INTRODUCTION
Weight gain in patients with type 2 diabetes and obesity on insulin therapy is a challenge to improving glycaemic control. Prior to the Pharmaceutical Benefit Scheme extended listing of exenatide in combination with insulin in October 2015, the Lyell McEwin Hospital (LMH) funded this treatment combination for selected patients.

OBJECTIVES
To study the efficacy and safety of exenatide in insulin-treated patients.

METHODS
Patients on insulin with progressive weight gain were started on exenatide. Weight, HbA1c and total daily insulin dose was measured at 3 months , 6 months, 1 year, 2 years and 3 years. Paired t tests and Wilcoxon signed rank test were used for statistical analysis.

RESULTS
Sixty-nine patients were started on a combination of insulin and exenatide between January 2011 to December 2013.
At 3 and 6 months, the mean weight reduction were 2.2 ± 4.5kg and 2.8± 4.8kg (P<0.05); the mean HbA1c reduction were 0.8± 1.4% and 0.9± 1.6% (p<0.05); and the mean reduction in total daily insulin doses were 52 ± 92 units (p<0.05) and 16 ±56 units (p= 0.23), respectively.

At 1 year and 2 years, the median weight reduction were 0.4kg (-35.4 to +7.5kg), W=93.5, P<0.05 and 6.4kg ( -28.5 to +3.8kg), W=14.5, P<0.05; median reduction in HbA1c were 1.3% ( -3.3 to +2.0%), W=85.5, p<0.05 and 2.0% (-4.2 to + 0.3%), W=3 , p<0.05; and the median reduction in insulin doses were 26 units (-256 to +120units), W=102.5, p<0.05 and 40 units (-350 to + 120 units), W=37, p<0.05, respectively.

At 3 years (n=7), there was a high rate of discontinuation and data was insufficient for analysis.

CONCLUSION
Exenatide and insulin combination was effective in reducing HbA1c, weight and insulin requirement in some patients up to 2 years. Over 50% of patients discontinued exenatide owing to lack of benefit or gastrointestinal side effects.