Medtronic’s MiniMed® 670G Review | World’s First "Artificial Pancreas

It’s almost been a year since the world’s first “artificial pancreas,” Medtronic’s MiniMed^® 670G System has been commercially available. The device is the only approved insulin pump in the world that automatically delivers basal insulin to control blood glucose levels.

We reviewed the MiniMed^® 670G system with renown diabetes expert, Dr. David Klonoff, medical director of the Diabetes Research Institute, Mills-Peninsula Medical Center in San Mateo, Calif., to learn more about the device. Here’s what we found out.

How does it work?

The main features of the 670G system include three components manufactured by Medtronic: a CGM, a pump and a dedicated algorithm that sets a target glucose level of 120 mg/dl, almost all of the time. The device features the company’s most advanced algorithm — SmartGuard(TM) HCL — the latest innovation in Medtronic’s phased approach toward developing a fully automated, closed-loop system, according to the company press release.

“It is a unique product that can deliver hybrid closed-loop control to manage diabetes,” Klonoff says, “this degree control of glucose levels between meals is a breakthrough in treating diabetes.”

The system also provides a manual mode of control with options to program insulin suspension for either a fall in the glucose level down to a low glucose threshold or for a predicted impending low glucose level.

However, Klonoff notes the system components cannot be swapped out with components made by another manufacturer. “If a patient insists on using a CGM, a pump or an algorithm developed by another manufacturer, then they cannot use the 670G because the 670G contains a specific set of products made by Medtronic,” he points out.

“Technology breeds competition,” says Klonoff. “I expect that eventually, competing products will appear and that some of them will be even better than the current 670G.”

However, he also expects that Medtronic will continue to develop better next-generation AP products themselves and that their future products will also be better than the current 670G.

Who is the system best suited for?

None of Klonoff’s patients are currently using the 670G, but several of his patients are getting ready to replace their current pumps and sensors with a 670G system.

He explains the device is suited for someone who is aiming for improved control and wishes to achieve an A1C in the 6 percent range, with little glucose variability (which means more time in the target range of 70-180 mg/dl) and only a very low risk of hypoglycemia, hyperglycemia, or DKA compared to the fairly frequent occurrence of these complications that patients not using the 670G might experience.

“The system is best for patients with good numeracy and mechanical skills to use this equipment, but that is true for all insulin pumps, even when they contain a bolus calculator which assists in selecting a dose of insulin,” Klonoff adds about the device. “The 670G automatically changes insulin sensitivity every 24 hours and also changes the maximum basal rates every 24 hours, which partially decreases the numeracy problem.”

Klonoff indicates a person must be comfortable with a device controlling the basal insulin delivery rate because this system does not allow for much intervention by a patient.

He considers the 670G to be safe and has no particular concerns about its use. Like other diabetes devices, he points out, there is a risk of incorrect dosage delivery due to sensor failure, miscalibration or insulin pump occlusions.

The sensor system on the 670G contains a system to measure the health of the glucose sensor and detect faults with the sensor performance, which provides a double check on the sensor data. If a problem is detected, then the patient is alerted and the system reverts to manual control rather than automatic closed-loop control.

According to Klonoff, the system has many fail-safe mechanisms and warnings for patient users. If the system is getting out of control, then it will automatically switch from automatic closed-loop control to patient-controlled open loop control.

The 670G is a hybrid closed-loop system. “Hybrid” for the device means that the system depends on the patient estimating the mealtime carbohydrate content and triggering delivery of such a dose when it is time to eat.

If the patient forgets to announce the meal, then it will be difficult for the system to deliver sufficient insulin to effectively control the rise in blood glucose following that meal.

Use in children

The product is not yet approved for children under 14, however, a study presented at the Endocrine Society meeting last month found the artificial pancreas safe and effective in young children aged 7-13 with type 1 diabetes.

If the safety and effectiveness of the 670G can be demonstrated consistently in clinical trials of children, then Klonoff expects that the system will eventually be approved for children.

He does not expect, however, that the device will ever be used in anyone under the age of 7 or in patients who require a total daily insulin dose of fewer than 8 units.

Klonoff definitely agrees that the device will be beneficial in preventing hypoglycemic events and DKA. “An artificial pancreas system is automatic and runs on well-thought-out automatic insulin delivery algorithms to maintain glucose levels in a very safe range that is far from a state of DKA and distinct from a state of hypoglycemia,” he explains.

The system contains alarms for elevated blood glucose levels, which typically precede the development of DKA.

There are about 30.3 million people with diabetes in the U.S., according to the Centers for Disease Control and Prevention. Klonoff says about 5-10 percent of these people with diabetes have type 1 diabetes and are candidates to use an AP product.

He says not all of the type 1 patients will receive this treatment because the use of an AP “requires the money or coverage to pay for it, the numeracy skills to make corrections on this system, and the mechanical skills to work with the equipment.” He says an AP system might eventually also be used for selected people with type 2 diabetes.

As far as accessibility, almost everyone will require insurance coverage to use an AP system. “It is costly, but the cost is the same as other Medtronic pumps and sensor systems,” Klonoff points out. He hears that most insurance plans are covering the system, provided that patients have a demonstrated need for better control in spite of currently using less sophisticated therapy and that they understand how to use the system.

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David C. Klonoff, M.D. is an endocrinologist specializing in diabetes technology. He is a Clinical Professor of Medicine at University of California, San Francisco and the Medical Director of the Diabetes Research Institute, Mills-Peninsula Medical Center in San Mateo, California