Interleukin-2 Plus Anti-HIV Therapy in HIV-Infected Children With Weakened Immune Systems

One of the challenges in effective combination therapy in HIV-infected patients is the ability to achieve immune reconstitution. IL-2 is hypothesized to restore and/or preserve the immune system when added to potent antiretroviral regimens. This study will evaluate restoration of immune functions of CD4 cells and will also determine the best way to deliver IL-2 in a safe and effective way. Part I: Patients add a 5-day course of subcutaneous IL-2 every 8 weeks for up to 48 weeks (6 cycles) to their HAART therapy. Three dose levels of IL-2 are administered. \[AS PER AMENDMENT 5/3/01: It is strongly recommended, but not required, that\] the first and second cycles of IL-2 are given in the hospital on an inpatient basis. The parent or patient is trained to give the injections and has the option of administering subsequent injections at home. Patients are monitored for CD4 and CD8 cell count and viral load. Enrollment into Part 1 begins at the lowest dose level; assuming no serious toxicities (Grade 3 or higher) occur, patients are enrolled into higher dose levels. The highest tolerated dose is established. Part 2: After the highest tolerated dose is established in Part 1, additional patients are randomized to receive HAART alone (Arm 1), HAART with high-dose IL-2 (Arm 2), or HAART with low-dose IL-2 (Arm 3). High-dose IL-2 is given twice daily at the highest dose tolerated in Part 1 for 5 days every 8 weeks for 6 cycles. Low-dose IL-2 is given once a day every day for 48 weeks. For Arms 2 and 3 \[AS PER AMENDMENT 5/3/01: (except patients in the pharmacokinetic substudy), it is strongly recommended, but not required, that\] IL-2 is given the first week on an inpatient basis by hospital personnel. As in Part 1, there is the option of administering the remaining injections at home. Intensive toxicity monitoring, routine lymphocyte subsets, and quantitative HIV RNA are performed on all patients at specified time points during the study. The first 12 patients in Arms 2 and 3 have pharmacokinetic testing with frequent blood samples drawn at intervals, some of which require staying up to 12 hours at the clinic. Diphtheria/tetanus immunizations and bacteriophage phi X174 immunizations are administered to all patients to determine antibody responses.