- Antiretroviral therapy (ART) experienced and currently receiving a stable regimen containing 3 nucleoside reverse transcriptase inhibitors (NRTIs), or 2 NRTIs plus a protease inhibitor (PI) or non-nucleoside reverse transcriptase inhibitors (NNRTI) for at least 3 months (there should be no significant ART modifications for at least 3 months and no ART change anticipated between Screening and initiation of the study therapy).