Endovasc Presents New Stent Coating Data at Athens 2001 Interventional Cardiovascular Therapeutics II.

Business Editors & Health/Medical Writers

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MONTGOMERY, Texas--(BW HealthWire)--June 27, 2001

Endovasc Ltd. Inc. (OTCBB:ENDV) presented data on long-term drug release from stents coated with its Prostaglandin E-1 (PGE-1) conjugate at the Interventional Cardiovascular Therapeutics II meeting held in Athens, Greece, on June 16 and 17, 2001. The meeting was organized by Lenox Hill Heart and Vascular Institute of New York, the Cardiology Division of the University of Athens, and sponsored by Hellenic Heart Foundation, Athens and Cardiovascular Research Foundation, New York.

The data presented in a poster by Dr. Diane Dottavio, Endovasc's director of research and development, included elution profiles out to seventy-five days. "The drug was still eluting therapeutic levels of PGE-1, but we had to stop somewhere and prepare the graphs," said Company Chairman and CEO, Dr. David P. Summers.

Abstract: Extended Local Drug Delivery Using PROStent E-1 to Reduce Frequency of Restenosis; D. Dottavio, D. Cardoza, G. Asongwe, and D. Summers; Endovasc Ltd. Inc., Montgomery, Texas; Background: Prostaglandin E-1 is a potent vasodilator and platelet aggregation antagonist. In endothelial cells, PGE-1 has been shown to raise intracellular c-AMP levels, which results in the down-regulation of production of inflammatory cytokines (IFN gamma, TNF alpha IL-2, etc.). In smooth muscle cells, PGE-1 elevated c-AMP causes disruption of the organization of skeletal fibers, thus preventing cellular migration. The pharmacological effects of this drug make it an attractive candidate for the prevention of thrombosis and restenosis after percutaneous coronary intervention. Methods: Twenty coronary stents were coated with either 100 micrograms or 250 micrograms of GPE-1, and overlaid with a thin coating of non-erodable polymer matrix to promote prolonged drug release. Five stents from each drug level group were expanded by insertion of a balloon catheter. The stents were examined with SEM before and after expansion, and in vitro PGE-1 release curves were performed using high performance liquid chromatography. Drug elution profiles were measured in phosphate buffered saline. Results: Both expanded and unexpanded stents released 20%-30% of the drug within the first 72 hours and 70%-80% within sixty days. Expansion of the stent did not damage the coating or change the release rate profile. The amount of drug loaded on the stent did not appear to change the kinetics of release. Conclusions: The slow release of prostaglandin E-1 coated on stents may provide a useful method to block restenosis.

"We are excited that the stent coating regulated the release so tightly," said Dr. Diane Dottavio, "showing that the release window with PGE-1 is very large and that minor variation in the dose is virtually inconsequential. We were pleased with the discussions and interest expressed by the participants of the meeting." The company will move forward this Summer into animal studies in a pig model.

Stents are tiny mesh tubes that are implanted into a blood vessel and serve as scaffolding to keep vessels open following surgery or angioplasty and from becoming blocked. Despite their utility, stents have been plagued by restenosis (re-blockage) and occlusion due to thrombosis. Although several medical device manufacturers have announced research and development of coated stents recently, Endovasc's patented biodegradable drug delivery stent coating utilizes the company drug, Prostaglandin E-1, a non-toxic, natural occurring hormone, chemically related fatty acid. It has potent inhibition effects on smooth muscle cell migration, antagonizes platelet aggregation and fibrin binding in and around the stent structure and has potent anti-inflammatory qualities. Previous company experiments in a pig model demonstrated effective anti-restenosis in coronary artery injury model using a single bolus of PGE-1 and plain ole balloon (POB) angioplasty.

Endovasc Ltd. Inc. is a biopharmaceutical/biotech company pioneering liposomal drug delivery technology. The Company's products and processes, which include Liprostin(TM) (liposome encapsulated PGE-1), NRA (Nicotine Receptor Agonist, angiogenesis agent), stent-coating technology and a biodegradable/resorbable stent, are covered by patents and trade secrets for competing in a multi-billion dollar market.

The foregoing statements are made under the "Safe Harbor" Private Securities Litigation Reform Act of 1995 and may contain forward-looking statements that involve risks and uncertainties that may not be evident at the time of this release.