title: Regimen simplification to atazanavir-ritonavir alone as maintenance antiretroviral therapy: final 48-week clinical and virologic outcomes.
abstract: BACKGROUND
  Simplified maintenance therapy with ritonavir-boosted atazanavir (ATV/RTV) alone is attractive because of nucleoside reverse-transcriptase inhibitor (NRTI)-sparing benefits, low pill burden, once-daily dosage, and safety.
  
  
  METHODS
  Subjects with virologic suppression after > or = 48 weeks of initial antiretroviral therapy with 2 NRTIs and a protease inhibitor (PI) were enrolled. Subjects switched to ATV/RTV at entry and discontinued NRTIs after 6 weeks. The primary end point was time to virologic failure (confirmed HIV-1 RNA level > or = 200 copies/mL). Drug resistance at virologic failure was evaluated by standard genotyping and single-genome sequencing (SGS). Residual viremia (1.1-49 copies/mL) was measured by single-copy assay.
  
  
  RESULTS
  Thirty-four subjects simplified to ATV/RTV alone, of whom 30 (88%) did not experience virologic failure by 48 weeks after simplification. Residual viremia did not change significantly after NRTI discontinuation among those without virologic failure but did increase 4-12 weeks before confirmed virologic failure. No major PI-resistance mutations were identified at virologic failure by standard genotyping or SGS.
  
  
  CONCLUSIONS
  In this pilot study, simplified maintenance therapy with ATV/RTV alone maintained viral suppression in most subjects through 48 weeks. PI resistance was not detected among subjects experiencing virologic failure. Larger, randomized trials are warranted to further define the efficacy and safety of this strategy.
authors.affiliation: Division of International Medicine and Infectious Diseases, Weill-Cornell Medical College, New York, New York, USA. tiw2001@med.cornell.edu
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Wilkin
authors.forename: John E
authors.initials: JE
authors.lastname: McKinnon
authors.forename: A Gregory
authors.initials: AG
authors.lastname: DiRienzo
authors.forename: Katie
authors.initials: K
authors.lastname: Mollan
authors.forename: Courtney V
authors.initials: CV
authors.lastname: Fletcher
authors.forename: David M
authors.initials: DM
authors.lastname: Margolis
authors.forename: Barbara
authors.initials: B
authors.lastname: Bastow
authors.forename: Gary
authors.initials: G
authors.lastname: Thal
authors.forename: William
authors.initials: W
authors.lastname: Woodward
authors.forename: Catherine
authors.initials: C
authors.lastname: Godfrey
authors.forename: Ann
authors.initials: A
authors.lastname: Wiegand
authors.forename: Frank
authors.initials: F
authors.lastname: Maldarelli
authors.forename: Sarah
authors.initials: S
authors.lastname: Palmer
authors.forename: John M
authors.initials: JM
authors.lastname: Coffin
authors.forename: John W
authors.initials: JW
authors.lastname: Mellors
authors.forename: Susan
authors.initials: S
authors.lastname: Swindells
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D000069446:Atazanavir Sulfate; D018791:CD4 Lymphocyte Count; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D017320:HIV Protease Inhibitors / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D009842:Oligopeptides / Q000627:therapeutic use*; D010865:Pilot Projects; D011725:Pyridines / Q000627:therapeutic use*; D019438:Ritonavir / Q000627:therapeutic use*; D016896:Treatment Outcome; D014766:Viremia / Q000188:drug therapy; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D009842:Oligopeptides; D011725:Pyridines; D000069446:Atazanavir Sulfate; D019438:Ritonavir