ADA 2009: Artificial Pancreas Showing Safety, Therapeutic Efficacy in Clinical Trials

Martha Kerr

June 12, 2009

June 12, 2009 (New Orleans, Louisiana) — A system that continuously administers insulin every 5 minutes, with sensors that detect blood glucose levels and adjust the dose of insulin accordingly, shows safe and effective glycemic control in young patients with type 1 diabetes, researchers announced here at the 69th Scientific Sessions of the American Diabetes Association.

Four patients have received the artificial pancreas to date, according to Howard C. Zisser, MD, director of clinical research at the Sansum Diabetes Research Institute in Santa Barbara, California.

The system consists of a conventional insulin pump with a sensor, connected to an external laptop computer equipped with programming the researchers call "artificial pancreas software."

"We are currently working with researchers at [the University of California at Santa Barbara] on mathematical modeling for an artificial pancreas based on our clinical data," Dr. Zisser told Medscape Diabetes & Endocrinology.

The system contains glucose sensors, which provide continuous readings. "Instead of 5 to 10 glucose readings per day, we get over 200 readings," he explained.

In addition to receiving a reading of the glucose level, "we also get the direction that the glucose level is heading...and we can make adjustments in real time. There is a lag time of about 5 minutes between the sensor detecting an increase in blood glucose and delivery of insulin," Dr. Zisser continued.

"There is also an onboard constraint that protects against overdosing.... If anything, we err on the side of underdosing," Dr. Zisser said.

While the system is currently in laptop format, improvements are continuing, and he predicts that fairly soon the system will be about the size of a cell phone.

To date, 4 patients at Schneider's Children's Medical Center in Tel Aviv, Israel, have received artificial pancreases. Their age range is 30 to 40 years, and patients had relatively stable type 1 diabetes before enrollment.

Closed-loop trials were performed on the subjects, lasting an average of 5 hours (range, 2 - 7 hours) and included a meal of 30 g of carbohydrate (CHO).

The mean Low Blood Glucose Index score was 0.02 (range, 0 - 0.06), the mean High Blood Glucose Index score was 9 (range, 4.2 - 15), and the median Daily Risk Range was primarily in the "low" range but increasing up to "moderate" on some readings.

"After a meal is consumed, the sensor readings increase and a series of insulin deliveries above basal are made. Glycemia normalizes several hours later, without any hypoglycemia," Dr. Zisser explained.

"The proposed system restored normoglycemia without any outside intervention from both induced hyperglycemia and unannounced meals," he reported. "The algorithm prevents excessive insulin dosing during hyperglycemia, and forced pump shut-off to prevent hypoglycemia."

"We expect FDA approval in the next 2 to 3 months, giving us a green light to begin clinical trials in the US," Dr. Zisser said.

"The big advantage of the [artificial pancreas] system is the continuous monitoring and delivery algorithm that they have developed," John Gerich, MD, professor of medicine at the University of Rochester School of Medicine in New York, said in an interview with Medscape Diabetes & Endocrinology during the meeting.

"I've been working on artificial pancreases for 30 years. They started off being the size of 3 filing cabinets," Dr. Gerich said.

"[This system] has a major disadvantage, and that is continuous access to the circulatory system. The risk of infection is high," Dr. Gerich pointed out. "And it is hard to beat subcutaneous insulin injections. They are easy and most type 1 diabetics don't really have a problem with them."

Dr. Zisser receives research support from Eli Lilly, Johnson & Johnsonm Insulet, Lifescan, MannKind, and Roche Diagnostic Corp. Dr. Gerich receives funding from Mannkind, the manufacturer of inhaled insulin.

American Diabetes Association (ADA) 69th Scientific Sessions: Late-Breaker Abstract 3. Presented June 7-9, 2009.

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