Lundbeck Completes Randomization in Landmark DEEp OCEAN Phase III Trial of Bexicaserin for Developmental and Epileptic Encephalopathies
Key Insights
Lundbeck has randomized the last patient in DEEp OCEAN, the broadest pivotal trial to date in developmental and epileptic encephalopathies (search), enrolling over 350 participants aged two to 65 years.
The Phase III trial evaluates bexicaserin, an oral, highly selective 5-HT2C receptor (search) superagonist, against placebo for reducing countable motor seizure frequency across diverse DEE syndromes including more than 60 genetic etiologies.
Headline results are expected at the end of Q4 2026 or Q1 2027, with a second pivotal trial in Dravet syndrome (search) (DEEp SEA) expected to complete randomization within months.
Lundbeck has reached a critical milestone in its DEEp clinical program, announcing that the last patient has been randomized in DEEp OCEAN (NCT06719141), a global Phase III trial evaluating the investigational molecule bexicaserin for the treatment of seizures associated with developmental and epileptic encephalopathies (search) (DEEs). The announcement, made from the company's headquarters in Valby, Denmark, marks the completion of enrollment in what is described as the broadest pivotal trial conducted to date in this heterogeneous group of severe, childhood-onset epilepsies.
The placebo-controlled, randomized, multicenter trial enrolled over 350 participants aged two to 65 years and will be succeeded by an open-label extension for eligible participants. Headline results are anticipated at the end of the fourth quarter of 2026 or early 2027.
Addressing a Critical Treatment Gap
DEEs encompass a diverse group of rare neurodevelopmental disorders that typically manifest in early childhood, characterized by refractory seizures and developmental stagnation or regression. According to the International League Against Epilepsy (ILAE), DEEs currently include more than 10 syndromes, such as Early Infantile DEE (EIDEE), Infantile Epileptic Spasms Syndrome (IESS), Dravet Syndrome (search), and Lennox-Gastaut Syndrome (search) (LGS), as well as etiology-specific syndromes including CDKL5-DEE and KCNQ2-DEE. The etiology remains unknown in approximately 50% of cases.
Historically, clinical development has focused on a limited number of individual DEE syndromes, leaving a substantial gap. "There are currently no antiseizure medications approved across all DEE subtypes, leaving many patients without suitable treatment options," the company noted. The DEEp OCEAN trial was specifically designed to address this unmet need.
"The DEEp OCEAN trial represents a comprehensive pivotal program in DEEs, with the most diverse DEE population studied to date," said Professor Ingrid Scheffer, lead investigator of the trial. "By including a broad range of DEE syndromes and more than 60 different genetic DEEs, this study is designed to reflect the real-world heterogeneity of these devastating conditions."
Mechanism of Action and Trial Design
Bexicaserin is an oral, highly selective superagonist of the 5-HT2C receptor (search), a serotonin receptor subtype involved in seizure modulation. The investigational compound acts via a dual mode of action, increasing inhibitory neuron activity while simultaneously decreasing excitatory neuron function. This mechanism is consistent with the observed reduction in multiple seizure types across a broad range of DEE syndromes with various etiologies demonstrated in the Phase IIa PACIFIC trial.
The DEEp OCEAN trial comprises a screening period of up to 35 days, followed by a 15-week treatment period consisting of a 3-week titration phase and a 12-week maintenance phase. Participants are randomized to receive either bexicaserin or placebo three times daily, with weight-based dosing used for pediatric participants. Following treatment, participants complete a taper period and safety follow-up, or may transition into the 52-week DEEp open-label extension study. The primary aim is to evaluate the efficacy, safety, and tolerability of bexicaserin in reducing countable motor seizure frequency.
Regulatory Momentum and Parallel Development
Bexicaserin has received Breakthrough Therapy Designation from both the U.S. Food and Drug Administration and China's regulatory authority for the treatment of seizures associated with DEEs in patients two years of age and older. The compound remains investigational and is not yet approved for marketing by any regulatory authority worldwide.
"The completion of randomization in DEEp OCEAN is an important milestone for the bexicaserin pivotal program, made possible by the commitment of patients, families, investigators, and advocacy communities," said Johan Luthman, Executive Vice President and Head of Research and Development at Lundbeck. "We look forward to headline results by the end of 2026 or early 2027."
Luthman also provided an update on the parallel DEEp SEA trial (NCT06660394), a Phase III study evaluating bexicaserin specifically in children and adults with Dravet syndrome (search). "We remain equally committed to the DEEp SEA trial in Dravet syndrome where we are seeing good progress in recruitment of patients and according to plan. We expect to close randomization within a few months," he said.
The breadth of the DEEp OCEAN trial positions Lundbeck to generate meaningful insights not only into seizure control but also into the potential best-in-class benefit-risk profile of bexicaserin across diverse DEE populations. With randomization now complete, participants will progress through the double-blind treatment period followed by the optional open-label extension.