Type 1 diabetics, who run the risk of dangerously low blood sugar, may be a
step closer to getting help from a crude artificial pancreas device that can
read blood sugar levels and automatically turn off the flow of insulin after a
clinical trial showed the device is safe.
The long-awaited results of the clinical trial may pave the way for US
approval of the device, made by Medtronic, which already sells insulin pumps
with an automatic shutoff feature in 50 countries outside the United States. The
feature is meant to guard against delivering insulin to diabetics if their blood
sugar is already too low.
As many as 3 million Americans have type 1 diabetes, in which the immune
system destroys cells in the pancreas that make insulin.
Type 1 diabetics must monitor their blood sugar and take insulin several
times a day. Too little insulin can cause high blood sugar, increasing the risk
of long-term complications such as eye damage, kidney failure and heart disease.
But too much insulin can cause blood sugar to drop too low, causing
hypoglycaemia, which can result in seizures, unconsciousness, brain damage and
US regulators have refused to allow insulin pumps with an automatic shutoff
feature on the US market without a large, carefully controlled clinical trial
proving they are safe.
The latest study, known as ASPIRE, which tested the system in 247 people with
diabetes in their homes, offered the proof.
It showed the device reduced the amount of time and the duration that a
diabetic's blood sugar fell below a certain threshold -- a measure known as area
under the curve -- by 37.5%. The device reduced the overall number of low blood
sugar episodes by 31.8%, compared to diabetics using an insulin pump without the
The findings were published online on Saturday in the New England Journal of
Medicine and presented at the American Diabetes Association meeting in
Dr Francine Kaufman, vice president of global medical affairs for Medtronic's
diabetes business, said the study showed that shutting off the flow of insulin
mimics what happens in healthy people in response to low blood sugar.
Kaufman, a paediatric endocrinologist who still has an active practice in Los
Angeles, said the device is intended to help diabetics who may find themselves
in a situation where they cannot help themselves.
"Many of my patients are 3 years old. So, if mom is not around, they don't
know how to do this on their own," she said. "We're going to take that and
automate it for them."
Dr Richard Bergenstal, of the International Diabetes Center at Park Nicollet
Health Services in Minneapolis, the study's lead author, highlighted the study's
findings."That is a significant reduction in the duration and severity of low
blood sugar," he told a news briefing at the diabetes meeting.
Diabetes advocates, researchers and medical device companies for decades have
spoken wistfully about the "holy grail" of an artificial pancreas, a complex
system of pumps and sensors aimed at automating the complex care and treatment
of type 1 diabetes by mimicking the function of a real pancreas.
The Medtronic device is decidedly not that. But it is the first device before
the US Food and Drug Administration to detect dangerous blood sugar levels and
automatically take action to correct it.
"The study results are important as we continue to move toward our goal of
developing a fully automated system, or artificial pancreas, that will one day
require very minimal interaction from the patient," Medtronic's Kaufman
In designing the study, researchers had to find a population of patients who
were especially prone to having hypoglycaemia at night. Bergenstal said as many
as 320 people tried to enrol in the study, but only 247 qualified.
Spears Mallis, a 34-year-old administrator for the Longstreet Cancer Center
in Gainesville, Georgia, was one. Mallis, an avid runner, has had type 1
diabetes for almost 17 years. For the past 16 or so, he has used an insulin
pump, often pared with a continuous glucose monitor, to keep track of his blood
sugar and deliver a steady flow of insulin.
But Mallis still suffers from occasional bouts of hypoglycaemia, which were
especially disturbing when he had a job that required him to travel. Like many
in the diabetes community, Mallis was aware of efforts several years ago by the
Juvenile Diabetes Research Foundation and others to push the FDA to set
guidelines for approving the Medtronic device. Some had even hoped the agency
would allow these devices on the US market without additional testing.
But in 2011, the FDA made clear the company would need a clinical trial, and
Mallis was on board. During the three-month trial, Mallis said the suspend
device kicked in several times.
"In one of my races, it went off and I had it go straight to suspend."
He said the device's alarm feature was loud enough to wake his wife, but
there were times he would sleep through it.
"After you have had type 1 diabetes for a while, your senses become lessened for
feeling low blood sugar."
Mallis said the device would stop the flow of insulin until he woke and took
action himself. His experience was typical. Bergenstal said for many
individuals, the device was suspended for the full two-hour maximum, despite the
"The study was also designed to see if cutting off
insulin for this period would cause insulin to 'rocket back up'," Bergenstal
Drifted back to normal
But at the end of the two-hour period, it just "gradually drifted back up
into the normal range", he said.
The study also showed the device had no impact on a measure of long-term
control of blood sugar called A1c.
Kaufman said Medtronic has presented the study results to the FDA and
received an approvable letter for its next-generation pump device that includes
the feature, meaning the device can be approved, provided the company meets
Chief Executive Omar Ishrak has said he expects device approval during the
current calendar year.
"We are just going back and forth on overall quality issues. We're working
very collaboratively with FDA to work through some of the issues," Kaufman
Meanwhile, the company and its rivals, including Johnson & Johnson's
Animas unit, are working on next-generation devices that add more automated
On Friday, the company presented results at the diabetes meeting on a study
of a system designed to predict when diabetics are heading for a dangerous low
and take pre-emptive action by decreasing the amount of insulin the pump
The night-time study of 20 adults with type 1 diabetes showed the software
control program helped people stay within a target range for 90% of the
Ramakrishna Venugopalan, director for research and development at Animas,
sees the development of an artificial pancreas as a step-wise process, in which
products begin to automate more and more of the functions now managed by
The company this month won approval for another feasibility study, its third
in three years.
Venugopalan still can't say when a fully automated artificial pancreas will
be available, but adds, "I don't think this is a pipe dream."