Efficacy and safety of linagliptin added to metformin and sulphonylurea in Chinese patients with type 2 diabetes: a sub-analysis of data from a randomised clinical trial

Objectives: To evaluate the efficacy and safety of linagliptin in Chinese patients with type 2 diabetes mellitus (T2DM) inadequately controlled by metformin and sulphonylurea. Research design and methods: Data for a pre-defined Chinese subgroup who participated in a Phase III randomised, placebo-controlled, 24 week trial (NCT00602472) were analysed. The primary endpoint was change in HbA1c from baseline to 24 weeks. Apart from safety endpoints, secondary endpoints included changes in FPG and measures of insulin secretion and resistance. Results: A total of 192 Chinese patients with T2DM participated in the pre-defined analysis; 144 and 48 patients received linagliptin or placebo, respectively, added to metformin and sulphonylurea. Baseline characteristics (mean [+/- SD]) for linagliptin and placebo were similar: HbA1c: 8.1% (+/- 0.85) and 8.1% (+/- 0.84); body mass index: 25.9 (+/- 3.2) and 25.6 (+/- 3.4) kg/m(2), respectively. Placebo-corrected mean (+/- SE) change in HbA1c from baseline at 24 weeks was -0.68% (0.14) with linagliptin-based treatment (95% CI: -0.96 to -0.39; P<0.0001). Placebo-corrected mean (+/- SE) change in FPG from baseline at 24 weeks with linagliptin was -18.8 (6.5) mg/dL (-1.0 [0.4] mmol/L; 95% CI: -31.7 to -5.9; P = 0.0044). Overall adverse event (AE) rates with linagliptin and placebo including background medication were similar (38.9% and 43.8%, respectively). Drug-related AEs were reported by 12.5% and 2.1% of linagliptin and placebo patients, respectively. Differences were due to hypoglycaemia (10.4% and 0.0%, respectively). No severe hypoglycaemia was reported in either group of this sub-population. Conclusion: Linagliptin in combination with metformin and sulphonylurea has a favourable safety profile and is an efficacious and well tolerated treatment option for Chinese patients with inadequately controlled T2DM. Reduction of sulphonylurea dose should be considered to minimise risk of hypoglycaemia. Although the findings of this pre-specified sub-analysis may be limited by the number of patients in the subgroup, the results were generally consistent with those for the overall population.