The FDA’s guidance on the quantity of bioavailability (BA) and bioequivalence (BE) testing samples to be retained by NDA applicants and contract research organizations (CRO) contains both draft and final language focusing on both the test article and reference standard.

The 22-page guidance’s final section, which covers quantity of reserve samples, is implemented immediately. The agency said it is activating this section of the guidance without prior public comment, deeming that prior input is not necessary as the guidance offers a less burdensome policy consistent with public health.

Revising the agency’s now withdrawn August 2020 Compliance Policy on the subject and superseding its 2004 guidance, the guidance also describes conditions under which the FDA does not generally take enforcement action against an applicant or CRO for retaining less than the quantity of reserve samples of the drug (test articles and reference standards) used in an in vivo BA or in vitro BE study.

The draft guidance offers drugmakers, site management organizations and CROs recommendations on procedures for handling reserve samples from relevant BA and BE studies.

The guidance also highlights:

• Handling, shipping and other retention parameters of testing samples
• How testing sites should randomly select samples for testing
• Storage of and access to reserve samples
• In-house sample studies conducted by a sponsor and/or drug manufacturer

Comments on the draft portion of the guidance are due by June 27.

View the guidance here.