Randomized, open-label, comparative trial to evaluate the efficacy and safety of three antiretroviral drug combinations including two nucleoside analogues and nevirapine for previously untreated HIV-1 Infection: the OzCombo 2 study. Comparison of first-line antiretroviral therapy with regimens including nevirapine, efavirenz, or both drugs, plus stavudine and lamivudine: a randomised open-label trial, the 2NN Study.
To assess and compare the efficacy and safety of three triple combination antiretroviral therapies in HIV-1-infected treatment-naive patients.
                Seventy treatment-naive HIV-infected adults with CD4+ T-cell counts >50/microL were randomized to receive either zidovudine + lamivudine + nevirapine (AZT + 3TC + NVP), stavudine + didanosine + nevirapine (d4T+ddI+NVP), or stavudine + lamivudine + nevirapine (d4T+3TC+NVP) for 52 weeks. Patient assessments were conducted monthly and included measurement of plasma HIV RNA levels and CD4+ T-cell counts and evaluations for drug toxicity.
                The mean time-weighted reductions in plasma HIV RNA in the AZT+3TC+NVP, d4T+3TC+NVP, and d4T+ddI+NVP groups were 1.29, 2.13, and 1.78 log(10) copies/mL, respectively (p =.389). The proportions of patients with HIV RNA <50 copies/mL in the AZT+3TC+NVP, d4T+3TC+NVP, and d4T+ddI+NVP groups were 73%, 68%, and 80%, respectively (p =.71). The mean time-weighted increases in CD4+ T-cell counts in the AZT+3TC+NVP, d4T+3TC+NVP, and d4T+ddI+NVP groups were 139, 113, and 174 cells/microL, respectively (p =.30). Three patients ceased assigned treatment due to rash (one from each treatment arm), and 5 of the 45 patients on d4T (3 from the d4T+3TC+NVP arm and 2 from the d4T+ddI+NVP arm) ceased assigned treatment due to neuropathy.
                All three-drug combinations were equally effective at suppressing viral load and increasing CD4+ T-cell counts. No significant differences were detected between the treatment groups in virological or immunological response or cessation of study drugs due to adverse events, although it is possible that the study was underpowered to detect differences. NVP was safe and efficacious in this setting, and efficacy was not influenced by nucleoside reverse transcriptase inhibitor backbone. The 2NN Study was a randomised comparison of the non-nucleoside reverse-transcriptase inhibitors (NNRTI) nevirapine and efavirenz.
                In this multicentre, open-label, randomised trial, 1216 antiretroviral-therapy-naive patients were assigned nevirapine 400 mg once daily, nevirapine 200 mg twice daily, efavirenz 600 mg once daily, or nevirapine (400 mg) and efavirenz (800 mg) once daily, plus stavudine and lamivudine, for 48 weeks. The primary endpoint was the proportion of patients with treatment failure (less than 1 log(10) decline in plasma HIV-1 RNA in the first 12 weeks or two consecutive measurements of more than 50 copies per mL from week 24 onwards, disease progression [new Centers for Disease Control and Prevention grade C event or death], or change of allocated treatment). Analyses were by intention to treat.
                Treatment failure occurred in 96 (43.6%) of 220 patients assigned nevirapine once daily, 169 (43.7%) of 387 assigned nevirapine twice daily, 151 (37.8%) of 400 assigned efavirenz, and 111 (53.1%) of 209 assigned nevirapine plus efavirenz. The difference between nevirapine twice daily and efavirenz was 5.9% (95% CI -0.9 to 12.8). There were no significant differences among the study groups in the proportions with plasma HIV-1 RNA concentrations below 50 copies per mL at week 48 (p=0.193) or the increases in CD4-positive cells (p=0.800). Nevirapine plus efavirenz was associated with the highest frequency of clinical adverse events, and nevirapine once daily with significantly more hepatobiliary laboratory toxicities than efavirenz. Of 25 observed deaths, two were attributed to nevirapine.
                Antiretroviral therapy with nevirapine or efavirenz showed similar efficacy, so triple-drug regimens with either NNRTI are valid for first-line treatment. There are, however, differences in safety profiles. Combination of nevirapine and efavirenz did not improve efficacy but caused more adverse events.
The combination of nevirapine, 3TC and d4T is as efficacious as a combination of efavirenz, 3TC and d4T. Once-daily NVP with twice-daily 3TC and d4T is as efficacious as twice-daily NVP, 3TC and d4T. However, toxicity may be increased in the once-daily NVP regime. Additional trials of sufficient duration are required to provide better evidence for the use of this combination as a first line therapy. Ideally, trials should use standardised assessment measures especially with respect to measuring viral load, so that results can be compared and combined in meta-analyses.