Deep brain stimulation, an established therapy that modifies the brain’s circuitry to treat symptoms of depression, Parkinson’s disease and other movement disorders, is attracting fresh attention from medical-device makers who believe it is underused.

St. Jude Medical Inc. recently introduced a new DBS system in the U.S., and Boston Scientific Corp. is planning its own entry late next year. Both already sell the implantable devices for DBS in Europe.

The shake-up in the U.S. reflects the promise that St. Jude — which recently combined with Abbott Laboratories — and Boston Scientific see in a market that for years has been served by just one company: Medtronic PLC.

Although DBS accounts for just $500 million of Medtronic’s roughly $30 billion in annual revenue, it is one of the company’s fastest-growing areas, expanding around 9% a year, according to a company presentation at a medical meeting in late 2015. The price of a Medtronic DBS system ranges from about $18,000 to $35,000.

“The last two decades, Medtronic has done the yeoman’s work of creating and legitimizing DBS,” said Brett Wall, head of the company’s brain business. “It’s about time someone else got in this market.”

Parkinson’s, an incurable, degenerative neurological disease, affects around one million people in the U.S. DBS, which involves embedding a wire in the brain and a pacemaker-like unit in the chest, has been shown to significantly increase control over symptoms in those with advanced Parkinson’s.

But not all patients stand to benefit from DBS. Some can control their symptoms using medication alone, while others have complications, such as dementia, that rule out surgery.

Even so, all three medical-device companies believe only a fraction of eligible patients are undergoing the surgical procedure. Maulik Nanavaty, head of neuromodulation at Boston Scientific, estimates that about 13% of Parkinson’s patients who could benefit from DBS have used it. Medtronic puts that figure at around 10%.

One reason for the modest use in the U.S., according to Allen Burton, medical director of neuromodulation at St. Jude, is a lack of familiarity. Many Parkinson’s patients are treated by primary-care doctors or community neurologists who lack connections with the roughly 100 specialist centers across the country that offer DBS.

The cost of DBS implantation can reach $100,000, but insurers typically reimburse most or all of the bill, according to the National Parkinson Foundation. As much of a deterrent to use is the time commitment required. The procedure involves a two-day hospital stay, plus numerous consultations before and after treatment. There is also the travel time to the specialist centers.

St. Jude is working with community neurologists to raise the profile of DBS and is considering advertising the procedure directly to patients. The device makers are also betting that improving the precision of DBS will make it more marketable.

With traditional DBS implants, the current radiates out from the end of the wire. Now Boston Scientific and St. Jude have developed devices that can “steer” the electrical impulse in a particular direction, with the aim of reducing side effects such as mood changes or speech difficulties. Medtronic plans to launch its own steerable device in the next two to three years, Mr. Wall said.

It also is working on a way to vary the strength of the electrical signal depending on the brain’s own activity, though that technology is at least five years away from launch.

Another approach: advocating use of DBS at an earlier stage. DBS is typically used in patients with advanced Parkinson’s, but the Food and Drug Administration earlier this year said Medtronic could market one of its devices when the disease had been diagnosed for as little as four years. That decision followed a large study by Medtronic showing that earlier-stage patients did better on medication plus DBS, compared with medication alone.

Even with such advances, medical-device makers could come up against a more fundamental problem: fear of surgery, particularly on the brain. “Many people would avoid brain surgery if they have other options,” said Jeff Bronstein, a neurologist at University of California, Los Angeles. “The risks are relatively small, but if you happen to be in the 1% to 2% that has a stroke, that’s a big deal.”

Concern about surgery risks means DBS is viewed “almost as a last resort, ” according to Patrick Hickey, an assistant professor of neurology at Duke University School of Medicine who has received grant funding from Medtronic. But he said it was gradually “becoming part of the treatment program” as doctors became more familiar with it.

Some believe DBS has more potential still. Among them are researchers at Vanderbilt University, who believe it could go beyond controlling the symptoms of Parkinson’s to delaying the progression of the disease itself.

David Charles, a professor of neurology at Vanderbilt who has done consulting work for Medtronic, said the research team was in the process of raising funds to run a large clinical test of that hypothesis, after a small study showed early-stage Parkinson’s patients on standard therapy were two to five times more likely to worsen in two years than those using DBS.

“DBS plus medicine seems to be not just a little better, but potentially is far superior to standard therapy,” Dr. Charles said. “That still needs to be proven.”

SOURCE: Dow Jones, 1/9/2017