Global biopharmaceutical company UCB has reported positive data for its Phase III GEMZ study which is investigating adjunctive fenfluramine in children and adults with CDKL5 Deficiency Disorder (CDD).  

The data were announced at the American Epilepsy Society (AES) meeting, Atlanta, USA. 

The results of the trial show positive efficacy and safety results for adjunctive fenfluramine, with the trial meeting its primary and secondary endpoints. Overall the therapy demonstrated a statistically significant reduction in countable motor seizure frequency (CMSF) and a clinically meaningful improvement on the Clinical Global Impression–Improvement (CGI-I) scale, compared with placebo. 

GEMZ is a randomised, double-blind, placebo-controlled, fixed-dose, multi-centre study examining the efficacy, safety, and pharmacokinetics of adjunctive fenfluramine treatment in 86 children and adults aged 1-1 – 35 years, with a CDD diagnosis and uncontrolled seizures. 

CDD is an ultra-rare developmental and epileptic encephalopathy (DEE) that is characterised by multiple types of drug-resistant seizures, as well as severe neurodevelopmental delays that can impact intellectual, motor, cortical visual, gastrointestinal and sleep functions.  

It’s caused by pathogenic variants in the Cyclin Dependent Kinase-like 5 (CDKL5) gene located on the X chromosome and affects four times more females than males.  

Phase III study results 

Study results show that patients treated with fenfluramine experienced a median reduction of 47.6% in countable motor seizure frequency (CMSF) compared to a 2.8% reduction for patients treated with a placebo. During a 14-week titration and maintenance period, the median figure was 52.7%.  

Most patients treated with fenfluramine experienced an overall reduction in seizures and the therapy was generally well tolerated with adverse events remaining consistent with the known safety profile of the therapy when used in Dravet syndrome and Lennox-Gastaut syndrome. 

“UCB is proud to share these important results with the medical community at AES, especially given the significant unmet need in CDD. Families affected by this ultra-rare condition face immense daily challenges with frequent, treatment-resistant seizures that are profoundly disruptive to daily life. These trial results emphasise the impact that seizure control can have on the lives of patients and their families, and we look forward to working with health authorities to make this treatment available as soon as possible,” said Fiona du Monceau, Executive Vice President, Patient Evidence, UCB.

Reece Armstrong, Editor, DDW