Metabolites in Safety Testing: “MIST” for the Clinical Pharmacologist

To address questions relating to the safety assessment of circulating drug metabolites in humans, the US Food and Drug Administration (FDA) and the International Conference on Harmonisation (ICH) have recently issued regulatory guidances1,2 that effectively require metabolite profiling in humans during early clinical development of a candidate drug. The clinical metabolite profiling results may require separate safety assessment studies in humans of stable circulating metabolites if such metabolites are not formed in sufficient concentrations in the plasma during nonclinical safety assessment of the parent drug. Clinical Pharmacology & Therapeutics (2010) 87 3, 345–350. doi:10.1038/clpt.2009.283