Phase 3 trial of Dravet seizure drug advances with patient grouping

Patients will be randomly assigned to groups in a Phase 3 clinical trial testing bexicaserin for seizures associated with Dravet syndrome, according to the treatment’s developer.

Lundbeck said it expects to complete patient randomization — assigning participants to groups receiving the treatment or a placebo — within the next few months in the Phase 3 DEEp SEA trial (NCT06660394).

The company said recruitment is progressing as planned following the completion of patient randomization in the companion Phase 3 DEEp OCEAN study (NCT06719141), which is testing the therapy in a broad population of people with other types of developmental and epileptic encephalopathies (DEEs).

DEEp SEA aims to enroll up to 160 children and adults, ages 2 to 65, across several sites worldwide. The placebo-controlled study is evaluating the efficacy and safety of oral bexicaserin in reducing the frequency of motor seizures in Dravet patients.

“The completion of randomization in DEEp OCEAN is an important milestone for the bexicaserin pivotal program,” Johan Luthman, PhD, executive vice president and head of research and development at Lundbeck, said in a company press release. “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.”

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Treatment shows promise in earlier trial, extension

Dravet syndrome is a form of epilepsy characterized by frequent and prolonged motor seizures, uncontrolled bursts of electrical activity in the brain that typically start in early infancy. As in other DEEs, these seizures can be difficult to control with available Dravet medications.

Bexicaserin, previously known as LP352, is an oral therapy designed to activate 5-HT2C receptors. These receptors primarily bind serotonin, a signaling molecule nerve cells use to communicate, with the aim of easing the abnormal electrical activity in the brain that drives seizures.

The Phase 3 trial program follows positive results from the Phase 1b/2a PACIFIC trial (NCT05364021), which demonstrated that bexicaserin was generally well tolerated and significantly reduced seizure frequency in adolescents and adults with Dravet and other DEEs. In the four participants with Dravet, all of whom received bexicaserin, the median seizure frequency decreased by 72.1%.

In the trial’s open-label extension (NCT05626634), in which all patients received bexicaserin, participants maintained a reduction in seizure frequency, with a median decrease of 59.3% after one year. Benefits were similar for participants who continued treatment and for those who switched from placebo.

The main goal of both Phase 3 trials is to assess bexicaserin’s efficacy in reducing seizures in children and adults compared with a placebo. After patient screening and initial evaluation, participants will start a three-week dose-adjustment period and then continue on the highest tolerated dose for 12 weeks (about three months).

Secondary goals include assessing the treatment’s safety and tolerability. Once patients complete the trials, those eligible may enroll in one-year open-label extensions, in which all participants will receive bexicaserin.

The treatment was initially developed by Longboard Pharmaceuticals, which was acquired by Lundbeck in 2024.

Bexicaserin has received U.S. Food and Drug Administration (FDA) breakthrough therapy, orphan drug, and rare pediatric disease designations. These designations aim to accelerate the development and regulatory review of medications intended to treat serious or life-threatening conditions.