What does PCORI consider sufficient evidence of efficacy for rare diseases?

The requirement for demonstrating evidence of efficacy for proposed interventions in rare diseases is similar to common diseases. The intervention(s) should have been previously studied and represent a realistic choice for patients and clinicians. However, if the existing evidence base regarding the intervention(s) for rare diseases is limited, it may be acceptable to show evidence of efficacy for a particular intervention in a different disease where some theoretical and/or biological propositions on such linkage have been developed. In these instances, the investigator should justify how the available evidence would be applicable to the rare disease of interest.