INTRODUCTIONTo lower the barrier for initiating insulin treatment and obtain adequate glycemic control in type 2 diabetes mellitus (T2DM), new basal insulin preparations with improved pharmacological properties and consequently a lower risk of hypoglycemia are needed. The objective of this trial was to confirm the efficacy and compare the safety of insulin degludec (IDeg) with insulin glargine (IGlar) in a multinational setting with two thirds of subjects enrolled in China.METHODSThis was a 26-week, randomized, open-label, parallel-group, treat-to-target, non-inferiority trial in 833 subjects with T2DM (48 % were female, mean age 56 years, diabetes duration 8 years), inadequately controlled on oral antidiabetic drugs (OADs). Subjects were randomized 2:1 to once-daily IDeg (555 subjects) or IGlar (278 subjects), both with metformin. The primary endpoint was the change from baseline in glycosylated hemoglobin (HbA1c) after 26 weeks.RESULTSThe completion rate was high (IDeg 94.2 %; IGlar 91.4 %). Mean HbA1c decreased from 8.3 to 7.0 % in both groups. Estimated treatment difference (ETD) [95 % confidence interval (CI)] IDeg-IGlar in change from baseline was -0.05 % points [-0.18 to 0.08], confirming the non-inferiority of IDeg to IGlar. The proportion of subjects achieving HbA1c <7.0 % was 54.2 and 51.4 % with IDeg and IGlar, respectively (estimated odds ratio [95 % CI] IDeg/IGlar: 1.14 [0.84 to 1.54]). The mean decrease in fasting plasma glucose, self-measured plasma glucose profiles, and insulin dose were similar between groups. Numerically lower rates of overall (estimated rate ratio [95 % CI] IDeg/IGlar: 0.80 [0.59 to 1.10]) and nocturnal (0.77 [0.43 to 1.37]) confirmed hypoglycemia were observed with IDeg compared with IGlar. No treatment differences in other safety parameters were found. Subjects were more satisfied with the IDeg device compared with the IGlar device as reflected by the total Treatment Related Impact Measures-Diabetes Device score (ETD [95 % CI] IDeg-IGlar: 2.2 [0.2 to 4.3]).CONCLUSIONIDeg provided adequate glycemic control non-inferior to IGlar and a tendency for a lower hypoglycemia rate. IDeg is considered suitable for initiating insulin therapy in T2DM patients on OADs requiring intensified treatment.TRIAL REGISTRATIONClinicaltrials.gov NCT01849289.