Prevalence of etravirine resistance associated mutations in HIV-1 strains isolated from infected individuals failing efavirenz: Comparison between subtype B and non-B genetic variants

Etravirine (ETR) is a non‐nucleoside analogue reverse transcriptase inhibitor (NNRTI) with a high genetic barrier to the development of resistance and with potential activity against Human immunodeficiency virus type 1 (HIV‐1) strains resistant to first‐generation NNRTIs. The objective of this study was to investigate the prevalence of ETR resistance associated mutations (RAMs) in HIV‐1 strains isolated from infected individuals failing efavirenz (EFV), as well as to evaluate possible differences in the distribution of ETR RAMs between subtype B and non‐B genetic variants. Nucleotide sequences of the protease and partial reverse transcriptase (RT) coding regions of the pol gene of 55 HIV‐1 strains isolated from infected individuals failing EFV on regular follow‐up at a reference center in Portugal, were retrospectively analyzed. The most prevalent ETR RAMs observed were L100I, V90I, and K101E, with a prevalence of 16.4% (n = 9), 9.1% (n = 5), and 5.5% (n = 3), respectively. Overall, 47.3% (n = 26) of the nucleotide sequences had at least one ETR RAM: 38.2% (n = 21) had one ETR RAM, 7.3% (n = 4) had two ETR RAMs and 1.8% (n = 1) had three ETR RAMs. No statistically significant differences were found in the distribution of ETR RAMs between subtype B and non‐B genetic variants. The results demonstrate that ETR rescue therapy is a viable option in treatment‐experienced individuals failing EFV and suggests that ETR may be equally useful in HIV‐1 infections caused by different genetic variants. J. Med. Virol. 84:551–554, 2012. © 2011 Wiley Periodicals, Inc.