EpyGenix Therapeutics, in partnership with Greenlight Clinical, is currently enrolling a Phase II, multicenter, randomized, double-blind, placebo-control clinical trial for EPX-100 (Clemizole Hydrochloride, oral solution) in children diagnosed with Dravet syndrome. In January 2020, Epygenix announced the completion of Phase I trials for EPX-100, establishing the safety of EPX-100 in healthy subjects and clearing the way for Phase II trials to begin in patients with Dravet syndrome.

The Phase II trial will assess the efficacy of EPX-100 in reducing seizures in children with Dravet syndrome ages 2-17. To qualify for this study, participants must have a clinical diagnosis of Dravet syndrome with a documented genetic mutation in the SCN1A gene and seizures that are not adequately controlled by current anti-epileptic drugs. Eligible participants must experience 4 or more convulsive seizures during a 4-week baseline period. The trial will last 20 weeks: a 4-week baseline observation, a 4-week dose titration, and a 12-week maintenance dose period. The primary outcome measure will be the change in seizure frequency, but the study will include assessment of other outcomes such as quality of life, behavior, and sleep. All of the results will be compared to participants that have randomly been assigned a placebo as a control measure, with all participants, caregivers, and clinicians blinded to who received the placebo to avoid any bias in the analysis of results. Participants will be closely monitored during the entirety of the 20-week study. Following the initial study, there may be an opportunity for participants to enter a follow-up open-label extension phase to monitor longer-term effects. You can read an informational announcement from EpyGenix about the trial here, or visit clinical trials.gov to see additional details and find study sites.

The potential for clemizole to act as an anti-epileptic came from drug screens in a zebrafish model of Dravet syndrome (1). Interestingly, clemizole was previously FDA-approved as an antihistamine. However, independent of its actions as an antihistamine, the anti-seizure properties of clemizole appear to act through the serotonin pathway. Other drugs that affect the serotonin pathway, such as lorcaserin or fenfluramine, also reduce seizure activity in the same zebrafish model of Dravet syndrome (2,3). Lorcaserin has shown promising results in small groups of patients with Dravet syndrome (2,4) and fenfluramine was recently FDA-approved for treatment of Dravet syndrome. These examples support the predictive power of screens in zebrafish to identify drugs that may benefit patients with Dravet syndrome and underline the serotonin pathway as a promising target for seizure-control in Dravet syndrome. Hopefully, this will hold true for EPX-100.

Despite the approval of several new medications in recent years for the treatment of seizures in Dravet syndrome, there remains a need for increased treatment options as many patients with Dravet syndrome still experience poor seizure control and struggle with significant side effects of currently available anti-seizure medications. You can learn about other drugs in the treatment pipeline that are being developed by EpyGenix at their website.

References:

  1. Baraban SC, Dinday MT, Hortopan GA. (2013) Drug screening in Scn1a zebrafish mutant identifies clemizole as a potential Dravet syndrome treatment. Nature Communications 4:2410. doi:10.1038/ncomms3410
  2. Griffin A, Hamling KR, Knupp K, Hong S, Lee LP, Baraban SC. (2017) Clemizole and modulators of serotonin signaling suppress seizures in Dravet syndrome. Brain. 140:669-683. doi:10.1093/brain/aww342
  3. Griffin A, Jaishankar P, Grandjean J, Olson SH, Renslo AR, Baraban SC. (2019) Zebrafish studies identify serotonin receptors mediating antiepileptic activity in Dravet syndrome. Brain Communications. doi: 10.1093/braincomms/fcz008
  4. Tolete P, Knupp K, Karlovich M, DeCarlo E, Bluvstein J, Conway E, Friedman D, Dugan P, Devinsky O. (2018) Lorcaserin therapy for sever epilepsy of childhood onset. Neurology 91(18):837-839. doi: 10.1212/WNL.0000000000006432