Diabetes drug shows new potential

A drug currently prescribed for people with type 2 diabetes might also prove useful for individuals who are newly diagnosed with the type 1 form of the disease. Whereas type 2 diabetes typically appears in adulthood, type 1 usually strikes in youth.

In experiments in mice with a disease similar to type 1 diabetes, researchers found that the drug exendin-4 activated idle beta cells in the pancreas. These insulin-making cells are destroyed at the onset of type 1 diabetes in an immune onslaught that ultimately eliminates the body’s capacity to make insulin. But the beta cells don’t all die at once.

Earlier work suggested that a drug called anti-CD3 monoclonal antibody can reverse type 1 diabetes in mice by thwarting the immune attack before beta cell reserves are depleted. Scientists are currently testing anti-CD3 drugs in people with type 1 diabetes.

Kevan C. Herold, an immunologist at Yale University, reasoned that exendin-4 (exenatide), which helps to regulate insulin manufacture, might complement the effect of the anti-CD3 drug. In the new study, Herold and his colleagues found that mice that had high blood glucose—a sign that their remaining beta cells were making very little insulin—didn’t benefit any more from combined therapy than they did from the anti-CD3 alone.

However, some mice in the study had only marginally high blood-glucose readings. In these mice, the combined therapy reversed diabetes more effectively than either drug alone, the scientists report in the November Endocrinology. Exendin-4 revived idle beta cells and boosted their insulin production, Herold says.

“There’s no reason why you couldn’t give this drug to people with type 1 diabetes,” Herold says. “You might expect the effect could be quite dramatic if they had good numbers of beta cells to begin with.”