Vaccine May Stop Immune Attack in Type 1 Diabetes
Early trial found it boosts insulin production, appears safe
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.
Steinman said he hopes to have the next trial under way in a year or so.
The study appeared online June 26 in the journal Science Translational Medicine.
Dr. Joel Zonszein, director of the clinical diabetes center at Montefiore Medical Center in New York City, expressed more caution about the vaccine. "The immune response in type 1 diabetes is very complex, and we've been burned many times with the idea of a vaccine for type 1 diabetes," he noted.
"Because this is a new technology -- a DNA-based vaccine -- I think it would have to be approved for use in something like advanced cancer first, because it may do good things and bad things.," Zonszein said. "We don't know, so we don't want to give it to otherwise healthy people with type 1 diabetes until we know what the potential for harm is."
Still, he said that the new vaccine is an exciting discovery. "This is a welcome discovery. It helps us to understand the immune process better," he said.