Rockley Photonics plows ahead in developing noninvasive glucose sensor

Hot on the heels of study data showing its cuffless blood pressure monitor is well on its way to reaching desired accuracy levels, Rockley Photonics is boasting similar progress in the development of another of its biosensor technologies—this one to monitor blood sugar levels for people with diabetes.

The company documented that progress in a pair of studies spanning both simulated benchtop testing and an actual in-human assessment, per a Tuesday announcement.

Taken together, the studies describe what could one day become a completely noninvasive option for glucose monitoring. That approach integrates Rockley’s short-wave infrared (SWIR) spectroscopy technology into its miniaturized photonic integrated circuit (PIC) chips, with the resulting mechanism embedded into a smartwatch-style wearable device to replace the current standard of adhesive, skin-puncturing continuous glucose monitors and fingerstick-taking blood glucose monitors.

In the benchtop study, researchers put the PIC technology to the test in a simulated tissue model. According to Rockley, those measurements showed that its biosensor could measure glucose levels with an accuracy of 5 mg/dL.

For comparison, current ISO standards require that more than 95% of an integrated CGM’s readings be within 15 mg/dL of actual blood sugar levels, while the FDA mandates that at least 87% of a device’s readings fall within 20% of a reference measurement—which translates to an allowed difference of roughly 20 mg/dL from the recommended blood sugar levels for people with diabetes, which should ideally land between 80 mg/dL and 130 mg/dL before a meal.

The other study, meanwhile, recruited 40 people with either Type 1 or Type 2 diabetes and lasted a total of 10 weeks. Though Rockley didn’t provide details about the content of the study, it reported that the results “demonstrated significant progress towards the development of a noninvasive wearable glucose monitor.”

CEO Andrew Rickman, Ph.D., doubled down on that conclusion in the release, saying of both studies: “The results confirm that Rockley’s integrated silicon photonic technology and novel processing of the SWIR signal offers a unique opportunity to realize the goal of a wearable, noninvasive glucose sensor for a host of medical applications.”

Neither study’s results have yet been published, and Rockley didn’t immediately respond to a request to view the data.

Just last month, fresh out of six months of bankruptcy proceedings, Rockley described the results of another pair of studies, this time focusing on applying the SWIR biosensing technology to blood pressure monitoring with an aim of replacing traditional inflating cuffs.

The first analysis was a clear success: After calibration using only one reference data point, Rockley’s sensor was able to track changes in 30 participants’ blood pressure levels with accuracy levels well within the bounds of two FDA-recognized standards when compared to readings from a “gold-standard” intra-arterial pressure transducer, or A-line.

The second study, however, showed the technology still has room to grow. While the first study took place in a single clinic visit, this one followed participants for about a month after the initial calibration. During that time, the biosensor fell short of the accuracy targets but was “within sight of meeting” the standards—and also maintained about the same error level over time, rather than increasingly diverging from the A-line’s results, per Rockley.