Closing the Loop in People With Type 1 Diabetes

The main objective of this study is to determine whether home use of fully closed-loop glucose control applying age-approved ultra-rapid insulin (Phase 2) is superior to standard insulin pump therapy with continuous glucose monitoring (CGM) in adolescents with type 1 diabetes on insulin pump therapy with sub-optimal glycaemic control (HbA1c ≥ 7.5% [Phase 2]).This is an open-label, multi-centre, randomised, crossover design study, involving a run-in period followed by two study periods during which glucose levels will be controlled either by an automated closed-loop system using age-approved ultra-rapid insulin or by participants' usual insulin pump therapy with continuous glucose monitoring in random order. A total of up to 30 adolescents (aiming for 24 completed participants) with T1D on insulin pump therapy will be recruited through diabetes clinics and other established methods.Participants will receive appropriate training in the safe use of the closed-loop devices. Participants will have access to the study team during the home study phase with 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 over the 8 week period. Secondary outcomes are HbA1c, time spent with glucose levels above and below target as recorded by CGM, and other CGM-based metrics in addition to insulin requirements. Safety evaluation comprises severe hypoglycaemic episodes, diabetic ketoacidosis (DKA) events and other adverse and serious adverse events.

Inclusion Criteria:The participant has type 1 diabetes as defined by WHO for at least 1 yearThe participant is aged 13 to 19 years (inclusive) (Phase 2)The participant will have been on an insulin pump for at least 3 months with good knowledge of insulin self-adjustmentThe participant is treated with one of the rapid acting or ultra-rapid acting insulin analogues (Insulin Aspart, faster acting insulin Aspart, Insulin Lispro, ultra-rapid Lispro insulin or Insulin Glulisine) 6. HbA1c ≥7.5% (58mmol/mol) based on analysis from local laboratory 7. The participant is willing to wear closed-loop devices 8. The participant is willing to follow study specific instructions 9. Female participants of child bearing age must have a negative urine-HCG pregnancy test at screening and should be using effective contraception if sexually active.Exclusion Criteria:Any physical or psychological disease or condition likely to interfere with the normal conduct of the study and interpretation of the study resultsKnown or suspected allergy against insulinTotal daily insulin dose more than or equal to 2 IU/kg/dayUse of a closed-loop system within the past 30 daysParticipant is pregnant or breast feeding or planning pregnancy within next 12 monthsSevere visual impairmentSevere hearing impairmentLack of reliable telephone facility for contactParticipant not proficient in English