CIPROSTENE PHASE III REANALYSIS SHOWS 42% REDUCTION IN RESTENOSIS

CIPROSTENE PHASE III REANALYSIS SHOWS 42% REDUCTION IN RESTENOSIS following balloon angioplasty. The reanalysis of the study results for the Upjohn drug, originally reported in 1988, was presented by Albert Raizner, MD, Baylor College of Medicine, at the American College of Cardiology annual meeting March 17. The original analysis of the study found only a trend in restenosis reduction in ciprostene-treated patients versus placebo. The reanalysis of the study found that six months after patients had undergone percutaneous transluminal coronary angioplasty (PTCA), the average minimal lumen diameter of patients had decreased by .33 mm the ciprostene group compared to .57 mm in the placebo-treated patients, a statistically significant difference of 42%. In the study, 311 patients were randomized to a 15-minute intracoronary infusion of ciprostene (40 nanograms/minute to 120 ng/min) or placebo prior to PTCA. After angioplasty, patients received an intravenous infusion of ciprostene or placebo for 48 hours. Approximately 70% of the patients had quantitative coronary angiographs conducted post-PTCA and at six months. Ciprostene therapy also reduced repeat angioplasty, coronary bypass surgery and myocardial infarction by 40%-50% in the U.S. study, Raizner reported. A European Phase III trial in 331 patients confirms the U.S. results with ciprostene, he said. When the data in the U.S. and European trials were combined, ciprostene was associated with a 33% reduction in total cardiovascular adverse events. Repeat angioplasties were decreased by 28%, coronary artery bypass graft (CABGs) by 47%, and myocardial infarctions by 53%. In addition, there was a reduction in deaths in the ciprostene patient group. Raizner explained that the reanalysis was conducted because the previous analysis of the Phase III trial was based on a visual interpretation of angiographic data rather than quantitative analysis of the angiograms. The decision to use visual interpretation, by which only the percent of stenosis can be assessed, was "made by the sponsor [Upjohn] despite objections of the investigators," Raizner commented. At a press briefing during the ACC meeting, Raizner said Upjohn "shelved" ciprostene after learning of the marginal results following the original analysis of the study. Upjohn said that the medical and commercial benefit [of ciprostene] did not warrant further development of the drug." The company said it has no plans to resume development of ciprostene, but would consider it as an outlicensing candidate. Raizner recommended that another Phase III trial of ciprostene be conducted to bolster the results from the studies he presented. "As cardiologists we have become so skeptical of any drug having an effect on restenosis...[that] we would like to see any drug confirmed in a comparable trial or even a larger-scale trial," Raizner said. "At the present time there really is nothing that is available ...that has been consistently shown to reduce the incidence of renarrowing after angioplasty," Mark Freed, MD, William Beaumont Hospital (Birmingham, Ala.) noted at the briefing. Freed presented results of a restenosis trial of Merck's Mevacor (lovastatin) and the angiotensin-converting enzyme (ACE) inhibitor Vasotec (enalapril) in combination with colchicine. The so-called Big MAC trial failed to show any difference between the combination drug therapy and placebo in preventing restenosis following PTCA.