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                                                                   EXHIBIT 10.40


                                VOTING AGREEMENT

         This VOTING AGREEMENT (this "Voting Agreement") is made and entered
into as of June 30, 2001, by and among Introgen Therapeutics, Inc., a Delaware
corporation ("Introgen"), Rhone-Poulenc Rorer International (Holdings), Inc., a
Delaware corporation ("RPRIH"), and Aventis Pharmaceuticals Products Inc., a
Pennsylvania corporation ("APPI", and together with RPRIH, the "Aventis
Holders"), each of whom is sometimes referred to herein as a "Party" and
collectively as the "Parties."

                                    RECITALS

         WHEREAS, Introgen and APPI are each a party to that certain Restated
p53 and K-ras Agreement of even date herewith, whereby each has agreed, among
other things, to enter into this Voting Agreement; and

         WHEREAS, as of the date hereof, the RPRIH is the holder of record of
3,968,893 shares of Introgen's Common Stock, par value $0.001 per share (the
"Existing Introgen Shares"); and

         WHEREAS, pursuant to that certain Series A Non-Voting Convertible
Preferred Stock Purchase Agreement of even date herewith by and among Introgen,
APPI and RPRIH (the "Stock Purchase Agreement"), Introgen has agreed to sell,
and APPI has agreed to purchase, at the Closing (as defined in the Stock
Purchase Agreement) 100,000 shares of Introgen's Series A Non-Voting Convertible
Preferred Stock, par value $0.001 per share (the "Series A Shares"), which
Series A Shares are convertible into shares of Introgen common stock. The
Existing Introgen Shares and the shares of common stock of Introgen actually
issued upon the conversion of the Series A Shares (the "Conversion Shares") are
collectively referred to herein as the "Introgen Shares;" and

         WHEREAS, APPI contemplates the formation of an affiliated or otherwise
related company ("Gencell") and may wish to transfer some or all of the Series A
Shares or Conversion Shares to Gencell; and

         WHEREAS, the Stock Purchase Agreement contemplates, among other things,
that the Company, APPI and RPRIH enter into this Voting Agreement and that this
Voting Agreement become effective upon the Closing of the purchase and sale of
the Series A Shares under the Stock Purchase Agreement (the "Effective Date");

                                    AGREEMENT

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants contained herein, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the Parties, intending
to be legally bound, hereby agree as follows:



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         1. Voting on Corporate Action.

                  (a) Voting Agreement.

                           (i) In the event that, following the Effective Date,
a Corporate Action (i) is approved by Introgen's Board of Directors or other
governing body and (ii) receives approval of the holders of not less than a
majority of Introgen's outstanding Voting Securities without taking into account
any such securities held by any of the Aventis Holders, each of the Aventis
Holders shall consent to and vote all of the Introgen Shares held by it in favor
of such Corporate Action at any meeting of stockholders (or by any action by
written consent) called to consider the approval of such Corporate Action.

                           (ii) In the event that, following the Effective Date,
a Corporate Action (i) is approved by Introgen's Board of Directors or other
governing body and (ii) is rejected by the holders of not less than a majority
of Introgen's outstanding Voting Securities without taking into account any such
securities held by any of the Aventis Holders, each of the Aventis Holders shall
consent to and vote all of the Introgen Shares held by it against such Corporate
Action at any meeting of stockholders (or by any action by written consent)
called to consider the approval of such Corporate Action.

                           (iii) A "Corporate Action" shall mean any matter put
to a vote of the stockholders of Introgen. "Voting Securities" shall mean, with
respect to any specified person, any class or classes of Capital Stock of the
specified person pursuant to which the holders thereof have the general voting
power under ordinary circumstances to elect at least a majority of the board of
directors, supervisory board, managers or trustees of the specified person
(irrespective of whether or not, at the time, stock of any other class or
classes have, or might have, voting power by reason of the happening of any
contingency). "Capital Stock" shall mean, with respect to any person, any and
all shares, interests, participation, rights or other equivalents in the equity
interests (however designated) in that person.

