An adaptive Simon Two-Stage Design for Phase 2 studies of targeted therapies.

The field of specialized medicine and clinical development programs for targeted cancer therapies are rapidly expanding. The proposed Phase 2 design allows for preliminary determination of efficacy that may be restricted to a particular sub-population defined by biomarker status (presence/absence). The design is an adaptation of the Simon Two-Stage Design. We provide examples where the adaptation can result in substantial savings in sample size and thus potentially lead to greater efficiency in decision making during the drug development process.