title: Abacavir once or twice daily combined with once-daily lamivudine and efavirenz for the treatment of antiretroviral-naive HIV-infected adults: results of the Ziagen Once Daily in Antiretroviral Combination Study.
abstract: The long intracellular half-life of abacavir (ABC) supports its once-daily use, and this would be expected to simplify treatment if ABC could be given as part of a complete once-daily regimen. A randomized double-blind clinical trial compared the efficacy and safety of 600 mg of ABC administered once daily (n = 384) versus 300 mg of ABC administered twice daily (n = 386) in combination with 300 mg of lamivudine (3TC) and 600 mg of efavirenz (EFV) administered once daily in antiretroviral-naive patients over 48 weeks. The baseline median plasma HIV-1 RNA level was 4.89 log10 copies/mL (44% with viral load >100,000 copies/mL), and the median CD4 cell count was 262 cells/mm. ABC administered once daily was non-inferior to the twice-daily regimen, with 66% and 68% of patients in these respective treatment arms achieving a confirmed plasma HIV-1 RNA level <50 copies/mL (95% confidence interval: -8.4%, 4.9%). The ABC once-daily and twice-daily regimens were similar with respect to infrequency of virologic failure (10% vs. 8%), emergence of resistance mutations, CD4 cell increases from baseline (median, 188 vs. 200 cells/mm), safety profile, and incidence of ABC-related hypersensitivity reactions (9% vs. 7%). ABC administered once daily in combination with 3TC and EFV administered once daily was non-inferior to the ABC twice-daily dosing schedule when combined with 3TC and EFV over 48 weeks.
authors.affiliation: Chelsea and Westminster Hospital, HIV Clinic, London, United Kingdom. gm@moyleg.demon.co.uk
authors.forename: Graeme J
authors.initials: GJ
authors.lastname: Moyle
authors.forename: Edwin
authors.initials: E
authors.lastname: DeJesus
authors.forename: Pedro
authors.initials: P
authors.lastname: Cahn
authors.forename: Steve A
authors.initials: SA
authors.lastname: Castillo
authors.forename: Henry
authors.initials: H
authors.lastname: Zhao
authors.forename: David N
authors.initials: DN
authors.lastname: Gordon
authors.forename: Charles
authors.initials: C
authors.lastname: Craig
authors.forename: Trevor R
authors.initials: TR
authors.lastname: Scott
mesh_terms: D000328:Adult; D000368:Aged; D000480:Alkynes; D019380:Anti-HIV Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D048588:Benzoxazines; D003521:Cyclopropanes; D015224:Dideoxynucleosides / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D019259:Lamivudine / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D010078:Oxazines / Q000008:administration & dosage / Q000627:therapeutic use*; D012367:RNA, Viral / Q000097:blood / Q000302:isolation & purification; D016896:Treatment Outcome; D019562:Viral Load; D000099227:Abacavir
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; D015224:Dideoxynucleosides; D019259:Lamivudine; D010078:Oxazines; D012367:RNA, Viral; D000099227:Abacavir; C098320:efavirenz