Maraviroc observational study: the impact of expanded resistance testing and clinical considerations for antiretroviral regimen selection in treatment-experienced patients.

Abstract Maraviroc (MVC) use has trailed that of other post-2006 antiretroviral therapy (ART) options for treatment-experienced patients. We explored the impact of free tropism testing on MVC utilization in our cohort and explored barriers to MVC utilization. The Maraviroc Outcomes Study (MOS) is an investigator-initiated industry-sponsored trial where consecutive ART-experienced patients receiving routine care with viral loads ≥1,000 copies/ml, and whose provider requested resistance testing and received standardized resistance testing (SRT; phenotype, genotype, coreceptor/tropism). Sociodemographic, clinical, and ART characteristics of those receiving SRT were compared to a historical cohort (HC). Subsequently, providers were surveyed regarding factors influencing selection of salvage ART therapy. The HC (n=165) had resistance testing 7/08–9/09, while prospective SRT (n=83) patients were enrolled 9/09–8/10. In the HC, 92% had genotypes, 2% had tropism assays, and 62% (n=102) changed ART after resistance...