Fast Acting Insulin Aspart Compared with Insulin Aspart in the Medtronic 670G Hybrid Closed Loop System in Type 1 Diabetes: An Open Label Crossover Study

This is a single-center randomized open label active-controlled crossover trial comparing efficacy and safety of fast acting insulin aspart (FA) (FIASP ® ) versus insulin aspart (IAsp) (NovoLog ® ) when used in the Medtronic 670G system in auto mode in patients with type 1 diabetes. Forty patients were randomized to either IAsp or FA. Each treatment period was 7 weeks and a standardized meal test was administered 6 weeks after the start of each treatment period. The primary endpoint was postprandial glucose (PPG) increment after the meal test at 1 h. Treatment with FA using the MiniMed 670G hybrid closed loop (HCL) led to a greater reduction in 1-h postprandial glucose increase compared with treatment with IAsp during the standardized mixed meal test. Change in glucose: [estimated treatment difference (ETD ± standard deviation [SD]); 95% confidence interval]: 70.27 (±17.36) mg/dL (3.9 ± 1.0 mmol/L) with FA versus 98.42 (±17.36) mg/dL (5.5 ± 1.0 mmol/L) with IAsp ( P  = 0.008). Patients spent 1.81% ( P  = 0.016) more time (equivalent to 26 min per day) in the 70-180 mg/dL (3.89-9.99 mmol/L) range with FA than with IAsp. The entire sample spent only 0.5% of time <54 mg/dL (<3.0 mmol/L) range. The increment in the 1 h postmeal test glucose was significantly lower with FA versus IAsp. FA in a HCL setting is safe and effective with patients spending more time in the 70-180 mg/dL (3.89-9.99 mmol/L) target range than with IAsp. Trial registration: Clinicaltrials.gov identifier: NCT03977727.