GRIN Therapeutics has launched its pivotal Phase 3 Beeline study in Europe, marking a major expansion of its global clinical program for investigational radiprodil in GRIN-related neurodevelopmental disorder (GRIN-NDD).
The registrational Phase 3 trial is designed to evaluate the efficacy and safety of radiprodil, a selective negative allosteric modulator of the NMDA receptor GluN2B subunit, in patients with GRIN-NDD caused by gain-of-function (GoF) variants.
The therapy targets underlying NMDA receptor overactivation, with the goal of addressing core disease features including seizures, behavioral symptoms, and broader functional impairments.
"This is an exciting and meaningful milestone for GRIN Therapeutics and, more importantly, for the GRIN-NDD community," said Bruce Leuchter, President and Chief Executive Officer of GRIN Therapeutics.
"Expanding the Beeline study into Europe brings us closer to delivering what we hope will be the first targeted, disease-modifying therapy for patients living with this complex and life-altering condition. We are deeply motivated by the families and caregivers who have helped shape this program, and we are committed to advancing radiprodil with urgency, rigor, and a clear focus on making a meaningful difference for patients and their families."
The Phase 3 program builds on earlier findings from the open-label Phase 1b/2a Honeycomb study, which showed encouraging clinical activity and tolerability of radiprodil in GRIN-NDD patients with GoF variants.
Among patients with countable motor seizures, the study reported a median 86% reduction in seizure frequency. Clinicians and caregivers also observed signs of broader clinical benefit, reflected in Clinician and Caregiver Global Impressions of Change.
Insights from the Honeycomb study, along with input from patients, caregivers, and investigators, helped shape the Phase 3 Beeline design. The trial includes disease-specific endpoints aimed at capturing meaningful behavioral changes and allows enrollment of patients with behavioral symptoms even in the absence of countable motor seizures.
The European rollout includes study sites in Belgium, France, Germany, Italy, Poland, the Netherlands, Slovenia, and Spain, alongside ongoing enrollment in the United States and United Kingdom. The expansion brings together experienced centers from earlier trials and new sites across the region, supporting efficient study execution.
