Abstracts

Rationale:  The stimulation of the Anterior Nucleus of the Thalamus for epilepsy (SANTE) study  (Fisher et.al.2010) demonstrated the safety  and efficacy of DBS, with a  median total  seizure frequency  reduction from baseline of 40.4% versus 14.5% for the placebo group at 3 months, and 75% at 7 years,  with open label therapy,  for those who completed their diaries. The  Food and Drug Administration (FDA) granted  pre-marked  approval for  Medtronic's Deep Brain Stimulation ( DBS) therapy as adjunctive treatment for reducing the frequency of seizures in patients 18 years or older    diagnosed with epilepsy characterized by  medically refractory partial-onset seizures.      Methods: After the randomized double blind portion of the study and subsequent restricted programming phase, subjects continued in a non-blinded long term follow-up (LTFU) phase of the study  , later transitioning into a reduced data collection continued therapy access phase (CAP) of the protocol .The objectives of CAP were to characterize the adverse events  and the incidence of sudden unexplained death in epilepsy (SUDEP) in subjects with refractory partial epilepsy treated with the DBS system stimulating the anterior nucleus of the thalamus ( ANT) Results: The study evaluated the safety of the Medtronic DBS therapy for epilepsy in 110 implanted subjects who accumulated 938 total device years of experience.Sixty-nine subjects were active in the LTFU phase, with 61 of them entering the CAP phase . Prior to study closure there were 57 active subjects across 14 study centers, all of which had more than 10 years of follow-up data with the highest reaching the 14 year visit.There were no unanticipated adverse device events.A SUDEP rate was determined based on the SANTE study experience (2 deaths in 938 years ) and on previous pilot studies of ANT stimulation in the treatment of epilepsy (0 deaths in 76 years). Definite and probable SUDEP in subjects receiving stimulation were combined to established a rate of 2 deaths per 1000 person-years. Including the 1 possible SUDEP resulted in a rate of 3 deaths per 1000 person years   Conclusions: The efficacy and safety of DBS for epilepsy has been demonstrated in 110 implanted subjects over a 7 year period.New data is presented that extend the length of follow-up  by approximately  4 years. No trends in worsening of adverse events were observed , indicating that the long-term safety profile remains stable . The definite and probable SUDEP rate  in subjects receiving DBS was 2 deaths per 1000 person- years .This SUDEP rate is lower than published  SUDEP rates of  at least 6.2 per 1000 patient- years in  epilepsy surgery candidates ( Devinsky et.al.  Lancet Neurol.2016;15:1075-88)   Funding: The SANTE trial was supported by Medtronic.Inc. Dr Salanova was the Indiana University  site Principal Investigator for the SANTE trial and receives no personal financial support from Medtronic. Dr Fisher was the  Principal Investigator of the SANTE trial and receives no personal financial support from Medtronic.