FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Aventis Inc.   2. Issuer Name and Ticker or Trading Symbol INTROGEN THERAPEUTICS INC [INGN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner _____ Officer (give title below) __X__ Other (specify below) 10% owner and beneficial owner (Last) (First) (Middle) 3711 KENNETT PIKE, SUITE 200,  3. Date of Earliest Transaction (Month/Day/Year) 03/21/2006 (Street) GREENVILLE, DE 19807 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common 03/21/2006   S   15,843 D $ 5.36 4,188,410 (1) I SFN (2)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Aventis Inc. 3711 KENNETT PIKE, SUITE 200 GREENVILLE, DE 19807				10% owner and beneficial owner
AVENTIS HOLDINGS INC 3711 KENNETT PIKE SUITE 200 GREENVILLE, DE 19807				10% owner and beneficial owner

Signatures

Kathleen A. Winter, President		03/23/2006
**Signature of Reporting Person		Date
Kathleen A. Winter, President		03/23/2006
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Updated to reflect the conversion of 100,000 Preferred Shares into 2,343,721 Common Shares on June 21, 2005, which shares are directly owned by Aventis Pharmaceuticals Inc.
(2)	For Reporting Person Aventis Holdings Inc., reflects ownership of (i) 1,844,689 shares of common stock owned directly by Aventis Holdings Inc., and (ii) 2,343,721 shares of common stock owned by its subsidiary Aventis Pharmaceuticals Inc. For Reporting Person Aventis Inc. reflects indirect ownership of shares owned directly by Aventis Holdings Inc. and Aventis Pharmaceuticals Inc.

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