UCB has announced that its phase 3 trial evaluating fenfluramine in CDKL5 deficiency disorder (CDD) achieved its primary and key secondary endpoints.
The study assessed 87 children and adults aged 1 to 35 with uncontrolled seizures linked to CDD. It evaluated the efficacy, safety, and pharmacokinetics of fenfluramine as an adjunctive treatment over a controlled, fixed-dose period.
CDD is an ultra-rare developmental and epileptic encephalopathy (DEE) marked by early-onset epilepsy and severe neurodevelopmental delays, including intellectual, visual, and sleep impairments.
Fiona du Monceau, Executive Vice President, Patient Evidence at UCB, said: “These results pave the way for creating significant therapeutic progress and represent an important milestone in UCB’s mission to bring meaningful innovation to individuals and families affected by developmental and epileptic encephalopathies.”
CDD is caused by mutations in the CDKL5 gene on the X chromosome. It occurs in an estimated 1 in 40,000 to 60,000 births, typically beginning within six weeks of life.
The trial’s primary measure was based on the median percent change in countable motor seizure frequency during the titration and maintenance phase.
UCB noted that fenfluramine was generally well-tolerated in this study, aligning with its established safety profile in previous trials focused on Dravet and Lennox-Gastaut syndromes.
The company is also running an open-label, long-term extension to evaluate safety and tolerability over 52 weeks.
Fenfluramine is already authorised in the EU and US for seizures associated with Dravet syndrome and Lennox-Gastaut syndrome. However, it has not yet been approved for CDD.
UCB plans to submit these results for regulatory approval in a bid to provide a much-needed treatment option to people affected by CDD.
