Electromagnetic Depression Treatment Nears Approval
Deep transcranial magnetic stimulation adds to psychiatry’s arsenal of electronicremedies
Photo: John Lund/Getty Images
A new type of brain stimulation device for combating difficult-to-treat cases of major depressive disorder is likely to break into the large American market soon. Its maker, Jerusalem-based Brainsway, plans to apply to the U.S. Food and Drug Administration for permission to market the device this month. The move follows initial results from a large-scale trial of the system, in which 30.4 percent of treated patients went into remission and 36.7 percent showed significant improvement. Research into device-based treatments for psychiatric problems has grown rapidly, and if the FDA gives its go-ahead, Brainsway’s system will become the fourth device-based therapy to go on the market since 2005.
Deep transcranial magnetic stimulation (TMS), as its name suggests, uses magnetic fields to stimulate activity in structures deep in the brain. The patient wears a helmet in which powerful, specially designed electromagnets have been carefully positioned. When a pulse of electricity flows through the magnets’ coils, the resulting magnetic field induces current to flow through a portion of the brain.
There are subtle differences between deep TMS and repetitive transcranial magnetic stimulation (rTMS), a brain stimulation tool widely used in research and also marketed as a treatment for depression. The electromagnetic elements in deep TMS are designed to produce a magnetic field that reaches its greatest strength deep within the brain. Ordinarily, magnetic fields fall away quickly inside the brain, but the orientation and structure of the coils in deep TMS lessens that effect. “The concept was to reduce the rate of reduction of the magnetic field as a function of distance,” says Abraham Zangen, coinventor of the technology. In contrast, rTMS typically uses a single coil that produces a tightly focused field just a few centimeters below the brain’s surface.
“The Brainsway coil is more like a shotgun than a rifle,” says Mark S. George, a pioneer of TMS and director of the brain stimulation laboratory at the Medical University of South Carolina, in Charleston. It’s unclear which weapon will be better at fighting depression. A tightly focused stimulation might be best if researchers knew exactly where to target that stimulation, he says, but they don’t.
The 30.4 percent remission rate Brainsway is claiming may not seem like much, especially when 14.5 percent of patients who underwent a sham procedure also recovered, but in the context of antidepressants it is quite good, according to experts. The patients enrolled in the trial had already been failed by at least one drug treatment, and studies have shown that the odds of success with subsequent drugs decrease. What’s more, as a group the treated patients on average showed a three-point improvement on the Hamilton depression rating scale, which doctors use to evaluate the severity of depression. “If you compared the three points to some antidepressant studies, it’s above average—quite a lot above average,” says Uzi Sofer, Brainsway’s CEO. “Some medications are approved and marketed with a 1.5- or 2-point difference in the Hamilton.”
Brainsway executives expect their device to have an easier time with regulators than previous devices did, particularly Neuronetics’ rTMS system, NeuroStar. Although it was ultimately approved, NeuroStar’s initial results were a bit ambiguous, and as the first of its kind, the device suffered from a procedural problem that meant it had to be compared to electroconvulsive therapy. ECT is an inconvenient treatment and can have side effects that scare many patients, but it’s amazingly effective and was a high bar for Neuronetics to hurdle. However, with NeuroStar already on the market, the FDA lowered the bar for Brainsway, and the company is expected to surmount it.
“If these data hold up under peer review, if they are as they seem, then they are unambiguous,” says George.