An Update on the Eversense CGM

By Lisa Foster-McNulty, MSN, RN, CDE

Several months ago, we reported on a Continuous Glucose Monitor CGM system which is made by a company called Senseonics.

The device had received CE Mark approval in Europe and was set to launch in Norway and Denmark by the end of 2016. It’s a 90 day implantable sensor which is inserted via a surgical procedure, and it features a transmitter which is body-worn over the sensor. A mobile app is used to view real-time glucose readings. The smartphone and the transmitter will both alert the user of glucose readings. The transmitter is body-worn and so will provide a vibration alert for a high or a low glucose value even when the phone is out of range.

The November 4, 2016 issue of Diabetes Care published data indicating that the new implantable system seems to be a safe and accurate option, as compared to other CGM systems on the market which feature user-inserted transcutaneous (through the skin) sensors. Since weekly sensor insertions are the hallmark of transcutaneous sensors, this implantable CGM system may be easier to use. The body-worn transmitter can easily be removed without the need to replace the sensor. This new type of CGM bypasses the need for warm up-time and the risk of damage to the inserted sensor. Still, there is a need for a minor surgical procedure every 90 days to implant the sensor, and that may be a deal-breaker for some potential users.

Researchers evaluated the use of the Senseonics Eversense CGM in 71 adults with Type 1 or Type 2 diabetes. The PRECISE (A Prospective, Multi-Center Evaluation of the Accuracy of a Novel Continuous Implanted Glucose Sensor) trial was a multicenter, multinational 180 day study. The system was used both at home and in the clinic, and researchers evaluated accuracy in eight in-clinic visits. The main thing they were looking at was the mean absolute relative difference (MARD) for “venous reference glucose values” (which means glucose samples drawn as lab work) over 4.2 mmol/L, or 75.6 mg/dl. This basically looks at the average error of the CGM as compared to laboratory measurement. For the implantable CGM system, the MARD value against the reference was 11.1%. It did perform less well in the hypoglycemic range.

Using a new data algorithm, real-time analysis indicated improved performance over the current algorithm, with MARD values against the reference of 10.5% for overall performance and 18.6% in the hypoglycemic range. With the implantable system, 99.2% of the samples fell within the clinically acceptable error zones. Alarm performance for thresholds of hypoglycemia and hyperglycemia were 81% and 88%, respectively, with true event rates of 67% and 90%, respectively.

Throughout the study, A1c improved from 7.54% to 7.19%. For participants with a baseline A1c of <7.5%, the A1c didn’t change significantly. However, participants with a baseline A1c of 7.5% or greater saw a decrease of 0.55%.

The analysis estimated that 100%, 82%, and 40% of sensors were functioning during in-clinic evaluations at days 45, 90, and 180, respectively. The median sensor life was 149 days.

Looking at safety, the researchers didn’t find any severe procedure or device related serious adverse events. There were 11 patients in which 14 device or procedure related non-severe adverse events happened, with 147 devices implanted, used, and removed in total. Five cases of skin reaction occurred, but after a temporary stop of 1-3 weeks, therapy resumed. There were two cases of incision site infection. One patient required antibiotic treatment, and the other resolved without treatment.

The researchers concluded that his study shows that the use of a long-term, implantable continuous glucose sensor is safe and effective, and provides some specific benefits to use. They felt that implantable CGM is a viable alternative to transcutaneous CGM.
Skin reactions and infections are potential complications to the use of this new type of CGM, and we think the need for a minor surgical procedure in a doctor’s office would be a deterrent to use for many. However, a sensor that lasts for 90 days is certainly novel. The improved accuracy of the new algorithm is helpful. It will be interesting to see how well this would be accepted if the FDA were to approve its use in the United States.