The FDA is seeking outside input on whether to reassess criteria for rare disease trials, including endpoint selection and the level of evidence needed to support efficacy and safety. The agency’s move comes as more therapies enter the rare disease review pipeline and regulators face recurring questions on how to structure development programs when patient populations are small. The announcement underscores the importance of alignment on endpoint strategy and data sufficiency across sponsors, investigators, and reviewers. For developers, the immediate implication is uncertainty around what regulators may view as “complete” evidence packages for rare-disease labeling decisions.