Friday, Jul 23, 1982

(TPA) Produced By Recombinant DNA Techniques

South San Francisco, Calif. -- July 23, 1982 --

Scientist at Genentech, Inc. reported today that genetic engineering methods had been used to produce a new enzyme which may improve therapy for dissolving blood clots.

Dr. Diane Pennica, addressing the Sixth International Congress on Fibrinolysis in Laussane, Switzerland, said today that tissue plasminogen activator (TPA) had been produced by recombinant DNA techniques in E. Coli and mammalian cell culture systems. The enzyme is a natural product produced by the body in response to blood clot formation. By activating another enzyme, TPA causes lysis of the fibrin threads which are formed during the clotting process.

Dr. Pennica said that she and her colleagues are collaborating with Dr. Desire Collen whose research group at the Center for Thrombosis and Vascular Research of the University of Leuven, Belgium first purified and characterized the enzyme from human tissues and cell cultures.

Heart attack, cerebral thrombosis (stroke), pulmonary embolism and deep vein thrombosis are among the leading acute health hazards in the industrialized countries. These diseases result from formation of blood clots that partially or totally obstruct blood vessels. When a major vein or artery is totally blocked, tissues served by the obstructed vessel die from lack of oxygen.

Current therapies run the risk of causing hemorrhaging. Preliminary studies indicate that hemorrhaging may not be an adverse reaction of TPA. Dr. Collen said his research group had conducted laboratory and small scale human studies with TPA extracted from human tissues. He said, "TPA appears to act directly and solely at the site of blood clots. Since only small quantities of the substance are needed to dissolve a clot and because TPA does not destroy the factors that balance the coagulation system, it may prove to be the ideal thrombolytic agent"

Genentech announced earlier that two Japanese companies, Kyowa Hakko Co., Ltd. and Mitsubishi Chemical Industries, were funding the research in exchange for licensing rights in Japan and possibly other Asian countries.

The Company's headquarters are located at 460 Point San Bruno Blvd., South San Francisco, California.

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