The purpose of this study is to see if 3 anti-HIV drug combinations are safe and effective in patients who have failed previous anti-HIV treatments using nelfinavir (NFV).

Patients receive 1 of 3 salvage regimens. Treatments A and B include delavirdine, 1 of 2 doses of indinavir, and 2 nucleoside reverse transcriptase inhibitors (NRTIs) to which the patient has not been exposed. Treatment C includes ritonavir, indinavir, and 2 NRTIs to which the patient has not been exposed. When virologic failure is first observed, the patient must return in 2 weeks for confirmation of failure and start the salvage regimen within 1 month of the first assay in which failure was observed. Patients who have less than 400 copies/ml HIV RNA after 16 weeks of therapy are considered responders and continue on the study. Those who have more than 400 copies/ml after 16 weeks of therapy are considered nonresponders and should be discontinued from the study. In addition, patients who respond and subsequently rebound with a viral load 0.5 log above the nadir and greater than 400 copies/ml on 2 consecutive assays at least 2 weeks apart are considered treatment failures and should be discontinued from the study. Patients have regular physical exams, as well as virologic, immunologic, and pharmacokinetic assessments.

Inclusion Criteria

Patients may be eligible for this study if they:

• Are HIV-positive.
• Had a viral load of less than 400 copies/ml, followed by an increase in viral load while taking an anti-HIV drug combination including NFV (treatment failure).
• Can start the study treatment within 1 month of treatment failure.
• Have a viral load of less than 30,000 copies/ml when they enter the study.
• Have not taken nonnucleoside reverse transcriptase inhibitors (NNRTIs) or protease inhibitors (PIs) other than NFV.