New data from the phase 3 GEMZ trial, presented at the 55th Child Neurology Society Annual Meeting, show that fenfluramine (Fintepla; UCB) consistently reduced seizure frequency across age groups in patients with CDKL5 deficiency disorder (CDD) — an ultra-rare, drug-resistant epilepsy that typically begins within the first three months of life.

The findings reinforce earlier positive results from the trial and support fenfluramine's potential as a treatment option for both children and adults with CDD. UCB has announced plans to seek regulatory approval for this new indication, which would make CDD fenfluramine's third approved epileptic encephalopathy indication, joining Dravet syndrome and Lennox-Gastaut syndrome. An open-label extension evaluating long-term outcomes over 52 weeks is ongoing.

By the Numbers:

• Ages 2–6: median seizure frequency reduced by 25.7% with fenfluramine vs. 0.1% with placebo
• Ages >6–35: median seizure frequency reduced by 48.2% with fenfluramine vs. 2.8% with placebo (nominal P <.001 for both)
• Overall trial: 38.1% of fenfluramine-treated patients rated as much or very much improved vs. 6.8% on placebo
• No cases of valvular heart disease or pulmonary arterial hypertension were observed

Why it matters: CDD is a devastating, drug-resistant epilepsy with very few treatment options. These results suggest fenfluramine could offer meaningful, age-consistent seizure relief for a patient population that has historically had limited therapeutic choices.