FDA Provides Guidance on Bioavailability Studies

FDA published draft guidance on Feb. 25, 2019 on submission of bioavailability (BA) information for oral dosage drugs in investigation new drug applications (INDs), new drug applications (NDAs), and NDA supplements. In the guidance, FDA provides recommendations on how sponsors can meet BA requirements set forth in 21 Code of Federal Regulations part 320, including recommendations on conducting relative BA studies during the IND process and bioequivalence (BE) studies conducted during the post-approval period for certain changes to drug product. The guidance does not discuss demonstration of BE for abbreviated new drug applications (ANDA) or ANDA supplements or demonstrating comparability or biosimilarity for biologics.
 
Specifically, the guidance addresses study design considerations, including in-vivo and in-vitro studies, and assessing BA for various dosage forms. Appendices provide recommendations for approaches for general study design and data handling, guidelines for conducting fed or fasted studies, and guidelines for conducting an in-vitro alcohol dose-dumping study.
 
Because the new guidance does not address every issue regarding the assessment of BA studies for INDs and NDAs, the agency is encouraging sponsors to contact the appropriate review division with specific questions not addressed by this guidance. When finalized, this guidance will revise and replace the March 2014 draft guidance, Bioavailability and Bioequivalence Studies Submitted in NDAs or INDs—General Considerations.