Bristol-Myers Squibb Avapro

Executive Summary

FDA requests additional information on studies supporting the promotional claim that the highest dose of Avapro (irbesartan, 300 mg once daily) reduces seated trough diastolic blood pressure more than the highest dose (100 mg daily) of Merck's Cozaar (losartan). FDA previously accepted two trials as evidence showing a superior effect for Avapro, however, the agency told Bristol April 6 that, "upon further review," FDA is asking for the protocol and complete set of data files from the "Oparil" study, a description of non-responders who were not titrated to a higher dose of either drug, the bioavailability of both products and an explanation of why there were fewer Avapro-treated patients included in the blood pressure analysis. Bristol submitted a prepublication manuscript for the Oparil trial in response to a March 25, 1998 FDA letter asserting that Bristol was making superiority claims on the basis of one unreplicated study ("The Pink Sheet" June 15, 1998, p. 19)