GRIN Therapeutics Presents Multiple Clinical Development Updates for Radiprodil at 2025 ILAE International Epilepsy Congress

Poster presentations included overviews of plans and designs for the global Phase 3 Beeline trial of investigational radiprodil in GRIN-related neurodevelopmental disorder (GRIN-NDD) and Phase 1b/2a Astroscape trial in tuberous sclerosis complex and focal cortical dysplasia type II together with results of a study assessing importance of caregiver perspectives in management of GRIN-NDD

NEW YORK, Sept. 2, 2025 /PRNewswire/ -- GRIN Therapeutics, Inc., a leader in the development of targeted disease-specific therapies to treat serious neurodevelopmental disorders, today announced presentations of three abstracts during the International League Against Epilepsy's (ILAE) 36th International Epilepsy Congress in Lisbon, Portugal. The poster presentations included overviews of GRIN Therapeutics' designs of the global Phase 3 Beeline clinical trial of radiprodil in eligible patients with GRIN-related neurodevelopmental disorder (GRIN-NDD) as well as the Phase 1b/2a Astroscape trial in tuberous sclerosis complex (TSC) and focal cortical dysplasia type II (FCD II). A third poster included results of a new study assessing caregiver perspectives on daily life with GRIN-NDD.

"Since last year's ILAE European Epilepsy Conference, our team has advanced radiprodil with a sense of urgency and purpose, moving closer to our goal of initiating a Phase 3 clinical trial for patients with GRIN-related neurodevelopmental disorder," said Bruce Leuchter, MD, President and Chief Executive Officer of Neurvati Neurosciences and GRIN Therapeutics. "The data and caregiver perspectives being shared at this year's ILAE conference highlight both the progress we have made and the unique opportunity before us. We are committed to translating this momentum into meaningful impact for patients, families, and caregivers, and to delivering the first disease-specific treatment for GRIN-related neurodevelopmental disorder."

Presentation Highlights

Title: Design of a Phase 3 Multicenter Study (Beeline) to Assess the Efficacy and Safety of Radiprodil, a Targeted Investigational Therapy for Patients With GRIN-related Neurodevelopmental Disorder
Key Information:

• In the Phase 1b Honeycomb trial, radiprodil was found to be generally well tolerated and associated with a substantial reduction in seizure frequency and signs of improved behavioral symptoms. Based on these findings, we are advancing plans with regulators for a global Phase 3 Beeline trial to further evaluate the efficacy and safety of radiprodil in GRIN-NDD patients with gain-of-function variants across multiple phenotypes.
• The Beeline trial will use several rating scales, including a newly developed GRIN-specific Clinical Global Impression of Severity (CGI-S) and change (CGI-C), which measure symptoms and impacts most meaningful to caregivers of patients with GRIN-NDD.

Title: Design and Baseline Characteristics of an Open-Label, Multicenter, Phase 1b/2a Study of Radiprodil in Patients With Focal Cortical Dysplasia Type II or Tuberous Sclerosis Complex
Key Information:

• The Astroscape trial is designed to evaluate the safety of radiprodil as a potential treatment for seizures and for a range of nonseizure symptoms of TSC and FCD II not adequately controlled by standard of care therapies.
• Radiprodil is a negative allosteric modulator of the NMDA receptor and thus may offer therapeutic benefit in TSC and FCD II - two disorders where receptor overexpression contributes to clinical symptoms associated with excitatory imbalance.
• The trial is enrolling ~30 patients across 20 sites in the European Union, Australia, United Kingdom, and Canada.
• Findings from the Astroscape trial will help determine the optimal paths forward for the clinical development of radiprodil in TSC and FCD II.

Title: Qualitative Research to Assess Caregivers' Perspectives on Signs and Symptoms of GRIN-related Neurodevelopmental Disorder
Key Information:

• This qualitative research is the first of its kind to characterize the complex range of symptoms associated with GRIN-NDD and their impacts on patients and caregivers.
• Regardless of genotype or phenotype, a key finding is that caregivers select improvements in patient communications and similar sets of non-seizure symptoms as the most important benefits of treatment.
• The GRIN-CGI-S and CGI-C to be used in the Beeline trial is based upon a conceptual model developed from these data.

About Radiprodil

Radiprodil is an investigational, potent negative allosteric modulator that selectively targets the GluN2B subunit of the N-methyl-D-aspartate (NMDA) receptor, being assessed for the treatment of GRIN-related neurodevelopmental disorder (GRIN-NDD). It has been awarded Breakthrough Therapy, Orphan Drug and Rare Pediatric Disease designations by the U.S. Food and Drug Administration as well as Priority Medicines (PRIME) designation by the European Medicines Agency (EMA) and a positive opinion for orphan designation from the EMA Committee for Medicinal Products for Human Use (CHMP). The planned global Phase 3 trial for radiprodil in eligible patients with GRIN-NDD will aim to evaluate the impact of a targeted disease-specific treatment on core aspects of the disease, including seizures, behavioral abnormalities and functional outcomes. Radiprodil is also being developed for the treatment of tuberous sclerosis complex (TSC) and focal cortical dysplasia (FCD) type II, two disorders associated with NMDA receptor overexpression. The Astroscape trial (ClinicalTrials.gov identifier: NCT06392009) is an ongoing, open-label Phase 1b/2a clinical trial assessing the safety, tolerability, pharmacokinetics (PK), and potential efficacy of radiprodil in patients with TSC or FCD type II.

About GRIN Therapeutics

GRIN Therapeutics, Inc. is dedicated to the research and development of precision therapeutics for pediatric neurodevelopmental disorders with the goal of bringing hope to patients and caregivers. Late last year, GRIN Therapeutics reported promising topline data from a Phase 1b/2a clinical trial (the Honeycomb Trial, ClinicalTrials.gov identifier: NCT05818943) evaluating investigational radiprodil in GRIN-related neurodevelopmental disorder (GRIN-NDD) in patients with gain-of-function (GoF) variants, leading to the decision to advance to a global pivotal Phase 3 trial. The company has an additional ongoing clinical trial to evaluate radiprodil for the potential treatment of tuberous sclerosis complex (TSC) and focal cortical dysplasia (FCD) type II. GRIN Therapeutics is an affiliate of Neurvati Neurosciences, a portfolio company of Blackstone Life Sciences. For more information, please visit www.grintherapeutics.com.

About Neurvati Neurosciences

Neurvati Neurosciences, a portfolio company of Blackstone Life Sciences, identifies and advances the development of high-potential drug candidates across the neuroscience landscape. Neurvati employs a collaborative model that establishes fit-for-purpose affiliate companies, aligning dedicated resources with long-term strategic capital to catalyze innovative treatment options in areas of unmet need. Neurvati's team of experienced advisors and drug developers seeks opportunities to challenge current treatment paradigms and make a difference for patients suffering from a wide range of neurological and psychiatric disorders. For more information, please visit www.neurvati.com.

About Blackstone Life Sciences

Blackstone Life Sciences is an industry-leading private investment platform with capabilities to invest across the life cycle of companies and products within key life science sectors. By combining scale investments and hands-on operational leadership, Blackstone Life Sciences helps bring to market promising new medicines and medical technologies that improve patients' lives and currently has more than $12 billion in assets under management.

Corporate Contact
Elliott Ruiz
+1 201.674.5417
[email protected]

SOURCE GRIN Therapeutics Inc.