An Open-label, Multi-centre, Randomised, 2-period Cross-over Study to Assess the Efficacy and Safety of Closed Loop Insulin Delivery Using Diluted Insulin in Comparison With Closed Loop With Non-diluted Insulin Over 21 Days in Children With Type 1 Diabetes Aged 1 to 7 Years in the Home Setting

The suggested clinical trial is part of the KidsAP project funded by the European Commission's Horizon 2020 Framework Programme. The project evaluates the use of the Artificial Pancreas (or closed loop systems) in very young children with type 1 diabetes (T1D) aged 1 to 7 years. The suggested trial is a feasibility study to pilot the setup of a large-scale outcome trial and to address the specific needs of this population. The results of the pilot trial will feed into the design of the outcome study.

In this study the investigators will compare closed loop insulin delivery using standard strength insulin to closed loop use with diluted insulin in very young children with T1D. Diluted insulin is a standard treatment approach for children with low insulin requirements. The investigators hypothesize that diluted insulin will lead to more stable glucose levels by reducing inaccuracies accentuated by delivery of minute amounts of insulin (frequently less than 0.1U/h [1μl/h with standard strength insulin] in small children compared to 1U/h in adults). These inaccuracies may result from pump plunger micro-jumps, tissues pressure build-up, and infusion set kinking. This study builds on previous and on-going studies of closed loop systems that have been performed in Cambridge in children and adolescents with T1D in clinical research facilities and in the home setting.

The study adopts an open-label, multi-centre, multinational, randomised, two-period crossover design contrasting closed loop glucose control using diluted insulin and closed loop using standard insulin strength under free-living home conditions. The two intervention periods will last 3 weeks each with a 1 to 4 weeks washout period in between. The order of the two interventions will be random. A total of up to 30 young children aged 1 to 7 years with T1D on insulin pump therapy will be recruited through outpatient diabetes clinics at participating clinical centres to allow for 24 completed subjects available for assessment in each of the study arms.

Prior to the use of study devices, participants and parents/guardians will receive appropriate training by the research team on the safe use of the study pump and continuous glucose monitoring system, and the hybrid closed loop insulin delivery system. Carers at nursery or school may also receive training by the study team if required. During the intervention periods, subjects and parents/guardians will use the closed loop system for 21 days under free-living conditions in their home and nursery/school environment without remote monitoring or supervision by research staff.

The primary outcome is time spent in target range between 3.9 and 10.0 mmol/l as recorded by CGM. Secondary outcomes are the time spent with glucose levels above and below target, as recorded by CGM, and other CGM-based metrics. Safety evaluation comprises the tabulation of severe hypoglycaemic episodes.