Eversense Implanted CGM Accurate for 90 Days in Diabetes

Miriam E Tucker

February 20, 2018

A novel implantable continuous glucose sensor provides accurate readings for 90 days in people with type 1 and type 2 diabetes, new results from a pivotal US trial indicate. The findings for Eversense (Senseonics) will be considered by the US Food and Drug Administration (FDA), with a decision on approval of the device expected in the first half of this year.

The results of the prospective, multicenter PRECISE II trial were published online January 30 in Diabetes Technology & Therapeutics by Mark P Christiansen, MD, of Diablo Clinical Research, Walnut Creek, California, and colleagues.

Eversense is designed to reduce the inconvenience and discomfort of weekly insertions required with current continuous glucose monitoring (CGM) systems, and thereby increase wearer adherence.

The system's cylindrical sensor is implanted 3 to 5 mm below the skin surface on the upper arm using a custom inserter, a procedure that can be performed by nonsurgically trained medical professionals.

A transmitter worn externally over the sensor wirelessly transmits glucose data every 5 minutes to a mobile app that displays the information in real-time. The transmitter also issues on-body vibrations to alert the user to immediate or impending hyper- and hypoglycemia.

Senseonics submitted a premarket approval application to the US FDA for Eversense in October 2016.

The company anticipates an FDA advisory panel hearing in the first quarter of 2018 and a decision on approval in the first half of the year, R Don Elsey, chief financial officer, Senseonics, Germantown, Maryland, told Medscape Medical News.

If approved by the FDA, Eversense will become the first implantable CGM system for use lasting at least 3 months. It will compete with the Abbott FreeStyle Libre, a so-called 'flash' CGM, which was approved in the United States last year. The Libre has a sensor worn on the upper arm for 10 days and a reader the patient uses to scan the sensor to obtain a glucose value; however, the system does not sound alarms to warn the patient of low or high glucose values.

More Than 90% of Values Align With Reference 

The initial PRECISE trial enabled the first version of the Eversense system to receive a European CE Mark in 2016. Reporting the results for this trial, Jort Kropff, MD, of the University of Amsterdam, the Netherlands, said there were several advantages to wearing a glucose sensor under the skin. For example, being able to take off the transmitter without removing the sensor, he noted, adding that the long-term stability of the implanted sensor is a major advantage over many current CGMs.  

PRECISE II evaluated the accuracy and safety of an updated version of the system, with revisions made to the algorithm and sensor configuration.

In PRECISE II, primary efficacy and safety analyses were conducted in 90 adults with diabetes (68% type 1, 32% type 2) implanted with a total of 106 sensors (15 patients wore two). Participants were blinded to the glucose data.

The primary effectiveness endpoint, mean absolute relative difference between paired Eversense and laboratory reference value (Yellow Springs Instrument) over a blood glucose range of 40 to 400 mg/dL, was 8.8%, significantly lower than the prespecified 20% performance goal, Christiansen and colleagues report. 

Effectiveness was not significantly affected by compression or exercise. Overall, 93.3% of the system's reading were within clinically acceptable error zones of the Clarke error grid. 

Among the 15 participants who wore two sensors implanted bilaterally, the absolute relative difference between the two sensors was also 8.8%. 

The system correctly identified 93% and 96% of hypoglycemic and hyperglycemic events that were detected by the laboratory reference.

Of the 106 sensors, 91% survived the entire 90 days. Most of the failures were caused by the sensor becoming insensitive to glucose because of degradation of the binding chemistry.

A total of 14 device-related adverse events occurred in seven participants, of which 12 were classified as mild (bruising, erythema, or pain/discomfort). There were no infections or skin reactions to the adhesive patch.

In one instance — deemed a serious event — the sensor had been implanted too deeply and required surgical intervention to remove.

Over 80% of Patients Say They'd Use Eversense Again

In a substudy assessing quality of life, 86% of participants reported feeling better about their diabetes control while using the device, and 84% said they would choose to have it inserted again.

"The results from this study demonstrate that the use of a long-term, 90-day, implantable continuous glucose sensor is accurate and safe with high rates of adherence to use," say Christiansen and colleagues.

"Additional clinical studies will be required to evaluate the accuracy and usability of the Eversense CGM system among pediatric patients, with reduced calibration frequency, and for extended durations through 180 days," they conclude.

The PRECISE II study was funded by Senseonics. Christiansen has reported no relevant financial relationships. Disclosures for the other authors are listed in the article.

Diabetes Technol Ther. Published online January 30, 2018. Abstract

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