COR Therapeutics' Once-A-Day Oral GP IIb-IIIa Inhibitor Continues to Show Promise in Clinical Trials.

SOUTH SAN FRANCISCO--(BW HealthWire)--Nov. 8, 1999--

Phase II Study Results Indicate Cromafiban

Provides Predictable and Consistent Inhibition of

Platelet Aggregation 

Results of a Phase II clinical trial of COR Therapeutics' (Nasdaq:CORR) oral GP IIb-IIIa inhibitor, cromafibarted.

Cromafiban has been demonstrated to achieve predictable and consistent levels of platelet aggregation inhibition at each dose level tested in single-dose and multiple-dose studies. Plasma concentrations have indicated a sufficiently long half life (21 hours) to allow for once-daily dosing. Results of a Phase II trial using several different doses of cromafiban each administered once a day for 14 days indicate little variability between peak and trough levels of platelet aggregation inhibition. Clinically relevant doses of cromafiban (those achieving between 40 and 70 percent platelet aggregation inhibition) produced peak-to-trough ratios of inhibition ranging between 1.2 and 1.4 to one. Mild bleeding was the most prevalent complication encountered during the trial. No major bleeding complications were reported.

The pharmacologic properties of cromafiban differ significantly from those of other oral GP IIb-IIIa inhibitors for which unsatisfactory Phase III clinical results have been reported. These other agents were short-acting inhibitors of platelet aggregation that required multiple daily doses and showed significant variability between peak levels of platelet aggregation inhibition achieved shortly after dosing and trough levels reached prior to the next dose. The trough levels of platelet aggregation inhibition achieved may have been insufficient to prevent blood clot formation, leading to disappointing clinical results.

"The predictable and consistent degree of platelet aggregation inhibition seen with cromafiban, coupled with the possibility of once daily dosing, clearly distinguishes it from these other compounds," reported Robert A. Harrington, MD, Associate Professor of Medicine at Duke University Medical Center and lead investigator for the cromafiban clinical development program. "Clinically, we must now assess how the different pharmacologic profile for cromafiban will affect outcomes among patients with a history of arterial thrombotic conditions."

Based upon successful trials of intravenous GP IIb-IIIa inhibitors in the prevention of myocardial infarction (heart attack) and death in patients presenting with acute coronary syndromes, physicians and researchers have proposed that oral GP IIb-IIIa inhibitor agents could help prevent catastrophic ischemic events when administered chronically to patients with a history of acute coronary syndromes or cerebrovascular accidents. Over six million people in the U.S. have a history of heart attack, stroke, or transient ischemic attacks.

Despite currently available therapies such as asprin, a significant number of ischemic events such as myocardial infarction, stroke and death occur each year. These events are generally the result of blood clots blocking the arteries supplying oxygen to heart or brain tissue. Blood clots consist of aggregates or clumps of blood components, known as platelets. GP IIb-IIIa inhibitors have been demonstrated to help prevent blood clot formation when adequate levels of platelet aggregation inhibition are achieved and maintained.

Multiple Phase II clinical studies of cromafiban are currently underway and initiation of the Phase III program is anticipated in the second half of 2000.

COR Therapeutics, Inc. is dedicated to the discovery, development and commercialization of novel pharmaceutical products for the treatment and prevention of severe cardiovascular diseases. COR has complementary research and development programs that seek to address critical needs in severe cardiovascular care, including unstable angina, acute myocardial infarction, deep vein thrombosis and restenosis. For additional information about COR Therapeutics, please visit the Company's Web site at http://www.corr.com.

In addition to the historical information contained herein, this press release contains forward-looking statements that involve risks and uncertainties. Actual results of the Company's activities may differ significantly from the potential results discussed in such forward-looking statements. These forward-looking statements are based on current expectations and the Company assumes no obligation to update this information. A full discussion of COR Therapeutics' operations and financial condition, and specific factors that could cause the Company's actual performance to differ from current expectations, can be found in the Company's SEC reports, including, but not limited to, the Company's Report on Form 10-Q for the quarter ended September 30, 1999, and Report on Form 10-K for the year ended December 31, 1998.