Closing the Loop in Adults With Type 1 Diabetes and HbA1C<7.5% Under Free Living Conditions

The main objective of this study is to determine whether day and night closed-loop insulin delivery for 4 weeks under free living conditions is superior to usual insulin pump therapy in adults with type 1 diabetes and HbA1C\<7.5%. This is an open-label, multi center, randomized, crossover design study, involving a 2-4 week run-in period, followed by two 4 weeks study periods during which glucose levels will be controlled either by an automated day- and night closed-loop system or by subjects usual insulin pump therapy in random order. A total of up to 34 adults (aiming for 24 completed subjects) aged 18 years and older with T1D on insulin pump therapy and HbA1C\<7.5% will be recruited through diabetes clinics and other established methods in participating centers. Subjects will receive appropriate training in the safe use of closed-loop insulin delivery system. Subjects will have regular contact with the study team during the home study phase including 24/7 telephone support. The primary outcome is time spent in target range between 3.9 and 10.0 mmol/L as recorded by CGM during home stay. Secondary outcomes are time spent with glucose levels above and below target, as recorded by CGM, and other CGM-based metrics.