Adding saxagliptin to extended-release metformin vs. uptitrating metformin dosage

Aim: To investigate whether patients taking metformin for type 2 diabetes mellitus (T2DM) have improved glycaemic control without compromising tolerability by adding an agent with a complementary mechanism of action vs. uptitrating metformin. Methods: Adults with T2DM and glycated haemoglobin (HbA1c) between 7.0 and 10.5% receiving metformin extended release (XR) 1500 mg/day for ≥8 weeks were randomized to receive saxagliptin 5 mg added to metformin XR 1500 mg (n = 138) or metformin XR uptitrated to 2000 mg/day (n = 144). Endpoints were change from baseline to week 18 in HbA1c (primary), 120‐min postprandial glucose (PPG), fasting plasma glucose (FPG) and the proportion of patients achieving HbA1c <7%. Results: At week 18, the adjusted mean reduction from baseline HbA1c was ?0.88% for saxagliptin + metformin XR and ?0.35% for uptitrated metformin XR (difference, ?0.52%; p < 0.0001). For 120‐min PPG and FPG, differences in adjusted mean change from baseline between saxagliptin + metformin XR and uptitrated metformin XR were ?1.3 mmol/l (?23.32 mg/dl) (p = 0.0013) and ?0.73 mmol/l (?13.18 mg/dl) (p = 0.0030), respectively. More patients achieved HbA1c <7.0% with saxagliptin + metformin XR than with uptitrated metformin XR (37.2 vs. 26.1%; p = 0.0459). The proportions of patients experiencing any adverse events (AEs) were generally similar between groups; neither group showed any notable difference in hypoglycaemia or gastrointestinal AEs. Conclusion: Adding saxagliptin to metformin XR provided superior glycaemic control compared with uptitrating metformin XR without the emergence of additional safety concerns (Clinical Trials.gov registration: NCT00960076).