It's a dream of medical science that looks tantalizingly within reach: the artificial pancreas, a potential breakthrough treatment for the scourge of type 1 diabetes.

Meant to mimic the function of a real pancreas, the artificial version is a complex device that combines a pager-sized continuous glucose monitor and sensor that tracks blood sugar with a pump that automatically delivers the correct dose of insulin at just the right time.

That technology could make a major difference to millions with the disease who must vigilantly monitor their blood sugar, even at night, and risk deadly consequences if they are slow to notice a dangerous change.

But it is caught up in America's long-running tug of war between supporters of more rapid medical innovation and those who seek better safety for new devices. A fresh confrontation is about to break open this week as the US Food and Drug Administration lays out a path toward regulatory approval for such devices, expected as early as Thursday.

Advocates of the artificial pancreas fear the bar will be set too high in terms of how the devices can be tested in patients, to what lengths companies will need to go to prove they are safe and whether a change in even one of its components will require a whole new round of testing.

Based on the FDA's track record with an early version of these devices, they expect the guidelines could delay access to the technology for many years. People on both sides of the debate have a personal stake in the outcome.

Jeffrey Brewer, president and chief executive of the Juvenile Diabetes Research Foundation, a powerful advocacy group, has a teenage son with type 1 diabetes. He notes that medical device giant Medtronic has a very early version of an artificial pancreas called the Paradigm Veo insulin pump, sold in 50 countries but not in the US.

The pump has an automated safety feature, called low glucose suspend, that shuts off the insulin flow when glucose falls dangerously low.

The Veo, and newer devices being developed, are meant to be worn outside the body, but are connected to patients through a tiny catheter placed just under the skin. That device could have prevented Brewer's son from overdosing on insulin and spending two days in the hospital.

Brewer says cumbersome FDA regulations in June requiring proof of safety and effectiveness for low glucose suspend, already widely used elsewhere, will set back US approval for at least 2-1/2 years.

He is worried the agency will take a similar approach when it issues final guidance, expected this week, on the more complex artificial pancreas.

'The biggest bottleneck right now is the FDA,' says Brewer, who charges that the agency is slowing down progress. 

Charles 'Chip' Zimliki, who heads an FDA initiative to speed up availability of an artificial pancreas, defends the agency's caution over a device on which many lives will depend. A type 1 diabetic himself, Zimliki says he wants to see these devices approved.     

But the FDA has been sharply criticized for approving devices that proved unsafe, such as artificial hips recalled last year by Johnson & Johnson. The agency is unlikely to skip any steps to get a device as complicated as an artificial pancreas to patients.     

'The FDA wants the artificial pancreas on the market as much as anyone else does. We just have to operate within US laws to make sure it is safe and effective,' Zimliki said in an interview earlier this year.

A Reuters analysis of significant complaints to the FDA over the Medtronic Paradigm Veo found about two dozen reports connected to the device, including one incident involving an overdose of insulin that was described as life-threatening and at least two others that sent patients to the hospital with high blood-glucose levels. The reports, dating back to July 2009, mostly did not specify the cause of malfunction.

Medtronic said it was not aware of any problems specifically related to its low glucose suspend feature. It said the devices have a high safety profile and that two dozen complaints would amount to one per 3,000 pumps.

Brewer's passion is born out of the fear and frustration shared by many parents of children with type 1 diabetes, in which the immune system destroys cells in the pancreas that make insulin. Type 1 diabetics currently must monitor their blood sugar and take insulin several times a day. Getting it right is tricky. Meals, exercise, stress, even a growth spurt, can alter blood sugar. And mistakes are costly.

Taking too little insulin can cause high blood sugar, increasing the risk of long-term complications such as eye damage, kidney failure and heart disease. Taking too much can cause blood sugar to drop, causing hypoglycemia, which can result in seizures, unconsciousness, brain damage and death.  -Reuters