Phase 3 Fenfluramine Trial Design in CDD: Study Population, Endpoints, and Dosing Strategy

Conducting controlled clinical trials in rare developmental and epileptic encephalopathies presents unique challenges, particularly in patient recruitment, endpoint selection, and the management of highly refractory seizure populations. In CDKL5 deficiency disorder (CDD), where patients frequently experience daily seizures despite multidrug treatment regimens, understanding the design and context of pivotal studies is critical for interpreting emerging data.

As part of this Special Report, Sam Amin, MD, discusses findings from a recent phase 3 randomized, double-blind, placebo-controlled study evaluating fenfluramine in patients with CDD. Amin, a study author with expertise in developmental and epileptic encephalopathies, provides insight into the rationale behind the study framework, including inclusion criteria, baseline patient characteristics, and the continued use of concomitant antiseizure therapies throughout the trial.

In this episode, Amin walks through the major structural elements of the study, including enrollment criteria, dosing considerations, and the primary efficacy endpoint centered on reduction in countable motor seizure frequency. He also highlights characteristics of the enrolled cohort, including baseline seizure burden and the prevalence of concomitant antiseizure medication use among participants.