obsolete Clinical Trial obsolete Clinical Trial, Phase IV true http://purl.bioontology.org/ontology/MESH/D017429 Clinical Trial, Phase 4 'Work that is a report of a planned post-marketing study of diagnostic, therapeutic, or prophylactic drugs, devices, or techniques that have been approved for general sale after clinical trials, phases I, II, and III. These studies, conducted in the United States or a foreign country, often garner additional data about the safety and efficacy of a product. [Curator team: []]' MESH:D017429