Introgen publishes preclinical findings demonstrating the potent anti-tumor properties of INGN 241 study featured on the cover of Molecular Medicine

Austin, TX, May 10, 2001- Introgen Therapeutics, Inc. (NASDAQ: INGN) announced today the publication of its preclinical studies in the current issue of Molecular Medicine demonstrating the potent anti-tumor effects of INGN 241 (an adenoviral vector encoding the mda-7 gene) in three of the most prevalent human cancers, breast, lung and colorectal.

The study also demonstrates, for the first time, that MDA-7 protein is released from cancer cells treated with Adenoviral-mda7. The lead author of the publication is Abner Mhashilkar, Ph.D., project leader of Introgen�s mda-7 program. The cover of Molecular Medicine featured a photomicrograph which demonstrates secretion of MDA-7 protein from INGN 241 treated cells, a result which may enhance the potency of INGN 241 therapy.

The research and paper are the result of the efforts of an international team of collaborators, including scientists from The University of Texas M. D. Anderson Cancer Center, the Imperial Cancer Research Technology in the United Kingdom, Corixa Corporation and Columbia University College of Physicians and Surgeons. The study was funded in part by grant R43 CA86587 from the National Cancer Institute.

�We have previously shown that INGN 241 will selectively kill lung tumor cells by inducing the cells to commit suicide, a process known as apoptosis,� said Sunil Chada, Ph.D., Introgen�s director of research and development and senior author of the manuscript. �These new functional studies indicate that the mda-7 gene has tumor suppressor activity in some of the most prevalent human cancers. Introgen�s research also demonstrates that the MDA-7 protein is secreted. These unique properties of INGN 241 suggest that it may be a potent anti-tumor agent for local-regional applications, and potentially for the systemic treatment of cancer.�

The studies involved functional biological assays coupled with genomic analytic tools. These studies indicated that INGN 241 suppressed growth in 19 out of the 20 tumor lines in which it was tested from three tumor types, breast, lung and colorectal cancers. Additionally, selective killing of tumor cells was observed in all three cancer types tested, but not in normal cells. INGN 241 treated cells released a secreted form of MDA-7 protein which may enhance the potency of the therapy.

�This discovery demonstrates the power of an integrated genomics approach for discovery and validation of therapeutic genes,� said Paul Fisher, Ph.D., Professor of Clinical Pathology, Director of Neuro-Oncology Research, and Michael and Stella Chernow Urological Cancer Research Scientist for the Departments of Neurosurgery, Pathology and Urology at Columbia University College of Physicians and Surgeons. �The findings of this research complement our increasingly sophisticated understanding of mda-7 mechanisms of action.�

The mda-7 gene was discovered at Columbia University in the laboratory of Dr. Paul Fisher. Commercial rights to the discovery were licensed to Genquest, Inc. which was acquired by Corixa Corporation in 1998. Introgen has an exclusive license from Corixa Corporation for the use of the mda-7 gene for gene therapy applications.

Introgen is a leader in the development and production of gene-based drugs for the treatment of cancer and other diseases. Introgen�s product candidates engage precise molecular targets to produce a highly specific therapeutic effect. Introgen specializes in combining appropriate gene delivery systems and therapeutic genes to make its gene-based drugs. Introgen�s lead product candidate, INGN 201, is currently in Phase III clinical trials for the treatment of head and neck cancer.

INGN 201 has been used in numerous clinical trials worldwide either alone or in combination with conventional treatments such as chemotherapy and radiotherapy. Introgen is also conducting a Phase II clinical trial for INGN 201 in lung cancer and Phase I trials for INGN 201 in additional cancer indications including prostate, ovarian, bladder, brain, and breast cancer. New applications using INGN 201 to stimulate the human immune system to attack tumor cells are being explored. Introgen�s second product candidate, INGN 241 (Adenoviral-mda7), for the treatment of solid tumors, is in Phase I clinical development.

Introgen controls a broad intellectual property portfolio that includes more than 200 pending and issued patents for a variety of gene therapy technologies. Introgen has FDA inspected fully staffed production facilities that are producing Phase III commercial inventory of INGN 201.

Certain statements in this press release that are not strictly historical may be �forward-looking� statements, which involve risks and uncertainties. Such forward-looking statements include, but are not limited to, those relating to safety and efficacy of drug product candidates, the efficacy of our drug product candidates in treating breast, lung and colorectal cancers, and Introgen�s ability to complete its clinical trials or successfully commercialize INGN 241 or any other product candidates.

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 without limitation, Introgen�s stage of product development and the limited experience in the development of gene-based drugs in general, its dependence upon proprietary technology and current competition, history of operating losses and accumulated deficits, Introgen�s reliance on collaborative relationships, and uncertainties related to clinical trials, safety, efficacy, the ability to obtain the appropriate regulatory approvals, 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 prospectus dated October 12, 2000 and the 10-Q filed on February 14, 2001. Introgen undertakes no obligation to publicly release the results of any revisions to any forward-looking statements that reflect events or circumstances arising from the date hereof.

Editor's Note: For more information on Introgen Therapeutics, or for a menu of archived press releases, please visit the Introgen�s Website at: http://www.introgen.com or call Introgen�s toll-free Investor Relations hotline at 1-877-776-GENE (4363).