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Exenatide, a New Drug for Type 2 Diabetes

Exenatide adds another option for patients with type 2 diabetes who require additional therapy beyond metformin or sulfonylurea.

Glucagon-like peptide 1 (GLP-1), an intestinal peptide that is secreted in response to meals, has several antidiabetic effects, including stimulation of insulin secretion. Exenatide (Byetta) is a GLP-1–receptor agonist that recently was FDA-approved for treating type 2 diabetes.

In an industry-sponsored randomized trial, 336 patients with suboptimally controlled type 2 diabetes during metformin monotherapy (mean glycosylated hemoglobin [HbA_1c] level, 8.2%) received placebo or exenatide (5 or 10 µg), injected subcutaneously twice daily. Metformin therapy was continued. At 30 weeks, mean HbA_1c levels increased by 0.1% in the placebo group and decreased by 0.4% and 0.8%, respectively, in the 5-µg and 10-µg exenatide groups. Compared with placebo, exenatide reduced postprandial glucose excursions and induced weight loss (mean, about 2 kg). For all these endpoints, differences between placebo and both exenatide doses were significant. Exenatide frequently caused nausea, but this adverse effect tended to lessen over time. The incidence of hypoglycemia was similar in all groups.

A second industry-sponsored trial was similar in design to the first, except that 733 patients with suboptimal control on both metformin and a sulfonylurea were enrolled. Findings from this trial (and from a study published in 2004 that included only patients on sulfonylurea monotherapy) were similar to findings in the first trial.

Comment: Exenatide adds another option for patients with type 2 diabetes who require additional therapy beyond metformin or sulfonylurea. The requirement to inject this drug will be a downside for many patients, and data on longer-term outcomes are needed. This is the second injectable noninsulin diabetes drug to be FDA-approved in recent months: The other is pramlintide (Symlin; a synthetic analog of the pancreatic hormone amylin), which lowers blood glucose levels by several mechanisms. At the time of publication, the full text of the 2004 article was available free of charge.

— Allan S. Brett, MD

Published in Journal Watch General Medicine May 24, 2005

Citation(s):

DeFronzo RA et al. Effects of exenatide (exendin-4) on glycemic control and weight over 30 weeks in metformin-treated patients with type 2 diabetes. Diabetes Care 2005 May; 28:1092-100.

• Original article (Subscription may be required)
• Medline abstract (Free)

Kendall DM et al. Effects of exenatide (exendin-4) on glycemic control over 30 weeks in patients with type 2 diabetes treated with metformin and a sulfonylurea. Diabetes Care 2005 May; 28:1083-91.

• Original article (Subscription may be required)
• Medline abstract (Free)

Buse JB et al. Effects of exenatide (exendin-4) on glycemic control over 30 weeks in sulfonylurea-treated patients with type 2 diabetes. Diabetes Care 2004 Nov; 27:2628-35.

• Original article (Subscription may be required)
• Medline abstract (Free)