title: Prevalence of nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance-associated mutations and polymorphisms in NNRTI-naïve HIV-infected patients.
abstract: BACKGROUND
  The efficacy of treatment containing nonnucleoside reverse transcriptase inhibitors (NNRTIs) could be compromised in NNRTI-naïve patients already harboring a virus resistant to NNRTIs. On the contrary, hypersusceptibility to NNRTIs in patients having failed nucleoside reverse transcriptase inhibitor (NRTI)-containing regimens has been described and has been associated with improved outcome.
  
  
  METHODS
  We assessed the prevalence of NNRTI resistance-associated mutations or polymorphisms in 146 antiretroviral-naïve patients and in 181 HIV-infected patients who were given an NNRTI-based regimen. We phenotypically evaluated the NNRTI susceptibility of 41 strains presenting with amino acid substitutions at positions involved in NNRTI resistance.
  
  
  RESULTS
  In the 268 genotypically analyzable samples, the overall prevalence of NNRTI resistance-associated mutations was 2% (6/268 patients). The prevalence of strains with amino acid substitutions at reverse transcriptase (RT) gene positions (A98, K101, K103, V106, V108, V179) involved in NNRTI resistance was 15%. Hypersusceptibility to NNRTI was rare (2%, 1/41) in those samples. RT substitutions at positions involved in NNRTI resistance were not associated with a significantly worse virologic outcome in NNRTI-treated patients. Our understanding of small shifts in IC50 values (higher or lower) toward NNRTI is very limited. The significance of many RT mutations on NNRTI susceptibility is not clear.
  
  
  CONCLUSIONS
  In contrast to resistance mutations, RT substitutions at positions involved in NNRTI resistance are frequent. They are not associated with a worse virologic outcome or with decreased phenotypic susceptibility to NNRTIs. It may be prudent not to rule out the use of NNRTIs in patients with small shifts in IC50 values or poorly understood mutations.
authors.affiliation: Department of Infectious Diseases, Nice University Hospital, France. clevenberghph@hotmail.com
authors.forename: P
authors.initials: P
authors.lastname: Clevenbergh
authors.forename: E
authors.initials: E
authors.lastname: Cua
authors.forename: E
authors.initials: E
authors.lastname: Dam
authors.forename: J
authors.initials: J
authors.lastname: Durant
authors.forename: J C
authors.initials: JC
authors.lastname: Schmit
authors.forename: R
authors.initials: R
authors.lastname: Boulme
authors.forename: J
authors.initials: J
authors.lastname: Cottalorda
authors.forename: A
authors.initials: A
authors.lastname: Beyou
authors.forename: J M
authors.initials: JM
authors.lastname: Schapiro
authors.forename: F
authors.initials: F
authors.lastname: Clavel
authors.forename: P
authors.initials: P
authors.lastname: Dellamonica
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D007557:Israel / Q000453:epidemiology; D008297:Male; D009154:Mutation; D011110:Polymorphism, Genetic; D015995:Prevalence; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D019380:Anti-HIV Agents; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase