated as long-term capital gain for federal income tax purposes. If Shares
purchased under an ISO are disposed of within such one-year period or within two
years after the Date of Grant, any gain realized on such disposition will be
treated as compensation income (taxable at ordinary income rates) to the extent
of the difference between the Exercise Price and the lesser of (1) the Fair
Market Value of the Shares on the date of exercise, or (2) the sale price of the
Shares.

                   (iv) Notice of Disqualifying Disposition of ISO Shares. If
the Option granted to Optionee herein is an ISO, and if Optionee sells or
otherwise disposes of any of the Shares acquired pursuant to the ISO on or
before the later of (1) the date two years after the Date of Grant, or (2) the
date one year after the date of exercise, the Optionee shall immediately notify
the Company in writing of such disposition. Optionee agrees that Optionee may be
subject to income tax withholding by the Company on the compensation income
recognized by the Optionee.

                                                  INTROGEN THERAPEUTICS, INC.


                                                  By:
                                                     --------------------------


               OPTIONEE ACKNOWLEDGES AND AGREES THAT THE VESTING OF SHARES
PURSUANT TO THE OPTION HEREOF IS EARNED ONLY BY CONTINUING CONSULTANCY OR
EMPLOYMENT AT THE WILL OF THE COMPANY (NOT THROUGH THE ACT OF BEING HIRED, BEING
GRANTED THIS OPTION OR ACQUIRING SHARES HEREUNDER). OPTIONEE FURTHER
ACKNOWLEDGES AND AGREES THAT NOTHING IN THIS AGREEMENT, NOR IN THE COMPANY'S
1995 STOCK OPTION PLAN WHICH IS


                                       -4-
<PAGE>   18
INCORPORATED HEREIN BY REFERENCE, SHALL CONFER UPON OPTIONEE ANY RIGHT WITH
RESPECT TO CONTINUATION OF EMPLOYMENT OR CONSULTANCY BY THE COMPANY, NOR SHALL
IT INTERFERE IN ANY WAY WITH OPTIONEE'S RIGHT OR THE COMPANY'S RIGHT TO
TERMINATE OPTIONEE'S EMPLOYMENT OR CONSULTANCY AT ANY TIME, WITH OR WITHOUT
CAUSE.

               Optionee acknowledges receipt of a copy of the Plan and
represents that he is familiar with the terms and provisions thereof, and hereby
accepts this Option subject to all of the terms and provisions thereof. Optionee
has reviewed the Plan and this Option in their entirety, has had an opportunity
to obtain the advice of counsel prior to executing this Option and fully
understands all provisions of the Option. Optionee hereby agrees to accept as
binding, conclusive and final all decisions or interpretations of the
Administrator upon any questions arising under the Plan or this Option. Optionee
further agrees to notify the Company upon any change in the residence address
indicated below.

Dated:
      -----------------------                    -------------------------------
                                                           Optionee

Residence Address:


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


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





                                       -5-
<PAGE>   19
                               CONSENT OF SPOUSE


               The undersigned spouse of Optionee has read and hereby approves
the terms and conditions of the Plan and this Option Agreement. In consideration
of the Company's granting his or her spouse the right to purchase Shares as set
forth in the Plan and this Option Agreement, the undersigned hereby agrees to be
irrevocably bound by the terms and conditions of the Plan and this Option
Agreement and further agrees that any community property interest shall be
similarly bound. The undersigned hereby appoints the undersigned's spouse as
attorney-in-fact for the undersigned with respect to any amendment or exercise
of rights under the Plan or this Option Agreement.


                                                  ------------------------------
                                                  Spouse of Optionee




                                       -6-
<PAGE>   20
                                    EXHIBIT A

                           INTROGEN THERAPEUTICS, INC.

                             1995 STOCK OPTION PLAN

                                 EXERCISE NOTICE


Introgen Therapeutics, Inc.
301 Congress Avenue
Suite 2025
Austin, TX  78701
Attention:  Secretary

               1. Exercise of Option. Effective as of today, ___________, 19__,
the undersigned ("Optionee") hereby elects to exercise Optionee's option to
purchase _________ shares of the Common Stock (the "Shares") of Introgen
Therapeutics, Inc. (the "Company") under and pursuant to the 1995 Stock Option
Plan, as amended (the "Plan") and the [ ] Incentive [ ] Nonstatutory Stock
Option Agreement dated ________, 19__ (the "Stock Option Agreement").

               2. Representations of Optionee. Optionee acknowledges that
Optionee has received, read and understood the Plan and the Stock Option
Agreement and agrees to abide by and be bound by their terms and conditions.

