Aphton's Basic European Patent Covering Immunogens To Neutralize a Key Hormone Involved in Prostate Cancer.

Business Editors/Health & Medical Writers

MIAMI--(BW HealthWire)--Aug. 3, 2000

Aphton's granted European Patent 0741744 for Immunogens Against Gonadotropin Releasing Hormone has completed the opposition period in the European Patent Office without any opposition filed. The granted European patent provides Aphton patent exclusivity for its anti-GnRH immunogen in Austria, Belgium, Switzerland, (Liechtenstein) Germany, Denmark, Spain, France, United Kingdom, Greece, Ireland, Italy, Luxembourg, Monaco, Netherlands, Portugal and Sweden. The coverage under this patent is in addition to that under Aphton's related patent, which was issued in the United States, US Pat. No. 5,688,506 (announcement of May 25, 2000).

The European patent 0741744 covers Aphton's proprietary immunogens for neutralizing the key reproductive hormone gonadotropin releasing hormone, called GnRH. Neutralizing (blocking) GnRH is therapeutic in the treatment of many major reproductive system diseases including prostate cancer, breast cancer, endometrial cancer and endometriosis. Aphton's unique therapeutic approach involves immunizing the patient with its proprietary anti-GnRH immunogen, called GnRH pharmaccine, which induces the patient to produce antibodies that neutralize (block) GnRH.

"We believe the fact that no opposition was filed speaks to the innovative nature of our new therapeutic approach to blocking GnRH," a company spokesperson said, adding that "the geographic coverage provided by Aphton's patents provide Aphton with a commanding competitive position in these very large markets." Aphton believes that its product will both pioneer and lead a new paradigm in the therapy of prostate cancer that will extend survival in patients, thereby satisfying a major unmet need in a market for which the drugs comprising the current standard of care have combined annual sales of approximately $2 billion worldwide.

In a related development, Aphton's scientists and collaborating researchers have published a scientific paper titled "Anti-GnRH antibodies can induce castrate levels of testosterone in patients with advanced prostate cancer" in the current issue of the peer-reviewed British Journal of Cancer (2000), 83(4):443-446. This pilot study, the first in humans with GnRH pharmaccine, was designed to assess the tolerance of Aphton's Anti-GnRH immunogen and the production of anti-GnRH antibodies from two low-dose levels of vaccine given to patients with locally advanced prostate cancer. As reported in the British Journal of Cancer publication, over 90% of the treated patients developed anti-GnRH antibodies during the course of the safety and dose-ranging study. Of these, over 45% exhibited strong anti-GnRH antibody responses and correspondingly significant reductions in serum testosterone and PSA (serum markers which indicate therapeutic benefit). Castrate levels of testosterone were achieved and maintained for up to 9 months in most of these "high" responding patients.

This study shows that patients with advanced prostate cancer can be treated with Aphton's anti-GnRH immunogen to induce blocking antibodies against GnRH and achieve castration levels of testosterone. Since this first pilot study in humans, Aphton's clinical trials program is directed, in part, to increase the percentage of patients exhibiting strong antibody responses (and therapeutic benefit), to achieve levels exhibited previously in patients with other Aphton immunogens. Aphton believes that for men with prostate cancer, successfully blocking GnRH, which also inhibits the production of the hormone testosterone, will slow the proliferation and metastasis of prostate cancer and extend life.

Aphton has a worldwide strategic alliance with SmithKline Beecham PLC (NYSE:SBH) covering all human indications for GnRH pharmaccine.

Aphton Corporation is a biopharmaceutical company developing products using its innovative vaccine-like technology for neutralizing hormones that participate in gastrointestinal system and reproductive system cancer and non-cancer diseases; and the prevention of pregnancy. Aphton has strategic alliances with Aventis Pasteur (NYSE:AVE), SmithKline Beecham PLC (NYSE:SBH), Schering Plough Animal Health (NYSE:SGP) and the World Health Organization (WHO).

Except for the historical information herein, the matters discussed herein include forward-looking statements that may involve a number of risks and uncertainties. Future results may vary insignificantly based on a number of factors including, but not limited to, intellectual property risks, risks in regulatory and market acceptance of new products and continuing demand for same, the impact of competitive products and pricing, changing economic conditions and other risk factors detailed in Aphton's most recent 10-K and other filings with the Securities and Exchange Commission.