How Bayesian Design Is Reshaping Clinical Development

In a recent video interview with Applied Clinical Trials, David Morton, PhD, director of biostatistics, Certara, discussed how the FDA’s increased support for Bayesian methods is expected to drive a shift from traditional frequentist approaches toward more flexible, probability-based trial designs. He emphasized the growing role of external data borrowing, adaptive decision-making, and simulation-driven planning in improving efficiency, particularly in rare disease and small population studies. Morton also highlighted the need for stronger upfront design, including justification of prior data and robust analytical frameworks, as well as greater cross-functional alignment and early regulatory engagement to support transparency, reduce uncertainty, and accelerate more data-driven development models.

Editor's note: This transcript is a lightly edited rendering of the original audio/video content. It may contain errors, informal language, or omissions as spoken in the original recording.

ACT: Do you see this guidance accelerating a broader shift toward more flexible, data-driven clinical development models in the coming years?

Morton: I do. While the guidance is technically nonbinding, it reflects the agency’s current thinking and encourages more complex, innovative designs.

It emphasizes early engagement with the FDA and alignment on priors before the trial begins. That creates a more collaborative and iterative regulatory process.

This represents a move away from rigid, fixed designs toward more evidence-based and adaptive learning approaches. There’s a stronger emphasis on probabilistic decision-making.

That said, adoption will depend on sponsor comfort with simulations and priors, as well as regulatory confidence. It’s not going to fully replace frequentist methods. Instead, we’ll likely see a hybrid ecosystem where Bayesian designs become standard in the right contexts.

Ultimately, this is another tool in the statistician’s toolbox that is now more widely accepted by the FDA. Being transparent and having those early conversations about priors and external controls can help reduce costs and accelerate timelines.