Efficacy and Safety of Insulin Degludec in a Flexible Dosing Regimen vs Insulin Glargine in Patients With Type 1 Diabetes (BEGIN: Flex T1): A 26-Week Randomized, Treat-to-Target Trial With a 26-Week Extension

OBJECTIVE: This study investigated the efficacy and safety of insulin degludec (IDeg) once daily (OD), varying injection timing day to day in subjects with type 1 diabetes. RESEARCH DESIGN AND METHODS: This 26-week, open-label, treat-to-target, noninferiority trial compared IDeg forced flexible (Forced-Flex) OD (given in a fixed schedule with a minimum 8 and maximum 40 hours between doses) with IDeg or insulin glargine (IGlar) given at the same time daily OD. In the 26-week extension, all IDeg subjects were transferred to a free-flexible (Free-Flex) regimen, which allowed any-time-of-day dosing, and compared with subjects continued on IGlar. RESULTS: After 26 treatment weeks, mean glycosylated hemoglobin was reduced with IDeg Forced- Flex (−0.40%), IDeg (−0.41%), and IGlar (−0.58%). IDeg Forced-Flex noninferiority was achieved. Fasting plasma glucose reductions were similar with IDeg Forced-Flex and IGlar but greater with IDeg (−2.54 mmol/L) than IDeg Forced-Flex (−1.28 mmol/L) (P = .021). At week 52, IDeg Free-Flex subjects had similar glycosylated hemoglobin but greater fasting plasma glucose reductions than IGlar subjects (−1.07 mmol/L) (P = .005). Confirmed hypoglycemia rates (plasma glucose <3.1 mmol/L or severe hypoglycemia) were similar at weeks 26 and 52. Nocturnal confirmed hypoglycemia was lower with IDeg Forced-Flex vs IDeg (37%; P = .003) and IGlar (40%; P = .001) at week 26 and 25% lower with IDeg Free-Flex vs IGlar (P = .026) at week 52. CONCLUSIONS: IDeg can be administered OD at any time of day, with injection timing varied without compromising glycemic control or safety vs same-time-daily IDeg or IGlar. This may improve basal insulin adherence by allowing injection-time adjustment according to individual needs.