Vaccine May Stop Immune Attack in Type 1 Diabetes
Early trial found it boosts insulin production, appears safe
"We just wanted to throw the off switch for the one cell being attacked," Steinman explained.
The researchers recruited 80 volunteers diagnosed with type 1 diabetes during the past five years. They were randomly placed in one of five groups. Four groups received various doses of the vaccine, and the fifth group received placebo injections. Shots were given weekly for 12 weeks.
No one in the study was able to stop using insulin. "That's a possible goal, but it's too early to start saying cure," Steinman noted.
It's difficult to measure insulin levels, because they can vary rapidly and dramatically. Instead, researchers measured an increase of a substance called C-peptide, a part of proinsulin that stays in the body longer than insulin. C-peptide levels are used as measure of insulin production.
C-peptide levels improved at all doses of the vaccine compared to the placebo, according to the study. And, it's believed that higher levels of C-peptide may be related to a reduction in some of the serious complications associated with type 1 diabetes, such as eye disease, kidney problems and heart disease.
No serious adverse events occurred during the trial.
Dr. Richard Insel, chief scientific officer at JDRF (formerly the Juvenile Diabetes Research Foundation), said, "The encouraging results from this initial trial ... in established type 1 diabetes not only demonstrated safety, evidence during the vaccine dosing period showed preservation of beta cell function, a decrease in detectable immune cells [that likely attack the beta cells], and a relationship between the two."
He added that further clinical trials will be needed to figure out the optimal dose for vaccine efficacy and safety.
The study was funded by Bayhill Therapeutics, which helped to develop the vaccine. The JDRF provided funding for the trial, as did the Iacocca Family Foundation.
Steinman said it's too soon to know how the vaccine might work in the real world. It's not clear how often someone would need to be given the vaccine, and how well the body might recover its ability to produce insulin once the autoimmune attack has stopped. It's also not clear if the vaccine might be more effective in people who've recently developed the disease, or in people who have a high risk of developing type 1 diabetes.