Primary resistance to maraviroc in a large set of R5-V3 viral sequences from HIV-1-infected patients.

Objectives: Evaluation of the prevalence of V3 mutational patterns associated with maraviroc resistance in R5-using variants.
Methods: V3 sequences were obtained from 809 plasma specimens collected from maraviroc-naive HIV-1-infected individuals on regular follow-up at Hospital Carlos III. Sequences considered to harbour R5-tropic viruses were examined for the presence of primary maraviroc resistance mutational patterns, as found in both in vitro and in vivo studies.
Results: A total of 498 R5-V3 sequences were identified. They belonged to recent HIV-1 seroconverters (55.6%), chronically antiretroviral-naive subjects (20.1%) and antiretroviral-experienced patients (24.3%). Most individuals (93.8%) were infected with HIV-1 subtype B. The overall prevalence of maraviroc resistance mutational patterns was low (≤5%). Likewise, specific polymorphisms 4L, 11R or 19S, recently found to be associated with lower clinical response to maraviroc, were found in <2% of tested samples. The rate of maraviroc resistance patterns did not differ significantly according to length of HIV-1 infection, antiretroviral exposure or HIV-1 subtype.
Conclusions: The prevalence of maraviroc resistance mutations is low in maraviroc-naive HIV-1-infected individuals.