Introgen Initiates Efficacy Analyses of ADVEXIN Phase 3 Clinical Trial Data for Head and Neck Cancer.

AUSTIN, Texas -- Introgen Therapeutics, Inc. (NASDAQ:INGN) announced today that it has initiated the efficacy analyses of its ADVEXIN[R] Phase 3 study. The efficacy evaluation of the study will incorporate the prospective analyses of patients defined by clinical and molecular prognostic biomarkers, including abnormal p53 protein levels. Abnormality of the p53 tumor suppressor is one of the most common and fundamental molecular defects in cancer. The Phase 3 study compares ADVEXIN p53 therapy versus methotrexate in patients with recurrent head and neck cancer. The prospective efficacy assessment of the randomized, controlled clinical trial is based upon analyses of prognostic biomarkers and clinical outcome.

The Phase 3 Statistical Analysis Plan was finalized in conjunction with the U.S. Food and Drug Administration (FDA) and incorporated into Introgen's Investigational New Drug application. Introgen previously announced it received permission from FDA to accelerate the Phase 3 safety analyses and to perform efficacy analyses for this study. In 2006, review by an independent Data Safety Monitoring Board noted no safety issues with the Phase 3 study. The Phase 3 efficacy analyses will utilize prospective, blinded prognostic biomarker testing of samples by an independent laboratory and will utilize a response confirmation board and statistical controls in the analyses process.

Max W. Talbott, Ph.D., Introgen's senior vice president of worldwide commercial development and regulatory affairs said, "Our initiation today of these new efficacy analyses is another milestone in our ADVEXIN registration process. We expect to conclude the analyses and make pending marketing authorization applications during 2007. This will include our head and neck cancer filings in the U.S. and Europe and our Li-Fraumeni Syndrome application in the European Union."

ADVEXIN's mechanism of action is targeted to restoring p53 tumor suppressor function and the detection of abnormal p53 is a logical prognostic biomarker for ADVEXIN efficacy. Analyses of prognostic biomarker defined patients in phase 2 ADVEXIN clinical trials showed high statistical correlation with survival and tumor response in recurrent head and neck cancer patients.

The endpoints of the Phase 3 study are tumor response and survival including evaluation of prognostic biomarker defined populations. Introgen has determined that there is sufficient enrollment in this study to provide for definitive determination of ADVEXIN's efficacy in the recurrent head and neck patient population. These analyses will also evaluate comparative toxicity of methotrexate and ADVEXIN. Methotrexate is a commonly utilized chemotherapy for the treatment of cancer.

About Biomarkers

Biomarkers are tests or measurements that predict response to treatment. Molecular biomarkers include measurements of genetic markers or molecular pathways while clinical biomarkers refer to clinical history or clinical measurements. Introgen's molecular biomarkers include the identification of aberrant p53 function by a routine assay performed by pathology laboratories worldwide detecting abnormally elevated levels of p53 protein in tumor tissues. Introgen believes that application of molecular and clinical biomarkers can predict the patients who are most likely to respond to ADVEXIN treatment.

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. ADVEXIN has demonstrated increased survival and tumor growth control in recurrent head and neck cancer patients. ADVEXIN has demonstrated clinical activity in a number of solid tumor types in multiple phase 1, 2 and 3 clinical trials conducted worldwide.

Introgen Therapeutics, Inc. is a biopharmaceutical company focused on the discovery, development and commercialization of targeted molecular therapies for the treatment of cancer and other diseases. Introgen is developing molecular therapeutics, immunotherapies, vaccines and nano-particle therapies to treat a wide range of cancers using tumor suppressors and cytokines. Introgen maintains integrated research, development, manufacturing, clinical and regulatory departments and operates multiple manufacturing facilities including a commercial scale cGMP manufacturing facility.

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 and the methods and processes and success of the analyses of the T301 phase 3 clinical study. 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.

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