Randomized, Open Label Study Evaluating the Lipid Profile Difference and Efficacy of a Combined Therapy Including Tenofovir, Emtricitabine + Atazanavir / r or NVP in Naive HIV - 1 Infected Patients.

Primary purpose of this study is to compare the efficacy and safety of two different nevirapine (Viramune) dosing regimens (once daily (QD) and twice daily (BID) application) and of atazanavir/ritonavir (Reyataz/Norvir), all on an emtricitabine/tenofovir disoproxil fumarate (DF) (Truvada) background. Patients will receive either nevirapine (NVP) 200 mg twice daily, or NVP 400 mg once daily , or ritonavir-boosted atazanavir (ATZ/r), all in combination with emtricitabine (FTC) and tenofovir DF (TDF). All patients receiving NVP will start at 200 mg once daily for 2 weeks, because it has been demonstrated that this lead-in dosing regimen reduces the frequency of NVP-induced rash. At Visit 3 (Week 2), patients increase the NVP dose to either 200 mg twice daily or to 400 mg once daily. Patients receiving ATZ/r will be treated with ATZ 300 mg once daily, boosted by 100 mg ritonavir (RTV) once daily. Background antiretroviral therapy for all patients consists of one tablet of Truvada. Treatment duration is 48 weeks (primary endpoint) with an extension to 144 weeks. Patients may also participate in the metabolic sub-study, comparing NVP and ATZ/r for signs and symptoms of lipodystrophy and serum lipid/glycaemic abnormalities.