Traumatic brain injury (TBI) often causes permanent neurological dysfunction. Although no medication has been validated yet to prevent secondary injury of brain tissue, recent animal studies have reported that perampanel, a glutamine receptor antagonist, could improve the neurological functions of animals with TBI by mitigating the abnormal calcium influx and cell death around the site of primary injury. The present study aims to elucidate the efficacy of perampanel administration in improving the neurological function of patients with TBI.

The perampanel for alleviation of secondary injury in TBI trial is a multicentre, phase-II, open-label randomised controlled trial targeting patients with mild-to-moderate TBI. This trial will include adult TBI patients with a Glasgow Coma Scale score of 9–14 from five tertiary centres. Patients with epilepsy as a comorbidity, delayed presentation of symptoms (>24 hours after injury) or Injury Severity Score of ≥25 will be excluded. The study participants will be randomly assigned to either the perampanel group (2 mg/day) or the control group (fosphenytoin administered at a dose of 15–18 mg/kg/day, followed by 5–7.5 mg/kg/day of fosphenytoin). In both groups, the medication will be initiated within 12 hours of the TBI diagnosis and continued for 7 days. The antiepileptic drugs can be increased, changed or added as necessary if early post-traumatic seizures are observed. The primary outcome is favourable neurological outcome, defined as a Glasgow Outcome Scale Extended score of ≥5 at 90 days after the TBI diagnosis, which will then be compared between the groups through an intention-to-treat analysis.

The present study has been approved by the Certified Review Board of Keio at the principal institution (approval number: N20240004). Written informed consent will be obtained from all participants or their legal representatives. The results will be disseminated via publications and presentations.

Japan Registry of Clinical Trials (jRCTs031250067).