• The WHOQOL questionnaire will be administered at entry and at week 12, 24, 36 and 48 and at any time of possible study discontinuation. The determination of triglycerides will be performed at screening and at week 4, 8, 12, 24, 36 and 48.
  

• QAT, general assessment, CD4+, CD8+, plasma HIV-1 RNA, hematology, biochemistry, hepatitis C/B markers, anthropometric and skin folds measurement, DEXA, bone mineral loss parameters, NVP concentration in saliva, in semen and in vaginal secretions.
  

Patients will receive one of the current standard of care regimens for the treatment of HIV infection, i.e. nevirapine (Viramune®) must be administered in conjunction with 2NRTIs, as prescribed by the investigator at the study sites. Patients randomized to the nevirapine (Viramune®)-arm of the study will receive 1x200mg tablet once daily for the first 14 days ("lead in" period) and 1x200 mg tablet twice daily at appropriately spaced intervals subsequently, plus their SOC combination of 2NRTIs as prescribed by the investigators (without changing their prior NRTIs). Patients randomized to continue their standard treatment will receive it as prescribed by the investigators. No dose modification of the study drugs is permitted during the trial. The study drug will be dispensed at randomization and every four weeks thereafter until completion of 48 weeks. After 6 months at least of treatment the switch from PI regimen to NVP regimen will be allowed to all patients included in the PI arm according to patient's willingness. In these patients AST and ALT should be checked at time 0 (switch) and every 2 weeks for 2 months.

Study Hypothesis:

Between treatment comparison of Nevirapine-based regimen versus PI-based regimen will be based on a null hypothesis of no treatment difference. The null hypothesis will be no difference between the two arms at week 24 (month 6th), against the alternative hypothesis that the mean change in physical domain of the QoL will be 10 points score (SD=20) and the difference between triglycerides normalized patients will be 20%.

Comparison(s):

The primary analysis on physical domain of QoL will be performed on the changes between last observation carried forward following the LCOF approach (i.e. visit 6 or in case of premature discontinuation visit 5 or 4) and baseline (visit 2) value using fixed-effects ANCOVA model with center and treatment groups as factors and baseline value and MMA type interaction will be also included in the main model.