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

Academic Article

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 testing (raltegravir 37%, etravirine 25%, darunavir 24%, MVC 1%). In the SRT cohort, 57% (n=48) changed regimens after standardized resistance testing (darunavir 48%, raltegravir 40%, and etravirine 19%). CCR5-tropic virus was identified in 43% of the SRT group, and MVC was used in 10% [or 20% of R5 tropic patients who underwent a subsequent regimen change (n=25)], a statistically significant (p=0.01) increase in utilization. The factors most strongly influencing utilization were unique patient circumstances (60%), clinical experience (55%), and potential side effects (40%). The addition of routine tropism testing to genotypic/phenotypic testing was associated with increased MVC utilization, raising the possibility that tropism testing may present a barrier to MVC use; however, additional barriers exist, and merit further evaluation.
  • Published In

    Keywords

  • Adult, Anti-HIV Agents, Cyclohexanes, Drug Resistance, Viral, HIV, HIV Fusion Inhibitors, HIV Infections, Humans, Male, Maraviroc, Microbial Sensitivity Tests, Salvage Therapy, Treatment Failure, Triazoles
  • Digital Object Identifier (doi)

    Author List

  • Willig JH; Wilkins S-A; Tamhane A; Nevin CR; Mugavero MJ; Raper JL; Napolitano LA; Saag MS
  • Start Page

  • 105
  • End Page

  • 111
  • Volume

  • 29
  • Issue

  • 1