Multicenter study to describe effectiveness of a direct brain responsive neurostimulator (RNS System) in adults with antiseizure medication (ASM)-resistant focal onset seizures (FOS).
A 5-year PMA post-approval study was required by FDA to monitor the safety and effectiveness of RNS System treatment in individuals ≥18 years of age with ASM-resistant FOS. The primary safety endpoint is pending at 5 years. Results of the three-year primary effectiveness analysis are provided.
The study design was prospective and observational for individuals meeting the RNS System approved indication (NCT02403843). The primary effectiveness endpoint was to demonstrate that the median percent reduction in disabling FOS at 30 to 36 months relative to the pre-implant period was comparable to the same interval in the controlled clinical study (Nair et al. 2020).
In addition to the RNS System, participants received standard epilepsy care. Data were collected at baseline and at a minimum of 4-month intervals post-implant. Case report forms were monitored against source documents.
Thirty-two sites implanted 324 participants. Baseline demographics for implanted participants included: female 59.6%, mean age 37.1 years (range 18-76), mean duration of epilepsy 17.8 years (range 2-62). Mean number of ASMs was 3.1 (range 1-8). By history, 87.7% of participants had generalized tonic-clonic, 87.7% focal impaired awareness, and 16.0% focal aware motor seizures.
Data from 255 participants were included in the primary effectiveness endpoint. The reduction in seizures overall was 82% (1st quartile 100%; 3rd quartile 29.2%). By onset zone, reduction for participants with mesial temporal lobe onset was 73.5% (97.8%; 25.0%), neocortex was 90% (100%; 47.8%), and mesial temporal with neocortical was 89.6% (100%; 15.6%). Improvement occurred with all seizure types.
A prospective observational multi-center multi-year RNS System post-approval study provides evidence for substantial seizure reductions in adults treated with direct brain responsive stimulation for ASM-resistant focal epilepsy.