Wednesday, Jun 15, 1994

Genentech Reports Discovery of New Blood Platelet Factor

Genentech scientists identify important blood-factor drug; company is confident in patent position

South San Francisco, Calif. -- June 15, 1994 --

Genentech, Inc. (NYSE: GNE) announced today the identification and cloning of an important protein involved in the production of platelets that may represent a new treatment for side effects from irradiation and chemotherapy in seriously ill cancer patients. Results of early in vitro and in vivo work with this protein will be published in the June 16 issue of NATURE.

Genentech scientists have identified and cloned the human protein (thrombopoietin) which induces primitive bone marrow cells to change and mature. As these cells mature, they grow larger and shed platelets that are critical to blood clotting.

Since the discovery of erythropoietin (EPO) and granulocyte colony stimulating factor (G-CSF), the specific stimulatory factors for red and white blood cells, scientists in several laboratories around the world have been racing to discover the factor that would stimulate platelet production.

"This discovery represents a potential major clinical advance in the areas of hematology and oncology," said Barry M. Sherman, M.D., Genentech vice president and chief medical officer. "By enhancing platelet production, physicians could prescribe chemotherapy in higher doses and improve cancer treatment outcomes. In addition, the new growth factor is likely to be useful in the rapidly expanding field of bone marrow transplantation, in which thrombocytopenia is a major complication."

Patients who undergo intensive chemotherapy experience thrombocytopenia, a sharp reduction in platelets, that can lead to dangerous bleeding. While current adjunctive treatments for chemotherapy side effects, such as EPO and G-CSF, stimulate the production of red and white blood cells suppressed by irradiation and chemotherapy, there is no way to replace lost platelets, except through transfusions. This new protein could potentially be used in conjunction with EPO and G-CSF to treat the serious side effects of depleted blood factors.

"Based on the strength of these preliminary findings, their potential to advance clinical medicine, and the commercial importance of a drug that fills this need, Genentech will continue to make this a high priority project," said Arthur D. Levinson, Ph.D., Genentech senior vice president.

Genentech is a leading international biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for significant unmet medical needs. The company has headquarters in South San Francisco, California and is traded on the New York and Pacific Stock Exchanges under the symbol GNE.

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