Ataluren for drug‐resistant epilepsy in nonsense variant‐mediated Dravet syndrome and CDKL5 deficiency disorder

Objective Ataluren is a compound that reads through premature stop codons and increases protein expression by increasing translation without modifying transcription or mRNA stability. We investigated the safety and efficacy of ataluren in children with nonsense variants causing Dravet Syndrome (DS) and CDKL5 Deficiency Syndrome (CDD). Methods This single‐center double‐blind, placebo‐controlled crossover trial randomized subjects to receive ataluren or placebo for 12 weeks (period 1), a 4‐week washout, then another 12‐week treatment (period 2). The primary outcome was ataluren’s safety profile. The secondary outcome measures were (1) changes in convulsive and/or drop seizure frequency and (2) changes in minor seizure types during ataluren treatment compared to placebo. Exploratory objectives assessed changes in cognitive, motor, and behavioral function as well as quality of life during ataluren therapy. Results We enrolled seven subjects with DS and eight subjects with CDD. Three treatment‐related adverse events (AE) occurred during the blinded phases. Two subjects withdrew due to AE. Ataluren was not effective in reducing seizure frequency or improving cognitive, motor, or behavioral function or quality of life in subjects with either DS or CDD due to nonsense variants. Limitations included a small sample size and 12‐week treatment phase, possibly too short to identify a disease‐modifying effect. Significance There was no difference between ataluren and placebo; ataluren is not an effective therapy for seizures or other disorders in children with DS or CDD due to nonsense variants. There were no drug‐related serious AE during the double‐blind period, consistent with ataluren’s favorable safety profile in larger studies. (Funded by Epilepsy Foundation, Dravet Syndrome Foundation, Finding A Cure for Seizures and Epilepsy and PTC Therapeutics, Inc.; ClinicalTrials.gov number, NCT02758626).