1st Patient Dosed in Phase 2 Study of EPX-100 for Dravet Syndrome

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by Forest Ray PhD |

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EPX-100 clinical trial

The first patient has been successfully dosed in a Phase 2 clinical trial testing Epigenix Therapeutics’ EPX-100 (clemizole) as an add-on therapy for children with Dravet syndrome.

“We are very excited to announce that [the] first patient has been successfully dosed in our trial. First patient dosing is an extremely important clinical milestone of EPX-100, as this is the crucial first step to evaluate the efficacy and safety of EPX-100 in patients,” Hahn-Jun Lee, PhD, president and CEO of Epygenix Therapeutics, said in a press release.

The trial (NCT04462770) is comparing the efficacy of EPX-100 with a placebo in children ages 2–17 with documented mutations in the SCN1A gene. Approximately 80% of Dravet patients carry mutations in this gene.

Up to 24 participants are currently being recruited at two U.S. locations; more information on enrollment can be found here.

To be eligible to participate, volunteers must have experienced their first seizure before reaching 18 months old, have seizures that are not completely controlled by anti-epileptic drugs, and carry a mutation in the SCN1A gene.

The 20-week study begins with a four-week observational period to establish each participant’s seizure frequency and treatment eligibility. Participants then will be assigned randomly to receive either an oral solution of EPX-100 or a placebo.

This will then be followed by a four-week titration phase to find the highest tolerated dose, starting at a daily dose of 2 mg/kg, with 1 mg/kg increments every seven days, after which patients will enter a 12-week maintenance phase.

The trial’s primary outcome measure is the change in seizure frequency between the four-week observational period and the final four weeks of the maintenance period.

Patients completing the trial will have the opportunity to enter a 52-week open-label extension phase.

EPX-100 is a repurposing of clemizole, an antihistamine used to treat itching in the 1950s and ’60s. In a large drug screen of more than 3,000 compounds looking for potential Dravet therapies, clemizole strongly suppressed spontaneous convulsive behavior in a zebrafish model of Dravet syndrome.

Investigators think it does this by modulating signals carried by serotonin, a chemical messenger molecule found throughout the brain and thought to be altered in people with Dravet, although the exact mechanism remains unknown.

“Beginning the process of evaluating EPX-100 in Dravet Syndrome patients is the culmination of a very exciting journey from the ‘aquarium’ to the ‘bedside,’ said Scott C. Baraban, PhD, chairman of Epygenix’s scientific advisory board.

A Phase 1 trial (NCT04069689) completed earlier this year found EPX-100 was safe and well tolerated among healthy adults, with no clinically significant abnormalities seen among participants.

The U.S. Food and Drug Administration designated EPX-100 an orphan drug in 2017, making it eligible for a suite of incentives meant to accelerate the development of new therapies for rare diseases. In 2019, the agency granted the treatment investigational new drug status for Dravet syndrome, enabling it to enter human clinical trials.