Combination antiretroviral therapies using protease inhibitors (PIs) are capable of suppressing plasma HIV RNA to undetectable levels. However, approximately 10% of patients who achieve undetectable viral loads will experience a detectable rise in HIV RNA each year. When HIV replication has been suppressed to very low levels, it may be possible to consolidate antiretroviral therapy into a simpler and potentially less toxic "maintenance" regimen without a PI. Such a regimen would ideally be potent enough to continue to maintain viral suppression but use agents that are better tolerated, more easily salvaged, less expensive, and/or more convenient than PI-containing regimens. Subsequent rises in HIV viremia with non-PI maintenance regimens may respond to resumption of the pre-maintenance PI-containing regimen, extending the use of the potent PI class.

Patients are randomized 1:1:1 to treatment with ddI/d4T/HU (Arm A) versus ddI/d4T/EFV (Arm B) versus continuation of the pre-entry PI-containing regimen (Arm C). Viral load is measured at Weeks 1, 2, 4, 8, 12, 16, 20, and 24, then every 8 weeks for up to 3 years. Upon virologic failure (plasma HIV RNA greater than or equal to 200 copies/ml), or drug intolerance, patients on the maintenance regimens (Arms A and B) restart their pre-entry PI-containing regimen. Patients on Arm C are managed according to best medical judgment of their primary care provider in the event of virologic failure.