A 52-week extension study of switching from gemigliptin vs sitagliptin to gemigliptin only as add-on therapy for patients with type 2 diabetes who are inadequately controlled with metformin alone.

We investigated the long-term efficacy and safety of gemigliptin and the efficacy and safety of gemigliptin treatment after once-daily treatment with sitagliptin 100 mg, in patients with type 2 diabetes. This was a 28-week extension of a 24-week, randomized, double-blind, parallel study of gemigliptin or sitagliptin added to ongoing metformin therapy. After randomization to sitagliptin 100 mg qd (S), gemigliptin 25 mg bid (G1) or gemigliptin 50 mg qd (G2) and after completing 24 weeks of treatment, 118 patients switched from gemigliptin 25 mg bid to 50 mg qd (G1/G2), 111 patients continued gemigliptin 50 mg qd (G2/G2) and 106 patients switched from sitagliptin 100 mg qd to gemigliptin 50 mg qd (S/G2). All 3 treatments reduced glycated haemoglobin (HbA1c) (S/G2,-0.99% [95% CI -1.25%, -0.73%]; G1/G2, -1.11% [95% CI -1.33%, -0.89%]; G2/G2, -1.06% [95% CI -1.28%, -0.85%]). The percentage of patients achieving HbA1c < 6.5% was 27.6% in the G1/G2 group at both Week 24 and Week 52, and ranged from 27.3% to 32.7% in the G2/G2 group (difference in proportions, 5% [95% CI -6%, 17%]), while it increased from 6.8% to 27.3% from Week 24 to Week 52 in the S/G2 group (difference in proportions, 20% [95% CI 7%, 34%]). Addition of gemigliptin 50 mg qd to metformin was shown to be efficacious for 52 weeks. Switching from sitagliptin 100 mg to gemigliptin 50 mg showed consistent glyacemic control over the previous treatment.