Corvas reports progress in antithrombotic drug programs; clinical supply manufacturing contract also announced.

WASHINGTON D.C.--(BUSINESS WIRE)--April 17, 1996--Corvas International Inc. (NNM:CVAS) Wednesday reported progress in the development of two new antithrombotic agents for the treatment of cardiovascular diseases.

The announcement was made by Dr. George P. Vlasuk, Ph.D., Corvas' vice president of biological research, at the annual meeting of the American Society for Pharmacology and Experimental Therapeutics, part of "Experimental Biology '96."

Vlasuk presented the first results from a Phase Ia human clinical trial of CVS-1123, an orally active thrombin inhibitor, as well as new preclinical data on NAPc2, a novel protein anticoagulant under development. Corvas also announced Wednesday that it has signed an agreement with Immunex Corp. for the manufacture of clinical supplies of NAPc2 in preparation for human trials, expected to begin in early 1997.

Oral Thrombin Inhibitor Clinical Results

Results from the Phase Ia clinical trial of CVS-1123 showed that the compound was well absorbed when administered orally to healthy male volunteers. No bleeding events or other drug-related adverse events were observed in this single-dose administration study. In addition, the anticoagulant effect of CVS-1123 was proportional to the dose of the agent.

"Completion of this first human study is an important step in our program to create safe, new antithrombotic drugs that can be administered on a chronic basis for the treatment for thrombotic diseases. The data are guiding our collaborative program with Schering-Plough on the development of these oral thrombin inhibitors," said Vlasuk.

NAPc2 Preclinical Data

Vlasuk also presented preclinical data on NAPc2, a protein anticoagulant being developed for acute thrombotic diseases, with an initial emphasis on venous thrombosis. NAPc2, a member of the NAP (nematode anticoagulant proteins) family of antithrombotic agents, is a potent inhibitor of Factor VIIa/Tissue Factor which initiates the body's blood clotting process.

In various animal models of thrombosis, including venous and arterial thrombosis, a recombinant form of NAPc2 demonstrated efficacy advantages over a commonly used anticoagulant, following both intravenous and subcutaneous administration.

"NAPc2 can be administered by subcutaneous injection and exhibits excellent duration of action in animals. If data from human trials confirm these properties, it may be feasible to administer treatment in an outpatient setting or even in the home," stated Vlasuk.

Corvas/Immunex Agreement

Corvas also announced that it has signed an agreement with Immunex for the manufacture of clinical supplies of NAPc2 for trials which Corvas intends to conduct in early 1997. Immunex is a biopharmaceutical company dedicated to developing immune system science to protect human health.

"We are pleased to be able to draw upon the extensive expertise of Immunex in the manufacture of biopharmaceutical products," said Howard R. Soule, Ph.D., Corvas vice president, product development. "Corvas scientists have been collaborating with the Immunex team to transfer our process technology for producing NAP to Immunex, and production of clinical supplies of NAPc2 is underway. Using this strategy, Corvas expects to enter the clinic in a timely manner and defer extensive investment until the potential of our product candidate is better defined."

Corvas International, based in San Diego, is a biopharmaceutical company engaged in the design and development of a new generation of therapeutic agents for the prevention and treatment of major cardiovascular and inflammatory diseases. Corvas is currently collaborating with Schering-Plough in the development of oral thrombin inhibitors for chronic cardiovascular disease, with Pfizer Inc. to develop neutrophil inhibitory factor (NIF) as a possible stroke therapy, and has product licensing agreements with Ortho Diagnostic Systems Inc., a Johnson & Johnson company and Centocor Inc.

Except for the historical and factual information contained herein, the matters discussed in this press release contain forward-looking statements which involved risks and uncertainties, including the timely development of the NAP product, competitive products and pricing, the company's lack of manufacturing facilities and limited manufacturing experience, and other risks detailed from time to time in the company's filings with the Securities and Exchange Commission.

Actual results may differ materially from those projected. These forward-looking statements represent the company's judgement as of the date of this release. The company disclaims, however, any intent or obligation to update these forward-looking statements.

For background information on Corvas' technology and product development programs, contact Angela Hartley, manager, investor relations, Corvas, at 619/455-9800. For information on Corvas International via facsimile at no cost, call 800-PRO-INFO and enter ticker symbol CVAS.

CONTACT: Corvas International Inc., San Diego

John E. Crawford/Angela L. Hartley, 619/455-9800

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