Of the three million Americans with epilepsy, almost a third aren't adequately treated with medication and continue to have seizures. Medtronic (Minneapolis) has just submitted a premarket approval (PMA) application with the FDA to use its deep brain stimulation device (DBS) for these patients with uncontrollable seizures.

Similar to a pacemaker, leads are implanted in the brain and then controlled electrical stimulation is sent to precisely targeted areas, Nina Graves, program director, Neuromodulation Emerging Therapies at Medtronic, told Medical Device Daily.

"It works around the clock, cycling one minute on and then five minutes off," Graves said of the Medtronic DBS, which is targeted for people with partial-onset seizures, a form of epilepsy that does not respond well to antiepileptic drugs.

"We are optimistic about the potential to bring Medtronic DBS Therapy to market in the U.S. to meet the unmet medical needs that exists in the treatment of severe epilepsy," said Rick Kuntz, MD, president of the Neuromodulation business and senior vice president at Medtronic.

Medtronic's PMA submission is based on data from the SANTE study (Stimulation of the Anterior Nucleus of the Thalamus in Epilepsy), a prospective, randomized, double-blind pivotal clinical trial that included 110 patients.

"At the end of the blinded phase, the active group had a 38% reduction and the control group had a 14% reduction," Graves said. "At the end of a year, we saw a 40% reduction in that same group. In the longer term phase [two years], we were at about 60% reduction of seizures."

The SANTE study found that stimulating the left and right anterior nucleus of the thalamus, which is the brain's central message and relay station, along with epilepsy medications produced a significant reduction in seizures. Of the 87 study participants who completed diaries through 13 months, 40% experienced a 50% or greater reduction in their baseline rate of seizures 13 months after implant.

Of the 86 study participants who had at least three months of data from long-term follow up, 60% experienced a 50% or greater reduction in their baseline rate of seizures. During the last three months of data for each patient, median seizure frequency was reduced by about two-thirds, 9% of study participants had no seizures and 19% experienced a greater than 90% reduction in seizure frequency.

No serious unanticipated device-related adverse events were reported. Interestingly, there was a "significantly higher incidence of spontaneously self-reported depression, memory impairment and anxiety in the active group compared to the control group during the blinded phase," according to Medtronic, but most events resolved spontaneously or with changes in medication or stimulation parameters.

The DBS treatment comes with a price tag of $20,000 to $30,000, not including hospital or physician costs.

"We anticipate we can use same CPT code, but we're not sure if we have coverage yet or not," Graves said.

Medtronic DBS therapy is already FDA-approved to treat essential tremor, advanced Parkinson's disease, dystonia and chronic, severe, treatment-resistant obsessive-compulsive disorder.