GENENTECH’s ACTIVASE APPROVED FOR ACUTE PULMONARY EMBOLISM

GENENTECH's ACTIVASE APPROVED FOR ACUTE PULMONARY EMBOLISM by FDA on June 5. The indication is the second for the clot dissolving agent, originally approved in November 1987 for acute myocardial infarction (MI). Genentech submitted a supplement to the Product License Application for the management of pulmonary embolism in January 1989. Two older thrombolytics, Abbott's Abbokinase and Hoechst-Roussel's Streptase, carry indications for the treatment of pulmonary embolism. The new labeling states that Activase is indicated "in the management of acute massive pulmonary embolism (PE) in adults: for the lysis of acute pulmonary emboli, defined as obstruction of blood flow to a lobe or multiple segments of the lungs; and for the lysis of pulmonary emboli accompanied by unstable hemodynamics, e.g., failure to maintain blood pressure without supportive measures." The diagnosis of pulmonary emboli "should be confirmed by objective means, such as pulmonary angiography or noninvasive procedures such as lung scanning," labeling adds. The cost of Activase therapy will be the same for PE patients as for those with acute MI, $2,200 for the one-time 100 mg dose. Of the 130,000 hospitalized each year with pulmonary emboli, approximately 10,000 will be eligible for treatment with Activase, Genentech said. Labeling recommends that the 100 mg dose be infused over two hours, instead of the three hours for acute MI. "Heparin therapy should be instituted or reinstituted near the end of or immediately following the Activase infusion when partial thromboplastin time or thrombin time returns to twice normal or less," labeling states. In the warnings section, Activase labeling states: "it should be recognized that the treatment of pulmonary embolism with Activase, alteplase, has not been shown to constitute adequate clinical treatment of underlying deep vein thrombosis." In addition, the "risk of reembolization due to the lysis of underlying deep venous thrombi should be considered." Pivotal data submitted for approval of the indication was derived from the multicenter Urokinase Pulmonary Embolism Trial (UPET) comparing Activase to Abbokinase. The study in 45 patients, published in the Aug. 6, 1988 Lancet, compared 100 mg Activase infused over two hours to 2,000 units/lb. bolus infusion followed by 2,000 units/lb. per hour for up to 24 hours. Heparin was not administered until either therapy was completed. At two hours, 13 of 22 (59%) patients in the Activase group showed moderate or marked lysis of clots and significant improvement in pulmonary hemodynamics (pulmonary artery, systolic, diastolic and mean pressure). At 24 hours, the conclusion of urokinase therapy, pulmonary perfusion as assessed by radionuclide scan was significantly improved in both Activase and Abbokinase groups, with no significant difference between the two.