USA – Clinical Drug Interaction Studies — Cytochrome P450 Enzyme- and Transporter-Mediated Drug Interactions

This final guidance helps sponsors of investigational new drug applications and applicants of new drug applications evaluate drug-drug interactions (DDIs) during drug development and determine essential information to communicate in labeling.

This final guidance describes clinical studies to evaluate the DDI potential of an investigational drug, including: (1) the timing and design of the clinical studies; (2) the interpretation of the study results; and (3) the options for managing DDIs in patients. Specifically, this guidance provides considerations for evaluating pharmacokinetic cytochrome P450 (CYP) enzyme- or transporter-mediated interactions.

A related final January 2020 FDA guidance for industry entitled In Vitro Drug Interaction
Studies — Cytochrome P450 Enzyme- and Transporter-Mediated Drug Interactions focuses on how to assess the DDI potential of a drug in vitro and how to use the results from those
assessments to inform clinical DDI studies. Together, these two final guidances on DDIs
describe a systematic, risk-based approach for evaluating DDIs and determining essential
information to communicate in labeling…