Combination sitagliptin/metformin improved beta-cell function, HbA1c at two years

American Diabetes Association 68th Scientific Sessions

Initial combination therapy with sitagliptin and metformin substantially improved blood glucose levels and markers of beta cell function in patients with type 2 diabetes at one and two years compared with monotherapy, according to data released at the 68th Annual Scientific Sessions of the American Diabetes Association.

Researchers examined the effect of initial combination therapy with sitagliptin (Januvia, Merck), a selective, once-daily dipeptidyl peptidase-4 inhibitor, and metformin in patients with type 2 diabetes. Patients were randomly assigned to one of five treatment groups: sitagliptin 100 mg/metformin 1,000 mg twice daily; sitagliptin 100 mg/metformin 2,000 mg twice daily; metformin 1,000 mg twice daily; metformin 2,000 mg twice daily; or sitagliptin 100 mg once daily. The study began with a 24-week, placebo-controlled phase (n=1,091), followed by a 30-week, double-blind, active-controlled period (n=762) and a study extension out to two years (n=587).

A subset of patients underwent a standard sampled meal tolerance test at week 54 (n=203) and/or week 104 (n=125) to assess beta cell function. At both dates, combination sitagliptin/metformin produced greater changes in beta cell function compared with either therapy alone.

Patients treated with combination sitagliptin/metformin experienced beneficial changes in glycemic control at two years (1.7% sitagliptin 50 mg/metformin 500 mg; 1.4% sitagliptin 50 mg/metformin 500 mg). Changes in HbA1c were smaller with metformin alone (1.3% metformin 1,000 mg; 1.1% metformin 500 mg) and sitagliptin alone (1.2%). – by Katie Kalvaitis

From the perspective of a physiologist, these researchers have characterized beta cell function in the best way that they could. They’ve shown that beta cell function is preserved and/or improved after one year or two years of therapy. No matter what you do beta cell function deteriorates with time. We continue to look for the drug that will do the trick for glucose but will also preserve beta cell function. From these study data, sitagliptin in combination with metformin can do that.

– Nir Barzilai, MD

Director, Animal Physiology Core, Diabetes Research Training Center,
Albert Einstein College of Medicine, New York

For more information:

Williams-Herman D, Xu L, Davies MJ, et al. Substantial improvement in beta-cell function with initial combination therapy of sitagliptin and metformin in patients with type 2 diabetes after one year of treatment. 543-P. Presented at: American Diabetes Association 68th Scientific Sessions; June 6-10, 2008; San Francisco