Investigating the efficacy and safety of a prototype ultra-low-cost insulin pump (ULCIP)

This first-in-human feasibility study will assess the ability of a prototype ultra-low-cost insulin pump (ULCIP) to safely deliver insulin therapy. An ultra-low-cost insulin pump (ULCIP) developed at the Centre for Bioengineering (University of Canterbury) has been tested extensively to IEC 60601-2-24, the international testing standard which applies to insulin pumps. Bench side testing has demonstrated accuracy of insulin delivery comparable to commercially available insulin pumps. This pump uses Medtronic consumables, a medtronic reservoir will be filled with insulin and a medtronic infusion set and cannula used to deliver insulin from the pump subcutaneously. 6 participants will complete a 4-8 day run-in period during which they use a Dexcom G7 continuous glucose monitor (CGM) while continuing their usual diabetes therapy at home. CGM data will be available to researchers. Participants will then the ULCIP for 9 hours in an inpatient clinical research facility, under the supervision of a diabetes physician and nurse. All 6 participants will use the ULCIP on the same day, adherence to the intervention will be determined by direct observation. The ULCIP will be used in manual mode, with basal rate, insulin sensitivity factor, and carbohydrate ratios programmed at the discretion of the study team based on insulin delivery and glucose data from the run-in period. Participants will consume two meals while using the ULCIP, each containing > 40 grams of carbohydrate. Study staff will assist participants in delivering a manual insulin bolus with the ULCIP, for each meal. While using the ULCIP, participants will continue to use the Dexcom G7 CGM and will have venous blood samples obtained from an indwelling cannula hourly (every 60 minutes) (total of 10 samples). The CGM measures glucose every 5 minutes and transmits the result via Bluetooth in real-time. An alert will be generated for any CGM reading < 3.9 mmol/L or > 13.9 mmol/L, following which study staff will respond in accordance with a pre-defined safety plan. The safety plan includes administration of oral carbohydrate and/or IV dextrose for hypoglycaemia, administration of correction boluses via the ULCIP if required for hyperglycaemia and cessation of the ULCIP in the case of ketosis, with subsequent treatment of ketosis with insulin given by alternative device. Venous blood samples will be used to test glucose and beta-hydroxybutyrate on a point-of-care meter (CareSens Dual). The ULCIP will be discontinued if a participant has a beta-hydroxybutyrate result > 1.0 mmol/L. Serum insulin levels will be measured from the venous samples, on an assay validated for the detection of short-acting insulin analogues in order to monitor administered insulin. After completion of 9 hours of use of the ULCIP participants will be assisted to transition back to their usual diabetes therapy. Participants will be invited to participate in an optional focus group, which will be conducted either while using the ULCIP in the inpatient facility or in the subsequent 30 days in the department seminar room. The focus group will be about an hour but will be guided by the participants ensuring they have enough time to express their views. The focus group will be led by a diabetes nurse and aims to gain an understanding of the ULCIP device usability and attitudes towards ultra-low-cost diabetes technology. Participants will be able to elect to have a private interview either during the inpatient phase or in the 30 days following the inpatient phase if they feel uncomfortable participating in a group interview.