Drug metabolism studies should be completed prior to Phase III, agency guidance says.

DRUG METABOLISM STUDIES SHOULD BE COMPLETED PRIOR TO PHASE III, FDA states in a guidance for industry on "Drug Metabolism/Drug Interaction Studies in the Drug Development Process: Studies In Vitro" released on April 9. "An understanding of the metabolic profile of a drug in vitro would be useful prior to the initiation of Phase II studies and is especially important before Phase III trials," the guidance states. "Sponsors are encouraged to conduct appropriate metabolic studies prior to the commencement of Phase III trials."