Results from a novel experimental therapy for Type 1 diabetes that boosts parts of the healthy immune system are reported August 23 in the scientific journal Diabetes. The trial was led by Carla Greenbaum, MD, Diabetes Research Program director at Benaroya Research Institute at Virginia Mason (BRI), and sponsored by the Immune Tolerance Network (ITN), a clinical trial network funded by the National Institutes of Health. The trial took a unique two-pronged approach to treating Type 1diabetes in newly diagnosed participants. Two drugs were administered in combination. One drug interferes with the immune response that causes Type 1 diabetes while a second drug simultaneously boosted the part of the immune response that usually regulates overactive immune cells.

Over 1 million people in the United States have Type 1 diabetes and the incidence is growing. In this disease, the body's immune system attacks and destroys the insulin-producing cells in the pancreas, called beta cells. However, at the time of diagnosis with Type 1 diabetes, a small number of beta cells may remain active in many individuals. Since even small amounts of natural insulin production can decrease the long-term effects of diabetes, therapies that attempt to rescue these remaining cells are badly needed.

In the clinical research trial, the combination of the two drugs Proleukin (IL-2) and Rapamune (sirolimus) were administered to see whether the drugs would affect the immune system to halt the autoimmune destruction of the remaining beta cells. The authors of the study describe successful boosting of regulatory components of the immune system in all nine subjects treated in the trial. However, other elements of the immune system also were expanded that were not anticipated. The temporary impairment of beta cell function led the authors to conclude that this drug combination was not having the desired overall effect. Monitoring of the insulin production in the nine subjects indicated that the beta cell preservation goal was not achieved, and the study was therefore stopped. "This study result has been extremely important to scientists looking for ways to stop the immune attack," says Dr. Greenbaum. "Our aim would be to harness the good effects of this therapy while preventing the bad effects." Participants who haven't yet completed the study will continue to be followed.

"The clinical and mechanistic findings from this study can help guide future treatments that boost good immunity," says Gerald Nepom, MD, PhD, Director of ITN. "This was an important clinical trial that will improve the design of subsequent trials to rescue beta cells in Type 1 diabetes."