Lundbeck data show seizures plunge on bexicaserin

VALBY, Denmark, Aug. 25, 2025 /PRNewswire/ -- H. Lundbeck A/S (Lundbeck) today announced that new data regarding bexicaserin, a novel treatment under investigation for seizures associated with Developmental and Epileptic Encephalopathies (DEEs), will be presented at the 36th International Epilepsy Congress (IEC) in Lisbon, Portugal (Aug 30 – Sept 3).

Bexicaserin is an investigational compound that is not approved for marketing by any regulatory authority worldwide. The efficacy and safety of bexicaserin has not been established.

"Patients with DEEs represent a challenging group of rare epilepsies, with few effective approved treatment options," said Johan Luthman, EVP and Head of Research and Development at Lundbeck. "As we are now in phase 3 trials with bexicaserin, we are optimistic about its potential. The clinical data so far suggests broad and durable anti-seizure activity across DEEs, and new preclinical data suggests modulation of the risk of sudden unexpected death in epilepsy (SUDEP). This marks a significant step forward in the potential to transform care for patients and address critical gaps in the treatment landscape."

The full results of the open label extension (OLE) of the Phase 1b/2a PACIFIC trial will be presented. It was designed to evaluate the long-term (up to 52 weeks), safety, tolerability, and efficacy of bexicaserin in individuals with a DEE. During the OLE, a median reduction of 59.3% in countable motor seizure frequency was observed, with 55% of participants experiencing sustained reductions of ≥50% compared to baseline before the PACIFIC trial. Bexicaserin was well tolerated, with no new safety signals observed.

"I am encouraged by the 100% enrollment of eligible participants and the high completion rate of over 90% in the open-label extension study. Such high retention underscores the tolerability as well as the duration of effect of bexicaserin across developmental and epileptic encephalopathies," said Ingrid E. Scheffer, Lead Investigator and Laureate Professor of Pediatric Neurology, The University of Melbourne and Austin Health.

Lundbeck will also showcase preclinical data in an audiogenic seizure model of SUDEP, the most common cause of premature death in children and adults with epilepsy.3,6 Bexicaserin significantly reduced seizures and respiratory arrest in the SUDEP model. Furthermore, preclinical data will be shared indicating the impact of bexicaserin on absence seizures, a type of seizure that is often more difficult to treat.4,7

Bexicaserin has entered late-stage clinical development through the global phase 3 program, DEEp, aimed at evaluating its safety, tolerability, and efficacy in the treatment of seizures in children and adults with DEEs. The DEEpSEA trial8 is currently recruiting participants with Dravet syndrome and the DEEpOCEAN trial9 is open to individuals with DEEs (including Lennox-Gastaut syndrome).

Both trials are randomized, double-blind, placebo-controlled and open for enrollment across the North America, Europe, Asia, Australia and Latin America, with additional sites being activated on a rolling basis.

Lundbeck's scientific presentations at IEC:

Long-term Safety, Tolerability, and Efficacy of Bexicaserin for the Treatment of Seizures in Participants With Developmental and Epileptic Encephalopathies: Primary Results of the 12-Month Phase 1b/2a PACIFIC Trial Open-Label Extension. Poster presentation, 31 August 2025; 13:45-15:15 WEST 1

Activation of Central 5-HT2C Receptors by Bexicaserin Modulates Seizures and Respiratory Arrest in a Mouse Model of SUDEP. Platform presentation, 31 August 2025; 14:30 – 15:00 WEST 3

Impact of Bexicaserin on Seizures and Interictal Spectral Power in the GAERS Absence Epilepsy Model. Poster presentation, 31 August 2025; 13:45-15:15 WEST 4

Seizure Reductions and Tolerability in Participants With Developmental and Epileptic Encephalopathies Newly Exposed to Bexicaserin: Interim Results From the Phase 1b/2a PACIFIC Open-Label Extension. Poster presentation, 1 September 2025; 13:45-15:15 WEST10

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