Comparing the effects of exenatide versus glimepiride in achieving glycaemic control in patients with type 2 diabetes mellitus poorly controlled with metformin

This study compared the efficacy and safety of exenatide versus glimepiride in achieving glycaemic (blood sugar) control in patients with type 2 diabetes mellitus (T2DM) uncontrolled by metformin. 

T2DM is a condition in which patients have high blood sugar levels (hyperglycemia). Metformin (Glucophage) is the most common drug used to treat patients with T2DM. However, sometimes metformin alone cannot effectively control blood sugar levels. Exenatide and glimepiride are drugs used as a supplement to metformin to achieve glycaemic control in T2DM patients. Exanatide (Byetta) is approved by the U.S FDA as treatment for patients with T2DM. It is administered through subcutaneous (under the skin) injections and works by stimulating the pancreas to produce insulin when blood sugar levels are high. Glimepiride (Amaryl) is an oral anti-diabetic drug that acts by increasing insulin release from the pancreas.

This study included 1029 patients with T2DM poorly controlled with metformin. Of these, 515 patients were randomly assigned to receive exenatide twice a day, while 514 patients received glimepiride once daily as additional drugs to metformin therapy. The authors of the study evaluated glycaemic control through the value of the glycated hemoglobin or HbA1c (a test that measures the average of blood sugar control from the last 2 to 3 months).

The results showed that 41% of patients in the exenatide group had treatment failure compared to 54% of patients treated with glimepiride. Additionally, 44% of patients in the exenatide group achieved glycaemic control compared to only 31% of glimepiride-treated patients. Also, patients who received exenatide had a significant decrease in body weight compared to those in the glimepiride group. Less patients in the exenatide group experienced hypoglycemia (abnormally low blood sugar levels) than patients treated with glimepiride. However, more patients treated with exenatide reported side effects such as nausea, vomiting, diarrhea or headaches in the first 6 months of treatment compared to patients in the glimepiride group.

In summary, this study showed that the addition of exenatide twice daily to metformin treatment improved glycaemic control and decreased hypoglycemic events compared with glimepiride once daily in T2DM patients uncontrolled by metformin alone.

The study is limited by the fact that the glimepiride dose used was fairly low.

This study was funded by Eli Lilly and Company and Amylin Pharmaceuticals, the manufacturers of Byetta.