Public Release: 

Introgen's gene drug demonstrates tumor growth control

Porter Novelli

Results of human melanoma studies published in International Journal Of Cancer

Houston and Austin, TX, October 25, 2001- Introgen Therapeutics, Inc. (NASDAQ: INGN) announced today that results of preclinical studies in melanoma have been published in the October 2001 issue of International Journal of Cancer in a manuscript entitled "Down-Regulated Melanoma Differentiation Associated Gene (MDA-7) Expression in Human Melanomas." The manuscript's authors include lead author Dr. Suhendan Ekmekcioglu, Instructor in the Department of Bioimmunotherapy at M. D. Anderson Cancer Center, Dr. Elizabeth Grimm, Ashbel Smith Professor in the Departments of Bioimmunotherapy and Surgical Oncology at M. D. Anderson Cancer Center, Dr. Sunil Chada, Introgen's director of research and development, and Dr. Abner Mhashilkar, project leader of Introgen's INGN 241 (Adenoviral-mda7) program. The published studies were designed to answer two important questions in understanding the role of the mda-7 gene in skin cancer. First, how MDA-7 protein is regulated as tumors develop from benign moles to the full-blown skin cancer known as melanoma and secondly, how over-expression of the mda-7 gene will affect melanoma cancer cell growth.

In the scientific publication, the researchers conclude that the MDA-7 protein is present in normal melanocytes (cells responsible for pigmentation in the skin) and early stages of melanoma tumors. However, as the cancer advances, the MDA-7 protein is lost. In the highly aggressive metastatic disease, MDA-7 protein is virtually non-existent. This study demonstrates that mda-7 is a key tumor suppressor gene whose function is lost as melanoma tumors grow more aggressively.

INGN 241 is a modified adenoviral vector that carries the cancer cell killing mda-7 gene. Previous studies indicated that Adenoviral-mda7 treatment results in targeted destruction of breast, lung and colon cancer cells, while sparing normal cells. A Phase I clinical study using INGN 241 is in progress. This ongoing study examines the use of the drug in cancer patients with various solid tumors.

"These results suggest that the normal function of the mda-7 gene is to supply a signal that stops cells from becoming cancerous, and in order for cancers to become aggressive, they must turn off the mda-7 gene," said Dr. Chada. "Thus, treatment of tumor cells with the mda-7 gene, using INGN 241, should block tumor growth."

"We have shown, for the first time in humans, that MDA-7 protein is lost as tumors advance to become more aggressive and ultimately metastasize," said Dr. Grimm. "We then hypothesized that replacing the mda-7 control function into tumor cells would stop tumor cell growth. In fact, when we treated melanoma cancer cells with Adenoviral-mda7 in the lab, they stopped growing and died. Just as important, when we performed the same experiment using normal, non-cancerous skin cells, Adenoviral-mda7 had no effect on their growth. Current therapies for advanced malignant melanoma (the most aggressive and advanced form of the disease) only provide a 20% survival rate at 5 years. Thus, novel therapies are urgently needed for this dire disease."

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. By selectively killing cancer cells and harnessing natural protection mechanisms, Introgen's product candidates may be less toxic than conventional treatments. 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 conducting two Phase III clinical trials for the treatment of head and neck cancer. Introgen's gene therapeutics have been used in approximately twenty clinical trials worldwide either alone or in combination with conventional treatments such as chemotherapy, surgery 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 the human immune system with INGN 201 are being explored. Introgen's second product candidate, INGN 241 (Adenoviral-mda7) for the treatment of solid tumors, is in Phase I clinical development.

The University of Texas M. D. Anderson Cancer ranks as one of the nation''s most respected and productive Comprehensive Cancer Centers and is devoted exclusively to cancer patient care, research, education and prevention. The mission of M. D. Anderson is to eliminate cancer in Texas, the nation and the world through outstanding integrated programs in patient care, research, education and prevention. Since 1944, nearly 500,000 patients have turned to M. D. Anderson for cancer care in the form of surgery, chemotherapy, radiation therapy, immunotherapy or combinations of these and other treatments. This multidisciplinary approach to treating cancer was pioneered at M. D. Anderson. Because they focus only on cancer, experts here are renowned for their ability to treat uncommon or rare cancers as well as they treat common cancers. This year, about 65,000 persons with cancer will receive care at M. D. Anderson, and about 18,000 of them will be new patients.

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, including INGN 241. 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, filed with the Securities and Exchange Commission and the 10-K filed with the Securities and Exchange Commission on September 19, 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.

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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 or call Introgen's toll-free Investor Relations hotline at 1-877-776-GENE (4363).

Editor's Note: For more information on M. D. Anderson Cancer Center, please visit the website at www.mdanderson.org.

M. D. Anderson Cancer Center
Julie Penne
(713) 792-0655
jpenne@mdanderson.org

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