Lundbeck Completes Enrollment in Phase III Dravet Trial

Copenhagen, Denmark, September 15, 2026

DEEp SEA Reaches Final Patient Milestone

The DEE​​p SEA Phase III trial is a randomized clinical study designed to assess the efficacy and safety of bexicaserin in patients with Dravet syndrome. The completion of randomization means that the planned patient population has now been enrolled and assigned to the relevant treatment groups. This represents a significant milestone in a late-stage drug-development program because the trial can now continue toward completion of treatment and collection of the data required for its primary and secondary analyses. Bexicaserin is an investigational small-molecule serotonin 5-HT2C receptor agonist being developed as a potential treatment for seizures associated with developmental and epileptic encephalopathies. The therapeutic approach is intended to address the abnormal neuronal activity that contributes to seizures in these severe neurological disorders. The DEEp SEA study builds on earlier clinical development of bexicaserin and is intended to generate pivotal evidence that could support future regulatory submissions if the trial meets its predefined objectives. As with all investigational medicines, the ultimate clinical benefit and safety profile will depend on the complete analysis of the Phase III results.

Investigating Bexicaserin in Dravet Syndrome

Dravet syndrome is a rare genetic epilepsy that typically begins during infancy and can involve frequent, prolonged and difficult-to-control seizures. The condition can also be associated with developmental delays, behavioral difficulties, movement disorders and other neurological complications. Because seizures may remain inadequately controlled despite available therapies, there remains a substantial need for new treatment options. Lundbeck is evaluating bexicaserin as part of its broader commitment to neuroscience and the development of therapies for serious neurological disorders. The drug’s mechanism of action is based on modulation of the 5-HT2C receptor, a serotonin receptor involved in neuronal signaling. By influencing this pathway, bexicaserin is being investigated for its potential ability to reduce seizure activity. The completion of patient randomization is particularly important in rare diseases because recruiting participants can be challenging due to the relatively small patient population and the specialized clinical centers required for conducting trials. Reaching this milestone therefore demonstrates meaningful progress in the global development program.

Phase III Data Could Guide Future Development

Following the final patient randomization, participants will continue through the study according to the established clinical-trial protocol. Researchers will collect efficacy, seizure-frequency and safety data that will ultimately contribute to the study’s final analysis. The resulting evidence will help determine whether bexicaserin provides a clinically meaningful benefit for patients with Dravet syndrome. For Lundbeck, successful completion of the DEEp SEA trial could represent a major milestone in advancing a potential new therapy for rare epilepsy. Phase III studies are generally designed to provide the robust evidence required to support regulatory decision-making, making the outcome of the trial particularly important for the future development of bexicaserin. The announcement also highlights the growing focus on precision neuroscience and rare-disease drug development, as researchers continue to investigate therapies that target specific biological pathways involved in severe epileptic disorders. While existing medicines can reduce seizures for some patients, many people with Dravet syndrome continue to experience significant disease burden, underscoring the importance of continued clinical research. For cGxP.wire readers, Lundbeck’s announcement represents a significant clinical-development milestone in rare neurological disease. The completion of patient randomization moves the DEEp SEA program closer to its pivotal data readout and provides an important update on the development of bexicaserin. Future Phase III results will be critical in determining whether the investigational therapy can advance toward potential regulatory review and ultimately provide another treatment option for patients and families affected by Dravet syndrome.

Source: Lundbeck press release