UCB Reports Positive Phase 3 Results for Fenfluramine in CDKL5 Deficiency Disorder

UCB, a prominent global biopharmaceutical company, has announced positive outcomes from its Phase 3 clinical trial assessing fenfluramine as an adjunctive treatment for CDKL5 deficiency disorder (CDD). This serious developmental and epileptic encephalopathy (DEE) typically begins in infancy and presents with severe challenges due to its limited treatment options. Affecting between 1 in 40,000 to 60,000 live births, CDD is characterized by refractory infantile-onset seizures and profound neurodevelopmental issues, including intellectual and motor impairments, cortical visual dysfunction, and sleep disturbances. The disorder is linked to genetic mutations in the CDKL5 gene on the X chromosome.

The recent study marks the third DEE patient group for which fenfluramine has demonstrated positive results in a Phase 3 setting. This success highlights UCB's commitment to advancing scientific research and innovation to address the substantial unmet needs of individuals with DEEs.

Conducted with 87 participants aged 1 to 35 diagnosed with CDD and experiencing uncontrolled seizures, the study was rigorously designed as a randomized, double-blind, placebo-controlled, fixed-dose, multi-center trial. The primary measure of the study was the median percent change in the frequency of countable motor seizures (CMSF) from the baseline through the titration and maintenance phases. The trial successfully met its primary and several key secondary goals, marking a significant achievement in potential CDD treatment advancements.

Fiona du Monceau, Executive Vice President of Patient Evidence at UCB, emphasized the importance of these findings, noting how they represent a critical milestone in the company's efforts to deliver meaningful therapeutic innovations to patients and families affected by DEEs. She acknowledged the contributions of patients, families, and researchers in reaching this point and expressed eagerness to collaborate with health authorities to make this treatment accessible swiftly.

Fenfluramine was generally well tolerated among trial participants, and its safety profile remained consistent with previous studies involving patients with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS). Currently, UCB is extending its research through an open-label, flexible-dose, long-term 54-week extension phase to further evaluate fenfluramine's safety and tolerability in both pediatric and adult patients with CDD.

Currently approved in the United States for treating seizures associated with DS and LGS in patients two years and older, fenfluramine has not yet received regulatory approval for CDD from any global health authorities. However, UCB intends to pursue regulatory approval promptly to provide this potential treatment to CDD patients.

These promising results reinforce UCB's dedication to exploring new therapeutic possibilities for DEEs, underscoring the company's resolve to improve treatment landscapes for rare and severe neurological disorders. The full findings of the Phase 3 study will be shared at an upcoming scientific conference, further contributing to the clinical understanding and treatment of CDD.