                  (b) Power of Attorney. If any of the Aventis Holders fails or
refuses to vote the Introgen Shares held by it as required by, or votes the
Introgen Shares held by it in contravention of this Section 1, then Introgen's
Chairman of the Board or Chief Executive Officer shall have an irrevocable
proxy, coupled with an interest, to vote such Introgen Shares in accordance with
this Section 1. Each of the Aventis Holders hereby grants to Introgen's Chairman
of the Board and Chief Executive Officer such an irrevocable proxy and hereby
appoints Introgen's Chairman of the Board and Chief Executive Officer, and each
of them acting singly, its attorney-in-fact to vote the Introgen Shares held by
it in accordance with the terms of this Section 1. In the event that any of the
Aventis Holders fails or refuses to comply for any reason with the provisions of
this Section 1, Introgen, at its option, may elect to proceed with the Corporate
Action notwithstanding such failure or refusal. The voting of shares pursuant to
this Voting Agreement may be effected in person, by proxy, by written consent or
in any other manner permitted by applicable law.

                  (c) The proxies granted pursuant to this Section 1 shall be
deemed coupled with an interest and are irrevocable for the term of this Voting
Agreement. It is agreed and understood that (i) monetary damages would not
adequately compensate an injured Party for the



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breach of this Section 1 by any Party, (ii) this Section 1 shall be specifically
enforceable, and (iii) any breach or threatened breach of this Section 1 shall
be the proper subject of a temporary or permanent injunction or restraining
order. Further, each Party waives any claim or defense that there is an adequate
remedy at law for such any breach or threatened breach.

                  (d) After receiving proper notice, one or more representatives
of each Aventis Holder, as a holder of Introgen Shares, shall be present, in
person or by proxy, at all meetings of stockholders of Introgen, as appropriate,
to vote upon a proposed Corporate Action so that all of the Introgen Shares
beneficially owned by the Aventis Holders and/or their respective affiliated
entities may be counted for the purposes of determining the presence of a quorum
at such meetings.

                  (e) The Aventis Holders shall not deposit any of the Introgen
Shares beneficially owned by either of them in a voting trust or subject any
such securities to any arrangement or agreement with respect to the voting of
such securities provided that this provision will not restrict the right of APPI
to transfer any Series A Shares or Conversion Shares to Gencell as contemplated
by Section 2.

                  (f) This Voting Agreement shall extend to any national or
state statutory approval rights for any Corporate Action that either Aventis
Holder may have by virtue of beneficially holding Introgen Shares.

         2. Gencell as a Party.

                  (a) APPI shall have the right to transfer some or all of its
Series A Shares or Conversion Shares to Gencell in accordance with the terms of
the Stock Purchase Agreement. In connection with any such transfer, APPI shall
cause Gencell to agree to be bound by the obligations of this Voting Agreement
as a Party with respect to such transferred shares and to execute and deliver to
Introgen a counterpart signature page to this Voting Agreement.

         3. Termination.

                  (a) This Voting Agreement, except for the obligation of
Introgen set forth in the last sentence of Section 4, shall terminate as to any
Introgen Shares on the earliest to occur of: (i) the date upon which such shares
are sold into an established trading market for such shares in accordance with
applicable securities laws, including sales made under Rule 144 under the
Securities Act of 1933, as amended; (ii) the date upon which such shares are
sold under an effective registration statement covering such shares filed with
the United States Securities and Exchange Commission under the Securities Act of
1933, as amended; (iii) the date upon which such shares are sold by either of
the Aventis Holders in a private sale to a non-affiliate (as such term
"affiliate" is defined in Rule 12b-2 of the General Rules and Regulations under
the Securities Exchange Act of 1934, as amended) of such Aventis Holder that is
not either (x) a direct competitor of Introgen whose main line of activity
(based on publicly-available information or, in the case of a privately-held
company, otherwise commonly known information regarding such competitor) is the
development of gene therapy products or (y) a pharmaceutical company; or (iv)
the date indicated in paragraph (b) below.



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                  (b) In any event, this Voting Agreement shall terminate on the
date corresponding to the tenth anniversary of the Effective Date of this Voting
Agreement.

