VNS therapy vs. discontinuation of VNS therapy: Long-term seizure outcome (P5.5-028)

Objective: Compare long-term seizure (sz) control in patients (pts) with continued vagal nerve stimulation (VNS) with those who discontinued VNS. Background: Long term VNS follow-up (f/u) studies show progressive improvement but are limited by lack of comparison groups. This study compared long-term sz control in pts who continued VNS stimulation (“VNS-on”) to those who underwent VNS then discontinued treatment (“VNS-off”). Question: Do pts with long-term VNS have greater sz reduction than those who discontinue VNS? Design/Methods: Refractory epilepsy pts with VNS therapy for ≥3 yrs (and f/u ≥2 yrs after VNS discontinuation for VNS-off) with clear baseline (pre-VNS) and last f/u sz frequencies were included. Pts with brain surgery Results: 49 pts included: 33 VNS-on, 16 VNS-off. VNS-on pts had treatment for 116.6 ± 43 months. VNS-off pts had VNS treatment for 78 ± 37 months, discontinued treatment, then had 95.63 ± 38 months additional follow-up. 50% responder rates between groups (VNS-on: 54.5%; VNS-off: 50%, p=NS) were similar. However, VNS-on pts had significant reduction in sz frequency at last f/u compared with baseline (−12.7 sz/month± 34.1, p = 0.04) compared with VNS-off pts both right before VNS was discontinued (−2.8 sz/month ± 18.5, p = 0.55) and last f/u (−4.4 sz/month ± 14.7, p = 0.25), though effect size was small (0.28). Conclusions: Pts with long-term VNS therapy and those who discontinued therapy had similar long-term 50% responder rates. However, pts with long-term VNS treatment may experience greater magnitude of sz reduction. Pts with poor VNS response may be more refractory. Larger confirmatory studies are needed. Disclosure: Dr. Gill has nothing to disclose. Dr. Yuan has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Supernus. Dr. Sperling has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Medtronic. Dr. Sperling has received research support from Eisai, Medtronic, Neurelis, Pfizer, SK Life Science, Takeda, Sunovion, UCB Pharma and Upsher-Smith. Dr. Mintzer has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai, UCB, Abbvie,Greenwich Laboratories. Dr. Mintzer has received research support from UCB. Dr. Skidmore has received research support from Neuropace. Dr. Nei has nothing to disclose.