Safety and efficacy of a 36-week induction regimen of abacavir/lamivudine and ritonavir-boosted atazanavir in HIV-infected patients.

PURPOSE: The ARIES study assessed safety and efficacy of an induction regimen with atazanavir/ritonavir (ATV/RTV) + abacavir/lamivudine (ABC/3TC) followed by simplification to ATV + ABC/3TC in antiretroviral-naïve patients.

METHODS: This report includes a noncomparative analysis of all patients in the induction phase of the ARIES study through 36 weeks (clinicaltrials.gov: NCT00440947). This open-label study included 515 antiretroviral-naïve,HLA-B*5701-negative patients receiving a regimen of ATV 300 mg, RTV 100 mg, and ABC/3TC 600 mg/300 mg once daily for 36 weeks; eligible patients were then randomized to continue the induction regimen or simplify to ATV 400 mg plus ABC/3TC 600 mg/300 mg once daily.

RESULTS: Eighty-six percent (442/515) of patients completed 36 weeks on study; 80% (410/515) achieved HIV RNA <50 copies/mL (84% and 76% of patients with baseline HIV RNA of < and >or=100,000 copies/mL achieved this endpoint). Virologic failure (VF) was uncommon (3%); treatment-emergent major protease inhibitor and nucleoside reverse transcriptase inhibitor mutations were detected in 0/15 and 4/15 patients, respectively. Median CD4+ cell increase was 171 (range, -176 to 718) cells/mm(3). Hyperbilirubinemia (13%), diarrhea (4%), nausea (2%), and rash (2%) were the most frequent drug-related Grade 2-4 adverse events. Few adverse events (3%) led to study discontinuation.

CONCLUSIONS: Induction with ATV/RTV + ABC/3TC once daily provides an efficacious and well-tolerated regimen for the initial treatment of HIV.