Praxis EMERALD Clinical Trial

KCNQ2 Cure hosted a webinar for the KCNQ2 community featuring a discussion with Praxis Precision Medicines.

Praxis Precision Medicines is a clinical-stage biopharmaceutical company focused on developing therapies for disorders of the central nervous system characterized by an imbalance between neuronal excitation and inhibition, a mechanism that is highly relevant to many developmental and epileptic encephalopathies (DEE), including KCNQ2-related epilepsy.

During the webinar, Praxis shared an overview of the EMERALD Study, a clinical trial for individuals with DEE. The discussion focused on the study design, participation options, and the potential therapeutic role of Relutrigine, an investigational medication currently in clinical development.

Relutrigine is a small-molecule therapy designed to target overactive sodium channels believed to contribute to seizure activity, while minimizing interference with normal neuronal signaling needed for healthy brain function. Although Relutrigine is not a gene-specific therapy, its mechanism of action may be relevant across multiple DEE diagnoses where neuronal hyperexcitability plays a role.

Relutrigine has already completed a Phase I clinical study in healthy adult participants to evaluate safety and dosing. Based on those results, the drug advanced to a Phase II clinical trial, which is currently ongoing. Early parts of the Phase II study included a small cohort of individuals with genetic DEEs, including SCN-related epilepsies. Interim results shared during the webinar demonstrated meaningful reductions in seizures over time, along with improvements on the Clinical Global Impression (CGI) scale.

The CGI is a clinician-rated assessment that evaluates overall functioning before and after starting a study medication. In this study, CGI measures include areas such as adaptive behavior, communication, alertness and awareness, and seizure severity and intensity.

The EMERALD Study is a Phase II/III double-blind, placebo-controlled trial, meaning that neither participants nor investigators know who is receiving Relutrigine versus placebo during the blinded portion of the study. Relutrigine is provided as a liquid formulation and can be administered orally or via G-tube.

The study lasts 32 weeks:

  • The first 16 weeks are double-blind, with participants randomized to receive either Relutrigine or a placebo.

  • The following 16 weeks are an open-label extension, during which all participants receive Relutrigine.

  • After completing the study, participants who experience benefit may be eligible to continue the medication through an expanded access program, if available.

Key inclusion criteria include:

  • A diagnosis of a Developmental and Epileptic Encephalopathy (DEE), which includes KCNQ2-related epilepsy

  • Ages 2 to 65 years

  • At least four countable motor seizures in the four weeks before screening

  • Participants may be taking antiseizure medications, but no more than two sodium channel blockers at the time of enrollment

  • Participants may be on the ketogenic diet

Participation options include:

  • In-person visits at a clinical trial site

  • At-home participation, where a study physician and nurse conduct visits and assessments in the participant’s home

  • A hybrid model combining home visits with select in-person site visits

The study plans to enroll approximately 160 participants and aims to complete enrollment within a relatively short timeframe.

If you are interested in learning more about the EMERALD Study or determining whether participation is appropriate for your family, additional information is available on the EMERALD Study website.

Additional notes shared during the webinar:

  • KCNQ2-related epilepsy is considered a DEE

  • Participants must remain on stable treatments and cannot change their current treatment for at least 30 days before screening.

  • At this time, enrollment is limited to participants in the United States. Still, trial sites in Italy, Germany, Spain, Brazil, and Australia are expected to open by the end of the year.

  • Travel stipends may be available for families who need assistance attending study-related visits.

As always, participation in a clinical trial is a personal decision, and families are encouraged to discuss potential involvement with their medical care team.

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