FDA Amends In-Vivo Option for Showing Bioequivalence to Durezol

The FDA revised its recommendations for in vivo studies intended to show bioequivalence to Durezol (difluprednate), and asked that generics makers now measure the active metabolite 9-difluoroprednisolone 17-butyrate.

Previous guidance advised sponsors to only measure the active ingredient, difluprednate, when conducting in vivo studies to show bioequivalence.

The revision comes after Alcon and Novartis petitioned the FDA to apply stricter requirements on bioequivalence studies intended to supplement applications for Durezol generics. The FDA approved the petition in part, but denied the request to remove the in vivo study option from the guidance.