Continuous glucose monitoring in children: an interview with Terrance Gregg, CEO of Dexcom

When did continuous glucose monitors first become available and how have they developed over time?

Scientific research into CGM-like sensors goes back more than 40 years. I was working with the first company to begin commercial development, MiniMed, back in 1992 when the science was really beginning to percolate. In 1999 the FDA approved the first CGM device for use in the United States.

These early iterations of CGM devices were sometimes found unreliable by patients as the readings simply were not accurate enough. Over the past four or five years companies, including Dexcom, have made tremendous improvements in sensor accuracy. By extension, CGM devices have continued to become a more valuable tool for patients in managing their diabetes.

Of course, we are pleased to note that the FDA recently approved Dexcom’s G4® PLATINUM (Pediatric) for use in patients 2-17. This approval is quite significant as it is the first CGM approved for young children ages 2-6.

What impact has continuous glucose monitoring had on the lives of diabetes patients?

CGM allows patients to see the speed and direction of their glucose levels with a push of a button. It is very important to have the knowledge not just where your blood glucose is now, but where it was 30 minutes ago and where it will be in another 30 minutes. Contrast this to self-monitoring blood glucose with fingersticks, which only gives readings on a single point in time and no insight on where blood glucose levels were, or the direction they are going.

Advances in CGM have led to monitors and sensors that are lightweight, portable and easy-to-use. Many devices offer customizable alarms that alert users if their levels are dangerously low or dangerously high.

Why is continuous glucose monitoring in children more challenging than in adults?

Physiologically, children have more rapid glucose variability. This increases the requirements for a sensor that is both highly accurate and highly responsive.

Other factors are at play as well. Children are extremely active and as such, present unique challenges for a wearable sensor.  The special adhesive that secures our sensor to the patient’s body has to be able to withstand the active lifestyle of our young users.  The sensor consistently meets the seven day target wear. 

In addition, our small sensor and transmitter size and discreet placement (abdomen and upper buttock) are especially important for younger patients because of their concerns around being noticed by other children. 

Please can you describe how Dexcom developed a pediatric continuous glucose monitor and what challenges had to be overcome in order to achieve this?

From a practical standpoint, getting kids in the 2-17 age group, particularly children 10 and younger, to sit still long enough for clinical evaluations is challenging.

Another big difference between adults and pediatric trials are the meal times. With adults, the meal times are precisely prescribed so we know exactly when the patient consumed carbohydrates, and how much they consumed. In the pediatric trials, spontaneity becomes a big factor because when kids are hungry, they eat. So that is another variable we had to manage in trial design.

What is remarkable about our pediatric trial is that, to the best of our knowledge, this is the first medical device trial specifically designed and approved by the FDA for studying a pediatric population. Dexcom was a true pioneer in this sense, as we had no benchmarks or designs to use as a guide. We were scouting new territory and are very proud of this contribution.

What impact do you think this pediatric continuous glucose monitor will have on the lives of parents of children with diabetes?

We hope our CGM reduces the stress of parents and other caregivers helping their loved ones manage their diabetes. In feedback from our trials we received nearly as many accolades on improving the lives of parents as we do in the improvement in the lives of the child. We get similar reports from spouses of type 1 diabetics.

Daily management of diabetes is relentless. There are no holidays, there are no vacations for the patients or their caregivers. There are multiple actions they must take 24/7/365 to keep the patient safe. It can be a tremendous strain, particularly overnight. A parent’s greatest fear is a child not waking up as a result of a severe glucose event that occurred during the night. Our pediatric indication is a step towards allaying those fears and increasing safety and security for type 1 adolescents.

What do you think the future holds for glucose monitoring and diabetes management?

The Dexcom G4® PLATINUM has a 13% MARD (Mean Absolute Relative Difference) – a measurement on the variation between reading from the CGM sensor and a fingerstick measurement. The lower the MARD, the more accurate the system.

