For more than 30 years, Cindy Tenney has constantly checked her blood sugar levels and adjusted her insulin intake to keep them normal.
But she recently took part in a trial of a first-generation Medtronic artificial pancreas that could do some of that work for her. It combined a continuous glucose monitor and insulin pump in a single device smart enough to stop pumping insulin when blood sugar levels get low.
Tenney said such a safeguard is especially valuable to Type 1 diabetics like herself when they're sleeping and may not realize what's happening with their blood sugar.
"That is incredibly important," said the Upland, Calif. resident. "That's the scariest time for a diabetic. When you're asleep and your blood sugar drops, you could pass on to a coma ... and potentially pass away."
Medtronic, along with some of its competitors, is getting close to bringing the product to market in the United States.
Tenney looks forward to the day when monitors and pumps are refined to also give more insulin to bring high sugar levels down. That would be like having an artificial pancreas, she said.
"Ultimately, there's not one single diabetic on Earth who wouldn't wish for an artificial pancreas," Tenney said.
For Type 1 diabetics, too much insulin sends blood sugar too low, causing seizures, unconsciousness, brain damage and death. But too little insulin can cause high blood sugar, increasing the chances of damage to the eyes, kidney and heart.
Dr. Richard Bergenstal of Park Nicollet's International Diabetes Center was one of the investigators in an extensive study of the system Tenney tried. Participants using it saw low blood sugar episodes drop by about one third. And no deaths or "severe adverse events" occurred among those patients. Bergenstal said the trial results may pave the way for federal Food and Drug Administration approval of the Medtronic device later this year.
"This is the first step in that building of an artificial pancreas," he said. "It detects low blood sugars and it interrupts or suspends the insulin to prevent that from being a danger."
Meanwhile, Bergenstal is engaged in the development of even more sophisticated devices that better mimic the functions of the pancreas.
"This is the Holy Grail, sort of," Bergenstal said. "Can we have an artificial pancreas that just detects the blood sugars and gives you either the right amount of insulin or insulin and this other hormone glucagon?"
Glucagon, a hormone produced in the pancreas, raises low blood sugar.
It's a significant challenge to engineer a device smart enough and durable enough to deal with all sorts of situations and scenarios — from inaccurate glucose readings to a blocked pump. The units must be as fail-safe as possible, since peoples' lives depend on them.
Pumps and monitors are now about the size of small cell phones. Medtronic even has a phone-size unit that combines a pump and a monitor. But some diabetics would like even more discrete devices. And they'd like to forego the half-dollar sized sensors that need to go on the skin to send glucose readings wirelessly to a monitor.
Dr. Yogish Kudva of the Mayo Clinic has been working on an artificial pancreas that uses components from Dexcom and Johnson & Johnson, two of Medtronic's rivals in the diabetes management business. He said many challenges remain but he sees the day coming when an artificial pancreas will transform the lives of many diabetics.
"That is the dream toward towards which we work," he said. "And that is a dream that is becoming more of a reality now."
Medtronic is the acknowledged leader in pumps and other devices that help diabetics manage their disease. The company, for instance, accounts for most of insulin pump sales. And Medtronic has been working on an artificial pancreas for more than a decade.
"We have all the pieces of the puzzle," said John Mastrototaro, chief technology officer for Medtronic's diabetes division, which accounts for about a tenth of Medtronic's $16 billion in annual sales.
"We do the insulin pump. We do the glucose monitor. We also develop the algorithms," said Mastrototaro. "We have all the pieces of the puzzle."
Mastrototaro said Medtronic has spent about a year trying to win FDA approval of the company's first shot at an artificial pancreas, supplying clinical, trial and other evidence supporting the device's safety and effectiveness.
"In the agency's eye, this is a really big deal," he said. "They call it half-way toward the artificial pancreas because it deals with the low blood sugars but doesn't deal with the highs."
Piper Jaffray medtech analyst Thom Gunderson believes everyone with type 1 diabetes would be in the market for an artificial pancreas.
"If you come up with the perfect artificial pancreas, they're all candidates for that," he said. By some estimates, that's as many as 3 million people.
Gunderson figures artificial pancreases would cost north of $10,000 and easily produce at least $15 billion in initial sales.
In addition, there'd be sales for related supplies and components and devices that wear out.
While Medtronic awaits FDA approval of its first-generation artificial pancreas, it's already embarking on trials of more sophisticated devices. The company is enrolling patients for a trial of a device that helps diabetics automatically maintain a target glucose level throughout the night, automatically pumping more or less insulin as needed.