A randomized controlled trial of single-class maintenance therapy with abacavir/lamivudine/zidovudine after standard triple antiretroviral induction therapy: final 96-week results from the FREE study

OBJECTIVES

The aim of the study was to test the antiviral efficacy of a triple nucleoside reverse transcriptase inhibitor (NRTI) regimen, with potential beneficial metabolic effects, as maintenance therapy after induction with dual NRTIs and a boosted protease inhibitor (PI).

METHODS

An open-label, noninferiority study was carried out. Antiretroviral therapy (ART)-naïve patients with CD4 count ≤ 350 cells/μL and HIV-1 RNA >30000 copies/mL (n=207) were treated with zidovudine/lamivudine and lopinavir/ritonavir. After achieving HIV-1 RNA <50 copies/mL on two consecutive occasions between weeks 12 and 24 after baseline, 120 patients (baseline: median HIV-1 RNA 5.19 log10 copies/mL; median CD4 count 180 cells/μL) were randomized to receive abacavir/lamivudine/zidovudine (ABC/3TC/ZDV) (n=61) or to continue the PI-based ART (n=59).

RESULTS

For the proportions of patients (intention-to-treat; missing=failure) with HIV-1 RNA <400 copies/mL (PI group, 66%; ABC/3TC/ZDV group, 71%) and <50 copies/mL (PI group, 63%; ABC/3TC/ZDV group, 62%) at 96 weeks, switching to ABC/3TC/ZDV was noninferior compared with continuing the PI regimen; the difference in failure rate (ABC/3TC/ZDV minus PI) was -4.4 percentage points [95% confidence interval (CI) -21.0 to +12.3 percentage points] and +0.4 percentage points (95% CI -16.9 to +17.7 percentage points), respectively. In the per protocol analysis, the difference in virological failure for HIV-1 RNA >400 copies/mL (0 of 39 patients in the PI group and two of 45 patients in the NRTI group) and for HIV-1 RNA >50 copies/mL (two of 39 and three of 45 patients, respectively) was +4.4 percentage points (95% CI -2.1 to +11.0 percentage points) and +1.5 percentage points (95% CI -8.6 to +11.7 percentage points), respectively, also showing noninferiority. Serum lipids significantly improved in the NRTI group, but not in the PI arm.

CONCLUSIONS

A single-class NRTI regimen after successful induction with standard ART had similar antiviral efficacy compared to continuation of a PI-based regimen at 96 weeks after baseline, with improved serum lipids.

Adherence over 48 weeks in an antiretroviral clinical trial: variable within patients, affected by toxicities and independently predictive of virological response

OBJECTIVES

To investigate adherence to antiretroviral therapy over 48 weeks, to investigate the association between adherence and treatment-related symptoms and to investigate the impact of adherence on virological response over 48 weeks among established predictors of treatment success.

METHODS

One-hundred-and-sixty HIV-1 infected protease inhibitor- and stavudine-naive patients participating in a trial of ritonavir/saquinavir versus ritonavir/saquinavir/ stavudine completed an adherence questionnaire and a symptom checklist at weeks 12, 24, 36 and 48. We calculated odds ratios between experienced symptoms and non-adherence. Regression models were used to determine predictors of HIV-1 RNA below 400 copies/ml at week 48, and of the area about the change from baseline over 48weeks (ACFB) in serum HIV-1 RNA.

RESULTS

The percentage of patients reporting missing medication, deviation from time schedule, and dietary prescriptions at separate time-points ranged from 12 to 15%, 32 to 35% and 17 to 22%, respectively. The percentage that changed their level of adherence during 48 weeks ranged from 29% for skipping medication to 48% for deviation from time-schedule. Experienced side-effects were associated with an increased likelihood of non-adherence. Not skipping medication was an independent predictor of both having a serum HIV-1 RNA below 400 copies/ml at week 48 and the ACFB over 48weeks in serum HIV-1 RNA.

CONCLUSIONS

Adherence was an independent predictor of virological response over 48 weeks. The level of adherence is variable within patients over time. This suggests the need for continued adherence monitoring in all patients as part of standard medical practice.