Sitagliptin and the Risk for Hypoglycaemia in Type 2 Diabetes Patients

Inclusion Criteria: * Male or female subject with diabetes mellitus type 2. * Age between 18 and 64 years, both inclusive. * HbA1c \<= 8.5%. * Stable treatment with insulin glargine (any dose) and metformin (\>= 1500 mg/day or at highest tolerated dose) for at least 3 months prior to inclusion into the trial with or without additional oral glucose-lowering agents (except thiazolidinediones). * Considered generally healthy (apart from diabetes mellitus type 2 and associated conditions such as hypertension, hyperlipidaemia and hyperuricaemia) upon completion of medical history, physical examination, vital signs, ECG and analysis of laboratory safety variables, as judged by the Investigator. Exclusion Criteria: * Known or suspected hypersensitivity to sitagliptin or related products. * More than one episode of severe hypoglycaemia with seizure, coma or requiring medical assistance of another person during the past 6 months or hypoglycaemic unawareness as judged by the Investigator. * Current or previous treatment (less than 3 months prior to screening) with insulin products other than insulin glargine and/or with Glucagon-like peptide (GLP) 1 receptor agonists and/or with thiazolidinediones. * Unwillingness to wash-off any oral glucose-lowering agents other than metformin.