FDA illuminates the single trial path

FDA has illuminated one of the most important and controversial pathways to approval of drugs for rare conditions, the use of “confirmatory evidence” to supplement data from a single clinical trial. The agency’s draft guidance on the topic helps explain approval decisions that have been attributed to “regulatory flexibility,” and provides insights into strategies to overcome difficulties that are inherent in the development of therapies for rare diseases.

Congress gave FDA authority to approve drugs based on “one adequate and well-controlled clinical investigation and confirmatory evidence” in 1997, and the agency and drug developers have been trying to understand what that means for 25 years. ...