FDA approval: maraviroc.

Abstract

Background: On August 6, 2007, the FDA granted accelerated approval for the CCR5 antagonist maraviroc, making it the first approved agent in this drug class. Indications: Maraviroc is indicated for treatment-experienced patients who have (1) detectable HIV RNA, (2) evidence of resistance to multiple antiretrovirals, and (3) infection with CCR5-tropic virus. This last criterion requires that patients undergo pretreatment testing with a viral tropism assay, which is currently offered by only one company (Monogram Biosciences). Although the test (Trofile) has been used previously in clinical trials of CCR5 antagonists, it did not become commercially available until maraviroc was approved. Approximately one half of all patients with highly drug-resistant virus are expected to have CCR5-tropic virus and, hence, will be candidates for maraviroc treatment. Maraviroc’s approval was based primarily on favorable 24-week results from the MOTIVATE studies, which were presented initially at this year’s Retrovirus Conference (ACC Apr 2 2007). In these two identical studies, a total of 1076 triple-class–experienced patients with CCR5-tropic virus at screening received an optimized background regimen plus …