A Study of Three Anti-HIV Drug Combinations in Patients Who Have Taken Amprenavir

To determine the proportion of patients treated with amprenavir, zidovudine (ZDV), stavudine (D4T) and lamivudine (3TC) whose HIV-1 RNA level remains below the level of detection during 96 weeks of therapy. To determine the proportion of patients treated with indinavir (IDV), nevirapine (NVP), 3TC, and d4T whose HIV-1 RNA level decreases and then remains below the level of detection, during the 96-week therapy period. To determine the viral effects, safety, tolerability, and pharmacokinetics of amprenavir in combination with zidovudine, stavudine, and lamivudine. \[AS PER AMENDMENT 2/27/98: To determine the proportion of patients with undetectable plasma HIV RNA, by treatment and baseline RNA cohort (either detectable or undetectable). To determine the durability of these regimens by estimating the distribution of time to loss of virologic suppression (or equivalently, time to virologic failure), by treatment and baseline RNA cohort.\] This study allows patients who have successfully participated in ACTG 347 or other trials involving amprenavir to continue treatment with amprenavir, ZDV, d4T, and 3TC. Additionally, this study provides patients whose HIV-1 RNA was not reduced to undetectable levels or who had a significant increase in plasma levels ("treatment failures") the opportunity to change to a potentially more active regimen that includes indinavir, nevirapine, lamivudine, and stavudine.

This study allows patients who have successfully participated in ACTG 347 or other trials involving amprenavir to continue treatment with amprenavir, ZDV, d4T, and 3TC. Additionally, this study provides patients whose HIV-1 RNA was not reduced to undetectable levels or who had a significant increase in plasma levels ("treatment failures") the opportunity to change to a potentially more active regimen that includes indinavir, nevirapine, lamivudine, and stavudine. Patients with HIV RNA less than 500 copies/ml on a regimen containing amprenavir are treated on Arm A; those with greater than or equal to 500 copies while on or intolerant to a regimen containing amprenavir are treated on Arm B. Arm A: Amprenavir + ZDV + d4T + 3TC. Arm B: IND + NVP + 3TC + d4T. Patients enrolled in Arm A who fail therapy may roll over to Arm B. Patients in Arm B who fail therapy discontinue study medications and seek best available treatment. \[AS PER AMENDMENT 2/27/98: Patients with HIV RNA less than 500 copies/ml currently on triple therapy with amprenavir + 3TC + ZDV (or d4T if ZDV-intolerant) are treated on ARM A. Patients with HIV RNA greater than or equal to 500 copies/ml, who have been intolerant to a regimen containing amprenavir or who were previously enrolled on ACTG 347 who elected to receive a treatment regimen other than amprenavir + ZDV (or d4T) + 3TC or IDV + NVP + 3TC + d4T or other regimens are assigned to Arm C. Arm A: Amprenavir + ZDV\* plus 3TC. Arm B: IDV\*\* + NVP + 3TC + d4T\*\*\*. Arm C: Observation only. Patients are followed for the duration of the study. * Patients intolerant of ZDV may elect to receive d4T. \*\*Patients intolerant of IDV may take study-provided nelfinavir. \*\*\*Patients who switched to open-label IDV/NVP/3TC/d4T prior to enrollment on this study and who were intolerant to any of the study medications may enroll into Arm B with appropriate substitution of the intolerant study drug(s). Patients initially assigned to Arm A who are intolerant of amprenavir or who fail therapy have the option of receiving Arm B therapy. Patients initially assigned to Arm B who are intolerant of any of the assigned study drugs may make an appropriate antiretroviral substitution (with approval of the protocol chair).\]