US FDA moves to clarify rules for drugs seeking approval based on one study

The US FDA has issued draft guidance designed to clarify what firms seeking to win approval for a drug based on only one clinical study will need to do.

The guidance – entitled “Demonstrating substantial evidence of effectiveness with one adequate and well-controlled clinical investigation and confirmatory evidence” – stresses that the “quality and quantity” are the key considerations.

According to the FDA, “The quantity of confirmatory evidence needed in a development program will be impacted by the features of, and results from, the single adequate and well-controlled clinical investigation that the confirmatory evidence is intended to substantiate.

“It may be possible for a highly persuasive adequate and well-controlled clinical investigation to be supported by a lesser quantity of confirmatory evidence, whereas a less-persuasive adequate and well-controlled clinical investigation may require a greater quantity of compelling confirmatory evidence to allow for a conclusion of substantial evidence of effectiveness.”

The FDA also covers instances when sponsors can include efficacy data from a separate study examining the drug in a closely related indication.

“A common example of this approach is the submission of a new drug application or a biologics license application (BLA) for a new indication for an already approved therapy, where one adequate and well-controlled clinical investigation of the drug for the new indication is supported by the results from the clinical investigation or investigations that formed the basis of the previous approval (for a different but closely related indication).

The agency adds that “in another example, one adequate and well-controlled clinical investigation in each of two related, unapproved indications can serve as confirmatory evidence for the other indication, thereby supporting concurrent approval of the drug for both indications.”

In the guidance the agency also makes clear that drug developers that do file based on data from a single study will need to include all the data generated by the that program, rather than cherry picking the information they submit.

“Sponsors must include in their marketing submissions a description and analysis of all data or information relevant to an evaluation of the safety and effectiveness of the drug product, from any source, foreign or domestic, to avoid selecting only those sources that favor a conclusion of effectiveness.”

The document builds on similar guidance issued in 2019.

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