               3. Rights as Shareholder. Until the stock certificate evidencing
such Shares is issued (as evidenced by the appropriate entry on the books of the
Company or of a duly authorized transfer agent of the Company), no right to vote
or receive dividends or any other rights as a shareholder shall exist with
respect to the Optioned Stock, notwithstanding the exercise of the Option. The
Company shall issue (or cause to be issued) such stock certificate promptly
after the Option is exercised. No adjustment will be made for a dividend or
other right for which the record date is prior to the date the stock certificate
is issued, except as provided in Section 11 of the Plan.

                  Optionee shall enjoy rights as a shareholder until such time
as Optionee disposes of the Shares or the Company and/or its assignee(s)
exercises the Right of First Refusal hereunder. Upon such exercise, Optionee
shall have no further rights as a holder of the Shares so purchased except the
right to receive payment for the Shares so purchased in accordance with the
provisions of this Agreement, and Optionee shall forthwith cause the
certificate(s) evidencing the Shares so purchased to be surrendered to the
Company for transfer or cancellation.

               4. Company's Right of First Refusal. Before any Shares held by
Optionee or any transferee (either being sometimes referred to herein as the
"Holder") may be sold or otherwise transferred (including transfer by gift or
operation of law), the Company or its assignee(s) shall have a right of first
refusal to purchase the Shares on the terms and conditions set forth in this
Section (the "Right of First Refusal").



<PAGE>   21
                             (a) Notice of Proposed Transfer. The Holder of the
Shares shall deliver to the Company a written notice (the "Notice") stating: (i)
the Holder's bona fide intention to sell or otherwise transfer such Shares; (ii)
the name of each proposed purchaser or other transferee (the "Proposed
Transferee"); (iii) the number of Shares to be transferred to each Proposed
Transferee; and (iv) the bona fide cash price or other consideration for which
the Holder proposes to transfer the Shares (the "Offered Price"), and the Holder
shall offer the Shares at the Offered Price to the Company or its assignee(s).

                             (b) Exercise of Right of First Refusal. At any time
within thirty (30) days after receipt of the Notice, the Company and/or its
assignee(s) may, by giving written notice to the Holder, elect to purchase all,
but not less than all, of the Shares proposed to be transferred to any one or
more of the Proposed Transferees, at the purchase price determined in accordance
with subsection (c) below.

                             (c) Purchase Price. The purchase price (the
"Purchase Price") for the Shares purchased by the Company or its assignee(s)
under this Section shall be the Offered Price. If the Offered Price includes
consideration other than cash, the cash equivalent value of the non-cash
consideration shall be determined by the Administrator in good faith.

                             (d) Payment. Payment of the Purchase Price shall be
made, at the option of the Company or its assignee(s), in cash, by check, by
cancellation of all or a portion of any outstanding indebtedness of the Holder
to the Company (or, in the case of repurchase by an assignee, to the assignee),
or by any combination thereof within 30 days after receipt of the Notice or in
the manner and at the times set forth in the Notice.

                             (e) Holder's Right to Transfer. If all of the
Shares proposed in the Notice to be transferred to a given Proposed Transferee
are not purchased by the Company and/or its assignee(s) as provided in this
Section , then the Holder may sell or otherwise transfer such Shares to that
Proposed Transferee at the Offered Price or at a higher price, provided that
such sale or other transfer is consummated within 120 days after the date of the
Notice and provided further that any such sale or other transfer is effected in
accordance with any applicable securities laws and the Proposed Transferee
agrees in writing that the provisions of this Section shall continue to apply to
the Shares in the hands of such Proposed Transferee. If the Shares described in
the Notice are not transferred to the Proposed Transferee within such period, a
new Notice shall be given to the Company, and the Company and/or its assignees
shall again be offered the Right of First Refusal before any Shares held by the
Holder may be sold or otherwise transferred.

                             (f) Exception for Certain Family Transfers.
Anything to the contrary contained in this Section notwithstanding, the transfer
of any or all of the Shares during the Optionee's lifetime or on the Optionee's
death by will or intestacy to the Optionee's immediate family or a trust for the
benefit of the Optionee's immediate family shall be exempt from the provisions
of this Section . "Immediate Family" as used herein shall mean spouse, lineal
descendant or antecedent, father, mother, brother or sister. In such case, the
transferee or other recipient shall receive and hold the Shares so


                                       -2-
<PAGE>   22
transferred subject to the provisions of this Section , and there shall be no
further transfer of such Shares except in accordance with the terms of this
Section .

                             (g) Termination of Right of First Refusal. The
Right of First Refusal shall terminate upon the closing of the first sale of
Common Stock of the Company to the general public pursuant to a registration
statement filed with and declared effective by the Securities and Exchange
Commission under the Securities Act of 1933, as amended.

