Zonagen Contracts Bridge Organics to Synthesize New Class of Compounds for the Treatment of Endometriosis.

Health/Medical Writers

THE WOODLANDS, Texas--(BW HealthWire)--June 15, 2001

Zonagen, Inc. (Nasdaq:ZONA)(PCX:ZNG) announced today that the Company has contracted Bridge Organics of Vicksburg, Michigan, to develop a commercially viable process for a new class of compounds for the treatment of endometriosis. The compounds, known as Selective Progesterone Receptor Modulators (SPRMs), were developed by the National Institute of Health (NIH). Zonagen licensed worldwide rights to this technology from the NIH in 1999. Bridge Organics is a research company engaged in preparation of complex organic compounds and in developing chemical processes for commercial scale production. Bridge Organics began operations in 1997 and was founded by five recently retired scientists/managers from Pharmacia & Upjohn. The founders have over 140 combined years of experience in chemical operations including extensive process related R&D.

Endometriosis affects 5,000,000 women in the U.S. alone and is a major female health issue. Symptoms include abdominal pain and cramping during the menstrual cycle, and in severe cases, may lead to infertility. Existing therapies to treat endometriosis are not optimal. Surgery to destroy lesions of endometriosis are expensive and gonadotrophin releasing hormone (GnRH) agonist therapy has unpleasant side effects and causes bone loss. A great need exists for therapies that potentially can be used for extended periods of time without serious side effects. The new lead compound being developed by Zonagen acts through an entirely different mechanism of action than existing therapies and is targeted to reduce endometrial lesions with no negative effects on bone density. Primate studies completed by the Company to date show the lead compound exhibits the desired effects on the monkey endometrium without negative impact on hormone or glucocorticoid levels.

"We have been encouraged by the results from the ongoing primate studies of our lead compound to treat endometriosis," said Joseph Podolski, President and CEO of Zonagen. He continued, "Besides endometriosis, this compound may have utility in treating uterine fibroids and breast cancer and potentially as an adjunct drug in providing more effective hormone replacement therapy. With the contracting of Bridge Organics we have begun the process of securing sufficient compound to conduct the necessary preclinical studies required for filing an Investigational New Drug Application (IND) in the United States. We anticipate the effort to secure sufficient material to commence initial preclinical studies, if successful, will take until the end of the year."

Zonagen, Inc. is engaged in the development of pharmaceutical products for the reproductive system, including sexual dysfunction, vaccine adjuvants, products for fertility and female health as well as urological applications, specifically prostate cancer.

Any statements that are not historical facts contained in this release such as the potential uses of the SPRM compounds in humans, are forward-looking statements that involve risks and uncertainties, including but not limited to those relating to the uncertainties involving the Company's early stage of development, clinical trial results and FDA approval in the U.S. and approval of regulatory authorities in other jurisdictions, substantial dependence on one product, history of operating losses, future capital needs and uncertainty of additional funding, uncertainty of protection for patents and propriety technology, litigation, governmental regulation, limited sales and marketing experience and dependence on collaborators, manufacturing uncertainties and reliance on third parties, competition and technology change, product liability and availability of insurance, and other risks identified in the Company's Annual Report on Form 10-K for the year ended December 31, 2000, as filed with the Securities and Exchange Commission.