Bexicaserin
An investigational treatment for Dravet Syndrome.
The same compound appears under different names depending on the context. Here is how to identify Bexicaserin wherever you encounter it, plus the key facts at a glance.
- Generic name
- Bexicaserin
- Development code
- LP352
- Drug class
- Selective serotonin receptor agonist
- Manufacturer
- Lundbeck (originally Longboard Pharmaceuticals)
- How it's taken
- Taken by mouth as an oral medication, twice daily.
A precisely targeted serotonin medication in Phase 3 trials for Dravet syndrome. Selectively activates one specific serotonin receptor (5-HT2C) to reduce seizures with potentially fewer drug interactions than broader-acting serotonergic therapies. Received FDA Breakthrough Therapy Designation.
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How Bexicaserin works
Bexicaserin activates a single serotonin receptor called 5-HT2C with high precision. This receptor plays a key role in controlling seizure activity in the brain. By targeting only this one receptor and avoiding the others, bexicaserin may reduce seizures effectively while causing fewer interactions with other medications your child might be taking.
Mechanism: Highly selective 5-HT2C serotonin receptor agonist with minimal off-target receptor activity
Side effects and safety
In Phase 1b/2a trials, bexicaserin was generally well-tolerated. Full side effect data is being collected in the Phase 3 DEEp SEA trial. The selective receptor targeting is designed to improve tolerability compared to non-selective serotonergic drugs.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Bexicaserin
Taken by mouth as an oral medication, twice daily. Specific dosing for the Phase 3 trial is being characterized. The oral formulation is convenient for chronic daily use.
Clinical trial results
The Phase 1b/2a PACIFIC trial in 52 patients with developmental epileptic encephalopathies showed a 72.1% median seizure frequency reduction in Dravet patients. The Phase 3 DEEp SEA trial enrolled children and adults aged 2-65 with Dravet syndrome in a randomized, placebo-controlled study over approximately 20 weeks (including screening, titration, and 12-week maintenance). Lundbeck announced on September 15, 2026 that the last patient had been randomized.
Main registered trial: NCT06660394 on ClinicalTrials.gov. Check it for the current status, sites and contacts before asking about enrollment.
Development history
Originally developed by Longboard Pharmaceuticals as LP352. Lundbeck acquired Longboard in 2024. The drug received FDA Breakthrough Therapy Designation for seizures in developmental epileptic encephalopathies based on strong Phase 2 data.
Explore Dravet Syndrome trials
Other Dravet Syndrome treatments
Common questions about Bexicaserin
▸What is Bexicaserin?
A precisely targeted serotonin medication in Phase 3 trials for Dravet syndrome. Selectively activates one specific serotonin receptor (5-HT2C) to reduce seizures with potentially fewer drug interactions than broader-acting serotonergic therapies. Received FDA Breakthrough Therapy Designation.
▸How does Bexicaserin work?
Bexicaserin activates a single serotonin receptor called 5-HT2C with high precision. This receptor plays a key role in controlling seizure activity in the brain. By targeting only this one receptor and avoiding the others, bexicaserin may reduce seizures effectively while causing fewer interactions with other medications your child might be taking.
▸What are the side effects of Bexicaserin?
In Phase 1b/2a trials, bexicaserin was generally well-tolerated. Full side effect data is being collected in the Phase 3 DEEp SEA trial. The selective receptor targeting is designed to improve tolerability compared to non-selective serotonergic drugs.
▸How is Bexicaserin taken?
Taken by mouth as an oral medication, twice daily. Specific dosing for the Phase 3 trial is being characterized. The oral formulation is convenient for chronic daily use.
▸Is Bexicaserin FDA approved?
Bexicaserin is currently in phase 3 clinical trials for Dravet Syndrome. It has not yet received FDA approval.
▸How does bexicaserin differ from fenfluramine?
Both target serotonin pathways but with different selectivity. Fenfluramine broadly releases serotonin and activates multiple serotonin receptor subtypes, while bexicaserin selectively activates only the 5-HT2C receptor. This precision targeting may result in fewer drug interactions and different side effects. Fenfluramine requires cardiac monitoring through a REMS program due to its historical association with heart valve damage; bexicaserin's selectivity profile has not shown similar cardiac concerns in early studies.
▸What did the PACIFIC trial show?
The Phase 1b/2a PACIFIC trial enrolled 52 patients with developmental and epileptic encephalopathies, including Dravet syndrome. In the Dravet subgroup, patients showed a 72.1% median reduction in seizure frequency. These results were strong enough to earn FDA Breakthrough Therapy Designation and advance the drug into the Phase 3 DEEp SEA trial.
▸Is bexicaserin available to patients?
No. Bexicaserin is in Phase 3 clinical trials and has not been approved by the FDA. Enrollment in the DEEp SEA trial is complete. Patients interested in bexicaserin studies should talk with their neurologist and check ClinicalTrials.gov for any open studies.
▸What age range does the Phase 3 trial cover?
The DEEp SEA Phase 3 trial enrolled patients ages 2-65 with Dravet syndrome, making it one of the few Dravet trials that includes both pediatric and adult patients. This broad age range could support approval for a wider population than some existing therapies.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- H. Lundbeck A/S · 2026-09-15. Lundbeck announces last patient randomized in DEEp SEA, a Phase III trial of bexicaserin in Dravet syndrome. https://www.prnewswire.com/news-releases/lundbeck-announces-last-patient-randomized-in-deep-sea-a-phase-iii-trial-of-bexicaserin-in-dravet-syndrome-302878650.html
- ClinicalTrials.gov. DEEp SEA: bexicaserin in Dravet syndrome (Phase 3). https://clinicaltrials.gov/study/NCT06660394