Early LGS-CORE Registry Data Show Only 4% of Reported Treatments Stopped All Seizures in Lennox-Gastaut Syndrome

SAN DIEGO, Oct. 20, 2026 /PRNewswire/ -- The Lennox-Gastaut Syndrome (LGS) Foundation will present the first data from its LGS Collaborative Outcomes Registry (LGS-CORE) at the 2026 NORD Rare Diseases & Orphan Products Breakthrough Summit, October 25 to 27 in Washington, DC. LGS-CORE is a real-world natural history study that has enrolled about 100 families toward a goal of 1,000. Early results show that most treatments reduce only some seizures, few stop them, and caregivers often cannot tell which medication is working.

LGS is a severe developmental and epileptic encephalopathy (DEE) that begins in childhood and affects ~50,000 Americans and over 1 million worldwide. Children and adults living with LGS have multiple drug-resistant seizure types, and most live with moderate-to-severe intellectual disability. There are no disease-modifying therapies, and there is no cure.

Preliminary findings from caregiver surveys include:

• Limited efficacy: Of 104 medications reported, 4% stopped all seizures, 21% reduced all seizure types, and 47% reduced only some. For 22%, caregivers didn't know whether the medication worked.
  
  
• Heavy polypharmacy: 40% of patients currently take at least four anti-seizure medications. The most common are cannabidiol, clobazam, valproic acid, and clonazepam.
  
  
• High seizure burden: Most patients have daily or weekly seizures. 75% have had a seizure lasting more than 5 minutes, and 27% visited the emergency department for seizures or related injuries.
  
  
• Unknown cause: For 64% of patients, the underlying cause of seizures is unknown.
  
  
• Surgery is common: 61% have had a surgical intervention, most often vagus nerve stimulation.

More than 95% of participants scored "Likely LGS" on the validated Refractory Epilepsy Screening Tool for LGS, confirming the registry is reaching the right patients.

"Families told us what their treatments actually do and don't do and their side effects, and the answer is sobering," said Helen Chen, PhD, Research Director of the LGS Foundation. "When their loved one takes four medications at once, no one can tell which one is helping. That is exactly the evidence gap we need to address."

About LGS-CORE

LGS-CORE is a real-world natural history study within the Foundation's Learn From Every Patient Database. It launched in February 2026 on NORD's IAMRARE™ registry platform.

• Who reports: Caregivers worldwide complete six longitudinal surveys on diagnosis, medical history, and treatment, under institutional review board (IRB) oversight.
  
  
• What comes next: Sample sizes will grow toward the 1,000-family goal as enrollment continues and families update their surveys over time.
  
  
• Data access: Data may be shared with researchers and trial sponsors as approved by the study's governing board.

Visit the Poster

• Title: The Lennox-Gastaut Syndrome (LGS) Collaborative Outcomes Registry (CORE): A Modular International Registry for LGS with Preliminary Insights into Prescribing Patterns and Caregiver-Reported Efficacy
  
  
• Authors: Helen Chen, PhD, Kathy Leavens, BSc, and Tracy Dixon-Salazar, PhD, LGS Foundation
  
  
• When and where: Poster 27B will be displayed throughout the Summit; Poster session is Oct. 26, 5:30pm and onwards, Grand Hyatt Washington, Washington, DC
  
  
• Partners: Contact [email protected] about LGS-CORE data or the LGS and Associated DEE Research Accelerator. Families can enroll at LGS-CORE Study.

About the Foundation

The LGS Foundation is dedicated to improving the lives of individuals affected by LGS and associated developmental and epileptic encephalopathies through research, education, advocacy, and support. The Foundation advances research that overlaps LGS with the many other DEEs that affect the community it serves.

About the National Organization for Rare Disorders

The National Organization for Rare Disorders (NORD®) is the leading independent advocacy organization representing all patients and families affected by rare diseases in the United States. NORD began as a small group of patient advocates that formed a coalition to unify and mobilize support to pass the Orphan Drug Act of 1983. Since then, the organization has led the way in voicing the needs of the rare disease community, driving supportive policies, furthering education, advancing medical research, and providing patient and family services for those who need them most.

SOURCE Lennox-Gastaut Syndrome (LGS) Foundation