New York, NY (March 1, 2002) -- A new clinical trial testing an HIV vaccine together with low daily doses of interleukin 2 (IL2) -- led by Dr. Kendall Smith, Chief of Immunology in the Department of Medicine at Weill Cornell Medical College -- is designed to determine whether it is possible to achieve control of HIV by enhancing the body's immunity to the virus. Dr. Smith's team has previously shown that low daily doses of the T cell growth factor IL2 can result in accelerated improvement of the immune system when given to individuals with chronic HIV infection. Now, the team is testing whether it is possible to generate protective immunity to HIV, so that antiviral drugs will no longer be necessary.

Dr. Smith and his research team discovered the IL2 molecule and IL2 receptors over 20 years ago, and since then, the team has pioneered studies that have determined how IL2 functions as a growth factor for T lymphocytes and Natural Killer (NK) cells, the principal cells known to fight viral infections.

Based on the team's studies of the way IL2 interacts with its receptor, the Weill Cornell researchers initiated clinical trials in 1994. Their initial phase I dose-finding/safety studies in 16 individuals established low doses of IL2 that are safe and non-toxic, even when given daily for several months.

They then extended their experience to 40 individuals with moderate immune system damage. This research demonstrated that low doses of IL2 could be given daily for as long as a year, resulting in an increase in NK cells, and the accelerated recovery of the numbers of circulating CD4+ T cells, which are the cells of the immune system that are destroyed by HIV.

On the basis of these findings, in 1998 they initiated a multicenter randomized controlled study of 115 subjects. The results of this study confirmed and extended the earlier experience of the Weill Cornell researchers. In addition, IL2 treatment lowered the levels of cholesterol and low-density lipoproteins in the blood, a beneficial result that was unexpected.

Because low dose daily IL2 therapy is not toxic, the way is now open to additional studies to determine how best to augment immune reactivity to HIV itself. A new, randomized, controlled trial testing an HIV vaccine in combination with low dose daily IL2 is now open at Weill Cornell. The idea of combining IL2 with an HIV vaccine is based on the Smith team's research into the way IL2 promotes the expansion of T cells that first must be activated by the virus. To determine the level of HIV immunity after the immunotherapy is given, the antiviral drugs will be withdrawn and the level of HIV in the blood will be carefully monitored. This "diagnostic treatment interruption" promises to be a rapid and sensitive way to determine the magnitude of the HIV immune response in the whole body, one that may define whether it is possible to prevent the virus from reappearing.

By this diagnostic treatment interruption approach, immune therapy trials can be conducted with relatively small numbers of HIV-infected subjects (that is, about 100) over short time intervals (months rather than years). Therefore, the most effective HIV vaccines and interleukins may be identified rapidly. This approach may also make it possible to decrease the time necessary for the identification of promising prophylactic vaccines and immunotherapies from decades to only a few years.

In summary, the Weill Cornell team is working towards both a cure and prevention of HIV infection.