180-Day Implantable CGM Deemed Safe in T1D Patients

— The system's accuracy stabilized with longer use, researchers reported

MedicalToday

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ORLANDO -- An implantable continuous glucose monitor (CGM) showed promise with 180-day use in a young population with type 1 diabetes, according to researchers here.

The Senseonics' Eversense XL CGM system demonstrated accuracy over 6 months of use, with an overall mean absolute relative difference (MARD) of 9.4% (95% CI 8.6%-10.5%), reported Ronnie Aronson, MD, of LMC Diabetes & Endocrinology in Toronto, and colleagues, at the Presented at the American Diabetes Association (ADA) annual meeting.

Action Points

  • Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

The system's accuracy stabilized with longer use, with the highest average MARD reported during the first 30 days of use:

  • Days 1-30: MARD of 10.6%
  • 1-60: 9.6%
  • 1-90: 9.1%
  • 1-120: 9.2%
  • 1-150: 9.3%
  • 1-180: 9.4%

"The smaller the [MARD] number, obviously the more accurate the sensor. Anything less than 10% is considered very good," Aronson said during an ADA presentation.

The system was FDA approved for adult wear up to 90 days, but the XL system for 180-day use was given CE mark approval in Europe in October 2017.

The sensor is subcutaneously implanted during an office visit, often into the upper arm, while a smart transmitter with a gentle adhesive backing is worn and changed as needed by the user. The user is then alerted to hyperglycemia and hypoglycemia through vibrations of the transmitter or alerts to a mobile application, such as on a smart phone or watch.

One drawback to the device is the need for two fingerstick calibrations per day, which some other CGMs, like the Dexcom G5 CGM and Abbott's FreeStyle Libre Flash Glucose Monitoring System, have been able to recently do away with. However, Aronson suggested Senseonics is currently looking into a new version that could eliminate the fingersticks.

The prospective, single-arm analysis included 36 users, including six adults and 30 adolescents with type 1 diabetes. "This was the first study of any CGM system in a pediatric population for more than a 14 day duration," said Aronson.

In addition to MARD values, efficacy was further evaluated against these Yellow Springs Instrument (YSI) glucose values for which the patients visited the clinic once a month to measure. Agreement between the system and YSI was generally high through the duration of use, while agreement within 15 mg/dL or 15% of YSI glucose values ranging between hovering around 83%:

  • Day 1-60: 82.9% (95% CI 78.4%-86.1%)
  • 1-120: 83.6% (95% CI 80.4%-85.7%)
  • 1-180: 83.4% (95% CI 79.7%-85.5%)

The system also appeared safe with 180 days of use, with no serious adverse events related to the insertion or removal of the device occurring in the study. Only mild skin reactions to the sensor and transmitter adhesive were reported, but resolved quickly. The system also received high marks from the users, the long sensor life, implanted design, and vibratory alerts among some of the most favored features.

After 180 days of use, a different site should be used for the next sensor's insertion, Aronson told , but safety of same-spot insertion should be assessed in future trials, he said.

  • author['full_name']

    Kristen Monaco is a senior staff writer, focusing on endocrinology, psychiatry, and nephrology news. Based out of the New York City office, she’s worked at the company since 2015.

Disclosures

Aronson disclosed relevant relationships with AstraZeneca, Janssen Pharmaceuticals, Novo Nordisk, Sanofi, Becton, Dickinson and Company, Boehringer Ingelheim Pharmaceuticals, Eli Lilly, Merck, Senseonics. Co-authors disclosed relevant relationships with industry.

Primary Source

American Diabetes Association

Aronson R, et al "First Assessment of the Performance of an Implantable CGM System through 180 Days in a Primarily Adolescent Population with Type 1 Diabetes" ADA 2018; Abstract #13-OR.