title: Addition of extended zidovudine to extended nevirapine prophylaxis reduces nevirapine resistance in infants who were HIV-infected in utero.
abstract: BACKGROUND
  In the Post-Exposure Prophylaxis of Infants (PEPI)-Malawi trial, most women received single-dose nevirapine (NVP) at delivery, and infants in the extended study arms received single-dose NVP along with 1 week of daily zidovudine (ZDV), followed by either extended daily NVP or extended daily NVP and ZDV up to 14 weeks of age. Although extended NVP prophylaxis reduces the risk of postnatal HIV transmission, it may increase the risk of NVP resistance among infants who are HIV-infected despite prophylaxis.
  
  
  METHODS
  We analyzed 88 infants in the PEPI-Malawi trial who were HIV-infected in utero and who received prophylaxis for a median of 6 weeks prior to HIV diagnosis. HIV genotyping was performed using the ViroSeq HIV Genotyping System.
  
  
  RESULTS
  At 14 weeks of age, the proportion of infants with NVP resistance was lower in the extended NVP and ZDV arm than in the extended NVP arm (28/45, 62.2% vs. 37/43, 86.0%; P = 0.015). None of the infants had ZDV resistance. Addition of extended ZDV to extended NVP was associated with reduced risk of NVP resistance at 14 weeks if prophylaxis was stopped by 6 weeks (54.5 vs. 85.7%, P = 0.007) but not if prophylaxis was continued beyond 6 weeks (83.3 vs. 87.5%, P = 1.00).
  
  
  CONCLUSIONS
  Addition of extended ZDV to extended NVP prophylaxis significantly reduced the risk of NVP resistance at 14 weeks in infants who were HIV-infected in utero, provided that HIV infection was diagnosed and the prophylaxis was stopped by 6 weeks of age.
authors.affiliation: Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Lidström
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Donald R
authors.initials: DR
authors.lastname: Hoover
authors.forename: George
authors.initials: G
authors.lastname: Kafulafula
authors.forename: Lynne M
authors.initials: LM
authors.lastname: Mofenson
authors.forename: Mary G
authors.initials: MG
authors.lastname: Fowler
authors.forename: Michael C
authors.initials: MC
authors.lastname: Thigpen
authors.forename: Newton
authors.initials: N
authors.lastname: Kumwenda
authors.forename: Taha E
authors.initials: TE
authors.lastname: Taha
authors.forename: Susan H
authors.initials: SH
authors.lastname: Eshleman
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage*; D024882:Drug Resistance, Viral / Q000187:drug effects* / Q000235:genetics; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000235:genetics / Q000635:transmission; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D007223:Infant; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D008295:Malawi; D008297:Male; D019829:Nevirapine / Q000008:administration & dosage*; D056990:Post-Exposure Prophylaxis; D011247:Pregnancy; D019562:Viral Load; D015215:Zidovudine / Q000008:administration & dosage*
chemical_list: D019380:Anti-HIV Agents; D015215:Zidovudine; D019829:Nevirapine