Continuous Glucose Monitor Options And The Discontinuation of the Navigator

Gretchen Becker Health Guide
  • Rumors are flying that the Abbott Navigator, a continuous glucose monitor (CGM), will be discontinued even before it receives FDA approval. Layoffs at the company are said to be in the works, according to a Reuters news release.


    Abbott denies the rumors, according to a second Reuters story.


    And an Abbott representative told me, "We are absolutely not pulling out of the market. Inaccurate information regarding Abbott's commitment to the FreeStyle Navigator Continuous Glucose Monitoring System has been circulated."


    In June, the Navigator received approval for use in Europe. Abbott says it plans a U.S. launch "very soon." But they've been saying that for several years, and the release date always seems to be next year.

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    At the current time, there are two other CGMs on the U.S. market: the DexCom Seven, and the Medtronic MiniMed Guardian REAL-Time CGM System, and some analysts speculate that the Navigator won't be able to keep up with the rapidly moving technology because the Dex and the MiniMed have a head start in capturing market share.


    Some insurance policies will cover the considerable expense of the CGMs for type 1 patients, but others won't. I suspect none of them will cover the devices for the average type 2.


    For example, Medicare thinks that people using insulin need only 100 test strips a month, or about three strips a day, at a cost of about $3 a day. The sensors for the CGMs cost about $10 a day. However, as with the strips, exceptions will most likely be made for people who really need the devices.


    In my case, even if I have to pay for a CGM and sensors myself, I think it would be cheaper in the long run than dealing with the aftermaths of a heart attack.


    But because many patients won't get insurance approval and many people can't or won't use medical devices or drugs that aren't covered by their insurance, some analysts see the market as limited to type 1 patients, especially those with so-called brittle diabetes (diabetes that is very difficult to control), or those who are no longer able to sense when they are hypoglycemic. The CGMs can be literally lifesaving in such patients.


    No one will say why it is taking Abbott so long to get FDA approval for their CGM. They initially asked the FDA to approve the devices as replacements for regular BG meters. In other words, you wouldn't need to confirm the readings with your regular meter.


    They didn't get that approval, so they reapplied for approval as an "adjunct" to the regular meters, which is the same type of approval that the MiniMed and Dex have received. Patients are told to confirm any high or low readings with regular blood glucose meters before adjusting insulin doses or taking steps to bring up lows.


    I had the opportunity to try two different CGMs, a MiniMed and a Dex, as part of a clinical study and a generous loan from a friend, and I think these monitors have the potential to have a tremendous impact on type 2 patients as well as saving the lives of type 1s and giving the parents of type 1 toddlers some peace of mind during the night (the CGMs have alarms that go off when you go too low [or too high]).


    Many patients with type 2 diabetes are told to test only first thing in the morning, or before meals, or two hours after meals. They haven't a clue about what is happening to their BG levels at other times. But the CGMs can show a patient what happens after eating various types of foods, and the patient can then adjust the diet accordingly.


    Many type 1s using the CGMs have been astounded to see how high their BG levels are going after their "healthy" low-fat breakfast of cereal, skim milk, toast, and orange juice. Before they had the CGMs, they'd test before breakfast, inject a bolus insulin, and test again before lunch, when they could very well have returned to their target levels. The CGMs, however, are showing that between breakfast and lunch, they're going very high, maybe even up to 300, and then coming down again before lunch.

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    Current studies suggest that these tremendous variations in BG levels may be almost as important as, or even more important than, average BG levels.


    I don't think type 2s not on a basal/bolus regimen need to use the CGMs 365 days a year. Once you learn how various foods affect you, you can then use that knowledge to choose suitable foods without testing every five minutes, as the CGMs do. One could get a CGM, use it for a week or so, and then set it aside to use again for a week next month. Gradually you'd learn more and more.


    Endocrinologists could buy the systems and loan or rent them to newly diagnosed patients, and this would greatly reduce the learning curve and help the patients choose the diet that was best for them before they'd burned out their beta cells by making poor choices.


    The CGMs also tell you what happens at night, when you're not apt to test very often. My A1c has always been higher than I'd expect from my meter readings, and many people said maybe I was going high at night. I wasn't. Instead, I discovered that I was probably going low around 3 every morning, and I adjusted my basal insulin to deal with this.


    I say "probably" because the CGMs can be affected by your circulation, and when you're in deep, deep sleep, not moving at all, your circulation decreases and the meters may read erroneously low. I was sometimes woken up by the low BG alarm, which said I was 50, and when I checked, my own meter said I was 80.


    Even after 10 years with type 2, I learned a lot by using a CGM, and my A1c dropped almost 1 point. Other people have reported similar A1c drops after using the CGMs. A few type 1s found that their A1cs went up. This is probably because they were having a lot of lows before they used the CGMs, and eliminating the lows, as many did, would raise the A1c. However, the lack of lows would greatly improve their quality of life.


    Many of us have been waiting for the Navigator to come on the market in 2008 before deciding which CGM to buy. Now there are hints that we might not have that choice.


    But market analysts are paid to try to ferret out information and then inform their clients so they can buy or sell their stock appropriately. Their analyses are not always correct. Company spokespeople are paid to provide a rosy picture of their company.


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    One can't really trust either side. But I do hope the rumors turn out to be false.

Published On: November 13, 2007