The United States Food and Drug Administration Study Data Technical Conformance Guide dated July 2020 states, “6.5 Pharmacologic Class 6.5.1 Medication Reference Terminology 6.5.1.1 General Considerations The Veterans Administration’s Medication Reference Terminology (MED-RT) should be used to identify the pharmacologic class(es) of all active investigational substances that are used in a study (either clinical or nonclinical). This information should be provided in the SDTM TS domain when a full TS is indicated. The information should be provided as one or more records in TS, where TSPARMCD= PCLAS. Pharmacologic class is a complex concept that is made up of one or more component concepts: mechanism of action (MOA), physiologic effect (PE), and chemical structure (CS).51 The established pharmacologic class is generally the MOA, PE, or CS term that is considered the most scientifically valid and clinically meaningful. Sponsors should include in TS (the full TS) the established pharmacologic class of all active moieties of investigational products used in a study. FDA maintains a list of established pharmacologic classes of approved moieties.52 If the established pharmacologic class is not available for an active moiety, then the sponsor should discuss the appropriate MOA, PE, and CS terms with the review division. For unapproved investigational active moieties where the pharmacologic class is unknown, the PCLAS record may not be available." https://www.fda.gov/media/136460/download