Genentech Inc. said the FDA Monday granted approval of the SouthSan Francisco company's application to amend its Activase label toinclude results of a 1993 study showing the clot-busting drug out-performed its major competitor, streptokinase.

Activase, or tPA, already captures 70 percent of the U.S. market forthrombolytic agents to treat heart attacks. In 1994, Genentechreported Activase sales of more than $280 million. Streptokinase,marketed by Astra AB and Kabi Pharmacia AB under the nameKabikinase, accounts for most of the remaining market share.

The FDA's action Monday sent Genentech's stock (NYSE:GNE) up$2.62 to $49.50, a 5.5 percent boost.

In 1993, Genentech sponsored a Global Utilization of Streptokinaseand tPA for Occluded Coronary Arteries (GUSTO) study. The head-to-head battle of the two products established Activase as thestandard for thrombolytic therapy after results of the 41,000-patienttrials showed tPA had a 1 percent survival advantage overstreptokinase.

In the GUSTO study, the dosage of tPA used to treat heart attackvictims was infused over 90 minutes instead of the three-hourregimen approved by the FDA in 1987.

Although Activase has been used widely under the acceleratedinfusion regimen since the GUSTO results, the FDA approval allowsGenentech to include it on the label along with the streptokinasecomparison and promote the GUSTO data in marketing.

Genentech President and CEO Kirk Raab said in a preparedstatement, "Now because these important findings are incorporatedinto the drug's labeling, more physicians are likely to apply this new,life-saving regimen in [acute myocardial infarction] care."

After the GUSTO study was reported, Genentech's share of thethrombolytic market jumped from 50 percent to 70 percent, despitethe fact Activase, at $2,200 per dose, was 10 times more expensivethan streptokinase.

Another potential competitor for Activase is being developed byBoehringer Mannheim Pharmaceuticals Corp., of Gaithersburg, Md.,a subsidiary of Bermuda-based Corange Ltd.

Boehringer Mannheim, this summer, is sponsoring a GUSTO IIIstudy to compare its thrombolytic, reteplase (rPA), with Activase.

GUSTO trials are coordinated by Eric Topol, chairman of thedepartment of cardiology at the Cleveland Clinic Foundation, andRobert Califf, professor of medicine at Duke University MedicalCenter in Durham, N.C. Since the first GUSTO trials, the acronymhas been changed to represent Global Utilization Strategy forThrombolysis of Occluded Arteries.

The ongoing GUSTO II trials are designed to test anticoagulants assubstitutes for heparin, but a 1,000-patient portion of the study alsowill compare the effectiveness of angioplasty to Activase in treatingheart-attack patients. A recent study coordinated at WilliamBeaumont Hospital, in Royal Oak, Mich., suggested angioplasty maybe more beneficial and cost-effective in some instances thanthrombolytics. (See BioWorld Today, March 23, 1995, p. 1.) n

-- Charles Craig

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