HIV disease is characterized by a progressive decline in CD4 cells and an increase in viral burden. Although antiretroviral therapy has been successful in controlling viral levels, its effects on CD4 cell counts have been modest. Intermittently administered IL-2 in the presence of HAART has been shown to increase CD4 cell counts, decrease lymphocyte activation markers, and increase certain lymphocyte functional activity in patients with early-stage HIV infection. ACTG 328 evaluated the effects of intravenous and/or subcutaneously administered IL-2 in conjunction with HAART in a group of more advanced HIV-infected patients over an 18- to 22-month period. As patients were enrolled in this study over an 18-month period, a follow-up protocol is required to provide continued IL-2 therapy for patients responding to IL-2 and patients in the control group who wish to receive this drug.

This study enrolls patients who participated in ACTG 328. Patients in Arm I of ACTG 328 (the control group receiving HAART only) who have a viral load of 5,000 copies/ml or less register for Step II. Patients in Step II receive subcutaneous [SC] IL-2 in combination with HAART. IL-2 is administered for 5 days every 8 weeks for the first 3 cycles. For subsequent cycles, the interval between cycles may be extended in 8-week increments for a maximum of 24 weeks, provided the patient's bimonthly CD4 count exceeds 500 cells/mm3. Patients in Arm I who have a viral load greater than 5,000 copies/ml register for Step I which requires a change in antiretroviral therapy. Patients who then achieve viral levels of 5,000 copies/ml or less may begin to receive IL-2 no earlier than 4 weeks and no later than 12 weeks after the change in HAART regimen. Patients whose viral load remains above 5,000 copies/ml for 12 weeks after the change in drug regimen are discontinued from the study. Patients in Arms II or III of ACTG 328 (IL-2-containing arms) who have had a 25 percent or greater increase in CD4 cell count above their Week 11 value and have a viral load of 5,000 copies/ml or less continue on SC IL-2 and HAART. Patients who meet the CD4 criteria but whose viral load is above 5,000 copies/ml change their HAART regimen. After a minimum of 4 weeks and a maximum of 12 weeks, these patients may receive IL-2 provided they have a viral load of 5,000 copies/ml or less. For this study, HAART is defined as one protease inhibitor and two nucleoside analogues. [AS PER AMENDMENT 9/16/99: All patients must receive a protease inhibitor or, with permission of the chair, a nonnucleoside reverse transcriptase inhibitor (NNRTI) plus either two nucleoside reverse transcriptase inhibitors (NRTIs) or another protease inhibitor or NNRTI.] The protease inhibitor provided on this study is indinavir (IDV). The nucleoside analogue combinations provided on this study are as follows: zidovudine (ZDV) plus didanosine (ddI), ZDV plus lamivudine (3TC), stavudine (d4T) plus 3TC, or d4T plus ddI. Other antiretroviral drugs may be used but are not provided by this study. Patients are monitored for CD4 counts at bimonthly intervals after the first IL-2 dose. CD4 counts and plasma storage for HIV RNA are done within 96 hours prior to each cycle of IL-2. Safety laboratory evaluations are obtained prior to and at the conclusion of each IL-2 course. TSH (thyroid-stimulating hormone), DTH skin testing, and real-time plasma HIV RNA are obtained at 6-month intervals.