CGM: What's around the corner?
The first continuous glucose monitoring (CGM) system was approved by the American Food and Drug Administration (FDA) 20 years ago. Sensors lasted for three days, and the person with diabetes was not able to view their levels in real-time – instead, they were stored for download and review by clinicians only. Fast forward to 2019, and CGM technology is much more advanced. We now have CGMs that allows multiple parents to monitor their child's glucose levels remotely and are accurate enough to allow pumps to suspend and re-start basal insulin in response to glucose levels. But what’s next? Here’s a rundown of some of the next generation of CGM devices on the horizon. These devices are not yet available in Australia, but we hope to see them hit our shores soon.
Dexcom G6 The Dexcom G6 has been available in the US since June 2018. Like the previous generation G5, insulin dosing decisions can be made with the G6 without confirmatory fingerprick tests. G6 sensors can be worn for ten days, the transmitter is flatter and slimmer than the G5, and sensors can be inserted with the push of a button with the new one-touch auto-applicator. Transmitters last for 3 months. Whereas many people extended sensor life with the G5 system by restarting sensors, the G6 sensors cannot be restarted, which is a design feature intended to ensure patient safety when they dose insulin from the G6, which does not need to be calibrated. The G6 can be used by people with type 1 aged 2 and up and with a 9% MARD (the Mean Absolute Relative Distance between the CGM readings and the blood glucose level measured with a standardized instrument) it is considered to be the most accurate CGM on the market.
Freestyle Libre 2 Abbot’s Freestyle Libre is a flash monitoring device that is moving towards becoming closer to a continuous glucose monitor with the release of the Libre 2. The Libre 2 has been available in Europe since 2018 and can be used by people aged 4 and up. With the first generation Libre, the sensor collecting glucose data in the background and the user can only access their data when they scan the sensor. By contrast, the Libre 2 sensor transmits glucose data continuously and directly to the reader using Bluetooth, and users can choose to be alerted to high and low glucose with alarms. The Libre 2 can be dosed from, and calibration is not required.
Eversense Eversense is an implantable device that was approved by the FDA in June 2019 for people aged 18 and up. The sensor is surgically implanted just below the skin and stays in place for 90 days. The sensor relays info to the Smart Transmitter which sits on the skin, and glucose values are sent via Bluetooth to the Eversense Mobile App on a smartphone. The transmitter is waterproof and rechargeable and, along with alarms on the phone, is able to vibrate to alert the wearer of high or low blood glucose. Eversense must be calibrated twice a day and is not approved to dose insulin from without a confirmatory fingerprick test. The next generation Eversense XL has a 180-day wear sensor and is currently available in Europe.
CT-100 The CT-100 continuous glucose monitor received approval in Europe in 2016 but is yet to be released. The seven-day sensor requires a once-daily calibration and accuracy is not impacted by paracetamol. Readings are relayed to the battery-powered transmitter, which has a two-year life, then via Bluetooth to a smartphone app. Trial data show an accuracy of 8.7% MARD, which would make it the most accurate CGM available when released.
SugarBEAT SugarBeat is a needle-free continuous glucose monitor anticipating launch in the UK this year. The system consists of disposable adhesive skin patches that connect to a rechargeable transmitter. Patches are changed every 24 hours and require a 30-minute warmup. The patch sends an electrical current across the skin, drawing glucose from the interstitial fluid into the patch. This is measured by the transmitter and sent via Bluetooth to a smartphone or smartwatch app. SugarBEAT must be calibrated, and insulin cannot be dosed from it without a confirmatory fingerprick. With the price point said to be comparable to glucose monitor strips, this could be a very affordable system. The company has not released information on age restrictions.
WaveForm The WaveForm continuous glucose monitor is anticipated to be approved and released in Europe late this year. The system uses a reusable, needle-free applicator, claimed to be virtually pain-free. It has a 14-day sensor wear, a rechargeable transmitter and a warm-up period of one hour or less. The transmitter sends readings via Bluetooth to a smartphone app every minute. Combined, the sensor and transmitter are about the size of a 10-cent piece. The company website does not give information about what age WaveForm is for, or its calibration requirements. There are exciting developments ahead for CGM, and the emerging technologies above will only make glucose levels easier to monitor. Currently, some Australians can access NDSS-funded access to Dexcom G5 and Medtronic CGM systems, including with type 1 under the age of 21, people with a history of severe hypoglycaemia and women who are trying to conceive, are pregnant or breastfeeding. We hope this access is extended to all people with type 1 in the near future. The Family Centre clinic can support you to access NDSS-funded CGM if you're eligible, and to trial the Freestyle Libre (first generation) or Medtronic Guardian Connect systems - just call the Family Centre on 9446 6446 or email us at hello@type1familycentre to enquire!