               5. Tax Consultation. Optionee understands that Optionee may
suffer adverse tax consequences as a result of Optionee's purchase or
disposition of the Shares. Optionee represents that Optionee has consulted with
any tax consultants Optionee deems advisable in connection with the purchase or
disposition of the Shares and that Optionee is not relying on the Company for
any tax advice.

               6. Restrictive Legends and Stop-Transfer Orders.

                             (a) Legends. Optionee understands and agrees that
the Company shall cause the legends set forth below or legends substantially
equivalent thereto, to be placed upon any certificate(s) evidencing ownership of
the Shares together with any other legends that may be required by state or
federal securities laws at the time of the issuance of the Shares:

                             THE SHARES REPRESENTED HEREBY HAVE NOT BEEN
                             REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
                             AMENDED (THE "ACT"), AND MAY NOT BE OFFERED, SOLD
                             OR OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED
                             UNLESS AND UNTIL REGISTERED UNDER THE ACT OR THE
                             ISSUER OF THE SHARES (THE "ISSUER") HAS RECEIVED AN
                             OPINION OF COUNSEL IN FORM AND SUBSTANCE
                             SATISFACTORY TO THE ISSUER THAT SUCH OFFER, SALE OR
                             TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE
                             WITH THE ACT.

                             THE SHARES REPRESENTED BY THIS CERTIFICATE ARE
                             SUBJECT TO CERTAIN RESTRICTIONS ON TRANSFER AND A
                             RIGHT OF FIRST REFUSAL HELD BY THE ISSUER OR ITS
                             ASSIGNEE(S) AS SET FORTH IN THE EXERCISE NOTICE
                             BETWEEN THE ISSUER AND THE ORIGINAL HOLDER OF THESE
                             SHARES, A COPY OF WHICH MAY BE OBTAINED AT THE
                             PRINCIPAL OFFICE OF THE ISSUER. SUCH TRANSFER
                             RESTRICTIONS AND RIGHT OF FIRST REFUSAL ARE BINDING
                             ON TRANSFEREES OF THE SHARES REPRESENTED HEREBY.



                                       -3-
<PAGE>   23
                            (b) Stop-Transfer Notices. Optionee agrees that, in
order to ensure compliance with the restrictions referred to herein, the Company
may issue appropriate "stop transfer" instruc tions to its transfer agent, if
any, and that, if the Company transfers its own securities, it may make
appropriate notations to the same effect in its own records.

                            (c) Refusal to Transfer. The Company shall not be
required (i) to transfer on its books any Shares that have been sold or
otherwise transferred in violation of any of the provisions of this Agreement or
(ii) to treat as owner of such Shares or to accord the right to vote or pay
dividends to any purchaser or other transferee to whom such Shares shall have
been so transferred.

                7. Successors and Assigns. The Company may assign any of its
rights under this Agreement to single or multiple assignees, and this Agreement
shall inure to the benefit of the successors and assigns of the Company. Subject
to the restrictions on transfer herein set forth, this Agreement shall be
binding upon Optionee and his or her heirs, executors, administrators,
successors and assigns.

               8. Interpretation. Any dispute regarding the interpretation of
this Agreement shall be submitted by Optionee or by the Company forthwith to the
Administrator of the Plan, which shall review such dispute at its next regular
meeting. The resolution of such a dispute by the Administrator shall be final
and binding on the Company and on Optionee.

               9. Governing Law; Severability. This Agreement shall be governed
by and construed in accordance with the laws of the State of Texas excluding
that body of law pertaining to conflicts of law. Should any provision of this
Agreement be determined by a court of law to be illegal or unenforceable, the
other provisions shall nevertheless remain effective and shall remain
enforceable.

               10. Notices. Any notice required or permitted hereunder shall be
given in writing and shall be deemed effectively given upon personal delivery or
upon deposit in the United States mail by certified mail, with postage and fees
prepaid, addressed to the other party at its address as shown below beneath its
signature, or to such other address as such party may designate in writing from
time to time to the other party.

               11. Further Instruments. The parties agree to execute such
further instruments and to take such further action as may be reasonably
necessary to carry out the purposes and intent of this Agreement.

               12. Delivery of Payment. Optionee herewith delivers to the
Company the full Exercise Price for the Shares.

               13. Entire Agreement. The Plan, the Notice of Grant, and the
Stock Option Agreement are incorporated herein by reference. This Agreement, the
Plan, the Notice of Grant, the Stock Option Agreement and the Investment
Representation Statement (if applicable) constitute the entire agreement of the
parties and supersede in their entirety all prior undertakings and agreements of
the Company and Optionee with respect to the subject matter hereof.