         4. Legend. Concurrently with (i) the execution of this Voting
Agreement, with respect to the Existing Introgen Shares outstanding on the date
of this Voting Agreement; and (ii) the issuance of the Conversion Shares, with
respect to such shares, there shall be imprinted or otherwise placed, on
certificates representing such shares a restrictive legend substantially to the
following effect (the "Legend"):

                  THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO
                  THE TERMS AND CONDITIONS OF A CERTAIN VOTING AGREEMENT DATED
                  AS OF JUNE 30, 2001 AMONG THE CORPORATION, THE ORIGINAL HOLDER
                  OF THESE SECURITIES AND CERTAIN OTHER PARTIES. COPIES OF SUCH
                  AGREEMENT MAY BE OBTAINED UPON WRITTEN REQUEST TO THE
                  SECRETARY OF THE CORPORATION.

If such shares are not certificated, then a substantially similar notification
shall be placed in an appropriate fashion with the person charged with
maintaining registration of the ownership of such shares so as to put on notice
of the terms and conditions of this Voting Agreement any transferee of such
shares. Following the termination of this Voting Agreement with respect to any
Introgen Shares, upon the request of the Aventis Holder that holds or held such
shares, Introgen shall issue to or as directed by such Aventis Holder a new
certificate or certificates representing such Introgen Shares that does not or
do not contain the Legend.

         5. Miscellaneous

                  (a) Governing Law. This Voting Agreement shall be governed in
all respects by and in accordance with the laws of the State of Delaware,
without regard to the principles of conflicts of law thereof.

                  (b) Equitable Relief. The Parties hereby agree that it would
be impossible to measure in money the damages that may accrue to a Party by
reason of a failure of another Party to perform any of the obligations under
this Voting Agreement, and further agree that the terms of this Voting Agreement
shall be specifically enforceable. If any Party institutes any action or
proceeding to specifically enforce the provisions hereof, any other Party
against whom such action or proceeding is brought hereby waives the claim or
defense therein that the instituting Party has an adequate remedy at law, and
such other Party shall not offer in any such action or proceeding the claim or
defense that such remedy at law exists.

                  (c) Successors and Assigns; Assignment. The provisions of this
Voting Agreement shall be binding on and inure to the benefit of the Parties and
their respective successors and permitted assigns. APPI shall have the right to
have Gencell assume those obligations of APPI under this Voting Agreement that
relate to any Introgen Shares transferred by APPI to Gencell in accordance with
Section 2. APPI shall cause Gencell to assume the those obligations of APPI
under this Voting Agreement that relate to any Introgen Shares transferred by
APPI to Gencell in accordance with Section 2.



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                  (d) Entire Agreement. This Voting Agreement constitutes the
entire agreement among the Parties with respect to the subject matter hereof,
and supersedes all prior or contemporaneous agreements and understandings,
whether written or oral, among the Parties with respect to such subject matter.

                  (e) Amendment. Except for the addition of Gencell as a Party
hereto in accordance with Section 2, no amendment or modification of any
provision of this Voting Agreement shall be effective unless in writing signed
by all of the Parties. No provision of this Voting 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 all of the Parties.

                  (f) Notices. All notices and other communications required or
permitted hereunder shall be in writing and shall be deemed to have been duly
given if personally delivered (by courier service or otherwise) or sent by
registered or certified mail (return receipt requested and postage prepaid), in
each case to the respective address specified below, or such other addresses as
may be specified in writing by such party to the other party hereto, or sent by
confirmed telecopier, as follows:


                  Aventis Holders:

                         Aventis Pharmaceuticals Products Inc.
                         Route 202-206
                         Bridgewater, New Jersey 08807-0800
                         Facsimile: (908) 231-3619
                         Attn: Senior Vice President - Corporate Development

                         and

                         Rhone-Poulenc Rorer International (Holdings), Inc.
                         3711 Kennett Pike, Suite 200
                         Greenville, Delaware 19807
                         Facsimile: (302) 777-7665
                         Attn: Phillip Ridolfi, President

