By Adam Brown and Kelly Close
Launch by end of 2017 in major pharmacies at lower price than other CGMs; No fingerstick calibration needed, 10-day wear, 12-hour warmup
The FDA and Abbott finally announced long-awaited US approval of the FreeStyle Libre real-time “flash glucose monitoring system.” In the US, it is approved for adults with diabetes only. Like the international version, the FreeStyle Libre sensor is considered a replacement for fingersticks – it does not require any daily fingerstick calibrations and real-time readings and trends can be used for insulin dosing.
FreeStyle Libre will be available in major retail pharmacies across the US by the end of the year (sign up for updates here). The cash price without insurance will be far less expensive than other sensors – we expect it will be sold for around $120 per month for three sensors, and each reader will be around $60 (one-time purchase). We’re not sure how FreeStyle Libre will be reimbursed by insurance, and if it is, what the out-of-pocket spending will be.
In the US, FreeStyle Libre has three notable changes:
A slightly shorter 10-day wear time.
A much longer 12-hour warmup after insertion.
Will require a prescription.
Outside the US, FreeStyle Libre is 14-day wear, 1-hour warmup, and does not need a prescription – see our 2015 test drive here.
The longer warm-up period is definitely the biggest change – it means when a new sensor is inserted, FreeStyle Libre will not show any real-time glucose data for the first 12 hours. During this time, users will go back to fingersticks. One option is to put a sensor on just before bed, which will get through much of the 12-hour warm-up for those who sleep close to eight hours or more per night. Another workaround is for users to buy two reader devices, alternate using them, and overlap sensor wear times to avoid 12 hours without Libre data. Read more on how to do this in the FAQ below!
FreeStyle Libre is considered a “continuous glucose monitor” (CGM), since it collects a glucose value every minute and displays a number and trend arrow. However, it does not have alarms and does not communicate continuously with the handheld reader device as other CGM devices do. To obtain a real-time glucose number and trend, the sensor must be “scanned” (within 1.5 inches) using the reader device. This can be done through clothing, making it far less visible, obtrusive, and painful than a fingerstick.
The Libre sensor is approved for upper arm wear, is waterproof for showering and swimming, is fully disposable, is not affected by Tylenol (acetaminophen), and can store up to eight hours of recent glucose data on the patch. If more than eight hours pass between scans (e.g., 10 hours sleeping), only the most recent eight hours of data will be captured. Abbott is working on an exciting continuous communication version of FreeStyle Libre in partnership with Bigfoot Biomedical – read more here on their automation plans, which include a pivotal trial with a pump expected next year. In this next-gen product, we are assuming there will be alarms.
At initial US launch, FreeStyle Libre will only communicate with the handheld reader device, meaning it won’t have smartphone connectivity. It is hoped that Abbott will submit the LibreLink (Android) and LibreLinkUp (remote monitoring) apps for FDA approval soon.
We are elated to see this real-time version of FreeStyle Libre coming to the US, since it has been available in Europe since fall 2014. People with diabetes globally have had a very positive response to this device, and it’s now used by more than 400,000 people across over 41 countries.
This long-awaited approval comes one year after the product’s FDA submission, and about a year since the blinded FreeStyle Libre Pro came to the US. We expect this real-time version will expand the US CGM market significantly – the lower price, no need for fingerstick calibration, small on-body footprint, ease of insertion, and pharmacy distribution are very welcome improvements for people with diabetes.
Abbott has set up a US website at www.freestylelibre.us for those looking for product updates. After signing up, you can also enter your healthcare provider’s information if you need help getting a prescription. We’ll write a follow-up once the product is officially available in pharmacies.
Frequently Asked Questions on FreeStyle Libre – Click to Skip Directly Down
Q: How much will I have to pay for FreeStyle Libre if I have insurance?
We’re not sure yet. With pharmacy distribution, insurance typically requires a copay or coinsurance – this can range from as little as $15 to $100 or more, depending on what “tier”/“preferred” level a device is covered. This varies by insurance plan, so we’ll have to wait and see how FreeStyle Libre is covered.
We speculated that the cash price for FreeStyle Libre (without insurance) will be around $120/month total for three 10-day sensors. We expect each reader (one-time expense) will be around $60.
Q: Why does the US version of FreeStyle Libre have a 12-hour warmup time vs. one-hour outside the US? Why is the wear time 10 days in the US instead of 14 days outside the US?
Each country’s regulators may take a different approach when reviewing medical devices for safety and efficacy. It is common for products to have different labeling and indications for use in different countries, even if they are the same.
In the US, FreeStyle Libre’s accuracy has improved a bit with these changes – the average measurement error relative to a reference value is 9.7%, an improvement from around 11% in Europe (and on par with 9.0% for Dexcom’s G5).
