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Implantable CGMS Submitted to FDA

Dec 3, 2016

Premarket Approval application submitted for Eversense® CGM system.

A new implantable continuous glucose monitoring (CGM) system appears to be a safe and accurate alternative to a transcutaneous system for patients with diabetes, according to data published in November 2016 Diabetes Care Journal.


It is known that continuous glucose monitoring (CGM) systems can lower mean glucose compared with episodic self-monitoring of blood glucose. Implantable CGM systems may provide additional benefits.

Implantable CGM systems may provide additional ease of use over transcutaneous CGM since Implantable CGM 2frequent sensor insertions through the skin are not needed and the transmitter can be removed easily without the need for sensor replacement, for example during personal care,” researchers wrote. “Furthermore, weekly sensor replacement with warm-up time and the risk of damage to the inserted sensor is no longer applicable.”

This is truly exciting news because this can replace the expensive sensors with an implantable sensor that is good for 3-6 months.  And even more exciting there are other CGM implantable systems that only need to be changed every 12-18 months that have not yet been submitted to the FDA. These implantable devices require a minor surgical procedure that may prove problematic for some patients.

To add to the body of evidence,  Eversense (Senseonics Inc.) implanted a CGM sensor in 71 participants age 18 years and older with type 1 and type 2 diabetes in a 180-day multinational-multicenter pivotal trial. Participants used the CGM system at home and in the clinic. CGM accuracy was assessed during eight in-clinic visits with the mean absolute relative difference (MARD) for venous reference glucose values >75 g/dL. (4.2 mmol/L) as the primary end point. Secondary end points included Clarke Error Grid Analysis and alarm performance. The primary safety outcome was device-related serious adverse events. This trial is registered with clinicaltrials.gov, number NCT02154126.

For the implantable CGM system, the MARD value against the reference was 11.1%. In the hypoglycemic range, defined as 75 mg/dL. (4.2 mmol/L.) or lower, was less than its overall performance (40 mg/dL. {2.2 mmol/L} to 398 mg/dL. {22.0 mmol/L}): 21.7% vs 11.6% MARD (P <.001).

Implantable CGM 3According to Clarke Error Grid Analysis, the estimated clinical performance of the implantable CGM system indicated that 99.2% of samples were in the clinically acceptable error zones A (84.3%) and B (14.9%). In terms of the in-clinic alarm performance for the thresholds of hypoglycemia, defined as less than 70 mg/dL.(3.9 mmol/L), and hyperglycemia, defined as greater than 180 mg/dL.(10 mmol/L), confirmed detection rates were 81% and 88%, respectively, with true event rates of 67% and 90%, respectively.

From baseline to the study’s conclusion, HbA1c improved from 7.54% to 7.19%. For those with a baseline HbA1c of less than 7.5%, HbA1c did not change significantly (–0.04%; P =.669) at the final study visit, according to a post-hoc analysis. Those with a baseline HbA1c of 7.5% or greater, however, experienced a decrease of 0.55% (P <.001).

Kaplan-Meier analysis estimated that 100%, 82%, and 40% of sensors were functional during in-clinic sessions at days 45, 90, and 180, respectively, with a median sensor life of 149 days.

In terms of safety, the researchers found no severe procedure- or device-related serious adverse events. In 11 patients, 14 device- or procedure-related non-severe adverse events occurred, with 147 devices implanted, use, and removed.

How It Works: Based on innovative fluorescence technology embedded within a tiny sensor, the Eversense CGM System measures glucose from interstitial fluid below the skin surface. The sensor wirelessly sends glucose data to the smart transmitter worn on the upper arm over the sensor insertion site. The smart transmitter calculates the current glucose value along with the direction it’s headed, how fast, and whether glucose values are expected to exceed pre-set low and high targets. Data and alerts are simultaneously sent to the smartphone app that provides real-time tracking, intuitive displays to help identify patterns, and information to help stay in range.

“The results from this study indicate that the use of a long-term implantable continuous glucose sensor is both effective and safe and is accurate,” the researchers concluded. “The results support implantable CGM as a worthy alternative to current transcutaneous CGM.”

Looking at its features and its functions, we see that the sensor lasts up to 90 days; the smart transmitter worn on the body has vibe alerts; you don’t need a separate receiver, just your smartphone; it also have predictive alerts before reaching low or high glucose alarm levels, then readings are sent to the app every 5 minutes; the transmitter is removable and rechargeable; and the main benefit is you don’t need expensive disposable sensors.

Practice Pearls:

  • From baseline to the study’s conclusion, HbA1c improved from 7.54% to 7.19%.
  • 99.2% of samples were in the clinically acceptable error zones A (84.3%) and B (14.9%).
  • With the large number of readings, it is much more effective in helping the patient achieve better outcomes with less hypoglycemia.

Kropff J, Choudhary P, Neupane S, et al. Accuracy and longevity of an implantable continuous glucose sensor in the PRECISE study: a 180-day, prospective, multicenter, pivotal trial. Diabetes Care. 2016 Nov 4. doi:10.2337/dc16-1525.