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Cambridge Hybrid Closed-Loop Algorithm in Children and Adolescents with Type 1 Diabetes: A Multicentre 6-Month Randomised Trial

Background: Closed-loop insulin delivery systems have the potential to address the issue of suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of Cambridge hybrid closed-loop algorithm with usual care over six months in this population.  
 
Methods: In a multicentre, multinational, one-period, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. We randomly assigned participants to closed-loop insulin delivery or to usual care (control) for six months. The Cambridge closed-loop algorithm running on a smartphone was used with either (i) modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration) or (ii) Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). Primary endpoint was change in HbA1c at six months combing data from both configurations. Analysis was by intention-to-treat. Trial registration ClinicalTrials.gov, NCT02925299.  
 
Findings: We randomised 133 participants (mean±SD baseline HbA1c 8·2±0·7% vs 8·3±0·7%), 65 to closed-loop and 68 to control. At six months, HbA1c was 0·32% lower with closed-loop compared to control (95%CI 0·04 to 0·59; p=0·02). Closed-loop usage was low with FlorenceM due to failing phone enclosures (40% [26, 53]; median [IQR]), but consistently high with CamAPS FX (93% [88, 96]). In post-hoc analysis, HbA1c in the CamAPS FX closed-loop cohort (n=21) was 1·05% lower (95%CI 0·67 to 1·43; p<0·0001) and time in target range 3·9‑10·0mmol/L 15·0 percentage points higher (95%CI 8·0 to 22·1; p=0·0001) compared to control (n=25), without increasing hypoglycaemia (p=0·15). Severe hypoglycaemia and DKA events were similar between closed-loop and control.  
 
Interpretation:The Cambridge hybrid closed-loop algorithm is safe and improves glycaemic control in children and adolescents with type 1 diabetes. Efficacy requires high usage of closed-loop as demonstrated with CamAPS FX.  
 
Clinical Trial: Trial registration ClinicalTrials.gov, NCT02925299.  
 
Funding: NIDDK. 
 
Declaration of Interest: MT reports receiving speaker honoraria from Novo Nordisk. RPW reports receiving grant support from MannKind, and Novo Nordisk, grant support and lecture fees from Dexcom, grant support, and advisory board fees from Eli Lilly, and grant support, travel support, and lecture fees from Tandem Diabetes Care. BAB reports receiving grant support, donated supplies, and advisory board fees from ConvaTec, grant support from Dexcom, grant support and honoraria from Insulet, grant support and advisory board fees from Medtronic MiniMed, and grant support from Tandem Diabetes Care. LADM reports grants from Medtronic. NM reports receiving grant support for devices from Medtronic. REJB reports receiving speaking honoraria from Eli Lilly and Springer Healthcare. SAW reports receiving consulting fees from Eli Lilly, Sanofi US Services, and Zealand, speaker honoraria from Dexcom, Insulet, Medtronic, and Tandem Diabetes Care, and grant support to his institution from Abbott and Medtronic. LK reports receiving grant support from Tandem Diabetes Care. CK reports receiving grant support from Tandem Diabetes Care. RWB reports receiving grant support and donated supplies from Abbott Diabetes Care, Ascensia Diabetes Care US, Beta Bionics, and Roche Diabetes Care, grant support, donated supplies, and consulting fees from Dexcom, Novo Nordisk, and Tandem Diabetes Care, grant support and consulting fees from Bigfoot Biomedical, and consulting fees from Eli Lilly and Insulet. RH reports receiving speaker honoraria from Eli Lilly, Dexcom and Novo Nordisk, receiving license fees from B. Braun and Medtronic; patents related to closed-loop, and being director at CamDiab. MEW reports patents related to closedloop and being a consultant at CamDiab. JW, CKB, JMA, AT, JS, LD, FC, ND, KKH, AG and DSF declare no competing financial interests exist. 
 
Ethical Approval: Approval was received from an independent research ethics committee in the UK (East of England–Cambridge East Research Ethics Committee), an independent review board in the USA (Jaeb Center for Health Research Institutional Review Board), regulatory authorities in the UK (Medicines and Healthcare products Regulatory Agency), and in the USA (Food and Drug Administration). Safety aspects were overseen by an independent data safety monitoring board.