Global biopharmaceutical company UCB (Euronext Brussels: UCB) on Friday announced positive top-line results from its Phase 3 GEMZ study evaluating adjunctive fenfluramine in individuals with CDKL5 deficiency disorder (CDD), a rare and severe developmental and epileptic encephalopathy.

The study met its primary and most key secondary clinical endpoints, demonstrating a significant reduction in countable motor seizure frequency compared to placebo.

The randomised, double-blind, placebo-controlled trial enrolled 87 patients aged one to 35 with uncontrolled seizures due to CDD. Fenfluramine was generally well tolerated, with a safety profile consistent with previous use in Dravet syndrome and Lennox-Gastaut syndrome.

CDD, caused by mutations in the CDKL5 gene on the X chromosome, affects approximately 1 in 40,000 to 60,000 live births and presents with early-onset epilepsy and severe neurodevelopmental impairments. The condition currently has limited treatment options and represents a high unmet medical need.

This marks the third developmental and epileptic encephalopathy population in which fenfluramine has shown positive Phase 3 outcomes. A long-term open-label extension is underway to assess safety and tolerability over 54 weeks.

UCB plans to pursue regulatory submissions to make fenfluramine available for CDD patients as quickly as possible. Full study results will be shared at an upcoming scientific conference.