Keywords: adaptive design, sample size re-estimation, simulation
Multi-stage adaptive designs offer the flexibility to make prospectively defined changes to aspects of trial conduct. At an interim analysis, a trial designer might envisage various opportunities, such as dropping arms, changing randomization scheme, or increasing sample size. When one or more of these adaptive components are being considered, natural questions arise: Does the proposed adaptation maintain trial integrity with respect to control of type I error? How often and when is a particular adaptation to be implemented? If a sample size re-estimation option is considered, we would like to characterize the distribution of the final sample size. When we cannot appeal to analytically derived solutions, simulation provides a means to answer these questions and gain insight into how the considered adaptations perform within a controlled simulated data environment. We will discuss aspects of planning and summarizing findings in the context of simulation reporting.
