title: Subgroup analysis of virological response rates with once- and twice-daily darunavir/ritonavir in treatment-experienced patients without darunavir resistance-associated mutations in the ODIN trial.
abstract: BACKGROUND
  ODIN (once-daily darunavir in treatment-experienced patients) was a 48-week, phase III, randomized, open-label trial comparing once-daily (qd) darunavir/ritonavir (DRV/r) 800/100 mg with twice-daily (bid) DRV/r 600/100 mg, both with an optimized background regimen [OBR; at least two nucleoside reverse transcriptase inhibitors (NRTIs)], in treatment-experienced, HIV-1-infected adults with no DRV resistance-associated mutations (RAMs) at screening. Week 48 analyses of virological response by subgroups are reported.
  
  
  METHODS
  A total of 590 patients were randomized to receive qd (n=294) or bid (n=296) DRV/r. Virological response (HIV-1 RNA <50 copies/mL) was assessed according to: screening HIV-1 RNA (≥ or <50000 copies/mL), CD4 cell count, prior protease inhibitor (PI) use, number of active NRTIs in the OBR, presence of mutations (primary PI mutations, PI RAMs or M184V/I), gender, age, race, HIV-1 clade and adherence.
  
  
  RESULTS
  Baseline characteristics were well balanced between arms and across subgroups. Response rates were comparable between qd and bid DRV/r treatments for all subgroups examined. Response rates were 78.4 and 76.8% in the qd and bid treatment arms, respectively, in patients with baseline HIV-1 RNA ≤ 50000 copies/mL and 52.8% in both arms in those with > 50000 copies/mL. Response rates for the qd and bid treatment arms by baseline CD4 cell count were also similar (69.6 vs. 65.2% for <200 cells/μL; 72.2 vs. 74.8% for 200- <350 cells/μL; 77.0 vs. 74.3% for ≥ 350 cells/μL).
  
  
  CONCLUSIONS
  DRV/r administered either qd or bid provided effective treatment for antiretroviral treatment-experienced patients with no DRV RAMs, with comparable response rates across all subgroups studied. Low patient numbers in specific subgroups may limit interpretation of these specific subgroup results.
authors.affiliation: Comprehensive Care Center, Fort Lauderdale, FL 33311, USA. msension@browardhealth.org
authors.forename: M
authors.initials: M
authors.lastname: Sension
authors.forename: P
authors.initials: P
authors.lastname: Cahn
authors.forename: P
authors.initials: P
authors.lastname: Domingo
authors.forename: S
authors.initials: S
authors.lastname: Hodder
authors.forename: M
authors.initials: M
authors.lastname: Opsomer
authors.forename: E
authors.initials: E
authors.lastname: Lathouwers
authors.forename: T
authors.initials: T
authors.lastname: Van de Casteele
authors.forename: F
authors.initials: F
authors.lastname: Tomaka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019380:Anti-HIV Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D000069454:Darunavir; D004334:Drug Administration Schedule; D024882:Drug Resistance, Viral / Q000187:drug effects; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy* / Q000453:epidemiology / Q000821:virology*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010349:Patient Compliance; D019438:Ritonavir / Q000008:administration & dosage* / Q000627:therapeutic use; D013449:Sulfonamides / Q000008:administration & dosage* / Q000627:therapeutic use; D019562:Viral Load; D055815:Young Adult
chemical_list: D019380:Anti-HIV Agents; D013449:Sulfonamides; D019438:Ritonavir; D000069454:Darunavir
keywords: HIV; darunavir; efficacy; once daily; treatment-experienced