Efficacy and Safety of Switching From Sitagliptin to Liraglutide in Subjects With Type 2 Diabetes Not Achieving Adequate Glycaemic Control on Sitagliptin and Metformin

Inclusion Criteria: * \- Informed consent obtained before any trial-related activities. Trial-related activities are any procedures that are carried out as part of the trial, including activities to determine suitability for the trial * \- Subjects diagnosed with type 2 diabetes and treated with metformin equal to or above 1500 mg/day (or maximum tolerated dose equal to or above 1000 mg/day) and sitagliptin 100 mg/day, both at a stable dose for at least 90 days prior to screening. Stable is defined as unchanged medication and dose * \- HbA1c 7.5% - 9.5% (58 mmol/mol - 80 mmol/mol) (both inclusive) * \- Body mass index equal to or above 20 kg/m\^2 Exclusion Criteria: * \- Any chronic disorder or severe disease which at the discretion of the investigator might jeopardise subject's safety or compliance with the protocol * \- Treatment with glucose lowering agent(s) other than stated in the inclusion criteria in a period of 90 days prior to screening. An exception is short-term treatment (equal to or less than 7 days in total) with insulin in connection with intercurrent illness * \- Female who is pregnant, breast-feeding, intends to become pregnant or of child-bearing potential not using adequate contraceptive methods (adequate contraceptive measures as required by local regulations or practice) * \- History of chronic pancreatitis or idiopathic acute pancreatitis * \- Screening calcitonin value equal to or above 50 ng/L * \- Personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2 * \- Diagnosis of malignant neoplasm in the previous 5 years (except basal cell skin cancer or squamous cell skin cancer) * \- Impaired liver function, defined as alanine aminotransferase equal to or above 2.5 times upper normal limit * \- Impaired renal function defined as estimated glomerular filtration rate 60 mL/min/1.73 m\^2 per modification of diet in renal disease formula * \- Any episode of unstable angina, acute coronary event, cerebral stroke/transient ischemic attack or other significant cardiovascular event as judged by the investigator within 90 days prior to screening * \- Heart failure, New York Heart Association class IV * \- Uncontrolled treated or untreated hypertension (systolic blood pressure equal to or above 180 mmHg and/or diastolic blood pressure equal to or above 100 mmHg)