FDA Releases Draft Guidance for Conducting Bioavailability and Bioequivalence Studies

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On March 18, FDA released draft guidance containing recommendations for sponsors and new applicants preparing bioavailability (BA) and bioequivalence (BE) data for products in investigational new drug applications (INDs), new drug applications (NDAs) and NDA supplements.
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This guidance revises previous BA and BE advice contained in FDA’s March 2003 guidance and applies to orally administrated drugs, but may apply to non-orally administered products when reliance on systemic exposure is suitable to BA and BE.

BA and BE are critical studies used to support INDs and NDAs. BA refers to the rate and extent to which the active ingredient or active moiety is absorbed from a drug product and becomes available at the site of action. This data is used to determine the fraction of drug absorbed and a drugs pharmacokinetics. In addition, BE studies between two products are used to establish the lack of a significant difference in the rate and extent to which the active ingredient given at same dosage and under similar conditions become available at the site of drug action. Properly designed BE studies are necessary for formulation and manufacturing changes during drug development and postapproval stages. BE studies also are key for the approval of generic products under abbreviated new drug applications (ANDAs).

FDA’s guidance focuses on the use of pharmacokinetic studies to document BA and BE data. Specifically, FDA provides recommendations on type of study, population composition, dosing, analytical methods, measures of systemic exposure, and other approaches to support BA and BE studies. Importantly, the guidance provides recommendations to sponsors seeking to make changes to a product during the pre- or post-approval period.

Failure to comply with FDA’s recommendations in the draft guidance could result in a delayed approval. Accordingly, any sponsor conducting these studies would need a strong justification for deviating from FDA’s recommendations.

Comments on FDA’s draft guidance are due May 19.

View the full draft guidance here.

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