NIH NEWS ADVISORY

Largest Ever Randomized Study of IL-2 in the Treatment of HIV to be Presented at ICAAC

At the 40th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Toronto, Dr. Donald Abrams from the University of California, San Francisco, will present preliminary data from the largest clinical trial to date on the safety and efficacy of IL-2 in treating people with HIV disease.

Interleukin-2 (IL-2) is an immune system protein that stimulates production of CD4+ T cells. Previous studies have tested a laboratory-synthesized, or recombinant, form of IL-2 as an immunity-boosting complement to antiretroviral therapy in small groups of patients with HIV. These trials have shown that IL-2 can significantly increase CD4+ T-cell levels in some patients receiving antiretroviral drugs. These studies have raised the possibility, however, that IL-2 might also increase the amount of HIV in the blood.

The trial headed by Dr. Abrams was conducted as part of NIAID's Community Programs for Clinical Research on AIDS (CPCRA). The researchers studied 511 patients receiving combination antiretroviral drug therapy with or without intermittent subcutaneous recombinant IL-2 and followed these patients for at least 12 months.

The study found that the addition of IL-2 to antiretroviral therapy produced sustained increases in CD4+ T-cell levels with no significant changes in viral load after one year of treatment. After this time period, CD4+ T-cell counts averaged 217 cells per cubic millimeter higher in the IL-2 group compared with those on antiretroviral therapy alone.

This study confirms the beneficial effects of recombinant IL-2 on CD4+ T-cell levels in HIV patients who receive antiretroviral therapy. It also provides convincing evidence to alleviate concerns about the effects of IL-2 on viral load, since differences in HIV levels over the course of the study were insignificant between the treatment and control groups.

The CPCRA study also helps lay the groundwork for two ongoing major Phase III trials on the clinical outcomes of IL-2 treatment for HIV. The ESPRIT trial will enroll 4,000 patients and involves 227 sites in 20 countries. The SILCAAT trial will enroll 1,400 patients at 100 sites in eight countries. The two trials will focus on patients with different starting CD4+ T-cell levels.

Dr. Abrams will present his data during a late-breaker session on Monday, September 18, at 12:30 p.m. ET.

Patients and their physicians can obtain information about the ESPRIT study by calling 1-800-AIDS-NIH.