A small study of people with type 2 diabetes who were taking antidiabetes pills plus insulin injections indicates that it may be feasible to replace insulin with injections of Byetta.

An accompanying editorial, however, is highly critical of the study, noting among other things that “no attempt was made to optimize insulin therapy” before substituting Byetta.

Byetta, which is known generically as exenatide, mimics the effect of incretin hormones that are produced in the gastrointestinal tract and boost the release of insulin triggered by glucose. In 2005, the US Food and Drug Administration approved exenatide as add-on treatment for type 2 diabetes.

The current study and editorial are published in the November issue of Diabetes Care.

Dr. Stephen N. Davis of Vanderbilt University in Nashville, Tennessee, and colleagues studied 49 patients who had type 2 diabetes for an average of 11 years and were on insulin plus oral antidiabetes drugs. The subjects were assigned either to Byetta, which replaced insulin, or to continue on their current treatment.

The researchers, most of whom are affiliated with Byetta makers Amylin Pharmaceuticals, Inc. and Eli Lilly and Company, report that the average A1C, which measures blood glucose levels over a period of time, rose slightly in the Byetta group and dropped a little in the insulin group during the 16-week study.

Eighteen of the 29 patients in the exenatide group achieved good glucose control, and the majority of these 18 patients also had reductions in A1C.

The researchers note that 79 percent of the exenatide group reported an adverse event compared with 56 percent of the insulin group.

In the editorial, Drs. Julio Rosenstock, of the Dallas Diabetes and Endocrine Center, and Vivian Fonseca, of Tulane University, New Orleans, write, “The overall effect on glycemic control was rather disappointing.”

They conclude, “This was clearly a negative trial, with a flawed study design and a conclusion that perhaps should have been stronger against substituting exenatide for insulin.”

SOURCE: Diabetes Care, November 2007.