ABSTRACT

Adaptive designs have received much attention recently for various goals, including sample size re-estimation and dose selection. Here two adaptive procedures for comparing two doses of an active treatment to placebo with respect to a binomial response variable using a double-blind randomized clinical trial are presented. The goals of the interim analysis are to stop for futility or to continue with one dose or both doses, and placebo, with a possible increase in the sample size for any group that continues. Various properties of the two procedures, which are both based on the concept of conditional power, are presented.