Sensors typically have the worst accuracy on day one, especially in the hours just after insertion. The longer 12-hour warmup gives FreeStyle Libre more time to acclimate to the body, likely reducing the chance of less accurate readings right after insertion. Since FreeStyle Libre intentionally does not accept fingerstick calibrations, there is no fingerstick check right after insertion to confirm readings are accurate. To be conservative on the safety front, perhaps the FDA wanted the longer 12-hour warmup period. On the plus side, this means that when FreeStyle Libre does start giving data after the 12-hour warmup, it should be much more accurate than one-hour after insertion.
While the US version of FreeStyle Libre includes this 12-hour warmup period, we’re glad Abbott could achieve strong accuracy and avoid the twice-daily fingerstick calibration used in other CGMs – this saves at least 20 fingersticks over the 10-day wear period.
We’re not sure why the wear time has changed from 14 days to 10 days. It’s possible the FDA saw changes in accuracy on days 11-14, or perhaps other factors played a role. It’s also possible Abbott made this decision on its own, assuming it was the fastest way to get the product approved.
Q: How can I avoid the 12-hour warmup period where no FreeStyle Libre data appears?
When a new FreeStyle Libre sensor is inserted and started, a 12-hour warmup period begins where no real-time glucose data is displayed. This means users will need to go back to taking fingersticks to monitor their glucose. One option is to start a new sensor just before going to bed, which will get users through most of the 12-hour warmup.
But for those who want uninterrupted FreeStyle Libre data, the solution is to have two readers and alternate them, starting a new sensor’s 12-hour warm-up in the last 12 hours of the current sensor’s life. For instance, if a currently-worn sensor is set to expire at 8 pm on Monday, the new sensor could be inserted 12 hours before at 8 am on Monday. This new sensor would need to be started with a secondreader. Once 8 pm rolls around, the current sensor will stop giving data just as the new sensor’s 12-hour warm-up is complete.
(For those wondering, each FreeStyle Libre reader can only be used with onesensor at a time, meaning a single reader cannot start the second sensor’s warm-up.)
Aside from wearing two sensors and managing two readers, the downside here is that data on each reader will only reflect half of a user total glucose data. We’re not sure if the FreeStyle Libre software can combine data from two readers to create one unified data set.
More importantly, we hope Abbott and FDA will work together to reduce the warmup time!
Q: Does wearing FreeStyle Libre mean I never have to take a fingerstick again?
No. Fingersticks will be required during the 12-hour warmup, since FreeStyle Libre won’t show data at the time (assuming the overlap strategy discussed above isn’t used).
Fingersticks are also required for treatment decisions whenever FreeStyle Libre displays a “Check Blood Glucose” symbol; when a user’s symptoms do not match Libre’s readings; when the user suspects readings may be inaccurate; or when the user experiences symptoms that may be due to high or low blood glucose.
That said, in clinical trials, FreeStyle Libre users generally stop taking fingersticks altogether, except for around 2-3 per week.
Q: Is FreeStyle Libre covered by Medicare?
No, but Medicare coverage discussions are underway. In a major plus, FreeStyle Libre should qualify for coverage, since it is approved as a replacement for fingersticks for making treatment decisions (like Dexcom’s G5).
Q: Is FreeStyle Libre available for those under 18 years?
At launch, FreeStyle Libre is approved for those 18+ years and it requires a prescription. For those under 18 years, this means a healthcare provider will need to prescribe FreeStyle Libre “off-label.” This is doable but depends on the provider.
Outside the US, FreeStyle Libre is approved down to age four. We hope to see Abbott and FDA work to update the US label and add pediatrics, now that it is approved in adults. There is no timing to share yet, but we do know that Abbott is continuing to evolve FreeStyle Libre, including new product features and indications.
Q: How is FreeStyle Libre different from Dexcom’s G5 and Medtronic’s Guardian Sensor 3 CGM devices?
Calibration: FreeStyle Libre does not require fingerstick calibration, whereas Dexcom requires two per day and Medtronic requires at least two per day (3-4 recommended).
Price/Distribution: FreeStyle Libre will be offered in pharmacies and at a much lower cash price than Dexcom and Medtronic CGMs. We’re not sure what Libre’s out-of-pocket price will be with insurance.
Warmup: FreeStyle Libre has a 12-hour warmup, whereas Dexcom and Medtronic have a two-hour warmup period.
Communication/Alarms: FreeStyle Libre does not have alarms and does not communicate continuously with a display device – the sensor must be scanned with the reader to obtain a real-time value. Dexcom and Medtronic send data continuously to phones/receiver/pumps (Dexcom) and the 670G pump (Medtronic), and both have alarms.
Wear time/Restart: FreeStyle Libre can be worn for 10 days, while Dexcom and Medtronic are 7-day wear. FreeStyle Libre cannot be “restarted” – it has a “hard stop,” meaning that once 10 days are up, a brand new sensor must be inserted. On the other hand, Dexcom and Medtronic sensors can be restarted – once an already-inserted sensor expires, it can go through a new two-hour warmup and continue giving data.