FDA awards RMAT designation to Dravet syndrome gene therapy
POLARIS program now testing ETX101 in 3 clinical trials, all recruiting
The U.S. Food and Drug Administration (FDA) has granted ETX101, an experimental gene therapy for Dravet syndrome, its regenerative medicine advanced therapy (RMAT) designation.
According to developer Encoded Therapeutics, the RMAT status was awarded following positive clinical trial data.
The regulatory designation is given to certain types of treatments, for serious conditions, that have shown promise in early testing. Such status is designed to help speed the development of important new therapies that meet unmet needs, and will give Encoded access to perks like more frequent interactions with the FDA during the therapy development process.
“The FDA’s decision to grant RMAT designation highlights the promising clinical efficacy and safety profile we have observed to date,” Kartik Ramamoorthi, PhD, CEO of Encoded, said in a company press release.
Encoded is currently running three Phase 1/2 clinical trials testing ETX101 — all of which are actively recruiting children with Dravet.
Collectively known as the POLARIS program, these studies are: ENDEAVOR (NCT05419492), which is enrolling participants at three sites in the U.S.; WAYFINDER (NCT06112275), enrolling at a site in Melbourne, Australia; and EXPEDITION (NCT06283212), recruiting at three sites in the U.K.
The U.S. and U.K. studies are open to children ages 6 to 47 months, or nearly 4 years of age, while the Australian site is enrolling youngsters ages 6 to 83 months, or approximately 7 years of age. All three studies aim to evaluate the safety of ETX101, as well as the treatment’s impact on seizure frequency.
RMAT status for Dravet gene therapy follows early trial data
According to Encoded, the FDA’s decision to grant RMAT status to the gene therapy candidate came “following review of preliminary seizure data from patients treated in [the company’s] ongoing Phase 1/2 program.” However, Encoded did not provide any specifics.
Ramamoorthi said the company plans to announce interim data from the POLARIS program before the end of 2025.
Earlier this year, Encoded completed construction of a manufacturing facility it says is able to produce ETX101 following the quality standards that would be needed to bring the therapy to market. The company said this facility has already started producing the gene therapy in anticipation of a pivotal study of ETX101, which Encoded plans to launch in the first half of 2026.
The company applauded the RMAT designation.
“This milestone, together with the transition to in-house … manufacturing, underscores both the clinical potential of ETX101 and our readiness to efficiently advance the program through development,” Ramamoorthi said.
ETX101 previously had been granted rare pediatric disease status in the U.S., and orphan drug designations in both the U.S. and the European Union. Each of these designations provides incentives for companies investing in the development of treatments for rare diseases. For its part, orphan drug status provides a period of market exclusivity should the therapy ultimately be approved.
This milestone, together with the [company’s] transition to in-house … manufacturing, underscores both the clinical potential of ETX101 and our readiness to efficiently advance the program through development.
The FDA also has granted ETX101 fast track status, which aims to speed the development and review of treatment for serious conditions that fill an unmet medical need.
Dravet is mainly caused by mutations in a gene called SCN1A. That gene helps the body make a protein that is part of a sodium channel in the brain. These channels are important for controlling the activity of certain nerve cells. When they don’t work properly, the balance of brain activity is disrupted, which can lead to seizures and other symptoms of the condition.
ETX101 is a one-time gene therapy designed to restore sodium channels on affected nerves, thus addressing the underlying cause of Dravet syndrome and easing symptoms.
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