The system won't replace those painful finger-prick blood tests that diabetics must perform regularly but it provides a more accurate way to measure a patient's glucose levels.
The company's glucose monitor is for doctors to use occasionally to help adjust patients' treatment. It marks a big step toward development of a continual glucose monitor that diabetics would always wear.
Diabetics' bodies cannot regulate glucose, or blood sugar. Millions control their glucose with insulin shots, other medications and special diets.
They have no way to measure how their glucose fluctuates while they sleep at night. To know if treatment is working, diabetics prick their fingers several times a day to perform a blood test.
A few blood tests a day don't give doctors a full picture of how well diabetics are doing, just a snapshot. For example, a patient could test his blood at noon and the glucose sharply rises two hours later. If doctors knew, the patient could adjust the testing schedule or even the treatment to better steady glucose levels.
The tighter control maintained on glucose, the less likely diabetics are to suffer blindness, heart disease and other complications.
"Continuous tissue glucose monitoring is a breakthrough technology that ultimately could revolutionize the care of diabetics," FDA Commissioner Jane Henney said today. "This new system is a first step in that direction. It identifies patterns or trends" that signal when a patient needs treatment adjustments.
Under MinMed's system, a sensor would be implanted just under a diabetic's abdomen skin for up to three days. The sensor records glucose levels every five minutes. A computer program downloads the records so the doctor can analyze daily glucose fluctuations and customize treatment.
The device doesn't measure glucose in blood like the finger-prick tests do. Instead, it measures the "interstitial fluid'' between cells, providing glucose readings different from those diabetics are used to. But MiniMed's research showed that interstitial fluid could accurately show trends in glucose fluctuations.
MiniMed studied the device in people with Type 1 diabetes, which typically strikes young people and requires daily injections of insulin to survive. As a condition of approval, the FDA is requiring the Sylmar, Calif., company to continue studying the device's effect in people with Type 2 diabetes, which typically occurs with aging and does not always require insulin treatment.