Valby, Denmark, September 3, 2026
H. Lundbeck A/S will present new mechanistic and clinical research on bexicaserin (LP352) at the European Epilepsy Congress, taking place September 5–9 in Athens, Greece. The company will highlight preclinical findings that provide further insight into bexicaserin’s dual mode of action, showing increased inhibitory and decreased excitatory neuronal activity in experimental models. Bexicaserin is an investigational oral, highly selective 5-HT2C receptor superagonist being developed for seizures associated with developmental and epileptic encephalopathies (DEEs), a group of rare and severe childhood-onset epilepsies. The European Epilepsy Congress program will include an oral presentation on the compound’s mechanism alongside clinical and preclinical findings from Lundbeck’s broader development program. Bexicaserin is currently being evaluated in the global Phase III DEEp Program, which includes studies in patients with DEEs, including Lennox-Gastaut syndrome and Dravet syndrome.
Lundbeck Explores Bexicaserin Dual Mechanism
The featured research examines how bexicaserin affects neuronal excitability, a central biological factor in seizure generation. Many DEEs are associated with abnormal network hyperexcitability, which can arise from excessive excitatory activity, insufficient inhibitory activity, or a combination of both. In preclinical studies using hippocampal brain tissue, bexicaserin increased inhibitory neuronal function while simultaneously decreasing excitatory neuronal function. Researchers reported that these effects were consistent with antiseizure activity across preclinical models representing different seizure types and underlying disease etiologies. The high affinity and selectivity of bexicaserin for the 5-HT2C receptor further support the proposed mechanism by linking the observed neuronal effects to the drug’s intended molecular target. The dual mechanism is particularly relevant to the heterogeneous nature of developmental and epileptic encephalopathies. DEEs encompass multiple rare epilepsy syndromes that can involve treatment-resistant seizures, frequent epileptiform activity and developmental slowing or regression. Patients can experience several seizure types that change over time, while the underlying causes can vary substantially between individuals. Lundbeck’s research therefore seeks to determine whether modulation of both inhibitory and excitatory neuronal activity could provide broad-spectrum antiseizure effects across different forms of DEE. However, the mechanistic findings are preclinical and do not establish clinical efficacy. Bexicaserin remains investigational and has not been approved for marketing by any regulatory authority worldwide.
Phase III DEEp Program Advances Bexicaserin
The new mechanistic findings are being presented alongside data from Lundbeck’s ongoing Phase III DEEp clinical development program. The program includes DEEp OCEAN, a randomized, double-blind, placebo-controlled Phase III study evaluating bexicaserin in children and adults with DEEs, including Lennox-Gastaut syndrome, and DEEp SEA, a separate Phase III trial evaluating the candidate in children and adults with Dravet syndrome. The studies are designed to assess the efficacy, safety and tolerability of bexicaserin, with countable motor seizure frequency serving as an important efficacy measure. DEEp OCEAN recently reached an important development milestone when the last patient was randomized in July 2026. Lundbeck said headline results from the study are expected at the end of the fourth quarter of 2026 or the first quarter of 2027. Recruitment in the DEEp SEA study is also progressing, with randomization expected to be completed in the following months. The advancement of both pivotal studies reflects Lundbeck’s strategy to evaluate bexicaserin across a broad spectrum of rare epilepsy syndromes rather than limiting development to a single genetic or clinical subtype.
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European Epilepsy Congress Highlights Clinical Research
At the European Epilepsy Congress, Lundbeck will present several additional datasets intended to expand understanding of bexicaserin. These include analyses of seizure response over time and responder rates from the Phase 1b/2a PACIFIC trial open-label extension, interim findings from an expanded-access program involving patients treated for up to two years, and research examining bexicaserin’s effects on neural circuits in a mouse model of sudden unexpected death in epilepsy (SUDEP). Together, these presentations span clinical experience, long-term treatment exposure and experimental neuroscience. The mechanistic work also provides context for Lundbeck’s broader investment in neuroscience and rare epilepsy drug development. By investigating how selective 5-HT2C receptor activation can simultaneously influence inhibitory and excitatory neuronal pathways, researchers are seeking to establish a stronger biological rationale for bexicaserin’s potential across diverse seizure types. The forthcoming Phase III results will ultimately be critical for determining whether the preclinical mechanism translates into meaningful reductions in seizures and an acceptable safety profile in people living with DEEs. Until those clinical studies are completed and reviewed by regulators, bexicaserin remains an investigational therapy.
Source: Lundbeck press release
