Long-term implantable continuous glucose monitor in type 1 diabetes

This trial is designed to evaluate data from a small group of participants to determine whether optimised sensor signal processing techniques with a new high definition sensor face have resulted in improved sensor performance. Additionally, reformulated device proteins may be assessed, and optimised manufacturing enhancements with the new high definition sensor face will be evaluated for both device tolerance and safety. The investigational device is a subcutaneously implanted metal sensor about the size of a large USB that is designed to measure interstitial glucose levels. The sensor contains a small battery and a transmitter that wirelessly transmits data from the device to a handheld receiver and is stored in the receiver’s memory for later download and processing. It is fully implantable i.e. nothing is worn on the skin and will remain in-situ for a minimum of four and a half months, and up to a maximum of eight months. It will be implanted into the subcutaneous tissue of the lower abdomen by a qualified surgeon under local anaesthetic and light sedation. It will be removed following completion of the study. Following implantation, the sensor requires no user interaction or maintenance, although the receiver needs to be kept close by to ensure that data packets are reliably recorded. The only maintenance required for the receiver is battery changes and download of receiver data. Participants will undergo monthly clinic visits during the 8 months of implanted sensor wear. During each monthly visit, participants will undergo a supervised meal-driven glucose excursion where hourly capillary blood finger-prick and 15-minute venous blood glucose sampling will occur for up to 6 hours. Monthly blood samples will be obtained for chemistry, HbA1c, antibody testing (at certain months only) and retention. Between clinical site visits, participants will carry a data logger receiver that records signal outputs from the implanted sensor (display shows date/time, but no glucose information), change the AAA batteries in the study receiver daily and confirm the receiver is receiving data, self-monitor blood glucose (SMBG) a minimum of 4 times per day, respond to texts or phone calls from study staff confirming the receiver is working with an appropriate date / time and record study activities in a participant diary. Participants will also wear a provided commercially approved continuous glucose monitor (CGM) (Dexcom G5) during the study and participants will be trained on the use of the CGM by the study site. Participants will calibrate the CGM as required and this will enable real-time sensor data to participants. Participant data from the CGM (de-identified) will be downloaded during the monthly in-clinic visit. Explantation of the sensor will occur following completion of their 8-month in-clinic visit, unless the 4-month or 6-month evaluation deem otherwise. The explantation procedure, in general, mimics the implantation procedure and is performed under local anaesthetic.