Diabetes, Endocrinology & Metabolism

The first once weekly diabetes drug has been approved by the Food and Drug Administration. An extended-release formulation of the type 2 diabetes medication exenatide, a glucagon-like peptide-1 (GLP-1) receptor, was approved on Jan. 27, the manufacturer announced.

The formulation, called Bydureon, is administered once a week in a subcutaneous injection, and is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes. The regular formulation of exenatide (Byetta), approved in 2005, is administered twice a day.

Approval was based on the results of the DURATION-5 study, which compared treatment with the two formulations in 252 patients with type 2 diabetes and inadequate glycemic control (mean baseline hemoglobin A_1c was 8.4%) with diet and exercise alone or with oral therapy, including metformin, a sulfonylurea, a thiazolidinedione, or a combination of two of these treatments.

The mean reduction in HbA_1c was 1.6 percentage points among those treated with 2 mg of extended-release exenatide once weekly, compared with a mean reduction of 0.9 percentage points among those treated with the regular form of exenatide (starting at 5 mcg twice daily increasing to 10 mcg twice daily after 4 weeks), a statistically significant difference, according to the prescribing information and the press release.

Extended-release exenatide has been approved with a Risk Evaluation and Mitigation Strategy (REMS), to ensure that the benefits of the drug outweigh the risks of acute pancreatitis and the "potential" risk of medullary thyroid cancer with treatment. There have been postmarketing reports of pancreatitis associated with exenatide, including nonfatal hemorrhagic or necrotizing pancreatitis.

In rats, extended-release exenatide causes thyroid C-cell tumors at clinically relevant exposures, but at this point, the relevance to humans is not known, according to a boxed warning in the prescribing information. It is contraindicated in people with a personal or family history of medullary thyroid cancer or those with Multiple Endocrine Neoplasia syndrome type 2 (MEN2).

01/27/12