In addition to the statistically significant reduction in seizure frequency in the active therapy group relative to those in the sham therapy condition, there were no serious, unanticipated device-related adverse events during the trial, nor was there a difference between the two groups with respect to the rate of adverse events, including depression, memory impairment, and anxiety, Dr. Morrell reported.
The findings suggest that responsive neurostimulation might be a promising treatment option for individuals with seizures that are resistant to conventional antiepileptic therapy. Importantly, the apparent increase in the number of patients experiencing at least a 50% reduction in seizure frequency relative to baseline during the open-label phase of the study suggests the system might become more effective over time, she noted.
The RNS has not yet received Food and Drug Administration approval, but NeuroPace plans to submit a premarket approval application to the FDA in early 2010, Dr. Morrell said.
My Take
A New Kind of Stimulation
The development and use of stimulation devices for medically refractory epilepsy represents an altogether new approach for these patients when surgery is not possible and pharmacology is ineffective. Open loop devices that deliver electrical stimulation on a duty cycle include the vagal nerve stimulator (Cyberonics), which is FDA-approved for refractory partial epilepsy, and the thalamic deep brain stimulator (Medtronic), which is FDA-approved for Parkinson's disease and essential tremor and is currently seeking FDA approval for refractory partial epilepsy. The RNS is the first closed loop stimulator and is distinctly different from other investigational and FDA-approved devices used to treat patients with epilepsy. The fact that in this day and age one can successfully and safely detect seizures using an implantable device on a long-term basis may provide hope for future advancements. With time, device technology is likely to be refined and improved, both through technical advances and as additional data are gathered and further studies are completed. Clinical experience will also help define proper patient selection, expectations, and effectiveness.
DR. KATHERINE NOE and DR. JOSEPH DRAZKOWSKI are epilepsy specialists at the Mayo Clinic, Scottsdale, Ariz. They were both investigators in the RNS trial.
VITALS
