Vaccine failed to slow progression of type 1 diabetes

SAN DIEGO — A vaccine designed to prevent beta cell destruction has proven unsuccessful in patients with type 1 diabetes. Although successful in animal models, the glutamic acid decarboxylase vaccine did not alter the course of insulin secretion loss in humans, according to findings presented at the American Diabetes Association's 71st Annual Scientific Sessions.

Researchers in the US and Canada enrolled 145 patients aged 3 to 45 years who received a diagnosis of diabetes less than 100 days prior to the start of the study. Patients were randomly assigned to one of three three-injection treatments: three injections of glutamic acid decarboxylase formulated with aluminum hydroxide 20 mcg (GAD-alum); two injections of GAD-alum plus one booster of aluminum hydroxide; or three injections of aluminum hydroxide, which was used as the control group.

According to the results, patients in all three groups had similar declines in beta cell function and, this, similar progression of their type 1 diabetes.

“The curves, in terms of the decline in beta cell function, were absolutely superimposable for the 1 year of follow-up, showing no effect whatsoever,” Jay Skyler, MD, chairman of the NIH-funded Type 1 Diabetes TrialNet study group, said during a press conference.

C-peptide levels were similar among all three groups: 0.412 nmol/L (95% CI, 0.349-0.478) for the GAD-alum group; 0.382 (95% CI, 0.322-0.446) for the GAD-alum plus booster group; and 0.413 (95% CI, 0.351-0.477) for the control group.

“Although GAD vaccine was ineffective in recent-onset diabetes, the vaccine might be beneficial for prevention of type 1 diabetes if given earlier in the course of disease, or could be a component of a combination therapy protocol in recent-onset type 1 diabetes,” the researchers wrote. “Clearly, however, GAD vaccine should not be used in type 1 diabetes in clinical practice.” – by Stacey L. Fisher

For more information:

Wherrett DK. State of the art lecture: TrialNet GAD65 Trial Results. Presented at: American Diabetes Association’s 71st Scientific Sessions; June 24-28, 2011; San Diego, Calif.
Wherrett DK. Lancet. 2011;doi:10.1016/S0140-6736(11)60895-7.

Disclosures: Dr. Skyler reports no relevant financial disclosures.

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