Tuesday, Nov 9, 1999

COR Therapeutics, Schering-Plough and Genentech Announce Plans to Study INTEGRILIN -- eptifibatide -- Injection in Combination with TNKase -- tenecteplase -- in Heart Attack Patients

Atlanta -- November 9, 1999 --

At the 72nd Annual Scientific Sessions of the American Heart Association today, COR Therapeutics, Inc. (Nasdaq:CORR), Schering-Plough Corporation (NYSE:SGP), and Genentech, Inc. (NYSE:DNA) announced a collaboration to study the antiplatelet agent INTEGRILIN-- in combination with the new single bolus fibrinolytic, TNKaseTM, in patients with acute myocardial infarction (heart attack).

The INTEGRITI (INTEGRILIN and Tenecteplase in Acute Myocardial Infarction) study will compare INTEGRILIN in combination with various doses of TNKase versus full-dose TNKase alone to assess the potential for improved blood flow through clogged arteries supplying oxygen-starved heart muscle.

"In the TIMI 10B study we observed restoration of normal coronary blood flow in 6 out of every 10 patients treated with TNKase," stated Eugene Braunwald, MD, Director of the Thrombolysis in Myocardial Infarction (TIMI) research network. "It is anticipated that significantly more patients may benefit from the dual effects of fibrinolysis with TNKase and inhibition of platelet aggregation with INTEGRILIN."

Previous studies have shown that normal blood flow is restored through clogged arteries in about one half of patients ninety minutes after initiation of fibrinolytic therapy as determined by an angiographic assessment known as TIMI grade 3 blood flow. In the remaining patients it is believed that continued platelet aggregation results in rapid re-occlusion of the artery. Fibrinolytic therapy does not prevent platelet aggregation.

GP IIb-IIIa inhibitors, such as INTEGRILIN (eptifibatide) Injection, have been shown to block platelet aggregation and total occlusion of the coronary arteries in patients with partially occluded coronary arteries (unstable angina). Preliminary trials of GP IIb-IIIa inhibitors in combination with fibrinolytic therapy in heart attack patients have demonstrated an improvement in blood flow through clogged coronary arteries versus that reported for fibrinolytic therapy alone.

"Given the devastating consequences of irreversible heart muscle injury in heart attack patients, it is hoped that this combination could ultimately lead to a further reduction in serious cardiovascular morbidity and mortality for thousands of patients each year," added Robert M. Califf, MD, Director of the Duke Clinical Research Institute in Durham, N.C. The INTEGRITI study is being conducted as a collaborative research effort between the TIMI and Duke clinical research networks.

Heart attack is the result of an occlusive clot in one of the coronary arteries which deprives heart muscle of oxygenated blood. Lack of oxygen supply results in irreversible heart muscle damage which can lead to death or serious chronic cardiovascular illnesses, such as congestive heart failure.

INTEGRILIN (eptifibatide) Injection is currently indicated for the treatment of patients with acute coronary syndrome (unstable angina and non-Q-wave myocardial infarction), including patients who are to be managed medically and those undergoing percutaneous coronary intervention (PCI). It is also indicated for the treatment of patients undergoing PCI.

INTEGRILIN is contraindicated in patients with a history of bleeding diathesis, or evidence of abnormal bleeding within the previous 30 days; severe hypertension (systolic blood pressure greater than 200 mm Hg or diastolic blood pressure greater than 110 mm Hg) not adequately controlled on antihypertensive therapy; major surgery within the preceding six weeks; history of stroke within 30 days, or any history of hemorrhagic stroke; current or planned administration of another parenteral GP IIb-IIIa inhibitor; platelet count less than 100,000/mm3; serum creatinine greater than or equal to 4.0 mg/dL (in patients with serum creatinine levels between 2.0 mg/dL and 4.0 mg/dL, a 135 microg/kg bolus and 0.5 microg/kg/min infusion should be administered); dependency on renal dialysis; or known hypersensitivity to any component of the product.

Previous clinical trials have shown that bleeding is the most common complication encountered during INTEGRILIN therapy. The majority of excess major bleeding events were localized at the femoral artery access site. Oropharyngeal, genitourinary, gastrointestinal and retroperitoneal bleeding were also seen more commonly with INTEGRILIN compared to placebo.

A bio-engineered plasminogen activator, Genenetech's TNKase (tenecteplase) is similar to Activase? (Alteplase, recombinant) which is a recombinant version of naturally-occurring tissue plasminogen activator (t-PA). TNKase, administered as a single bolus, has been designed to prolong its half-life and increase specificity to fibrin, a key component to intracoronary clots. TNKase is currently under regulatory review for marketing approval for the treatment of acute myocardial infarction by the U.S. Food and Drug Administration and the European Regulatory Authority with marketing partner Boehringer Ingelheim.

TNKase has been studied in clinical trials involving more than 21,000 patients worldwide. The most significant clinical adverse events observed in trials with TNKase include intracranial hemorrhage and stroke, which are similar to those seen with other thrombolytics. As with all thrombolytic agents, Activase therapy increases the risk of bleeding, including intracranial bleeding, and should be used only in appropriate patients.

COR Therapeutics, Inc. and Schering-Plough Corporation are worldwide partners for INTEGRILIN. Both companies market and sell the drug in the United States. Schering-Plough markets INTEGRILIN in Europe. COR has the right to co-promote INTEGRILIN in Europe at a later date.

COR Therapeutics, Inc. is dedicated to the discovery, development and commercialization of novel pharmaceutical products for the treatment and prevention of severe cardiovascular diseases.

Schering-Plough Corporation is a research-based company engaged in the discovery, development, manufacturing, and marketing of pharmaceutical products worldwide.

Genentech, Inc. is a leading biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for significant unmet medical needs. Twelve of the approved products of biotechnology stem from Genentech science. Genentech markets seven products directly in the United States. The company has headquarters in South San Francisco.

COR forward-looking statement: 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.

Note to Editors: INTEGRILIN is a registered trademark of COR Therapeutics, Inc. TNKase and Activase are registered trademarks of Genentech, Inc.

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