An improved biomarker-guided adaptive patient enrichment design for oncology trials

The use of biomarkers to guide adaptive enrichment designs in oncology trials presents a promising strategy for increasing trial efficiency and improving the chance of identifying efficacious treatment in the right population. With a well-defined biomarker, such designs can enhance study power and reduce costs by adapting the trial focus to promising populations. However, existing adaptive enrichment designs may not have sufficiently flexible interim decision-making rules, testing procedures, and sample size re-estimation, limiting their full potential. In this research, we propose an improved biomarker-guided adaptive enrichment design that supports dynamic interim decision-making based on treatment effects observed in biomarker-positive, biomarker-negative, and overall populations. The design includes options for early stopping for efficacy or futility in both biomarker-positive and overall populations and incorporates sample size re-estimation using an improved conditional power method to optimize study power. Simulation results show that the proposed design maintains strong control of type I error and delivers high statistical power, with a high probability of correct interim decisions in cases where treatment is effective in either the biomarker-positive or overall population. This novel framework provides a more flexible and efficient approach to conducting oncology trials with heterogenous populations, ensuring that the most appropriate patient populations are selected as the trial progresses.