Introgen Presents Biomarker Data Demonstrating Abnormal p53 Predicts ADVEXIN Efficacy in Head and Neck, Lung, Prostate and Li-Fraumeni Cancers

Introgen Therapeutics, Inc. (NASDAQ:INGN) today reported the results of new data analysis from multiple Phase 2 clinical studies showing a statistically significant correlation between the abnormal p53 biomarker and tumor response after treatment with ADVEXIN in patients with head and neck, lung, prostate and Li-Fraumeni Syndrome cancers. These data were presented at the Mary Crowley Medical Research Center Conference on Cancer Gene Therapy in Dallas. The Company will utilize these biomarker findings for its ongoing analyses of its randomized Phase 3 trial comparing ADVEXIN therapy to methotrexate for the treatment of recurrent head and neck cancer. Prior to the initiation of the Phase 3 analyses, the Company gained consent from the U.S. Food and Drug Administration to amend the ADVEXIN Investigational New Drug Application and Statistical Analysis Plan to include analyses of patient populations identified by the abnormal p53 biomarker. These prospective analyses and evaluations will be included in the ADVEXIN U.S. and international regulatory submissions. "These findings provide important support for our regulatory filings,” said Max W. Talbott, Ph.D., Introgen’s senior vice president of Worldwide Commercial Development and Regulatory Affairs. "They provide further justification for incorporating p53 biomarker analyses in our regulatory submissions for recurrent head and neck cancer in the United States and will advance our European Union application for ADVEXIN in Li-Fraumeni Syndrome, an inherited cancer disorder characterized by the development of multiple tumor types with abnormal p53.” In 54 late-stage cancer patient samples evaluated from the Company’s Phase 2 studies, tumor response after ADVEXIN monotherapy was observed in 35 percent of patients with the abnormal p53 biomarker and all tumor responses occurred in the abnormal p53 biomarker group (p = 0.0013). The majority of these patients had recurrent disease after receiving standard therapies. Introgen has previously reported study results demonstrating a statistically significant correlation between the abnormal p53 biomarker and increased survival after ADVEXIN therapy in head and neck cancer patients. "The results presented today confirm and extend previous biomarker data correlating the abnormal p53 biomarker with increased tumor responses following ADVEXIN treatment and support its use as a biomarker to predict ADVEXIN efficacy,” said John Nemunaitis, M.D., a principal investigator of the studies and executive director of the Mary Crowley Medical Research Center. "Importantly, the data from multiple tumor types indicate an absolute correlation of tumor response and abnormal p53 as 100 percent of the responding tumors had the abnormal p53 biomarker.” About ADVEXIN ADVEXIN p53 therapy is a targeted molecular therapy with broad applicability in a wide range of tumor types and clinical settings because it targets one of the most fundamental and common molecular defects, abnormal p53 tumor suppressor function, associated with cancer initiation, progression and treatment resistance. Introgen believes that ADVEXIN has demonstrated increased survival and tumor growth control in recurrent head and neck cancer patients. In addition, ADVEXIN has demonstrated clinical activity in a number of solid tumor types in multiple phase 1, 2 and 3 clinical trials conducted worldwide. Introgen’s first clinical trial was initiated in 1995 and approximately 30 clinical trials have been conducted to date in more than ten different oncology indications. Neither ADVEXIN nor any of Introgen’s other adenovirus products have ever been put on clinical hold by FDA or other regulators due to safety concerns or for any other reason. About Introgen Therapeutics, Inc. Introgen Therapeutics, Inc. is a biopharmaceutical company focused on the development, manufacturing and commercialization of targeted tumor suppressors, a new class of therapies for the treatment of cancer. Introgen’s technology delivers targeted molecular therapies that increase production of normal cancer-fighting proteins and cytokines. The Company is developing a proprietary pipeline of product candidates utilizing molecular biomarkers to identify patients most likely to benefit from its therapies which target central cancer-causing mechanisms. ADVEXIN®, its lead product candidate, targets abnormal p53, a fundamental cancer defect present in over 50 percent of all tumors. Introgen is analyzing its phase 3 clinical trial for recurrent head and neck cancer using ADVEXIN as a monotherapy. The Company plans to complete regulatory filings in both the United States and in Europe by the end of 2007. Statements in this release that are not strictly historical may be "forward-looking” statements, including those relating to Introgen’s future success with its ADVEXIN clinical development program for treatment of cancer. The actual results may differ from those described in this release due to risks and uncertainties that exist in Introgen’s operations and business environment, including Introgen’s stage of product development and the limited experience in the development of gene-based drugs in general, 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 filings on Form 10-K and Form 10-Q. 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 at: www.introgen.com.