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Monday, November 18, 2013

FDA Approves RNS Stimulator for Seizure Reduction

Last week, the U.S. Food and Drug Administration (FDA) approved a new stimulation device for seizure reduction in epilepsy patients who have not found relief with medication. The RNS stimulator, manufactured by Neuropace, Inc. of Mountain View, CA, consists of a small neurostimulator implant which is connected to one or two electrodes that are placed in the brain region where the seizures are suspected to originate.

“The neurostimulator detects abnormal electrical activity in the brain and responds by delivering electrical stimulation intended to normalize brain activity before the patient experiences seizure symptoms,” said Christy Foreman, director of the Office of Device Evaluation in the FDA’s Center for Devices and Radiological Health, in a press release.

This approval comes after a three-month randomized control trial of 191 patients with drug-resistant epilepsy. The trial found that patients using the RNS system (turned on) had a nearly 38-percent reduction in seizures per month, compared with an approximately 17 percent reduction in the average number of seizures per month in patients who had the implanted device turned off. At the conclusion of the three-month period, median seizure reduction was 34 percent in patients with active use of the RNS system, compared with 19 percent in patients with the system turned off.

     Over the course of the trial, 29 percent of patients with an active device experienced at least a 50 percent reduction in the overall number of seizures, compared to 27 percent for those with the implanted device turned off. In the two years of follow up, patients using the device showed a persistent reduction in seizure frequency.

The most frequent reported adverse events included infection at the implant site and premature battery depletion. Patients who use the RNS stimulator are unable to undergo MRI, diathermy, electroconvulsive therapy or transcranial magnetic simulation, the FDA warned. 

      Stay tuned for an extended discussion on this device approval in an upcoming issue of Neurology Today. For our previous coverage of the RNS stimulator, see our archives: