Efficacy and safety over 26 weeks of an oral treatment strategy including sitagliptin compared with an injectable treatment strategy with liraglutide in patients with type 2 diabetes mellitus inadequately controlled on metformin: a randomised clinical trial

The aim of this work was to compare treatment intensification strategies based on orally administered vs injectable incretin-based antihyperglycaemic agents in patients with type 2 diabetes mellitus on metformin monotherapy.

In a 26 week, open-label study, 653 patients (baseline HbA_1c = 8.2% [66 mmol/mol]) were randomised at 111 sites in 21 countries in a 1:1 ratio to a strategy using oral agents (starting with sitagliptin 100 mg/day) or a strategy using the injectable drug liraglutide starting at a dose of 0.6 mg/day, up-titrated to 1.2 mg/day after 1 week. The following patients with type 2 diabetes mellitus were recruited for the study: those aged 18–79 years, on a stable dose of metformin monotherapy ≥1,500 mg/day for ≥12 weeks, with an HbA_1c ≥7.0% (53 mmol/mol) and ≤11.0% (97 mmol/mol) and a fasting fingerstick glucose (FFG) <15 mmol/l (<270 mg/dl) at the randomisation visit, deemed capable by the investigator of using a Victoza pen injection device (containing 6 mg/ml liraglutide; Novo Nordisk, Bagsværd, Denmark). Women taking part in the study agreed to remain abstinent or use an acceptable method of birth control during the study. Randomisation was performed via a computer-generated allocation schedule using an interactive voice response system. After 12 weeks, patients on sitagliptin with HbA_1c  ≥ 7.0% (53 mmol/mol) and fasting glucose >6.1 mmol/l had their treatment intensified with glimepiride; patients on liraglutide with HbA_1c  ≥ 7.0% (53 mmol/mol) had the dose up-titrated to 1.8 mg/day. The primary analysis assessed whether the strategy using oral drugs was non-inferior to that using an injectable drug regarding HbA_1c change from baseline at week 26 using a per-protocol (PP) population and a non-inferiority margin of 0.4%.

In the PP population (522 patients included: oral strategy, n = 269; injectable strategy, n = 253) antihyperglycaemic therapy was intensified at week 12 in 50.2% and 28.5%, respectively. HbA_1c decreased over 26 weeks in both treatment strategy groups, with a larger initial reduction at week 12 in the injectable strategy group. The LS mean change in HbA_1c at week 26 was −1.3% (95% CI −1.4, −1.2) in the oral strategy group and −1.4% (95% CI −1.5, −1.3) in the injectable strategy group; the study met the non-inferiority criterion. Both treatment regimens were generally well tolerated; hypoglycaemia was reported more often with the oral strategy, while nausea, vomiting, diarrhoea and abdominal pain were reported more often with the injectable strategy.

An oral, incretin-based treatment strategy with sitagliptin and, if needed, glimepiride may be a good approach in many patients with type 2 diabetes mellitus for managing inadequate glycaemic control on metformin monotherapy, as compared with an injectable treatment strategy with liraglutide. The oral and injectable strategies had similar effects on HbA_1c and had good overall tolerability.