The FDA has called a 2-day meeting of its Clinical Chemistry and Clinical Toxicology Devices Panel this week that could have major implications for the care of diabetes.

The first session on Thursday will focus on the pre-market approval (PMA) application from Dexcom for a new indication for their G5 continuous glucose monitor (CGM) as a replacement -- not just as an adjunct, its currently approved use -- for fingerstick blood glucose testing in diabetes.

At the second session on Friday, the advisors will consider a 510(k) application from Alere to add a point-of-care diagnostic claim to its Afinion HbA1c assay, which would be a first for this class of product.

In briefing documents released Tuesday, agency staff didn't raise major objections to either request but indicated that the FDA wants input from the clinical community on whether these devices are ready for the expanded uses.

Standalone Approval for CGM?
The device from Dexcom was approved for sale in 2012, but the company was required to file a PMA application for the added indication, which would permit patients to make treatment decisions based on the interstitial fluid glucose concentration reported by the CGM.



Patients who use a CGM are required to double check the readings from the device against the results from a fingerstick test before they make treatment-related decisions such as insulin dosage adjustments. The CGM is currently an "adjunctive device to complement, not replace" information from other sources, said the FDA briefing documents. Many patients skip the double-checking step, however, relying on the readings from the CGM even though it constitutes off-label use, according to the diabetes research organization JDRF.

The level of accuracy of Dexcom's CGM device is "close to, but not as good as" other self-monitoring blood glucose meters on the market in the U.S., FDA staff indicated in their briefing document, but added that the device adds other information that the meters don't provide, and that it could lead to better glucose management overall.

The agency put forward a series of questions for the panel to consider before they voted on whether or not to approve the expanded indication. The first has to do with the studies that Dexcom has done of the device, and whether they are well-designed and can provide "reasonable assurance" that use under the indication is safe and effective. Another question is whether users of the device will know how to safely use it under the new indication.

In an email, diabetes advocacy group DiaTribe wrote that Thursday's decision could "mark a groundbreaking change in the treatment of diabetes." Medicare still considers CGM devices to be "precautionary" and so they aren't eligible for coverage, though that position has been challenged in at least one court case.

It isn't clear when the FDA will rule on Dexcom's application; the agency is not obliged to follow recommendations of its advisory committees, though it usually does.

HbA1c Assay for Diagnosis
In 2010, the American Diabetes Association (ADA) began to recommend that HbA1c be used to diagnose diabetes, but they added that "point of care assays are not sufficiently accurate at this time to use for diagnostic purposes," according to the FDA's briefing documents.

FDA staff said they do not know if the ADA had concerns about the CLIA-waived tests, or if they also had concerns about the newer "moderate/high complex" test as well. They have invited the ADA to the panel meeting to present their rationale. The agency wrote on its website that they are seeking feedback from the clinical community to "determine significant, scientific and practical, reservations or support for using this point-of-care HbA1c test as an aid."

The FDA also posted a series of questions that the panel will be asked to address, including questions about risks, and company strategy. They said that Alere has indicated that they will seek a CLIA waiver for their new test in the future even though it is intended for use in moderate complexity point of care laboratory settings that require several operator steps. They will also ask the panel to discuss the benefits and disadvantages of the design of the new Afinion HbA1c Dx assay.