Vildagliptin versus insulin in patients with type 2 diabetes mellitus inadequately controlled with sulfonylurea: results from a randomized, 24 week study

Objective: There is limited evidence to guide the selection of second-line anti-hyperglycemic agents in patients with type 2 diabetes mellitus (T2DM) who are inadequately controlled with sulfonylurea monotherapy and are intolerant to metformin. We compared the efficacy and safety of vildagliptin 50 mg qd and Neutral Protamine Hagedorn (NPH) insulin qd in such patients. Methods: This was a 24 week, multicenter, randomized, open-label study. The co-primary endpoints were (i) proportion of patients achieving HbA1c <7.0% without any confirmed hypoglycemic events (HEs) or weight gain >= 3% (composite endpoint); (ii) rate of confirmed HEs. Treatment satisfaction was assessed using the TSQM-9 questionnaire at study end. Results: A total of 162 patients were randomly assigned to vildagliptin (n=83) and NPH insulin (n=79). Similar proportion of patients achieved the composite endpoint in vildagliptin versus NPH insulin group (35.4% versus 34.2%; OR 0.985; 95% Cl 0.507, 1.915; p=0.96). After 24 weeks, 48.8% of patients in the vildagliptin group and 60.8% in the NPH insulin group achieved HbA1c <7.0%; 13.4% in the vildagliptin group and 29.1% in the insulin group had at least one confirmed HE; while 11.0% in the vildagliptin group and 22.8% in the insulin group experienced weight gain. The rate of confirmed HEs was significantly lower in patients receiving vildagliptin versus NPH insulin (1.3 versus 5.1 events per year). The TSQM-9 score for 'convenience' at week 24 increased significantly more with vildagliptin than with NPH insulin. Conclusions: Addition of vildagliptin and NPH insulin resulted in a similar number of patients reaching HbA1c target without HEs or weight gain in T2DM patients inadequately controlled with sulfonylurea. The addition of vildagliptin to sulfonylurea could be considered as a treatment option prior to intensification with insulin, with the advantages of a lower HE rate and greater patient convenience. Study results are limited by a higher drop-out rate in the vildagliptin arm.