                         with copies to (which shall not constitute notice):

                         Charles D. Dalton
                         Vice President, Legal - Corporate Development
                         Route 202-206
                         Bridgewater, New Jersey 08807-0800
                         Facsimile: (908) 231-4480

                         and



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                         Joe S. Poff
                         Baker Botts L.L.P.
                         One Shell Plaza
                         Houston, Texas 77002
                         Facsimile: (713) 229-7710

                  Introgen:

                         Introgen Therapeutics, Inc.
                         301 Congress Ave., Suite 2025
                         Austin, Texas 78701
                         Facsimile: (512) 708-9311
                         Attn: David G. Nance

                         with a copies to (which shall not constitute notice):

                         Rodney Varner, Esq.
                         Wilson & Varner, L.L.P.
                         301 Congress Avenue
                         Austin, Texas 78701
                         Facsimile: (512) 498-9141

                         and

                         Wilson Sonsini Goodrich & Rosati
                         Professional Corporation
                         8911 Capital of Texas Highway, Suite 3350
                         Austin, Texas 78759
                         Facsimile: (512) 338- 5499
                         Attn: Christopher J. Ozburn, Esq.

                  (g) Delays or Omissions; Waiver. Except as expressly provided
in this Voting Agreement, no delay or omission to exercise any right, power or
remedy accruing to any Party, upon any breach or default of this Voting
Agreement by another Party, shall impair any such right, power or remedy of the
non-breaching Party, nor shall it be construed to be a waiver of any such breach
or default, or an acquiescence therein, or of or in any similar breach or
default thereafter occurring; nor shall any waiver of any single breach or
default be deemed a waiver of any other breach or default theretofore or
thereafter occurring. Any waiver, permit, consent or approval of any kind or
character on the part of any Party of any breach or default under this Voting
Agreement or any waiver on the part of any Party of any provisions or conditions
of this Voting Agreement must be in writing and shall be effective only to the
extent specifically set forth in such writing.

                  (h) Counterparts. This Voting Agreement may be executed in two
or more counterparts, each of which shall be deemed an original, and all of
which together shall constitute one and the same instrument.



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                  (i) Titles and Subtitles. The titles and subtitles used in
this Voting Agreement are used for convenience only and are not to be considered
in construing or interpreting this Voting Agreement.

                  (j) Telecopy Execution and Delivery. A facsimile, telecopy or
other reproduction of this Voting Agreement may be executed by one or more
Parties, and an executed copy of this Voting Agreement may be delivered by one
or more Parties by facsimile or similar electronic transmission device pursuant
to which the signature of or on behalf of such Party can be seen, and such
execution and delivery shall be considered valid, binding and effective for all
purposes. At the request of any Party hereto, all Parties shall execute an
original of this Voting Agreement as well as any facsimile, telecopy or other
reproduction hereof.

                  (k) Severability. If any provision of this Voting Agreement
should be held invalid, illegal or unenforceable in any jurisdiction, 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
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.

                  (l) Further Assurances. Each of the Parties shall execute such
documents and perform such further acts as may be reasonably required or
desirable to carry out or to perform the provisions of this Voting Agreement.





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         IN WITNESS WHEREOF, the Parties have executed this Voting Agreement as
of the date first written above.


                              Introgen Therapeutics, Inc.


                              By:  /s/ David G. Nance
                                 -----------------------------------------------
                                       David G. Nance
                                       President and Chief Executive Officer



                              Aventis Pharmaceuticals Products Inc.

                              By:        /s/ Thomas Hofstaetter
                                        ----------------------------------------

                              Name:      Dr. Thomas Hofstaetter
                                        ----------------------------------------

                              Title:     Senior Vice President
                                        ----------------------------------------



                              Rhone-Poulenc Rorer International (Holdings), Inc.

                              By:        /s/ Phillip R. Ridolfi
                                        ----------------------------------------

                              Name:      Phillip R. Ridolfi
                                        ----------------------------------------

                              Title:     President
                                        ----------------------------------------



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                         VOTING AGREEMENT SIGNATURE PAGE