Longboard Pharmaceuticals Reports Positive Interim Results from Bexicaserin Study in DEE Participants

Longboard Pharmaceuticals, Inc., a clinical-stage biopharmaceutical company headquartered in La Jolla, California, has announced promising interim results from a 52-week open-label extension (OLE) of the PACIFIC Study. The study focuses on evaluating bexicaserin (LP352) for patients aged 12-65 with Developmental and Epileptic Encephalopathies (DEEs), including Dravet syndrome, Lennox-Gastaut syndrome, and other DEEs.

According to Dr. Randall Kaye, Longboard’s Chief Medical Officer, the data reveal a durable and sustained reduction in seizures along with favorable safety and tolerability across a range of DEE patients. Patients who transitioned from the PACIFIC placebo group to bexicaserin in the OLE also showed compelling seizure reduction. Dr. Kaye emphasized the company’s commitment to advancing bexicaserin rapidly due to unmet needs in DEE patients. Additional analyses are expected as participants progress in the OLE Study and transition to an Expanded Access Program. An End of Phase 2 meeting is scheduled for this summer, with plans to initiate a global Phase 3 program for bexicaserin later in the year.

The PACIFIC OLE Study, a 52-week Phase 2 open-label study, aims to evaluate long-term safety and determine the impact of multiple doses of bexicaserin on countable motor seizures and other seizure types in DEE patients. The interim analysis was conducted around the 6-month mark of the OLE Study, which included participants who had completed the initial PACIFIC Study.

Efficacy results from the interim analysis showed a median reduction in countable motor seizure frequency of 56.1% over approximately six months. Participants initially randomized to the bexicaserin group in the PACIFIC Study experienced a 54.9% median reduction, while those in the placebo group who transitioned to bexicaserin in the OLE saw a 57.3% median reduction.

In terms of safety and tolerability, favorable results were observed, with 100% of PACIFIC Study completers enrolling in the OLE and 95.1% remaining in the ongoing study. One participant discontinued due to an adverse event of lethargy, and another withdrew consent. Common treatment-emergent adverse events (AEs) occurring in more than 5% of participants included upper respiratory tract infections, COVID-19, pneumonia, sinusitis, seizures, and decreased appetite.

The PACIFIC Study itself is a Phase 1b/2a double-blind, placebo-controlled clinical trial designed to evaluate the safety, tolerability, efficacy, and pharmacokinetics of bexicaserin in DEE patients aged 12-65 across 34 sites in the United States and Australia. Following a screening period and baseline evaluations, participants underwent dose titration over 15 days and continued on the highest tolerated dose for 60 days during the maintenance period. Eligible participants could then enroll in a 52-week open-label extension study.

Longboard Pharmaceuticals is dedicated to developing innovative treatments for neurological diseases. The company is advancing a portfolio of product candidates designed to be highly selective for specific G protein-coupled receptors (GPCRs). Bexicaserin (LP352), an oral 5-hydroxytryptamine 2C receptor superagonist with no observed impact on 5-HT2B and 5-HT2A receptor subtypes, is set to enter a global Phase 3 program. Additionally, Longboard is developing LP659, an oral sphingosine-1-phosphate receptor modulator, for rare neuroinflammatory conditions, with Phase 1 single-ascending dose clinical trial results expected in the second quarter of 2024.

Overall, the interim results from the PACIFIC OLE Study underscore the potential of bexicaserin to significantly reduce seizures in DEE patients while maintaining a favorable safety profile. Longboard remains focused on advancing its clinical programs to address significant unmet medical needs.