KNOLL'S RYTHMOL (PROPAFENONE) IS APPROVABLE

KNOLL'S RYTHMOL (PROPAFENONE) IS APPROVABLE for the suppression of ventricular arrhythmias. In July 1985, FDA's Cardio-Renal Drugs Advisory Committee concluded that Rythmol was effective for the indication but that additional data was needed before the drug could be approved. Knoll received notice of approvable status March 30; the product has not been approved to date. Once approved, Rythmol will complement Knoll's Isoptin (verapamil) line, which includes Isoptin I.V., Isoptin tabs, and Isoptin-SR tabs. Knoll has several other cardiovasculars in the pipeline: Arvin (ancrod), currently in Phase II trials for stroke; anipamil, a second generation calcium channel blocker; and gallopamil, a calcium channel blocker in Phase II for hypertension. Knoll indicated that it will be in communication with FDA over the possible impact that the National Heart, Lung & Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST) might have on the indications that will appear on Rythmol's labeling. Interim results of CAST, announced at a press conference in April, showed that patients assigned to Bristol-Myers' Enkaid (encainide) and Riker's Tambocor (flecainide) showed a higher incidence of deaths or non-fatal cardiac arrests than the corresponding placebo groups ("The Pink Sheet" May 1, p. 10). After reviewing CAST's results, FDA put forth the recommendation that Enkaid and Tambocor not be used for treatment of non-life-threatening arrhythmias, but only for treatment of life-threatening arrhythmias. Rythmol, like Enkaid and Tambocor, is a Class 1C anti-arrhythmic. Knoll is seeking an indication for both non-life-threatening and life-threatening arrhythmias. Knoll maintains that although Rythmol is in the same class as Enkaid and Tambocor, it is a different chemical entity and -- unlike the other anti-arrhythmics -- has beta-blocking properties. The company said it will have to evaluate the CAST data before any conclusions can be made or any actions taken with respect to Rythmol's indications. Bristol-Myers and Riker both agree to change the labeling for their respective anti-arrhythmics and to stop promotions of the drugs for treatment of non-life-threatening arrhythmias. The firms also sent out letters to doctors and pharmacists informing them of the study results and the impending labeling changes.