Genentech's New tPA To Start Phase III

After positive results in two Phase II studies, Genentech'snew-generation tissue plasminogen activator, TNK-tPA, will now enter Phase III testing. The follow-up to the company's best-selling Activase (alteplase) product is easier to administer and may restore blood flow more quickly than its parent.

The two Phase II studies, TIMI 10B and ASSENT, evaluated the safety and efficacy of a single bolus of TNK-tPA at various doses in patients with acute myocardial infarction. TIMI-10B compared the rate of arterial patency at 90 minutes after TNK-tPA and Activase (90-minute infusion) treatment. A total 886 patients were enrolled into the study. Several studies have indicated that achieving artery patency more quickly results in the salvage of more cardiac tissue (Marketletters passim).

ASSENT used the same protocol as TIMI-10B but looked at safety (particularly the rate of intracranial hemorrhage) and mortality as the primary endpoints. More than 3,000 patients were enrolled in this study.