Abstract

A main objective in dose-finding trials besides the characterisation of dose-response relationship is often to prove that the drug has effect. The sample size calculation prior to the trial aims to control the power for this effect proof. In most cases however, there is great uncertainty concerning the anticipated effect of the drug during planning. Sample size re-estimation based on an unblinded interim effect estimate has been used in this situation. In practice, this re-estimation can have drawbacks as sample size becomes variable which makes planning and funding complicated. Further it introduces the risk that people start to speculate about the effect once the re-estimated sample size is communicated. In this talk, we will investigate a design which avoids this problem but controls the power for the effect proof in an adaptive way. We discuss methods for proper statistical inference for the described design.