Background: Progressive weight gain in patients with type 2 diabetes and obesity on insulin therapy is a challenge to achieving good glycaemic control. The combination of exenatide and insulin has shown some reduction in weight and HbA1c in this group of patients in the UK and USA. This treatment combination is not subsidized by the pharmaceutical benefit scheme (PBS) in Australia    

Objective: To test the efficacy and safety of exenatide in insulin-treated patients with type 2 diabetes 

  Methods: Patients with poorly-controlled type 2 diabetes or progressive weight gain on large doses of insulin therapy were initiated on twice-daily exenatide funded by the hospital. Weight, total daily insulin dose and HbA1c were measured at baseline and 3 months. Adverse effects during treatment were recorded. Wilcoxon signed rank test was used to compare these parameters.

 Results: Thirty patients had been commenced on a combination of exenatide and insulin therapy. Ten patients ceased exenatide before 3 months owing to adverse effects (nausea, vomiting) and non-adherence to treatment. In the remaining 20 patients, there was a significant reduction in weight, HbA1c and total daily insulin dose (p<0.05). Median change in weight was -2.2kg (range -13 to +5.5kg). Median change in HbA1c was -1.1% (range -4.2 to +1.8%). Median change in total daily insulin dose was -20.5units (range -414 to +54units). Sixteen patients had a reduction of total daily insulin doses (range -7 to -414 units) whilst 4 patients had an increase in insulin doses (range 10 to 54 units).

Conclusion: Adding exenatide to insulin in this small patient group showed a significant reduction in HbA1c, weight and insulin requirement after three months. Identifying patients with type 2 diabetes and obesity on insulin who will respond to an addition of exenatide is important as this treatment should be considered in this group of patients.