Exhibit 99.1

FOR IMMEDIATE RELEASE
INTROGEN THERAPEUTICS REPORTS FIRST QUARTER 2005 FINANCIAL RESULTS
Results in Line with Expectations
AUSTIN, TX, May 10, 2005— Introgen Therapeutics, Inc. (NASDAQ: INGN) announced today its results for the quarter ended March 31, 2005, reporting progress during the period in its research and development programs and clinical trial programs.
Introgen reported a net loss of $6.2 million, or $0.20 per share, for the quarter ended March 31, 2005. These results compare to a net loss of $4.4 million, or $0.16 per share, for the previous quarter ended December 31, 2004 and a net loss of $5.4 million, or $0.21 per share, for the comparable prior year quarter ended March 31, 2004.
During the quarter ended March 31, 2005, cash, cash equivalents and short-term investments decreased $5.5 million. At March 31, 2005, Introgen had cash, cash equivalents and short-term investments of $32.6 million.
Revenue was $509,000 for the quarter ended March 31, 2005, compared to revenue of $1.2 million for the quarter ended December 31, 2004 and $109,000 for the quarter ended March 31, 2004. Operating expenses were $7.0 million for the quarter ended March 31, 2005, compared to $5.8 million for the quarter ended December 31, 2004 and $5.7 million for the quarter ended March 31, 2004.
Quarterly Conference Call
Introgen has scheduled a conference call to discuss the financial results at 4:30 p.m. eastern time today. Interested parties can access a live Internet broadcast at www.introgen.com. For those unable to listen to the broadcast the call will be archived at Introgen’s Website at www.introgen.com in the Investor Relations section.
Introgen is a leading developer of biopharmaceutical products designed to induce therapeutic protein expression using non-integrating gene agents for the treatment of cancer and other diseases. Introgen maintains integrated research, development, manufacturing, clinical and regulatory departments and operates a commercial-scale, cGMP manufacturing facility.
Certain statements in this press release that are not strictly historical may be “forward-looking” statements, which are based on current expectations and entail various risks and uncertainties. Such forward-looking statements include, but are not limited to those relating to Introgen’s future success with its clinical development program for treatment of cancer or other diseases. There can be no assurance that Introgen will be able to commercially develop gene-based drugs, that necessary regulatory approvals will be obtained or that any clinical trials or studies undertaken will be successful or that the proposed treatments will prove to be safe and/or effective. The actual results may differ from those described in this press release due to risks and uncertainties that exist in Introgen’s operations and business environment, including, but not limited to, Introgen’s stage of product development and the limited experience in the development of gene-based drugs in general, Introgen’s dependence upon proprietary technology and the current competitive environment, history of operating losses and accumulated deficits, reliance on collaborative relationships, and uncertainties related to clinical trials, the safety
and efficacy of Introgen’s product candidates, the ability to obtain the appropriate regulatory approvals, Introgen’s patent protection and market acceptance, as well as other risks detailed from time to time in Introgen’s filings with the Securities and Exchange Commission including its annual report on Form 10-K filed with the Securities and Exchange Commission on March 15, 2005 and its quarterly report on Form 10-Q filed with the Securities and Exchange Commission on November 15, 2004. Introgen undertakes no obligation to publicly release the results of any revisions to any forward-looking statements that reflect events or circumstances arising after the date hereof.
###
Editor’s Note: For more information on Introgen Therapeutics, or for a menu of archived press releases, please visit Introgen’s Website atwww.introgen.com.
Contact:
Introgen Therapeutics, Inc.
C. Channing Burke
(512) 708 9310 Ext. 322
Email: c.burke@introgen.com