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Beeline Phase 3: radiprodil for GRIN-related neurodevelopmental disorder

A Multinational, Multicenter Study With an Open-Label Phase 1b and a Randomized, Double-Blind, Placebo-Controlled Phase 3 Followed by an Open-Label Extension to Assess the Efficacy, Safety, Tolerability, and Pharmacokinetics of Radiprodil in Participants With GRIN-Related Neurodevelopmental Disorder

Phase 3 Interventional GRIN Therapeutics, Inc. · NCT07224581

This Phase 3 test will see if radiprodil can reduce seizures and improve developmental and behavioral symptoms in people with GRIN-related neurodevelopmental disorder caused by gain-of-function GRIN gene variants.

Quick facts

PhasePhase 3
Study typeInterventional
Enrollment100 (estimated)
Ages1 Month to 18 Years
SexAll
SponsorGRIN Therapeutics, Inc. Industry-sponsored
Locations17 sites (Los Angeles, California and 16 other locations)
Trial IDNCT07224581 on ClinicalTrials.gov

What this trial studies

This randomized, double-blind, placebo-controlled Phase 3 trial enrolls participants with GRIN-related neurodevelopmental disorder caused by gain-of-function variants into two cohorts (with qualifying motor seizures or without qualifying seizures). Participants are randomized 1:1 to receive radiprodil or matching placebo, undergo a 4-week fixed titration, then enter a maintenance period of 12 weeks (cohort 1) or 24 weeks (cohort 2) followed by taper and follow-up. After the blinded Part A, eligible participants may enter an open-label extension to receive radiprodil long-term while safety and outcomes are monitored. Key eligibility includes confirmed GoF variants in GRIN1, GRIN2A, GRIN2B, or GRIN2D, stable background antiseizure/nonpharmacologic therapies, and cohort-specific seizure or symptom thresholds.

Who should consider this trial

Good fit: Ideal candidates have a confirmed gain-of-function variant in GRIN1, GRIN2A, GRIN2B, or GRIN2D and either meet the qualifying motor seizure frequency for Cohort 1 or have significant neurodevelopmental symptoms with a GRIN-CGI-S score ≥4 for Cohort 2.

Not a fit: Patients without gain-of-function GRIN variants, those who do not meet the seizure or symptom thresholds, or those with medically unstable conditions or recent changes in antiseizure therapy are unlikely to receive benefit from participation.

Why it matters

Potential benefit: If successful, radiprodil could reduce seizure frequency and improve developmental and behavioral outcomes for people with gain-of-function GRIN variants.

How similar studies have performed: Radiprodil has been examined in earlier parts of the RAD-GRIN-101 program and supported by preclinical rationale, but robust large randomized Phase 3 evidence of clinical benefit in GRIN-NDD is still limited.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

Part A, Participant:

* Diagnosed with GRIN-NDD with GRIN1, GRIN2A, GRIN2B, or GRIN2D gene variants known to result in GoF of the NMDA receptor
* Phase 3 Cohort 1 (Qualifying Seizures Cohort) ONLY: Experiencing at least 1 CMS per week and ≥4 CMS (generalized or focal) during screening
* With history of inadequate response to at least 2 standard antiseizure medications (ASMs)
* Phase 3 Cohort 2 (Without Qualifying Seizures Auxiliary Cohort) ONLY: With significant neurodevelopmental symptoms and a GRIN-CGI-S score ≥4
* On a stable dose of standard ASMs for at least 4 weeks prior to screening and should remain on stable doses throughout study participation
* On stable nonpharmacological treatments such as ketogenic diet and should remain stable throughout study participation

Part B:

\- Participant has completed Part A and is eligible to continue study participation according to the judgement of the investigator and sponsor.

Exclusion Criteria:

PART A, Participant:

* Has clinically relevant medical, neurologic, or psychiatric condition and/or behavioral disorder (including those related to GRIN-NDD) that would preclude or jeopardize participant's safe participation or study drug administration or the conduct of the study according to the judgement of the investigator or sponsor.
* Is receiving \>4 standard ASMs at screening
* Has a body weight of less than 5 kg at screening

Part B:

\- Participant has clinically relevant medical, neurologic, or psychiatric condition and/or behavioral disorder (including those related to GRIN-NDD) that would preclude or jeopardize participant's safe participation of study drug administration or the conduct of the study according to the judgement of the investigator or sponsor.

Where this trial is running

Los Angeles, California and 16 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions GRIN-related Neurodevelopmental DisorderBeelineGRIN1GRIN2AGRIN2BGRIN2DGRIN-NDD
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.