SCHERING "DEAR DOCTOR" LETTER ON NITRO-DUR "SPECIAL REPORT"

SCHERING "DEAR DOCTOR" LETTER ON NITRO-DUR "SPECIAL REPORT" of angina pectoris treatment went out Oct. 27 to recipients of the promtional material. The letter was sent to satisfy complaints expressed by FDA in a Aug. 28 regulatory letter ("The Pink Sheet" Sept. 4, T&G-9). FDA "has requested that we contact you regarding the 'Special Report' entitled 'Angina Pectoris: Treatment Update,' which you received as a supplement to the May 1-14, 1989 issue of Internal Medicine World Report," the Schering letter says. The supplement "was sponsored by Schering/Key, and presented a number of unsupported conclusions regarding efficacy of Nitro-Dur (nitroglycerin), as derived from an unblinded patient preference study, sponsored by our firm." * The study purported to demonstrate Nitro-Dur's superiority to isosorbide dinitrate (Wyeth-Ayerst's Isordil) for the reduction of anginal episode and concomitant sublingual nitroglycerin use. "On the basis of these conclusions, the report advised that angina patients currently treated with other antianginal treatments should be switched to Nitro-Dur," the letter notes. "However," Schering stated, "the design of the study was incapable of supporting such conclusions." The differences "were potentially attributable to factors such as improved patient compliance, rater bias, placebo effect, or other sources of bias, rather than superior efficacy of Nitro-Dur," the firm said. FDA found the report "particularly egregious" in light of recent findings of a large study, in which Schering participated, that indicates that transdermal nitroglycerin, used as currently labeled, is not superior to placebo in treating angina pectoris. The "Dear Doctor" letter refers to the cooperative study and notes that in a review of the study, an FDA advisory panel determined that "due to the development of tolerance . . . continuous 24-hour transdermal dosing nitroglycerin was not effective in treating or preventing angina due to coronary artery disease." Class labeling for these products has been revised to recommend intermittant dosing, the letter says. Schering also has agreed to comply with FDA's request to submit all future material on scientific/educational activities on Nitro-Dur for preclearance. According to minutes of a Sept. 22 meeting between Schering and FDA, the requirement of prospective review of these materials "will be re-evaluated in six months."