The USFDA, along with other regulatory agencies such as the EMA in Europe and PMDA in Japan, recommend evaluating investigational drugs for their potential to be the victim or perpetrator of drug interactions in order to improve the drug’s effectiveness and safety. In a recent presentation, an overview of enzyme inhibition studies is provided along with critical considerations in study design, from determination of supporting data to conclusive interpretation; frequently asked questions; and recommendations for successful regulatory submission. The following article captures the main points of this presentation.

Common Terms When Discussing CYP inhibition

• Cytochrome P450s (CYPs) are membrane-bound, heme-containing enzymes.
• The perpetrator, or precipitant, is the drug causing the interaction and an inhibitor of drug metabolizing
• The victim, or object, is the affected drug and is a substrate of one or more affected enzymes.