NeuroPace has announced that interim results from its ongoing long-term treatment study demonstrate the RNS system significantly reduces seizure frequency among adults who have a common form of epilepsy that is difficult to treat with medication.
Results of the ongoing study, which were recently published in Neurology, include data on 230 people with medically intractable partial onset epilepsy enrolled at 33 Comprehensive Epilepsy Centers in the USA. The median reduction in seizure frequency compared to patients’ pre-implant seizure frequency was 60% at the beginning of the third year post-implant and 66% at the beginning of the sixth year.
NeuroPace received premarket approval from the US Food and Drug Administration (FDA) for the RNS system in November 2013. It is approved as a treatment for adults with partial onset seizures with one or two seizure onset zones whose seizures have not been controlled with two or more antiepileptic drugs.
“The interim study results, which covered 1,293 patient stimulation years, confirm our belief that the therapeutic benefits of the RNS system are not only sustained, but actually increase over time for many people,” said Martha Morrell, chief medical officer of NeuroPace and clinical professor of neurology at Stanford University. “Beyond the sustained seizure frequency reduction, patients in this study gained significant improvements in quality of life in areas such as memory, language, attention, and overall health. This patient population has been unable to find relief with other treatments, and we are extremely hopeful that the RNS system can help hundreds of thousands of adults in the USA with refractory partial seizures in the future.”
The study is an ongoing seven-year, multicentre prospective open-label study for participants who previously completed a feasibility or randomized controlled trial of the RNS system. Ninety-seven per cent of these patients elected to continue treatment and participate in the study. The median reduction in seizure frequency in the pivotal study was 44% at one year and 53% at two years, and ranged up to 66% over post-implant years three through six. Furthermore, 23% of patients experienced at least one six-month period free of seizures. For comparison, these patients had to average at least three seizures per month in order to enrol in the original trial. The study also demonstrated significant improvements in overall quality of life and indicates a more positive perception of cognitive function, relationships and social function, overall health, and vulnerability to seizures. There were no serious unanticipated device related adverse events in the trial and responsive neurostimulation was well-tolerated and safe over time.
As a closed-loop system, the RNS system monitors the brain’s own signals, interprets those signals, provides stimulation when needed, and then assesses the brain’s response. The breakthrough aspect of the RNS system is its advanced detection and stimulation capabilities. This is unlike all other existing neurostimulation therapies, which continuously or intermittently stimulate the brain without determining the need for treatment or monitoring the response.
The RNS system has been evaluated in three clinical trials, including a prospective, randomised, double-blinded, sham stimulation controlled pivotal study and the current study. Results of the clinical trials demonstrate that the substantial clinical improvements experienced by patients over the short- and long-term are meaningful and durable over many years of therapy. At this time, some patients have been treated with the RNS system for more than 11 years, and more than 1,500 patient years of experience with responsive neurostimulation have been accumulated to date.