Bayesian Methodology Coming to Vaccine Clinical Trials

The U.S. Food and Drug Administration (FDA) recently announced in the Federal Register the availability of a new draft guidance titled "Use of Bayesian Methodology in Clinical Trials of Drug and Biological Products."

Posted on January 12, 2026, this non-binding document provides recommendations for clinical trial sponsors submitting investigational new drug applications, new drug applications, biologics licensing applications, or supplements to the FDA.

The guidance fulfills a commitment under the sixth reauthorization of the Prescription Drug User Fee Act, which aimed to enhance the review of complex innovative trial designs, including greater use of Bayesian approaches.

The FDA said in a press release that statistical methods in clinical trials rely primarily on data from the current study alone, often requiring large sample sizes, long timelines, and high costs.

Bayesian methodologies offer a flexible alternative by formally incorporating prior information — such as data from previous studies, real-world evidence, historical controls, or even adult data for pediatric trials — to update beliefs as new trial data arrive.

"Bayesian methodologies help address two of the biggest problems of drug development: high costs and long timelines," commented FDA Commissioner Marty Makary, M.D., M.P.H. "Providing clarity around modern statistical methods will help sponsors bring more cures and meaningful treatments to patients faster and more affordably."

For the whole document, visit the FDA's guidance page for FDA-2025-D-3217.

Separately, on January 14, 2026, the FDA announced a collaboration with the European Medicines Agency to develop 10 guiding principles for industry and product developers to consider when using artificial intelligence (AI) to advance drug and biological product development.

"Overall, these announcements signal stronger regulatory support for AI and data-efficient approaches that could accelerate vaccine development, commented Don Hackett of Vax-Before-Travel."

"The previous multi-year approval process does not meet society's needs in 2026," added Hackett.