36-Month VNS Outcomes in Drug-Resistant Epilepsy Show Significant Seizure Control

Adjunctive vagus nerve stimulation (VNS) therapy significantly reduced severe disabling seizures in a varied population with drug-resistant epilepsy (DRE) according to results from the CORE-VNS (NCT03529045) study presented at the 2025 American Epilepsy Society (AES) Annual Meeting. 

The prospective, multicenter, multinational observational study included 555 individuals with DRE who were receiving their first implantation with VNS therapy. The study population ranged in age from 1 to 71 years (mean age: 23.8 y) and had a balanced gender distribution (51.2% male, 48.8% female). Most had significant prior experience with anti-seizure medications (mean number tried: 6.8), and some level of cognitive impairment was common (68.4% vs 31.6%). Seizures were classified and tracked using the 2017 International League Against Epilepsy (ILAE) classification scheme.

Key findings at 36 months post-implantation included:

• Median reduction in focal impaired awareness motor (FIA-M) seizures: 80.1% (95% CI: -90, -66.7).
• Median reduction in focal impaired awareness non-motor (FIA-NM) seizures: 94.4% (95% CI: -100, -77.3).
• Median reduction in focal-to-bilateral tonic-clonic (FBTC) seizures: 95% (95% CI: -100, -72.7)
• Median reduction in generalized tonic-clonic (GTC) seizures: 84% (95% CI: -100, -66.7).
• Median monthly frequency of GTC seizures reduced from 4 (95% CI: 2.3, 6.7) at baseline to 1 (95% CI: 0, 1.7).
• 11.6% of the CORE-VNS cohort reported adverse events likely related to VNS, predominantly dysphonia, dyspnea, and cough—consistent with established safety profiles.

The results suggest adjunctive VNS therapy can meaningfully and safely reduce the burden of severe seizures, and with participants having reported a decreased utilization of rescue medications, emergency services, and seizure-related hospitalizations during the follow-up period, it may also lead to downstream reductions in acute care utilization.  

Source: Sen A, Kwan P, Verner R, et al. CORE-VNS study full cohort at 36 months demonstrates significant reduction in severe disabling seizures. Presented at: American Epilepsy Society Annual Meeting; December 5–9, 2025; Atlanta, GA.