Soticlestat is associated with sustained seizure reductions in patients with Lennox-Gastaut syndrome and Dravet syndrome, according to interim data from an ongoing phase 2 clinical trial presented at the American Academy of Neurology’s (AAN) 75th Annual Meeting between April 22 and 27 in Denver, Colorado.

Safety findings from the interim analysis were consistent with previous studies, and there were no new safety signals, according to the data.

Read more about Lennox-Gastaut syndrome epidemiology

The clinical trial sponsored by Takeda called Endymion 1 assesses the long-term safety and tolerability of soticlestat in combination with other anti-seizure treatments in patients with Lennox-Gastaut syndrome and others who have completed another trial called Elektra or had received 10 or more weeks of treatment. The primary outcome measures include the incidence of treatment-emergent adverse events, and the secondary outcome measures include any change from baseline in seizure frequency.

At the time of the interim analysis, 83 patients with Lennox-Gastaut syndrome were enrolled in the study and had a median exposure to soticlestat of 88.3 weeks. 

The results showed that 72 patients (86.7% of all patients with Lennox-Gastaut syndrome) experienced treatment-emergent adverse events while 36 (43.4%) experienced at least 1 drug-related treatment-emergent adverse event, which was serious in 5 patients. A total of 10 patients discontinued the treatment due to the treatment-emergent adverse events.

The median reduction in all seizure frequency from baseline in the ELEKTRA trial at weeks 1 to 12 was 28.4%, while it was 17.7% at weeks 49 to 60 and 27.7% at weeks 97 to 108.

Soticlestat is a highly selective, oral cholesterol 24-hydroxylase inhibitor that is being developed to treat Lennox-Gastaut syndrome, Dravet syndrome, and other epileptic encephalopathies.

Lennox-Gastaut syndrome is 1 of the most medically refractory epilepsy syndromes.


Yao Y, Dlugos DJ, Asgharnejad M, Jagannatham NVMP, Mitra PK. Long-term treatment effects of soticlestat in patients with Dravet syndrome or Lennox–Gastaut syndrome: interim data from the ENDYMION 1 trial. Oral presentation at the American Academy of Neurology’s (AAN) 75th Annual Meeting; April 22-27, 2023; Denver, CO.

A study of soticlestat in adults and children with rare epilepsies (Endymion 1). US National Library of Medicine. Last updated May 13, 2022. Accessed April 25, 2023.