The FDA published draft guidance designed to facilitate the use of Bayesian methodologies in clinical trials of drugs and biologics.



RT’s Three Key Takeaways:

  1. FDA draft guidance on Bayesian trials – The FDA released draft guidance to encourage and clarify the use of Bayesian methodologies in clinical trials of drugs and biologics to improve efficiency, reduce costs, and shorten development timelines.
  2. Expanded use of prior and external data – Bayesian approaches allow sponsors to combine trial data with prior information, real-world evidence, or external controls to support adaptive designs, dose selection, subgroup analyses, and even primary efficacy and safety inference.
  3. Support for innovative and small-population trials – The guidance aligns with PDUFA VII commitments and highlights particular value for rare and pediatric indications, while inviting public comment to inform final regulatory standards.


The US FDA today published draft guidance designed to facilitate the use of Bayesian methodologies in clinical trials of drugs and biologics, helping drug developers make better use of available data, conduct more efficient clinical trials, and deliver safe and effective treatments to patients sooner. 

“Bayesian methodologies help address two of the biggest problems of drug development: high costs and long timelines,” said FDA Commissioner Marty Makary, MD, MPH. “Providing clarity around modern statistical methods will help sponsors bring more cures and meaningful treatments to patients faster and more affordably.”

Bayesian approaches use a different framework from traditional statistical approaches. In a Bayesian analysis, data from a study are combined with relevant prior information to form a new distribution that can be used for inference and to draw conclusions about safety and efficacy. 

Examples of Bayesian calculations used in various ways in clinical trials can include:

  • Determining futility or success earlier in adaptive trials.
  • Informing design elements like dose selection in subsequent trials.
  • Incorporating information from other sources, such as previous clinical study data, real-world evidence, and external or nonconcurrent controls.
  • Facilitating subgroup analyses.
  • Supporting primary inference in a trial.

The guidance provides recommendations on the appropriate use of Bayesian methods, with an emphasis on the use of these methods to support primary inference. Bayesian methods may be especially valuable for sponsors targeting rare or pediatric indications, where patient populations are smaller.

The publication of this guidance — Use of Bayesian Methodology in Clinical Trials of Drugs and Biologics Guidance for Industry — is intended to satisfy the FDA’s commitment in the Prescription Drug User Fee Act (PDUFA) VII. As part of the sixth reauthorization of the PDUFA, the FDA and industry agreed to performance goals around enhancing the capacity to review complex innovative trial designs, including a commitment to publish draft guidance on the use of Bayesian methodology in clinical trials of drugs and biological products (see PDUFA VII Performance Goals Letter, Section I.L.4.f).

The FDA is seeking public comment on the draft guidance, titled Use of Bayesian Methodology in Clinical Trials of Drugs and Biologics; Draft Guidance for Industry.