Nine-year Prospective Safety and Effectiveness Outcomes from the Long-Term Treatment Trial of the RNS® System

Abstract

Objective: Report the complete follow up experience of 33 epilepsy centers who participated in a 7 year prospective open-label long-term treatment (LTT) study of the RNS® System (NeuroPace, Inc.). Background: Patients participated in the LTT study following a 2 year randomized, double-blinded controlled pivotal study, or a prior 2 year feasibility study. Design/Methods: 256 adults with medically intractable focal onset seizures localized to 1 or 2 seizure foci were treated in the pivotal (N=191) or feasibility (N=65) studies and 230 transitioned into the LTT study. Efficacy assessments included median % change in seizure frequency. Safety was assessed by reporting of adverse events. Results: Mean age was 34.0 years, mean epilepsy duration was 19.6 years, mean number of AEDs was 2.9, and median seizure frequency was 10.2 seizures/month. Total follow-up was 9 years with 1895 patient implant years. The median % reduction reached 75% at the end of year 9 (n=168). In addition, 30% of subjects experienced ≥ one period of ≥ 6-months without seizures and 19% experienced ≥12 months without seizures. A LOCF analysis showed a median % reduction of 67.2% (IQR: 23 to 94.5%) with 33% of patients having a 90% or greater reduction in seizures in their most recent 3 months. Risk for infection was 3.7% per procedure, and all but one infection was soft tissue only. There were 16 deaths; 2 due to suicide, 1 each due to status epilepticus, herpes encephalitis, sepsis, lung/colon cancer, and lymphoma, and 4 due to definite, 2 due to probable, and 3 due to possible SUDEP. Conclusions: Patients treated with the RNS System experienced sustained reductions in seizures, with a third of patients having a 90% or greater reduction in their seizures during their last 3 months. The study supports the long-term effectiveness and safety of treatment of medically intractable focal seizures with brain responsive neurostimulation. Disclosure: Dr. Nair has nothing to disclose. Dr. Morrell has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with NeuroPace, Inc. Dr. Morrell holds stock and/or stock options in NeuroPace, Inc, which sponsored research in which Dr. Morrell was involved as an investigator. Dr. Morrell holds stock and/or stock options in NeuroPace, Inc.