As more companies eye the ever-expanding continuous glucose monitoring (CGM) universe, an almost unheard-of little startup in California is developing a new sensing product that could truly change the game.
The idea sounds a bit contradictory, on its face: a device that has a CGM sensor and transmitter that communicates directly to a smartphone, but has similarities with traditional glucose test strips... Huh?
The company is Metronom Health, a small Orange County startup that spun out from life sciences tech accelerator Fjord Ventures. They're developing a CGM sensor that's tinier than anything on the market, resembling a small, flat strand of thread about the size of two human hairs. It's made of flexible polymer and would be inserted under the skin for 14-day wear. In addition to measuring glucose, it measures oxygen concentration, which helps boost accuracy in detecting glucose levels.
“We wanted to build a CGM more like a test strip... something that can be fabricated at low cost and be made available to the mass market. That includes being able to trust the device, and having some smart information coming back (to the user) instead of just data overload," says Metronom's Co-Founder and Chief Scientific Officer Troy Bremer.
He tells us their product will beat the competition on accuracy, user-friendliness, and cost – the latter through the ease of mass production -- helping Metronom Health to succeed in this space where other new players will not.
Metronom's Small and Flexible CGM
Though founded nearly a decade ago, Bremer says the company has been in stealth mode and is just now starting to showcase its unique system, exhibited for the first time at the recent ATTD conference in Europe:
Sensor: The size of a tiny strand that can fit on the size of a quarter, the flexible polymer sensor is put in place with an insertion device. It will have 14-day wear time, and will not experience any interference from acetaminophen-containing meds like Tylenol, as has been the case with other CGMs on the market. The sensor will measure glucose readings every 5 minutes, and be fully disposable after it’s finished. It will not require regular fingerstick calibrations, but you can calibrate if you feel more comfortable doing so.
Transmitter: This square-ish separate piece with rounded corners is also fully disposable. At just about 4 millimeters thick, it's about two-thirds the size of an existing first-generation FreeStyle Libre sensor (which itself is about the size of two quarters stacked together). Metronom's transmitter will have Bluetooth connectivity built in, allowing direct communication with a smartphone app – iOS at first, and eventually Android to follow.
Adhesive: Metronom Health says it has a proprietary adhesive that is mechanically “more like skin” so that it’s more comfortable and moves along with the body more than existing CGM adhesives do today. It's also made from hydrophobic material, making it highly water resistant, so it's expected to have fewer issues with peeling. It’s currently good to go for 14+ days, and they’re conducting more clinical research on even longer wear time for different body and skin types.
Alerts: Yes, this system will offer real-time alerts for High and Low blood sugars like existing CGM devices from Dexcom and Medtronic. Bremer says they also have “a couple of unique twists” on the audio alerts to make them less obtrusive and more flexible, but he won’t elaborate at this time.
Data Sharing: Their app will connect with Apple HealthKit, allowing for direct sharing with other apps and diabetes platforms with smartwatch connectivity. Users will also be able to share data with caregivers, healthcare professionals, etc.
This brief video on Metronom's website offers a walk-through of how this CGM will work.
The 'Smart Sensing' Science Behind It
The real big difference between Metronom Health’s prototype versus existing CGMs on the market is how it measures glucose levels, via new "proprietary opto-enzymatic glucose sensing technology."
Like other CGMs, this system taps into interstitial fluid under the skin (rather than glucose in the blood from finger stick tests), but instead of an electrochemical response being measured, Metronom’s CGM sensor contains enzymes that allow for extremely accurate testing. The enzyme glucose oxidase reacts with glucose to produce hydrogen peroxide, which is then broken down into into oxygen and water by a second enzyme called catalase. This allows the system to detect oxygen levels proportional to the glucose concentration.
That is key because if oxygen levels decrease due to compression of the sensor, the system won't mistake that for a drop in glucose levels -- as can be the case with other detection technology.
Metronom's patented Smart Sensing technology is unique in several ways:
- the sensor contains that separate oxygen conduit, allowing detection of oxygen concentrations independently of the glucose signal
- the sensor contains three "reaction chambers" for detecting different glucose concentrations, which allow for increased accuracy, especially when users are in the hypoglycemic (low blood sugar) range
- the hydrogel polymers they use are extremely precide and only gas-permeable, which is what prevents drugs like acetaminophen (Tylenol) from interfering with sensor performance
- unlike electrochemical sensors used in other systems, the opto-enzymatic technology used here eliminates many common problems that decrease accuracy in traditional CGM sensing, Bremer tells us
Think of it this way: Lots of CGM users right now get “compression lows” from turning over in bed on the sensor. That wouldn’t happen with what Metronom is developing, as it balances both glucose and oxygen from different sides of the sensor, making results more accurate. It also alarms for any site issues that may require you to calibrate, or re-adjust your body position (like stop sleeping on the sensor).
In short, this device is expected to be more reliable, accurate, comfortable, and robust (by staying on better) than anything that exists today.
“(Other CGMs) only have one view of the world,” Bremer says. “But we have two, because we’re monitoring both oxygen and glucose. We have an orthogonal means to assess the environment. This allows us to decide if sensor site is stable, or if it's drifting and leading to inaccurate results over time.”
Moving Towards Market
Right now, Metronom is collecting data in the diabetes data space and comparing that with its early prototype research. An initial 7-day clinical study was conducted in 2015 with 20 patients – 10 with T1D, 10 with T2D – comparing this CGM prototype tech with existing fingersticks and lab results. For each sensor, the retrospective data showed a MARD value (measure of CGM accuracy) of 9% over the course of the study. (The lower the MARD number, the better, and a single-digit value is considered state of the art.) The 2015 study also showed no significant change in hyperglycemia or hypoglycemia (blood sugar highs or lows).
Inpatient and outpatient studies will be done over the course of 2018. They hope in early 2019 to pursue CE Mark regulatory approval overseas, and from there they will move forward with U.S. filing probably in early 2020.
While many small companies are working on new CGM technologies, Metronom believes it is uniquely positioned to succeed because it can achieve lower cost in all stages of R&D – from early design and manufacturing to end-user commercialization. As of now, there are no specifics on cost to the consumer, but they're saying it would be “significantly more affordable" than what’s on the market today.
“Unless you can compete on manufacturing, performance, accuracy, reliability, and affordability, and ease of use… I don’t think you’re going to be a competitor who is going to be able to stay in the market. We’re offering advantages in all of those areas," Bremer says confidently.
And about their prospects for regulatory approval, he simply says: “The FDA approval timeline has been quite variable with the (other CGM) submissions. It looks variable, but I’d hope we would be done within a year.”
We sure hope their ambition pays off!