Comparison of the Efficacy and Safety of Two Intensification Strategies in Subjects With Type 2 Diabetes Inadequately Controlled on Basal Insulin and Metformin

Inclusion Criteria: * Informed consent obtained before any trial-related activities. (Trial-related activities are any procedure that would not have been performed during normal management of the subject). * The subject must have completed the end of treatment visit of NN1250-3643 with Insulin degludec once daily + metformin. * Ability and willingness to adhere to the protocol including self measurement of plasma glucose according to the protocol Exclusion Criteria: * Participated in NN1250-3643 and treated with insulin glargine * Previous treatment with glucacon like peptide (GLP-1) receptor agonists (e.g. exenatide, liraglutide) * Impaired liver function, defined as alanine aminotransferase (ALAT) 2.5 times the upper limit of normal at end of treatment in NN1250-3643 * Impaired renal function defined as serum-creatinine = 125 µmol/l (= 1.4 mg/dl) for males and = 110 µmol/L (= 1.3 mg/dl) for females or according to local label for metformin \[For France: glomerular filtration rate below 60 ml/min, calculated by the Cockroft \& Gault formula\] at end of treatment in NN1250-3643.