title: Low rate of emergence of nevirapine and lamivudine resistance after post-partum interruption of a triple-drug regimen.
abstract: BACKGROUND
  Emergence of nevirapine (NVP) resistance may be a consequence of its use in monotherapy to prevent HIV mother-to-child transmission (MTCT). The aim of this study was to evaluate the emergence of strains resistant to NVP and lamivudine (3TC) after discontinuation of antiretroviral therapy (ART) with 3TC/zidovudine (ZDV)/NVP.
  
  
  METHODS
  Twenty pregnant women (ART-naive or preexposed only to ZDV), to whom 3TC/ZDV/NVP was prescribed as MTCT prophylaxis, were studied. They received ART for a median of 4 months with median viral load (VL) at labour <50 copies/ml. Samples were collected between 1 and 15 months (median: 3 months) after ART interruption. Sequence-selective real-time PCR (SPCR), which quantifies minority viral populations containing K103N, Y181C and M184V mutations, and standard genotypic sequencing were assayed.
  
  
  RESULTS
  No mutations associated with resistance to 3TC or NVP were found by standard population sequencing. Analysis of K103N by SPCR showed that 35% of the patients contained < or =0.1% of viruses carrying either the AAC or AAT mutations. For Y181C mutation, 10% of the patients contained <0.5% of viruses with TGT codon change. For M184V mutation, one patient contained 6.2% of virus with GTG mutation and 13 patients (65%) contained <0.9% of mutated viruses. Four women were re-exposed to 3TC/ZDV/NVP and achieved HIV VL <50 copies/ml. No perinatal transmission occurred in any of the 22 births.
  
  
  CONCLUSIONS
  NVP associated with ZDV/3TC as a regimen to prevent MTCT may involve a low risk for the selection of antiretroviral-resistant strains and may not jeopardize the use of these same drugs for future treatment.
authors.affiliation: Fernandes Hospital, Infectious Diseases Unit, Buenos Aires, Argentina.
authors.forename: Héctor
authors.initials: H
authors.lastname: Pérez
authors.forename: Moira
authors.initials: M
authors.lastname: Vignoles
authors.forename: Natalia
authors.initials: N
authors.lastname: Laufer
authors.forename: Alejandro
authors.initials: A
authors.lastname: Gómez
authors.forename: Patricia
authors.initials: P
authors.lastname: Coll
authors.forename: Jorge
authors.initials: J
authors.lastname: Lottner
authors.forename: María
authors.initials: M
authors.lastname: Rolón
authors.forename: Horacio
authors.initials: H
authors.lastname: Salomón
authors.forename: Pedro
authors.initials: P
authors.lastname: Cahn
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000494:pharmacology; D004279:DNA, Viral / Q000235:genetics; D004334:Drug Administration Schedule; D024921:Drug Resistance, Multiple, Viral / Q000187:drug effects*; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics; D006801:Humans; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D019259:Lamivudine / Q000008:administration & dosage* / Q000494:pharmacology* / Q000627:therapeutic use; D009154:Mutation; D019829:Nevirapine / Q000008:administration & dosage* / Q000494:pharmacology* / Q000627:therapeutic use; D049590:Postpartum Period; D011247:Pregnancy
chemical_list: D019380:Anti-HIV Agents; D004279:DNA, Viral; D019259:Lamivudine; D019829:Nevirapine