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.

Short-term safety and tolerability of a once-daily fixed-dose abacavir-lamivudine combination versus twice-daily dosing of abacavir and lamivudine as separate components: findings from the ALOHA study.

STUDY OBJECTIVE: To evaluate the short-term (12 wks) safety and tolerability of a once-daily, fixed-dose abacavir-lamivudine combination versus twice-daily dosing of the separate components, both with background antiretroviral therapy. DESIGN: Phase IIIB, randomized, open-label, parallel-group, multicenter study. SETTING: One hundred forty-six human immunodeficiency virus (HIV) clinics. PATIENTS: Six hundred eighty antiretroviral therapy-naïve patients with HIV type 1 RNA greater than 1000 copies/ml at baseline. INTERVENTION: Patients were randomly assigned in a 2:1 manner to receive either abacavir 600 mg-lamivudine 300 mg once/day or abacavir 300 mg twice/day and lamivudine 150 mg twice/day. Subjects were stratified based on choice of third or fourth antiretroviral drug (nucleoside reverse transcriptase inhibitor [NRTI], NNRTI, or protease inhibitor), assigned before randomization. MEASUREMENTS AND MAIN RESULTS: The primary end point was occurrence of grades 2-4 adverse events and serious adverse events; abacavir hypersensitivity reactions were considered serious adverse events. Baseline characteristics were similar between the once-daily (455 patients) and twice-daily (225 patients) groups. The rates of all grades 2-4 adverse events were similar: once-daily 33% (150 patients), twice-daily 31% (69). A slightly larger proportion of patients in the twice-daily group experienced drug-related grades 2-4 adverse events: once-daily 10% (47), twice-daily 16% (36). Rates of all serious adverse events (once-daily 11% [49], twice-daily 10% [22]) and drug-related serious adverse events (once-daily 5% [21], twice-daily 8% [17]) were similar. The rate of suspected abacavir hypersensitivity reaction was 5.3% (once-daily 4.4% [20], twice-daily 7.1% [16]), with a higher rate for the NNRTI stratum of the twice-daily group (8.6% [10]) than in any other stratum (once-daily, NNRTI 4.3% [10]; twice-daily, protease inhibitor 5.6% [6]; once-daily, protease inhibitor 4.6% [10]). CONCLUSION: In the short-term, the rates of adverse events in the once-daily and twice-daily groups appeared to be similar. The rate of suspected abacavir hypersensitivity reaction in the once-daily group was lower than the rate in the twice-daily group.

Randomized, double-blind, placebo-matched, multicenter trial of abacavir/lamivudine or tenofovir/emtricitabine with lopinavir/ritonavir for initial HIV treatment.

BACKGROUND: Abacavir sulfate/lamivudine (ABC/3TC) and tenofovir DF/emtricitabine (TDF/FTC) are widely used nucleoside reverse transcriptase inhibitors for initial HIV-1 treatment. This is the first completed, randomized clinical trial to directly compare the efficacy, safety, and tolerability of these agents, each in combination with lopinavir/ritonavir in antiretroviral-naive patients. METHODS: Six hundred and eighty-eight antiretroviral-naive, HIV-1-infected patients were randomized in this double-blind, placebo-matched, multicenter, noninferiority study to receive a once-daily regimen of either ABC/3TC 600 mg/300 mg or TDF/FTC 300 mg/200 mg, both with lopinavir/ritonavir 800 mg/200 mg. Primary endpoints were the proportion of patients with HIV-1 RNA below 50 copies/ml at week 48 (missing = failure, switch included analysis) and the proportion of patients experiencing adverse events over 96 weeks. RESULTS: At week 48, 68% in the ABC/3TC group vs. 67% in the TDF/FTC group achieved an HIV-1 RNA below 50 copies/ml (intent-to-treat exposed missing = failure, 95% confidence interval on the difference -6.63 to 7.40, P = 0.913), demonstrating the noninferiority of ABC/3TC to TDF/FTC at week 48. Noninferiority of the two regimens was sustained at week 96 (60% vs. 58%, respectively, 95% confidence interval -5.41 to 9.32, P = 0.603). In addition, efficacy of both regimens was similar in patients with baseline HIV-1 RNA >or= 100 000 copies/ml or CD4 cell counts below 50 cells/microl. Median CD4 recovery (ABC/3TC vs. TDF/FTC, cells/microl) was +250 vs. +247 by week 96. Premature study discontinuation due to adverse events occurred in 6% of patients in both groups. Protocol-defined virologic failure occurred in 14% of patients in both groups. CONCLUSION: Both ABC/3TC and TDF/FTC provided comparable antiviral efficacy, safety, and tolerability when each was combined with lopinavir/ritonavir in treatment-naive patients.

First large, multicenter, open-label study utilizing HLA-B*5701 screening for abacavir hypersensitivity in North America.

A hypersensitivity reaction is associated with abacavir in approximately 2-8% of exposed patients. The frequency of the HLA-B*5701 allele varies across racial groups and significantly correlates with risk of hypersensitivity. Studies in Europe and Western Australia demonstrated that prospective screening can significantly reduce the rate of hypersensitivity by avoiding the use of abacavir in patients carrying the HLA-B*5701 allele. Prospective HLA-B*5701 screening in a large, racially diverse North American population resulted in less than 1% of individuals diagnosed with a suspected abacavir hypersensitivity reaction (ABC HSR) and no positive skin patch test through 30 weeks among HLA-B*5701-negative individuals.