FDA Approves FreeStyle Libre System for Patients

Roxanne Nelson BSN, RN, and Miriam E Tucker

September 27, 2017

( updated ) The US Food and Drug Administration (FDA) has approved the FreeStyle Libre Flash Glucose Monitoring System for use by adult patients with diabetes.

This is the first glucose monitoring system geared to diabetes patients that does not require finger-stick calibration.

Last year the FDA approved the professional version of the system, to be used by clinicians for monitoring glucose in patients with diabetes.

Both systems are manufactured by Abbott.

The FreeStyle Libre system reduces the need for finger-stick testing and, instead, continuously measures glucose levels with a small sensor that is self-applied and is approximately the size of two stacked quarters inserted into the back of the upper arm for up to 14 days. Users then wave (or "flash") a dedicated, mobile scanner over the sensor to obtain readings. In the United States, the device is intended for use in individuals aged 18 years or older.

It is similar to conventional continuous glucose monitors (CGMs) in that it measures interstitial fluid glucose levels in real time. But the FreeStyle Libre offers certain advantages, such as longer sensor wear and lower cost. Also in contrast to CGMs, it doesn't require finger-stick blood glucose measurements for calibration (it is factory-calibrated).

Other advantages, according to the company, are that it receives glucose readings through clothing and is also water-resistant and so can be worn in the shower and during swimming. Furthermore, use of the FreeStyle Libre avoids interference with acetaminophen (paracetamol), an active ingredient in more than 500 common over-the-counter medications. Acetaminophen can falsely raise reported glucose levels in certain CGMs to appear as if they are at dangerously high levels.

However, the FreeStyle Libre does not have an alarm for users for low and high glucose values, a feature available in CGM systems.

"The FDA is always interested in new technologies that can help make the care of people living with chronic conditions, such as diabetes, easier and more manageable," said Donald St Pierre, acting director of the Office of In Vitro Diagnostics and Radiological Health and deputy director of new product evaluation in the FDA's Center for Devices and Radiological Health, in a statement.

"This system allows people with diabetes to avoid the additional step of finger-stick calibration, which can sometimes be painful, but still provides necessary information for treating their diabetes — with a wave of the mobile reader," he added.

The FreeStyle Libre system is already being widely used outside of the United States. It was licensed in Europe in 2014 — where it is approved for use in people with diabetes (of any type) including children down to the age of 4 years — and it is currently available in over 40 countries and being used by more than 400,000 people living with diabetes, Abbott says.

US Launch by Year End With Price Similar to That in Other Countries

Recent "real-world" data presented earlier this year show that use of the FreeStyle Libre led to improved glycemic control. The study looked at 400 million individual glucose measurements from 50,831 FreeStyle Libre users, for a total of 279,446 sensor readings.

Overall, an average of 16.3 scans were performed each day. When divided into 20 equally sized groups by scan rate (2542 in each), HbA1c declined from 8% in the cohort reporting the lowest scan rate (4.4 times/day) to 6.7% for those with the highest scan rate (48 times/day).

As scan rates increased, hypoglycemia rates below 70, 55, and 45 mg/dL dropped by 15%, 40%, and 49% (all P < .001).

For the US approval, the FDA evaluated data from a clinical study of individuals aged 18 or older with diabetes and compared readings obtained by the FreeStyle Libre with those obtained by an established laboratory method used for analysis of blood glucose.

Associated risks of using this device might include hypoglycemia or hyperglycemia in cases where information provided by the device is inaccurate and used to make treatment decisions and mild skin irritations around the insertion site, the agency notes.

It warns also that it does not provide real-time alerts or alarms in the absence of a user-initiated action.

In the United States, three sensors a month will be required, as they are only approved for 10 days of wear, in contrast to the 14 days of wear approved in the European Union (which therefore necessitates use of only two sensors a month).

Abbott says the FreeStyle Libre system will be available by prescription before the end of the year at major retail pharmacies in the United States.

Regarding the cost, spokesperson Vicky Assardo told Medscape Medical News that the company wouldn't discuss specifics "until closer to launch."

"But I can tell you that the cost (per day) is very similar to and consistent with the cost for cash pay in Europe [taking into account three sensors per month vs two]."

In Europe, as of February this year, the annual cost for one reader and 26 sensors (replaced every 2 weeks) was approximately €1600 (about US $1885).

"The pricing is similar to blood glucose monitoring but significantly lower than competitive CGM systems," she said, adding, "This pricing structure has been put in place very deliberately to remain consistent around the world, with the ultimate goal of making FreeStyle Libre widely accessible.

"To ensure accessibility to the FreeStyle Libre system, Abbott has secured partial or full reimbursement in 17 countries, including France, Japan, and the United Kingdom."

In the United Kingdom, the system will be reimbursed by the National Health Service starting on November 1 this year. There are some fears there, however, that coverage of the device could be subject to a "postcode lottery," as discussed by Partha Kar MD, FRCP, clinical director of diabetes at Portsmouth Hospitals NHS Trust, United Kingdom, in a recent blogpost.

Better for Type 2 Diabetes Than Type 1?

Asked to comment on the US approval of the FreeStyle Libre, David T Ahn, MD, an endocrinologist and diabetes technology expert at the University of California, Los Angeles, said: "What's most exciting to me…is the…real-time visibility of blood sugars, [which] is so important for empowering patients in the day-to-day. You can instantly get feedback on what happens to your sugars when you're eating, exercising, or sleeping. You can't [normally] get that type of visibility with finger sticks."

Dr Ahn feels the product is potentially more of a breakthrough in type 2 diabetes management than for type 1 diabetes, however.

"Finger sticks have often been a barrier in managing type 2 diabetes. Not only does the Libre potentially replace finger sticks, but it also provides an order of magnitude more information than finger sticks, so not only is it painless, but it's better-quality information. For reference, a FreeStyle Libre records your sugar 96 times a day," he told Medscape Medical News.

"On the other hand, my concern with type 1 diabetes patients is that they typically have greater glycemic variability, so the lack of passive alarms and the inability to share glucose data on the cloud is a big disadvantage of the Libre compared with…CGMs on the market for type 1 diabetes." 

Those features — the passive alarms, and the data-sharing feature — while really valuable for type 1 diabetes, are less necessary in type 2 diabetes, he added.

"That's a big reason why I think the cost/benefit ratio tips in favor of the Libre…for a larger proportion of type 2 diabetes patients than traditional CGM.

"Eliminating finger sticks is a huge paradigm shift for managing diabetes," he concluded. "But the accuracy, reliability, and the economics will dictate how transformative it will actually be to our patients' lives."

Dr Kar said the issue of which diabetes patients will most use this device may depend on "market forces." In the United Kingdom, for example, access to traditional CGM "isn't great," he explained, so many type 1 diabetes patients opt for the FreeStyle Libre.

"At the end of the day, it's a question as to how you see Libre — whether it's just a modern way of doing blood glucose monitoring or a 'cheaper' CGM," he added.

"To me, it's a great innovation for anyone — which includes the system or the individual who can afford it. In the UK, it's unlikely the system can afford it for type 2 diabetes — and thus will be niched into type 1 diabetes," but "it may be different in the US," he observed.

Finally, with respect to the alarms, Dr Kar said it's all about "how you use the Libre."

While traditional CGM "gives you the alarm when you have a hypo, the trend in Libre readings gives you the opportunity to avoid it altogether — thus bringing it that extra functionality."

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