A Study of the Effectiveness of Different Anti-HIV Treatments in HIV-Positive Individuals Who Have Been on a Protease Inhibitor-Containing Drug Regimen for at Least 16 Weeks

The purpose of this study is to compare different treatments for HIV infection to see which works best to lower HIV levels and to raise the number of CD4 cells (cells of the immune system that fight infection), in HIV-positive individuals who have been on a protease inhibitor-containing drug regimen for at least 16 weeks. Researchers have found that combination anti-HIV therapy (multiple drugs given together) can help prevent AIDS-related illnesses and help people with AIDS live longer. In this study, the anti-HIV drug efavirenz (EFV) will be tested with 1 or 2 other protease inhibitors (PIs) to see which combination works best to treat HIV infection. EFV has been shown to limit the amount of HIV virus produced by infected cells.