Safety of Interleukin-7 in HIV Infected People Currently Taking Anti-HIV Drugs

CD4 count is the best predictor of HIV disease progression. IL-7 plays an important role in immune system function, especially in the development of T cells, including CD4 cells. IL-7 may improve HIV-specific immune responses by increasing the number of CD4 cells and boosting immune response. This study will evaluate the safety of a single IL-7 dose given under the skin in HIV infected patients who are currently on potent antiretroviral therapy (ART). This study will last 13 weeks. Participants will be stratified into two groups by viral load: Stratum 1 participants will have viral loads of less than 50 copies/ml, and Stratum 2 participants will have viral loads between 50 and 50,000 copies/ml. Participants will receive one dose of either IL-7 or placebo at study entry. Five different dosing levels of IL-7 will be tested sequentially in both strata. Dose escalation will occur independently in each stratum and enrollment in a stratum will end when the maximum-tolerated dose is reached. As of 10/23/06, due to adverse events associated with the 60 mcg/kg dose level, all participants will receive up to the 30 mcg/kg dose level, with no further dose escalation. New participants will enroll in Stratum 2 only. There will be 9 study visits; medical and medication history, a physical exam, lymph node and spleen assessment, and blood collection will occur at most visits. Participants will undergo an electrocardiogram at study entry and on Day 1, and a spleen ultrasound at Week 3. Urine collection will occur on Day 4 and at Weeks 2 and 3.