Beeline: a Phase 3 Study in GRIN-related Neurodevelopmental Disorder

Participants are assigned in a 1:1 ratio to receive either radiprodil or placebo duringPart A with the opportunity to receive radiprodil in the Open‐Label Extension, Part B.The dosing regimen includes a fixed titration schedule over 4 weeks.This study is divided into the following parts:Part A: Randomized, double‐blind, placebo‐controlled ‐ Screening/Observation Period: To assess eligibility ‐ Titration Period (approximately 4 weeks): Titration of radiprodil or placebo totarget dose ‐ Maintenance Period (Part A): Target dose of radiprodil or placebo maintained for 12weeks (Phase 3 Cohort 1) or 24 weeks (Phase 3 Cohort 2) ‐ Tapering and Follow‐up Period: Gradual decrease and Follow‐up Period forparticipants not entering Part BPart B: Open‐label safety follow‐up period ‐ Open‐Label Treatment Period: Participants will continue to receive radiprodil untilsuch time as either the participant withdraws/is withdrawn from the study, sponsorterminates the study, or market access is available ‐ Tapering and Follow‐up Period: Gradual decrease and follow‐up observation period forparticipants upon leaving the study