Perampanel as an Add-On Therapy in Patients with Refractory Status Epilepticus and Postanoxic Encephalopathy: A Real-Life Single-Center Retrospective Cohort Study

Background: Data on the efficacy of perampanel in refractory status epilepticus (RSE) and postanoxic encephalopathy (PAE) are limited; its use in such conditions is currently off-label. Methods: We conducted a retrospective cohort study of consecutive adult patients with RSE, including PAE, exhibiting electroencephalographic patterns indicative of status epilepticus who were treated at our center (January 2018 to December 2022) with assessment of clinical and electroencephalographic outcomes. Results: Thirty-six patients were included in the study, of whom 29 had nonanoxic RSE and 7 had PAE. Within the nonanoxic RSE subgroup, 45% (13 of 29; 95% confidence interval [CI] 27–63%) of study participants were responders, 34% (10 of 29; 95% CI 17–52%) were partial responders, and 21% (6 of 29; 95% CI 6–35%) were nonresponders. In the PAE subgroup (n = 7), no patients fully responded to perampanel; 43% (3 of 7; 95% CI 6–80%) were partial responders, and 57% (4 of 7; 95% CI 20–95%) were nonresponders. Responder and nonresponder study participants exhibited overlapping baseline characteristics. No significant differences in duration of hospitalization were observed between responders and nonresponders in both subgroups. Responders in the RSE subgroup had a median discharge modified Rankin Scale score of 3 (interquartile range 3–4), and nonresponders had a median discharge modified Rankin Scale score of 5 (interquartile range 5–6). Conclusions: Despite limitations from the retrospective design and the small population size, this study suggests that perampanel use in nonanoxic RSE appears to yield promising results at moderate doses, including a tendency toward a better functional outcome at discharge, without significant adverse effects. However, in patients with PAE, the drug seems to show suboptimal performance. Perampanel appears to have promising efficacy as an add-on therapy in nonanoxic RSE. However, in patients with PAE, its efficacy seems to be lower. Further studies are warranted to confirm these observations.