FDA approves new continuous glucose monitor

Many people we talk to ask about the future of a continuos glucose monitoring system that will eliminate the need for the numerous daily fingerpricks. Here's the latest on one company's efforts.

From the Sept. 2005 JDRF Research Frontline Newsletter

Diabetes product providers continue to develop and refine diabetes management devices that could ultimately represent the component parts of an artificial pancreas. In August, the Food and Drug Administration (FDA) approved the Guardian RT Continuous Glucose Monitoring System, a blood sugar monitor that works both as a round-the-clock tracking device, recording a patient's blood glucose for up to three days, and as an alarm, sounding when blood sugar changes precipitously.

Patients wearing the beeper-sized, wireless monitor can get realtime glucose readings every five minutes, and also track how diet, exercise, and medication are affecting their blood sugar levels.

"Continuous monitors represent where diabetes selfmanagement is heading," says JDRF Scientific Program Manager Aaron Kowalski, who has type 1 diabetes.

Manufactured by Medtronic, Inc., the Guardian RT uses a sensor inserted in the abdomen just under the skin. The sensor transmits information to the monitor and records up to 288 readings a day. These data can be downloaded onto a PC to view trends in the individual's blood glucose activity. It also alerts users to high or low blood glucose levels. After three days, the sensor must be replaced.

While the manufacturer continues to evaluate training, education, and reimbursement fees, the Guardian RT is being sold only in selected U.S. cities. It requires a physician's prescription.

Currently, the only other continuous glucose monitors approved for use by the FDA are Medtronic's CGMS System Gold, an earlier model similar to the Guardian RT, and the GlucoWatch G2 Biographer, a wristwatch-like device manufactured by Cygnus.

Clinical trials show continuous monitors are effective, but at this point in their development they don't work well enough to replace conventional fingerstick glucose meters. As a result, the FDA requires that continuous monitors, including the Guardian RT, be used to complement fingerstick testing and give patients additional information about glucose level trends.

But taking a longer view, continuous monitors represent an important step toward an artificial pancreas, which would sense glucose levels and dispense appropriate amounts of insulin automatically.

"Technology will probably be reoriented around identifying trends and taking measures to prevent extreme highs or lows," says Dr. Kowalski. "Ultimately, it may be more important to know which way your glucose levels are heading than what your exact reading may be."