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                                                                   EXHIBIT 10.38

                           K-ras ASSIGNMENT AGREEMENT

K-ras ASSIGNMENT AGREEMENT, effective as of July 2, 2001, among Aventis
Pharmaceuticals Products Inc. (formerly Rhone-Poulenc Rorer Pharmaceuticals
Inc.), a Pennsylvania corporation ("APPI"), Aventis Pharma S.A., a company
organized under the laws of France ("APSA" and, together with APPI, the "Aventis
Parties") ("Assignors"), having an office for the transaction of business at
Route 202-206, Bridgewater, NJ, and Introgen Therapeutics Inc., a Delaware
corporation ("Introgen Therapeutics"), ("Assignee"), having an office for the
transaction of business at 301 Congress Avenue, Austin, Texas.

                                   WITNESSETH

WHEREAS, Assignors and Assignee have entered into a Restated p53 and K-ras
Agreement, dated as of June 30, 2001 (the "Restated Agreement"; capitalized
terms used herein and not otherwise defined herein having the respective
meanings given in the Restated Agreement), providing for the restructuring of
the Original p53 Agreement and the Original K-ras Agreement, so that Introgen
Therapeutics takes over from the Aventis Parties the further development and
commercialization of the gene therapy products for the delivery of the p53 and
K-ras inhibition genes, including the INGN 201 product, and that Aventis retain
a potential economic upside in those products by making an additional equity
investment in Introgen Therapeutics; and

WHEREAS, pursuant to Section 4.2.2 of the Restated Agreement, Assignors have
agreed to enter into this Assignment Agreement providing for the assignment of
Assignor of the K-ras Materials and K-ras Documentation ("Assigned Matter")
under Section 4.2.1 of the Restated Agreement;

NOW, THEREFORE, for and in consideration of the mutual consideration provided
for in the Restated Agreement, and for other good and valuable consideration,
the receipt and sufficiency of which is hereby acknowledged, and pursuant to the
terms and conditions of the Restated Agreement, the parties hereto agree as
follows:

1. Assignment of Rights. Each Assignor hereby assigns and relinquishes its
right, title and interest, that any Assignor may have with respect to or in
connection with the K-ras Materials and K-ras Documentation under Section 4.2.2
of the Restated Agreement unless otherwise required to retain such rights and
obligations under a Third Party Agreement or by law and as further limited in
Sections 4.2.1, 7.2 and 7.3 of the Restated Agreement. .

3. Representations and Warranties. The Assignors are not making any
representations or warranties of any nature or kind with respect to the Assigned
Materials, except as expressly made and contained in the Restated Agreement.

4. Conflicts with Restated Agreement. In the event that any provision of this
Agreement is construed to conflict with a provision of the Restated Agreement,
the provision in the Restated Agreement shall be deemed controlling.

5. Governing Law. This Agreement shall be construed and enforced in accordance
with the laws of the State of New York without giving effect to the choice of
law principles thereof which would require the application of the laws of a
jurisdiction other than New York.



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IN WITNESS WHEREOF, each party hereto has caused this Assignment and Assumption
Agreement to be duly executed by its duly authorized officer effective as of the
date indicated above.



INTROGEN  THERAPEUTICS, INC.           AVENTIS PHARMACEUTICALS PRODUCTS INC.


By:      /s/ DAVID NANCE               By:      /s/ THOMAS HOFSTAETTER
   -------------------------------        --------------------------------------

Name:    David Nance                   Name:    Dr. Thomas Hofstaetter
     -----------------------------          ------------------------------------

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


                                       AVENTIS PHARMA S.A..

                                       By:     /s/ FRANCOIS MEYER
                                          --------------------------------------

                                       Name:   Francois Meyer
                                            ------------------------------------

                                       Title:  SVP DIA France, Head of Gencell
                                             -----------------------------------




                 [SIGNATURE PAGE TO K-ras ASSIGNMENT AGREEMENT]