Virologic and Immunologic Activity of Continued Lamivudine (3TC) vs Delavirdine (DLV) in Combination With Indinavir (IDV) and Zidovudine (ZDV) or Stavudine (d4T) in 3TC-Experienced Subjects

To compare the proportion of patients in the 2 zidovudine (ZDV)-containing arms who have a plasma HIV RNA concentration below the limit of detection (defined as 500 copies/ml or less) at Weeks 20 and 24 \[AS PER AMENDMENT 8/24/98: HIV RNA concentration below the limit of detection is now defined as 200 copies/ml or less\]. To compare the safety and tolerability of the different treatment regimens. To compare the decrease in plasma HIV-1 RNA and the change in CD4 count from baseline to the average of Weeks 20 and 24 \[AS PER AMENDMENT 12/19/97: and to the average of Weeks 44 and 48; AS PER AMENDMENT 8/24/98: and the average of Weeks 88 and 96\] in the 2 ZDV-containing arms. To study the emergence of resistance to ZDV, lamivudine (3TC), stavudine (d4T), delavirdine (DLV), and indinavir (IDV) in treated patients. To correlate the antiviral and immunologic activity and emergence of drug resistance with pharmacologic parameters of study drugs. To delineate the pharmacokinetic interactions of IDV and DLV. \[AS PER AMENDMENT 12/19/97: To delineate the possible development of cellular resistance to nucleoside analogs and the consequences of switching nucleoside study drugs on intracellular phosphorylation.\] To document rates and patterns of adherence over the course of the study, from day of randomization through 48 weeks. \[AS PER AMENDMENT 8/24/98: To define long-term durability of the virologic activity of the different treatment regimens, as defined by the proportion of patients with plasma HIV-1 RNA levels that remains below the limit of detection. To define long-term tolerability of the different treatment regimens.\] Although a change in reverse transcriptase (RT) inhibitors is recommended when adding or changing protease inhibitors in a treatment regimen, the choice of available RT inhibitors is often limited by prior exposure, toxicity, or pharmacologic interaction with the protease inhibitors. This study addresses the question of whether to continue 3TC or substitute the nonnucleoside reverse transcriptase inhibitor (NNRTI) DLV when adding IDV to therapy for patients previously treated with ddI or d4T plus 3TC who have greater than 500 copies/ml of plasma HIV-1 RNA. Although the activity of DLV as monotherapy or in combination with nucleoside reverse transcriptase inhibitors is of limited duration due to rapid emergence of resistance, it is possible that DLV will contribute significantly to the activity of 3-drug regimens that include a new RT inhibitor plus a protease inhibitor. Although a change in reverse transcriptase (RT) inhibitors is recommended when adding or changing protease inhibitors in a treatment regimen, the choice of available RT inhibitors is often limited by prior exposure, toxicity, or pharmacologic interaction with the protease inhibitors. This study addresses the question of whether to continue 3TC or substitute the nonnucleoside reverse transcriptase inhibitor (NNRTI) DLV when adding IDV to therapy for patients previously treated with ddI or d4T plus 3TC who have greater than 500 copies/ml of plasma HIV-1 RNA. Although the activity of DLV as monotherapy or in combination with nucleoside reverse transcriptase inhibitors is of limited duration due to rapid emergence of resistance, it is possible that DLV will contribute significantly to the activity of 3-drug regimens that include a new RT inhibitor plus a protease inhibitor. Patients with greater than 500 HIV-1 RNA copies/ml are randomized to 3 treatment arms as follows: Arm I: d4T + ZDV placebo + DLV + IDV Arm II: ZDV + d4T placebo + 3TC + IDV Arm III: ZDV + d4T placebo + DLV + IDV Treatment on all arms is given for 24 weeks. \[AS PER AMENDMENT 12/19/97: The study is no longer partially blinded, and placebo agents are no longer given; treatment duration is now 48 weeks.\] \[AS PER AMENDMENT 8/24/98: study duration is now 96 weeks.\] Rollover patients from ACTG 306 with greater than 500 HIV-1 RNA copies/ml previously assigned to ZDV/3TC are nonrandomly assigned to Arm I; those previously assigned to ddI/3TC or d4T/3TC are randomized to Arm II or III. Non-rollover patients are randomized to Arm II or III. Rollover patients from ACTG 306 with 500 HIV-1copies/ml or less continue on their previously assigned regimen \[AS PER AMENDMENT 12/19/98: current regimen must be ZDV/3TC, ddI/3TC, or d4T/3TC.\] for the study duration or until an increase occurs. If this increase occurs, patients previously assigned to ZDV/3TC are nonrandomly assigned to Arm I for the remaining study weeks, while those previously assigned to either ddI/3TC or d4T/3TC are randomized to Arm II or III for the remaining study weeks. Patients who received ddI/d4T or ddI/3TC in ACTG 306 are stratified by whether patients received monotherapy or combination therapy during the first 24 weeks \[AS PER AMENDMENT 12/19/97: 48 weeks\]; \[ AS PER AMENDMENT 8/24/98: 96 weeks.\] of ACTG 306.