FDA Panel Supports Dexcom CGM For Insulin Dosing in Diabetes

A US Food and Drug Administration (FDA) advisory panel has voted in favor of allowing the Dexcom G5 Mobile continuous glucose monitoring (CGM) system to be used as a replacement for fingerstick glucose monitoring in patients with diabetes.

At a hearing held July 21, 2016, the FDA's clinical chemistry and clinical toxicology advisory panel voted 8 to 2 in favor of safety, 9 to 1 for efficacy, and 8 to 2 that the benefits of the proposed new indication would outweigh the risks.

Currently, the Dexcom G5 CGM is indicated for adjunctive use along with self-monitoring of blood glucose (SMBG), done using a fingerstick test, to provide trend information and alert the patient of high and low blood glucose values. If the FDA follows the panel's advice, the new indication would allow patients to skip the premeal fingersticks and instead use the CGM's data to determine their insulin doses, as well as make other lifestyle decisions such as whether to exercise.

The new label would provide instructions for patients on how to use the CGM's data to determine their insulin doses, including how to adjust insulin doses up or down based on the trend arrows that the device displays. The label would also advise when SMBG testing is necessary, including twice daily for calibration, when the CGM fails to provide a reading, or when symptoms don't match the reading.

Despite the overall favorable vote, many panelists expressed discomfort with the meal dosing simulation model data presented by the company — validated with clinical data from just 71 patients with type 1 diabetes — to support the indication, rather than results from actual patients in randomized clinical trials. Panel members advised the company to gather additional post-marketing data.

Patients Already Using Devices in This Way

Most panelists also said that Dexcom would need to provide training beyond simply a pamphlet or video to make sure that patients understand how to properly use the CGM data to determine insulin doses. There was debate, however, regarding the extent to which the company could provide usage information vs how much of the responsibility would fall to healthcare providers, who would also need to be up to speed.

The stronger vote on efficacy reflected the fact that the Dexcom technology has advanced considerably in recent years. The current G5 iteration is nearly as accurate as SMBG, with a mean absolute relative difference of about 9%, compared with 4% to 9% for the various cleared SMBG meters.

Also influencing the vote was the fact that many current Dexcom users are already using the devices off-label to dose insulin (69% according to market survey data presented during the public comment session by DiaTribe founder Kelly Close) and at least now the company would be able to advise patients about this use, which it is currently forbidden to do.

Over 30 people, including endocrinologists and patients, spoke during the public comment session — many with travel expenses paid by Dexcom — nearly all in favor of approval for the dosing indication. Representatives from the American Diabetes Association, Endocrine Society, and American Association of Clinical Endocrinologists also spoke in support of the indication. Continue Reading