Preliminary Safety Study of a Single-dose Perampanel Drip Infusion in Brain Tumor Patients to Prevent Early Postoperative Seizures: The poSTOP Seizure-1 SF Study

Early postoperative seizures, defined as occurring within 7 days after surgery, are a significant complication that occurs following neurosurgical procedures involving cerebral manipulation. As a result, short-term antiseizure medication is typically administered in Japan despite the lack of consensus regarding its prophylactic use. Perampanel hydrate, an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist, was recently introduced in an intravenous formulation in Japan, providing new potential for early postoperative seizures prevention during the perioperative period. This study aimed to evaluate the safety and feasibility of a single-dose intravenous infusion of perampanel hydrate during brain tumor surgery. We conducted a single-arm, open-label, exploratory safety trial involving 10 adult patients undergoing brain tumor resection. Each participant received a 6 mg intravenous dose of perampanel hydrate during surgery, with no additional antiseizure medication administered postoperatively unless clinically indicated. The primary endpoint was the incidence of grade 3 or higher adverse events related to the study drug. Secondary endpoints included hematological toxicity, the incidence of early postoperative seizures, anesthetic recovery time, and perampanel hydrate blood concentration profiles. No grade 3 or higher adverse events were observed. Minor adverse events included transient grade 2 liver enzyme elevations and postoperative restlessness, both of which resolved within a week. Notably, no cases of early postoperative seizures occurred, and perampanel hydrate blood levels remained high even 7 days after a single administration. Intravenous perampanel hydrate appears safe and well tolerated in the perioperative setting and may effectively prevent early postoperative seizures. Further studies are planned to evaluate its efficacy in larger patient cohorts.