                                       -4-
<PAGE>   24
Submitted by:                               Accepted by:

OPTIONEE:                                   INTROGEN THERAPEUTICS, INC.


                                            By:
                                               ---------------------------

                                            Its:
---------------------------                     --------------------------
      (Signature)


Address:                                    Address:

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

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






                                       -5-
<PAGE>   25
                                    EXHIBIT B

                       INVESTMENT REPRESENTATION STATEMENT


OPTIONEE                                    :

COMPANY                                     :     INTROGEN THERAPEUTICS, INC.

SECURITY                                    :     COMMON STOCK

AMOUNT                                      :

DATE                                        :

In connection with the purchase of the above-listed Securities, the undersigned
Optionee represents to the Company the following:

                             (a) Optionee is aware of the Company's business
affairs and financial condition and has acquired sufficient information about
the Company to reach an informed and knowledgeable decision to acquire the
Securities. Optionee is acquiring these Securities for investment for Optionee's
own account only and not with a view to, or for resale in connection with, any
"distribution" thereof within the meaning of the Securities Act of 1933, as
amended (the "Securities Act").

                             (b) Optionee acknowledges and understands that the
Securities constitute "restricted securities" under the Securities Act and have
not been registered under the Securities Act in reliance upon a specific
exemption therefrom, which exemption depends upon, among other things, the bona
fide nature of Optionee's investment intent as expressed herein. In this
connection, Optionee understands that, in the view of the Securities and
Exchange Commission, the statutory basis for such exemption may be unavailable
if Optionee's representation was predicated solely upon a present intention to
hold these Securities for the minimum capital gains period specified under tax
statutes, for a deferred sale, for or until an increase or decrease in the
market price of the Securities, or for a period of one year or any other fixed
period in the future. Optionee further understands that the Securities must be
held indefinitely unless they are subsequently registered under the Securities
Act or an exemption from such registration is available. Optionee further
acknowledges and understands that the Company is under no obligation to register
the Securities. Optionee understands that the certificate evidencing the
Securities will be imprinted with a legend which prohibits the transfer of the
Securities unless they are registered or such registration is not required in
the opinion of counsel satisfactory to the Company and any other legend required
under then applicable state or federal securities laws.

                             (c) Optionee is familiar with the provisions of
Rule 701 and Rule 144, each promulgated under the Securities Act, which, in
substance, permit limited public resale of "restricted securities" acquired,
directly or indirectly from the issuer thereof, in a non-public offering subject
to the satisfaction of certain conditions. Rule 701 provides that if the issuer
qualifies under Rule 701 at


<PAGE>   26
the time of the grant of the Option to the Optionee, the exercise will be exempt
from registration under the Securities Act. In the event the Company becomes
subject to the reporting requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, as amended (the "Exchange Act") ninety (90) days
thereafter (or such longer period as any market stand-off agreement may require)
the Securities exempt under Rule 701 may be resold, subject to the satisfaction
of certain of the conditions specified by Rule 144, including: (1) the resale
being made through a broker in an unsolicited "broker's transaction" or in
transactions directly with a market maker (as said term is defined under the
Exchange Act); and, in the case of an affiliate, (2) the availability of certain
public information about the Company, (3) the amount of Securities being sold
during any three month period not exceeding the limitations specified in Rule
144(e), and (4) the timely filing of a Form 144, if applicable.

               In the event that the Company does not qualify under Rule 701 at
the time of grant of the Option, then the Securities may be resold in certain
limited circumstances subject to the provisions of Rule 144, which requires the
resale to occur not less than two years after the later of the date the
Securities were sold by the Company or the date the Securities were sold by an
affiliate of the Company, within the meaning of Rule 144; and, in the case of
acquisition of the Securities by an affiliate, or by a non-affiliate who
subsequently holds the Securities less than three years, the satisfaction of the
conditions set forth in sections (1), (2), (3) and (4) of the paragraph
immediately above.

                             (d) Optionee further understands that in the event
all of the applicable requirements of Rule 701 or 144 are not satisfied,
registration under the Securities Act, compliance with Regulation A under the
Securities Act, or some other registration exemption will be required; and that,
notwithstanding the fact that Rules 144 and 701 are not exclusive, the Staff of
the Securities and Exchange Commission has expressed its opinion that persons
proposing to sell private placement securities other than in a registered
offering and otherwise than pursuant to Rules 144 or 701 will have a substantial
burden of proof in establishing that an exemption from registration is available
for such offers or sales, and that such persons and their respective brokers who
participate in such transactions do so at their own risk. Optionee understands
that no assurances can be given that any such other registration exemption will
be available in such event.

                                          Signature of Optionee:


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                                 Date:                     , 19
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