French surgeon performs an operation to fit a prosthesis onto a pancreas tumour to facilitate circulation in the biliary tract on a patient in an operating room at the Ambroise Pare hospital in Marseille, southern France March 25, 2008.
Credit: Reuters/Jean-Paul PelissierBy Julie SteenhuysenCHICAGO | Fri Jun 24, 2011 5:05pm EDT
CHICAGO (Reuters) - Researchers are coming closer to developing an "artificial pancreas," a long-sought system of insulin pumps and glucose sensors that deliver insulin to diabetics, mimicking the function of a real pancreas.
The devices have been in development for more than three decades, but lawmakers and diabetes advocates are ramping up the pressure and U.S. regulators this week outlined a regulatory path for a preliminary version of the device.
And while a seamless device that tracks a diabetic's blood sugar and automatically administers the right dose of insulin is still years away from commercial use, results of several studies being presented this week at the American Diabetes Association meeting in San Diego show real promise.
In one, researchers from Boston University and Massachusetts General Hospital tested a system using Abbott Laboratories' FreeStyle Navigator continuous glucose monitor and two insulin pumps made by Insulet Corp, all controlled by a laptop.
The system, which is designed to better mimic the body's natural mechanism of controlling both high and low blood sugar, was portable enough to allow adults with type 1 diabetes to roam around a hospital and use an exercise bike.
At the end of the 51-hour study, which involved daily exercise, two nights and six meals -- all of which affect a diabetic's blood sugar levels -- six patients had an average blood glucose in the normal range -- in the high 140s, which is about the equivalent of an A1c reading of about 7.
"It is very good. This is what we would call near normal blood glucose," said Dr. Steven Russell of Massachusetts General Hospital in Boston who is developing the system with Edward Damiano, a biomedical engineer at Boston University.
In another study, a team at Mayo Clinic hooked patients up with devices called accelerometers that tracked movements and found that even moderate exercise plays a role in glucose. The team, led by Yogish Kudva, will incorporate this data into a sophisticated software program that acts as the "brain" of an artificial pancreas system, analyzing blood sugar and calculating when diabetics need a dose of insulin.
The team plans to start a clinical trial with the system this year or early next year, Kudva says.
CLOSING THE LOOP
So-called closed-loop systems -- in which a computer calculates a person's insulin dose and delivers insulin automatically through an insulin pump -- are a far cry from the earliest version of an artificial pancreas developed in the late 1970s, says Dr. Aaron Kowalski of the Juvenile Diabetes Research Foundation or JDRF.
"The problem is it was the size of a refrigerator," said Kowalski, who oversees the group's Artificial Pancreas Project, a multimillion-dollar initiative aimed at accelerating progress toward a closed-loop automated insulin-delivery system .
With that device, patients were hooked up to an IV and could not leave their hospital bed.
Researchers have since been working to develop a so-called artificial pancreas to deliver insulin to patients with type 1 diabetes, an autoimmune disease in which the body destroys its own ability to make insulin, rendering sufferers unable to properly break down sugar.
People with the condition must frequently monitor and take insulin to regulate blood sugar and prevent diabetic complications such as eye damage, kidney failure and heart disease.
An estimated 3 million Americans have type 1 diabetes, usually diagnosed in childhood or in young adults.
The JDRF is working with Johnson & Johnson's Animas unit, which makes insulin pumps, and DexCom Inc, which makes continuous glucose monitoring devices.
Kowalski said nearly five years into the project, researchers are showing promising results, but he is frustrated with the pace of progress.
"People need better tools. Despite insulin pumps and continuous glucose monitors, there are still big challenges in diabetes management," Kowalski said.
The group on Wednesday urged a Senate hearing to call on the FDA to stop delaying the study and approval of an artificial pancreas.
They cited a study published in the British Medical Journal that found that if an artificial pancreas were available, Medicare would save nearly $2 billion over 25 years in costs related to diabetes complications.
The group is pushing to move beyond studies in academic settings and begin studies of the devices outside of the hospital setting.
"It's great that we can do this in academic centers, and we're learning a ton, but we need to get these projects to reach people with diabetes," he said.
"We need to see these products commercialized. That is the big challenge, and that is why we are working with the FDA."
FDA WANTS APPROVAL, TOO
Charles "Chip" Zimliki, chairman of the U.S. Food and Drug Administration's Artificial Pancreas Critical Path Initiative, which was created in 2006 to accelerate the availability of an artificial pancreas system, says he is eager to have a system approved.
"The FDA wants the artificial pancreas on the market as much as anyone else does. We just have to operate within U.S. laws to make sure it is safe and effective," Zimliki said.
Last week, the agency released guidance for how to develop a low glucose suspend system, an automatic shut-off mechanism used with an insulin pump. Medtronic already sells pumps with this the feature in Europe. It safeguards against a dangerous drop in glucose levels by temporarily halting glucose delivery.
By year-end, FDA plans to release detailed guidance on more complicated closed-loop systems, Zimliki said.
"We think of this system, the artificial pancreas, as one unit. There is going to have to be agreement among various companies to determine who is the reporting party for submitting it," he said.
"That is a relatively new idea with respect to these systems."
Zimliki, who is a type 1 diabetic, thinks the first approved devices will be ones that deliver insulin only, but he is very encouraged by the system being developed by the team at Boston University and Massachusetts General.
"They have what I call the Cadillac of closed-loop systems," he said. In addition to delivering insulin, the device also delivers an infusion of glucagon, a hormone released by the pancreas to raise blood sugar levels.
"They are showing some very promising results," he said.
(Reporting by Julie Steenhuysen, editing by Matthew Lewis)
