The US Food and Drug Administration (FDA) on Tuesday released a batch of 21 new and 16 revised draft guidances intended to help drugmakers conduct the studies needed to support the approval of certain generic drugs.

Since formalizing its process for making such guidance available in 2010, FDA has published hundreds of product-specific bioequivalence guidances for various products. This is FDA's fourth recent release of new and revised bioequivalence guidance for generic drug developers. The agency previously released 34 new and 33 revised study recommendations in October, 19 new draft guidance documents and 19 revisions in June, as well as 31 draft guidance recommendations in January and revisions for 11 products.

FDA's latest release of product-specific bioequivalence guidances includes 37 new and revised draft guidances (21 new, 16 revised) covering a total of 33 drug products. Some of the drugs, such as the antifungal Nystatin and Triamcinolone acetonide are covered by separate guidances for different dosage forms.

The guidances each specify the studies, ranging from in vitro testing to multiple in vivo studies, that FDA expects to see support abbreviated new drug application (ANDA) approvals, and often include provisions for obtaining a waiver for in vivo testing if a product meets certain criteria.

For instance, in its draft recommendations for generic versions of Gilead's hepatitis C combination Epclusa (sofosbuvir/velpatasvir), FDA says sponsors will be expected to conduct two in vivo studies in healthy patients to demonstrate bioequivalence, without the option for waiving in vivo testing.

FDA, Federal Register