ESPRITA Randomized, Open-Label, Phase III, International Study of Subcutaneous Recombinant IL-2 in Patients With HIV-1 Infection and CD4+ Cell Counts 300/mm^3 or Greater: Evaluation of Subcutaneous Proleukin in a Randomized International Trial

Much progress has been made in implementing potent antiretroviral therapy that is able to maximally suppress viral replication. However, these drug combinations do not result in viral eradication and, for many patients, virologic and immunologic control cannot be maintained. Even among patients with apparent virologic control, a "ceiling effect" seems to exist with failure of CD4 cell counts to rise on average more than 100 to 150 cells/mm^3, at least during the first 2 years of therapy. The incomplete recovery of immune function after initiation of therapy remains an obstacle in the management of HIV. Preservation of immune function by direct expansion of CD4 lymphocytes with rIL-2 could represent a significant additional treatment strategy. It also has been speculated recently that rIL-2 in combination with potent antiretroviral therapy may be a useful approach for purging HIV from the latently infected CD4 cells. It is hoped that intervention with rIL-2 therapy in combination with antiretroviral therapy at an early stage of HIV infection can prevent CD4 T-cell depletion and result in fewer AIDS-defining illnesses than with antiretroviral therapy alone. Patients are randomized to receive subcutaneous (SC) rIL-2 therapy or no rIL-2 therapy. All patients must be taking a regimen of combination antiretroviral treatment, with the choice of therapy at the discretion of the treating clinician. Antiretroviral medications are not provided by this study. Recombinant IL-2 is given SC for 5 consecutive days every 8 weeks for at least 3 cycles unless toxicities or other contraindications develop. After the first three cycles, additional cycles are given at the discretion of each patient's physician, with a general goal of maintaining the patient's CD4 cell count at twice the baseline level or at 1,000 cells/mm^3 or above for as long as possible. Patients in the no rIL-2 group receive no injections. Patients in both treatment groups are seen every 4 months for follow-up data collection to monitor viral load and CD4 cell counts. All patients are followed for a minimum of 4 years. During the trial, patients in the no SC rIL-2 group are not given rIL-2 at any point. However, at the end of the study, if rIL-2 is found to be effective in reducing the rate of disease progression [AS PER AMENDMENT 12/15/00: (new and recurrent events)], including death, all patients are offered rIL-2.