Friday, Aug 20, 1993

STILE Study for Peripheral Arterial Occlusion Discontinued

Efficacy of Thrombolysis in PAO Not Evaluable in this Study; More Study Needed

South San Francisco, Calif. -- August 20, 1993 --

Genentech, Inc. (NYSE: GNE) announced today that a study comparing different forms of thrombolytic therapy with - surgery for peripheral arterial occlusion (PAO)blood clots in the limbs was stopped and enrollment discontinued based on an interim analysis of 300 patients. The STILE (Surgery and Thrombolysis for Ischemia of the Lower Extremity) study's preliminary results showed a difference favoring surgery based upon the primary efficacy end point between those patients randomized to receive thrombolytic therapy either Genentech's Activase® (Alteplase recombinant) t-PA or Abbott's Abbokinase® (urokinase) and those randomized to undergo surgery. The trial was not discontinued due to safety issues.

"Although a thorough review of the data remains to be done, a significant number of patients were considered to be technical failures of the thrombolytic arm of the study due to difficulties encountered in placing the catheter delivering the drug into the clot," said Genentech Vice President and Chief Medical Officer Barry Sherman. "This mechanical difficulty had an obvious negative effect on the results of the thrombolytic arm of the trial. If the thrombolytic agent cannot be delivered directly to the clot, you can't really tell whether the thrombolytic is effective in dissolving the clot."

Once all of the data have been analyzed, Genentech will consider whether additional trials will be conducted in the broad PAO patient population. In addition, the company will continue to investigate the effectiveness of Activase in treating specific sub-populations of PAO. Genentech has two Phase III clinical trials planned to test the efficacy of Activase in treating two specific PAO patient populations: those patients at high risk of requiring a limb amputation, and those patients whose clots are acute, that is, only a few hours old, rather than chronic. Both are scheduled to begin in the third quarter of 1993.

Dr. Sherman also said, "It should be very clear that there is no relationship between this study for PAO and the excellent results Activase demonstrated in the GUSTO trial in treating life threatening heart attacks."

Genentech, Inc. is a leading biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for significant 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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