Diabetes Treatment Falls Short in Study

In a large-scale test, transplanted pancreas cells eliminated the need for insulin in some diabetes patients, but for many the benefit was short-lived.

In numerous cases in which the treatment was initially successful, too many transplanted cells eventually stopped working.

The authors of the study, published in today’s issue of the New England Journal of Medicine, said that refining their methods should improve the success rate.

Chief study author James Shapiro of the University of Alberta in Edmonton, Canada, said the transplanted cells seemed to stop working because not enough survived the initial transplant.

“We’ve only got a small number of cells that end up engrafting, and they’re all having to work at maximum capacity,” Shapiro said. “When an engine runs at 3,000 revs every minute of the day and doesn’t get a break, eventually some of them start to burn out.”

The technique, originally announced in 2000, is known as the Edmonton protocol.

This was the first international test of the method, to see if it could successfully be applied on a large scale.

It was designed to help people with Type 1 diabetes, an autoimmune disease that destroys pancreas cells that produce the insulin needed to process blood sugar. Type 1 diabetes affects as many as 2 million Americans.

Processed pancreas cells from dead donors were given to 36 patients in North America and Europe. The treatment was tested in “the worst of the worst” patients, Shapiro said.

A year later, 44% no longer needed insulin because the injected cells were processing blood sugar properly. An additional 28% needed significantly less insulin. But at the two-year mark, 11 of the 16 patients who responded best were back on insulin.

“Analyzed another way, 58% of subjects reached insulin independence at some point during the trial, but 76% had become insulin-dependent again by two years after transplantation,” Jonathan Bromberg and Derek LeRoith of the Mount Sinai School of Medicine in New York wrote in a Journal editorial.

The study shows that more research is needed before this technique approaches the success rate of a regular pancreas transplant, they wrote. When a patient receives the entire organ instead of processed cells, they added, the success rate is 50% to 70% after five years.