A 2-in-1 adaptive design to seamlessly expand a selected dose from a phase 2 trial to a phase 3 trial for oncology drug development

In oncology, dose-finding studies are largely performed only in Phase I clinical trials and the maximum tolerated dose (MTD), a dose initially developed for systemic chemotherapies, is by default selected for the Phase 3 confirmatory trial. With the advent of anti-cancer therapies such as molecular targeted agents and immunotherapies, a paradigm shift is underway from the use of conventional MTD approaches to improved dose selection strategies for oncology programs. In response to this new challenge, new study designs are needed to optimize dose selection while still bring life-changing new therapies to patients as soon as possible. In this paper, we propose a 2-in-1 adaptive design starting with a Phase 2 trial with randomized evaluation of multiple doses and only select one dose to expand to a Phase 3 trial if efficacy evidence is observed based on an interim evaluation. The lowest dose will be selected if multiple doses show promising efficacy unless the higher dose demonstrates a more compelling treatment effect, and study will be seamlessly expanded to a Phase 3 trial with the selected dose with patients enrolled in the Phase 2 portion also used for the statistical inference in the Phase 3 portion. The overall Type I error can be controlled under a mild assumption. Simulation studies are conducted to confirm the control of Type I error and to demonstrate the desirable operating characteristics of the proposed design.