Monday, May 5, 1997

Genentech Announces Plans to Study TNK-tPA in Phase III

South San Francisco, Calif. -- May 5, 1997 --

Genentech, Inc. (NYSE: GNE) announced today positive preliminary results from two Phase II trials of second-generation tissue plasminogen activator (t-PA) -- called TNK-tPA -- in acute myocardial infarction.

TNK-tPA is a selectively mutated version of natural t-PA. TNK-tPA has been designed to demonstrate that it may be easier to administer and potentially restore blood flow more quickly than Activase®, (Alteplase, recombinant).

Two Phase II studies were conducted in parallel to evaluate the efficacy and safety of a single bolus of TNK-tPA at various doses in patients with acute myocardial infarction. The TIMI 10B trial evaluated the efficacy of TNK-tPA versus Activase at restoring blood flow in coronary arteries at 90-minutes following treatment. A total of 886 patients presenting within 12 hours of symptom onset at 76 sites in North America and Europe were randomized to receive intravenously either a single bolus of TNK-tPA or a 90-minute infusion of Activase.

The ASSENT trial examined the safety of TNK-tPA, evaluating the rates of intracranial hemorrhage (ICH) and mortality in patients treated with the same doses of TNK-tPA compared to Activase as in the TIMI 10B trial. More than 3,000 patients presenting within 0-12 hours were enrolled at 295 sites world-wide. Results of both Phase II trials, including mortality rates, will be presented in August at the European Society of Cardiology meeting in Stockholm.

"We are very pleased with the preliminary results which show that TNK-tPA is a promising new single-bolus thrombolytic agent," said Arthur D. Levinson, Ph.D., Genentech's President and Chief Executive Officer. "Based upon the two Phase II trials which provide us with substantial data, Phase III planning for TNK-tPA is currently underway."

The North American sites were coordinated at Brigham and Women's Hospital in Boston under the chairmanship of Eugene Braunwald, M.D. Sites outside North America were coordinated by Frans Van de Werf, M.D., Ph.D., at the University of Leuven in Belgium. TNK-tPA is a co-development effort between Boehringer Ingelheim, GmbH and Genentech.

Each year, nearly 1.5 million Americans suffer heart attacks; nearly one-third of these heart attacks are fatal. A heart attack, or acute myocardial infarction, is caused by an inadequate supply of oxygenated and nutrient-enriched blood to the heart, resulting in the death of a portion of the heart muscle.

Genentech, Inc. is a leading biotechnology company that discovers, develops, manufactures, and markets human pharmaceuticals for significant unmet medical needs. Eleven of the currently marketed biotechnology products stem from Genentech science, six of which Genentech markets directly in the United States. The company has headquarters in South San Francisco, California, and is traded on the New York Stock Exchange and Pacific Exchange under the symbol GNE.

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