118-LB: Feasibility of a Prototype Dual Function Glucose Sensing Insulin Delivery Cannula in People with Type 1 Diabetes

Background: SynerGTM (Pacific Diabetes Technology, Portland, OR), a prototype subcutaneous cannula combining glucose sensing and insulin infusion could reduce the burden on people with diabetes (PWD) using insulin pump therapy (IPT) and glucose sensors. Aim: To assess and refine SynerGTM sensor accuracy, evaluate insulin infusion site function, and user tolerability. Method: Adults with type 1 diabetes established on IPT participated. Following a 48-hour run-in using a commercially available infusion set with a study pump (Medtronic 780G), a SynerGTM set was inserted subcutaneously in the anterior abdomen and attached to the pump. Participants were blinded to the investigational device readings. A standardised meal was eaten 60 minutes post-insertion. Glucose was measured on arterialised blood by YSI and finger-stick test strips (Roche Accu-Chek Guide) every 10 minutes for 60 minutes before and every 15 minutes for 4 hours after the meal. An insulin bolus was delivered immediately prior to the study meal using SynerGTM. Insulin continued to be delivered using SynerGTM at home and fingerstick readings continued. A second meal test as described above was performed on day 4 before study conclusion. A commercially available (Dexcom G6) continuous glucose monitor (CGM) was inserted prior to the 48 hour run-in preceding day 1 and worn throughout the study. Result: In 15 participants 99% of 679 data pairs of SynerGTM vs. YSI and 1305 data pairs vs. capillary glucose measurement were in zones A and B of the consensus error grid. MARD was 13.5% and 13.5% respectively. No artifact sensor spikes were observed with bolused insulin. SynerGTM was well tolerated and there were no significant differences in CGM time in range or TDD of insulin compared with run-in. Conclusion: This study proves the feasibility of SynerGTM as the first single through-the-skin device providing co-located insulin infusion and glucose sensing for PWD who take insulin.