Weekly exenatide reformulation lowers HbA1c more than twice-daily dose, study reports

A new study shows that a special formulation of exenatide taken once-weekly led to better HbA1c levels compared to those who took standard exenatide (Byetta) twice-daily.
Exenatide, a GLP-1 agonist drug prescribed for type 2 diabetes, works by increasing insulin secretion and lowering appetite. In its form as Byetta, the drug is injected twice daily.
Researchers from Rockwood Center for Diabetes and Endocrinology at the Rockwood Clinic in Spokane in Washington have been carrying out a number of studies to test whether a reformulated form of the drug improves its effectiveness.
A group of 375 people with type 2 diabetes received either a higher, longer-acting dose (taken once per week) or a lower, shorter-acting dose (taken twice per day) of exenatide for 28 weeks, with the primary outcome changes in HbA1c. The longer-acting dose is a reformulated form of exenatide in which the active molecules are packaged inside biodegradable microsphere and diluted with Miglyol, an MCT oil used as a drug carrier.
Within the study, participants took exenatide in addition to other diabetes medication they were taking, which included any of the following: metformin, sulphonylureas and thiazolidinediones (TZDs).
The results showed that HbA1c levels decreased to a greater degree in the reformulated once-weekly dose group, an average reduction of 15 mmol/mol (1.4%) compared to 11 mmol/mol (1%) in the twice-daily group.
However, the researchers found that after 28 weeks there were no differences between the two groups for weight loss.
A greater number of adverse events were reported in patients on the reformulated once-weekly dose (162 adverse events) compared with the standard twice-daily formulation (108 adverse events). There were lower rates of gastrointestinal side effects in the reformulated exenatide group but greater incidences of hypoglycemia and injection-site nodules.
The findings appear in the journal Diabetes, Obesity and Metabolism.