Next generation versions will seek to reduce overall MARD into single digits (i.e., less than 10%). We also hope next generation devices will reduce the number of fingersticks. Right now patients still require two fingersticks a day. When we ask patients on a priority basis what is most important to them, reducing the number of fingersticks for calibration regularly ranks in the top five. Someday a device may be available that is calibrated at the factory, eliminating the need for fingersticks entirely.

Research on CGMs is also underway as part of a developmental artificial pancreas device system (APDS) for people with type 1 diabetes. The investigative device would include a CGM and an insulin pump. The combination monitor and pump track glucose levels and automatically pump the appropriate amount of insulin as determined by a computer algorithm.

What are Dexcom’s plans for the future?

We want to introduce connectivity to a mobile phone as a next generation service, making it easier for patients to visualize their own levels and also allow others to monitor remotely. This phone connectivity provides a second source of security when a child or loved one is not in the nearby vicinity, and could be customized with alarms to alert patients or caregivers on their phone if glucose levels are too low or high.

Examples of where this connectivity is valuable includes travel, obviously, but also things as simple as a sleepover. Improving the portability of CGM data allows children to have experiences that they otherwise might not – parents are highly reluctant to have their children away from the home when they don’t know what they are eating or if they are watching their levels closely. This mobile connectivity is so important in providing that remote monitoring capability and peace of mind.

From a business perspective, Animas and Tandem are the two companies that we partner with on developing integrated CGM and insulin pump technology. Animas has incorporated our technology into their Vibe pump, which has been available in Europe since 2011 and has a good chance of being approved for U.S. sale in in 2014. Tandem is developing a combination pump/CGM device that we hope to have available also in 2014.  

Additionally, there are approximately 25 artificial pancreas projects being conducted around the world and Dexcom technology is at use in 22 of them.

Where can readers find more information?

For more information about the Dexcom G4® PLATINUM and its new approval for children ages two to 17, visit Dexcom online at

The American Diabetes Association also offers a Diabetes Basics educational site, and the Centers for Disease Control and Prevention maintain a National Diabetes Education Program.

The JDRF website is also a great resource to learn more about research and education on type 1 diabetes, or get involved in the organization’s philanthropic mission.

About Terrance Gregg

Terrance H. Gregg is CEO of Dexcom, Inc., first joining the Dexcom Board of Directors in 2005 and subsequently appointed President and CEO in 2007 and CEO in 2011.

In 2002 he retired as President of Medtronic MiniMed, a world leader in diabetes management systems. He became President and Chief Operating Officer of MiniMed, Inc. in 1996 and was instrumental in Medtronic’s $3.4 billion acquisition of MiniMed in 2001. He also served in executive positions with Smith and Nephew and Allergan, Inc.

Mr. Gregg served as the 2003-2004 Chair of the Research Foundation Board of the American Diabetes Association. In 2010, Mr. Gregg and his wife were recognized by the Juvenile Diabetes Research Foundation (JDRF) with one of its highest honors, the 2010 Angel Award. Most recently, Mr. Gregg was honored as one of the San Diego regional finalists for the Ernst and Young Entrepreneur of the Year Award 2011 and named by, one of 28 chief executives whom exemplify cutting-edge leadership and innovative thinking in the medical device industry, as its inaugural CEO Class of 2011.

Mr. Gregg currently serves on several advisory boards, including the Scripps Translational Science Institute.

Mr. Gregg received a Bachelor of Science degree from Colorado State University in 1971.

April Cashin-Garbutt

Written by

April Cashin-Garbutt

April graduated with a first-class honours degree in Natural Sciences from Pembroke College, University of Cambridge. During her time as Editor-in-Chief, News-Medical (2012-2017), she kickstarted the content production process and helped to grow the website readership to over 60 million visitors per year. Through interviewing global thought leaders in medicine and life sciences, including Nobel laureates, April developed a passion for neuroscience and now works at the Sainsbury Wellcome Centre for Neural Circuits and Behaviour, located within UCL.



The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News-Medical.Net.
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