Status of Controlled Clinical Trials in Peripheral Vessel Atherosclerosis

Abstract

There are two general strategies to test the efficacy of drugs which may cause atherosclerosis regression in man. The first is to study drug effects on atherosclerosis-related morbidity or mortality, a strategy which has been accepted for many years. For example, the Coronary Drug Project¹ studied the effects of six drugs in men aged 30 to 64 years who had recovered from one or more episodes of myocardial infarction (MI). Fifty-three clinics recruited 8,341 patients who were randomly assigned to one of six treatment groups. Three study groups (conjugated estrogens, 2.5 mg/day; conjugated estrogens, 5.0 mg/day; and dextrothyroxine sodium, 6.0 mg/day) were discontinued before the scheduled conclusion of the project, whereas patients in the remaining groups (Clofibrate, 1.8 g/day; niacin, 3.0 g/day; and lactose placebo 3.8 g/day) were followed to the end of the study. The results of that study indicated that there was no evidence of significant efficacy of Clofibrate or of niacin with regard to total mortality or cause-specific mortality. Five-year mortality rates were 20.0% for Clofibrate, 21.2% for niacin, and 20.9% for the placebo.