A device that combines an insulin patch pump with a continuous glucose monitor (CGM) in the same unit was shown to function in a small, early proof-of-concept study in people with type 1 diabetes (T1D). 

“Simplifying device requirements, reducing the number of insertion sites, and potentially streamlining replacement schedules are all meaningful from a patient perspective,” study investigator Hannah Cunningham, MBBS, of the Department of Medicine, The University of Melbourne, Melbourne, Australia, told Medscape Medical News.

The current standard of T1D care involves wearing two separate devices, an insulin pump — either with tubing or a “patch” pump — along with a CGM inserted at a different site on the body. The two devices are generally placed at least 3 inches apart to avoid interference between subcutaneously deposited insulin and glucose sensing. Replacement schedules for the two devices often differ, ie, every 2-3 days for the pump vs 10-15 days for the CGM sensor. 

The investigational device, called niia (PharmaSens), overcomes these limitations via a “sensing cannula,” a 31-gauge steel insulin infusion catheter with a glucose sensor attached to the outer surface of the catheter walls.

Feasibility Study

The feasibility study included 18 adults with T1D who were already using current diabetes technology. An initial pilot study included three participants who wore the device for 10-12 hours and underwent a meal test. The second phase included 15 participants who wore the device for 72 hours while staying in a hotel, with two meal tests and one free-living day. 

The prototype device included the “SynerG” CGM sensor fully integrated into the pump, but with an external electronic module housing the CGM transmitter placed alongside the device and connected by a short wire. Full integration is expected in future product iterations, as is the development of the device for automated insulin delivery. For this preliminary study, however, insulin was dosed manually.

Of a total of 38 devices used in the study, 12 were excluded prior to insertion (10 due to needle blockages and two due to defective covers). Another nine failed immediately after insertion, requiring reinsertion. All of the failures were of the CGM, not insulin delivery. The 14 devices that provided sensor information lasted an average of nearly 10 hours. A total of 12 lasted the entire three days.

Compared with values obtained from simultaneous glucose analyzer and fingerstick blood glucose measurements, the mean absolute relative differences during the meal tests were 11.6% and 12.0%, respectively. The percentage of readings falling within the acceptable accuracy ranges (zones A and B) were 100% and 99.35%, respectively.

Mean glucose levels, time in range, and total daily insulin doses on day 2 were comparable to baseline. There were no serious adverse events.

Cunningham told Medscape Medical News that the high failure rate “can be explained primarily by the fact that we used a prototype that, although extensively tested before starting the study, was nonetheless still in its early stages of product development.”

The failures that were due to cannula blockages “can be eliminated by optimizing this manufacturing process,” she said.

While declining to provide a specific timeline for product development, Cunningham did say “we expect all-in-one systems to be available within the next 3-4 years, and our goal is to be the first to offer them.”

The study was jointly funded by Pacific Diabetes Technologies and PharmaSens. Cunningham had no disclosures, but six of the co-investigators declared being PharmaSens employees, and two others reported having disclosures with multiple companies involved in diabetes device development. 

Miriam E. Tucker is a freelance journalist based in the Washington DC area. She is a regular contributor to Medscape, with other work appearing in the Washington Post, NPR’s Shots blog, and Diatribe. She is on X @MiriamETucker and Bluesky @miriametucker.bsky.social.