Long-term efficacy and safety of atazanavir/ritonavir treatment in a real-life cohort of treatment-experienced HIV patients

Purpose of the study

Atazanavir (ATV)-based regimens have demonstrated efficacy and safety in both ARV-naïve and -experienced patients. However, few reports have assessed effectiveness beyond 2 years. The aim of this study was to describe the long-term outcomes of ATV/r containing regimens in ARV-experienced patients in a clinical setting.

Methods

Non-comparative, retrospective, observational study which collected data from 3 European databases (France-DatAids, Germany-KompNet, Sweden-InfCare). Clinical data for ARV-experienced adult patients who started an ATV/r-based regimen between October, 2004 and March, 2007 were extracted every 6-months (maximum follow-up 5 years). Primary endpoint was the proportion of patients remaining on ATV treatment by baseline HIV-1 RNA (< 500 or ≥ 500 c/mL). Secondary endpoints included virologic response and reason for discontinuation. The duration of treatment and time to virologic failure were analyzed using the Kaplan-Meier method.

Summary of results

Data for 1294 ARV-experienced patients (prior ARV exposure: mean, 5.70 years) were analyzed. Patients were predominantly male (74%); median age 43 years (min, max: 18, 85); 75% had prior exposure to PIs (mean: 3.5 years). At baseline (BL), 56% of patients had HIV-1 RNA < 500 c/mL and 37% had < 50 c/mL. The estimated proportion of patients remaining on ATV during the follow-up period was 52% (median duration of treatment: 3.7 years); 54% for patients with BL HIV-1 RNA < 500 c/mL and 50% for those with BL HIV-1 RNA > 500 c/mL. The estimated probability of discontinuation was 21% during the first year and decreased at each subsequent 1-year treatment interval. Time to virologic failure is presented in Figure 1.

Fig 1

Time to virologic failure (two consecutive HIV-1 RNA ≥ 50 c/mL or one HIV-1 RNA ≥ 50 c/mL followed by discontinuation)

The most frequent reasons for discontinuation were "unknown" (32%), adverse events (25%), patient withdrew consent (13%) and lack of efficacy (11%). Hyperbilirubinemia was reported as reason for discontinuation in 12 patients. No unexpected changes in metabolic parameters were observed and renal AEs were reported rarely (1.9/100 patient-years)•

Conclusions

In real life setting, ATV/r-based regimen demonstrated sustained virological efficacy in an ARV-experienced population including patients with previous virological failure. After long-term treatment a high proportion of patients remained on an ATV regimen and no unexpected AEs were observed.