title: Compilation and prevalence of mutations associated with resistance to non-nucleoside reverse transcriptase inhibitors.
abstract: BACKGROUND
  Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are an important component of antiretroviral therapy for HIV type-1 (HIV-1)-infected patients. Development of NNRTI resistance can lead to treatment failure and is conferred by the presence of specific resistance-associated mutations (RAMs) in the reverse transcriptase. In addition to the widely used list of NNRTI RAMs provided by the International AIDS Society-USA HIV-1 Drug Resistance Mutation Group, which were identified on the basis of clinical experience with the approved NNRTIs, a more comprehensive list of NNRTI RAMs is needed to guide the study of baseline and emerging resistance to new NNRTIs.
  
  
  METHODS
  We conducted an extensive review of the existing literature on NNRTI resistance, together with several in vitro and in vivo studies on the mechanism of HIV-1 resistance to approved NNRTIs and to NNRTIs formerly or currently in clinical development.
  
  
  RESULTS
  In total, 44 NNRTI RAMs were identified. These included V90I, A98G, L100I, K1O1E/P/Q, K103H/N/S/T, V106A/I/M, V108I, E138G/K/Q, V179D/E/F/G/I, Y181C/I/V, Y188C/H/L, V189I, G190A/C/E/Q/S, H221Y, P225H, F227C/L, M230I/L, P236L, K238N/T and Y318F. These NNRTI RAMs were observed, either alone or in combination with others, ranging in frequency from 0.02% to 56.96% in a panel of 101,679 NNRTI-resistant isolates submitted to Virco BVBA (Mechelen, Belgium) for routine clinical resistance testing. Phenotypical data from site-directed mutants helped to establish the contribution of each mutation to NNRTI resistance.
  
  
  CONCLUSIONS
  The list of 44 NNRTI RAMs compiled in this study provides a comprehensive overview of mutations that play a role in HIV-1 NNRTI resistance and can be used to guide further in vitro and in vivo research on the mechanisms of HIV-1 NNRTI resistance.
authors.affiliation: Tibotec BVBA, Mechelen, Belgium. ltambuyz@its.jnj.com
authors.forename: Lotke
authors.initials: L
authors.lastname: Tambuyzer
authors.forename: Hilde
authors.initials: H
authors.lastname: Azijn
authors.forename: Laurence T
authors.initials: LT
authors.lastname: Rimsky
authors.forename: Johan
authors.initials: J
authors.lastname: Vingerhoets
authors.forename: Pierre
authors.initials: P
authors.lastname: Lecocq
authors.forename: Guenter
authors.initials: G
authors.lastname: Kraus
authors.forename: Gaston
authors.initials: G
authors.lastname: Picchio
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: de Béthune