Bayesian sequential decision-making for rare disease clinical trials

Background Rare disease clinical trials face challenges due to limited sample sizes and ethical imperatives to minimize futile treatments. Bayesian sequential design dynamically optimizes decisions under uncertainty, offering efficiency gains over traditional fixed-sample approaches. Methods Propose a framework integrating sequential Bayes factor and adaptive stopping rules for trials with binary endpoint. Bayesian posterior probabilities define early termination thresholds (superiority/futility), while Bayes Factor Design Analysis validates trial feasibility. Sequential Bayes factor updates iteratively guide interim decisions based on evidence strength. Results The approach enables earlier trial termination (for superiority or futility), reducing sample size, time, and costs. Patients avoid unnecessary exposure to futility treatments, while results remain interpretable even if thresholds are unmet. Conclusion The primary goal is to confirm treatment efficacy earlier, enabling trials to be stopped promptly for either superiority or futility treatments. This strategy reduces sample size, time, and financial costs, and prevents patient exposure to futile treatments. Moreover, the study aims to promote the adoption of Bayesian sequential decision-making, thereby accelerating rare disease clinical trial approvals and drug marketing.