Cancer drug preserves insulin cells in diabetes

* Rituxan stops immune cells that destroy healthy tissue

* Single dose slowed development of diabetes

* Multiple doses may be required

By Gene Emery

BOSTON, Nov 25 (Reuters) - Rituxan, a drug used to treat cancer and rheumatoid arthritis, may help slow the development of newly discovered type 1 or juvenile diabetes, researchers reported on Wednesday.

The drug may interfere with the body's mistaken destruction of the insulin-producing cells in the pancreas, the researchers reported in the New England Journal of Medicine.

"What this study does is open the door to a whole new way to approaching type 1 diabetes," Dr. Mark Pescovitz of Indiana University, who led the study, said in a telephone interview.

Rituxan, known generically as rituximab, is made by Genentech, a unit of Roche Holding AG (ROG.VX: 行情), and Biogen Idec Inc. (BIIB.O: 行情). It was designed to wipe out immune cells known as B lymphocytes, which proliferate out of control in lymphoma.

The same cells are also involved in the autoimmune destruction of healthy cells and tissue seen in rheumatoid arthritis and, in theory, in juvenile diabetes.

Usually, by the time diabetes symptoms appear, 80 to 90 percent of those insulin-producing cells have been destroyed. The Pescovitz team gave Rituxan hoping to save the remaining cells.

The treatment worked at first and the body produced more insulin. But over time, the effects faded, and insulin production began to decline at the same rate as among people who received placebo.

Pescovitz said he was not disappointed. Further tests will show if repeated treatments with Rituxan or newer drugs that also eliminate B lymphocytes will keep insulin production up.

"When you look at rituximab in patients with rheumatoid arthritis, patients do require redosing at four- to six-month intervals," he said.

That was not tried in this study, said Pescovitz, because "at the time, we didn't know if it would work and we didn't know if it would be safe. So we aimed for a one-year endpoint and a single course of drug. We got what we hoped we would see."

About 15,000 children and teenagers in the United States are diagnosed with type 1 diabetes each year, according to the Center for Disease Control and Prevention. Type 1 diabetes accounts for about 5 percent of diabetes cases globally.