Comparison of efavirenz and nevirapine based HAART regimens in 4187 patients with up to 6 years of follow up, a prospective, open label observational study

Background: Non nucleoside reverse transcriptase inhibitors (NNRTI) based regimens are widely recommended as 1st line HAART and they are preferred in resource constrained settings due to high efficacy and low cost. Few studies compare effectiveness of efavirenz (EFV) and nevirapine (NVP) in large, prospective cohorts with extended follow up (f/u). Objective: To determine the effectiveness, rate of discontinuation or change, toxicity and mortality of patients with EFV versus NVP based regimens as initial HAART in a nation wide cohort. Methods: Prospective, open label, f/u of patients enrolled in the Chilean AIDS Cohort (ChiAC) from October 2001 to March 2008. All subjects receiving at least one dose of EFV or NVP were included. Primary outcomes were survival, maintenance of initial HAART, reason for change of NNRTI, viral suppression and immune recovery. Results: Of 5120 patients initiating first HAART in ChiAC, 4187 started a NNRTI based regimen (plus 2 NRTIs); 3107 (74.2%) with EFV and 1080 (25.8%) with NVP. Median f/u was 2.7 years. At baseline the NVP group had a significantly less advanced stage (CDC classification) and higher median CD4 count (151 vs 86 cell/mm3 in EFV, p < 0.001), but similar viral load (VL) compared to the EFV group. Rate of change or discontinuation was significantly lower for EFV (12.8% vs 22.3%, p < 0.001), due to fewer adherence problems or toxicity. Timing for change was similar in both arms (median 950 vs 1008 days for EFV and NVP respectively). There were no statistical differences in viral suppression rate (<80 cps/mL) at any time: 67.2, 74.9, 74.4, 65.1, 59.8% vs 63.6, 74.3, 72.7, 61.7, 59.4% at 6, 12, 24, 36 and 48 months for EFV and NVP respectively. At 12 months of f/u median CD4 cell count was similar for groups (242 for EFV and 250/mm3 for NVP). Mortality for the total period was 2.89 and 2.85 per 100pts-year for EFV and NVP respectively (p = NS). Conclusion: Efavirenz based HAART regimens were associated with similar viral and immune outcomes as Nevirapine based regimens, despite more severe disease at baseline in the EFV group. Discontinuation of NVP was more frequent, mainly due to toxicity and lower adherence, but not to viral failure. Abstracts for SupplementInternational Journal of Infectious DiseasesVol. 14Preview Full-Text PDF Open Archive