Honeycomb: Evaluation of Radiprodil in Children with GRIN-related Disorder

Study RAD-GRIN-101 is a phase 1B trial to assess safety, tolerability, PK, and potential efficacy of radiprodil for the treatment of GRIN-related disorder in children with a Gain-of-Function (GoF) genetic variant. The study is open-label, so all participants will be treated with radiprodil.

Subjects' participation in the study is expected to last up to six months in Part A.

After the end of part A, all participants who are still eligible can choose to continue to receive radiprodil as part of an open-label long-term treatment period (Part B).

Inclusion Criteria

• Age: ≥6 months to ≤12 years, with GRIN gene variants known to result in GoF of the NMDA receptor.
• Cohort 1 must have at least 1 observable motor seizure per week and ≥4 observable motor seizures (generalized or focal) during the prospective 4-week Observation Period and must have failed to obtain adequate seizure control with at least 2 antiseizure medications (ASMs) used at appropriate dose and duration.
• Cohort 2 must have significant behavioral and/or motor symptoms based on caregiver report with a CGI-S score ≥4.
• Stable antiseizure therapies and nonpharmacological treatments such as ketogenic diet throughout screening and study participation.

Exclusion Criteria

• Any other clinically relevant medical, neurologic, or psychiatric condition and/or behavioral disorder unrelated to GRIN-related disorder that would preclude or jeopardize participant's safe participation or the conduct of the study according to the judgement of the investigator.
• Clinically significant laboratory or ECG abnormalities.
• Severe hepatic dysfunction (Child-Pugh grade C).
• History of brain surgery for epilepsy or any other reason.
• Receiving treatment with contraindicated concomitant drugs such as agonists or antagonists of the glutamate receptor, including but not limited to felbamate, memantine, and perampanel.
• Receiving treatment with hormonal therapy such as adrenocorticotrophic hormone or prednisolone.