A retrospective, observational study of perampanel in refractory and super-refractory status epilepticus

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.

Efficacy of Perampanel in Refractory and Super-Refractory Status Epilepticus with Suspected Inflammatory Etiology: A Case Series

(1) Background: Increasing evidence supports the anti-inflammatory and neuroprotective role of perampanel (PER), mediated by decreased expression of pro-inflammatory cytokines and by interference with apoptosis processes. Therefore, the use of PER to treat status epilepticus (SE) with suspected inflammatory etiology is appealing and deserves further investigation. (2) Methods: We retrospectively analyzed seven patients (five F, two M; median age: 62 years) with refractory and super-refractory SE due to a probable or defined inflammatory etiology and treated with PER. (3) Results: PER was administered as the third (4/7) or fourth drug (3/7), with a median loading dose of 32 mg/day (range: 16-36 mg/day) and a median maintenance dose of 10 mg/day (range: 4-12 mg/day). In five cases, SE was focal, while in two patients, it was generalized. SE was caused by systemic inflammation in three patients, while in the other four subjects, it was recognized to have an autoimmune etiology. SE resolution was observed after PER administration in all cases, particularly within 24 h in the majority of patients (4/7, 57.1%). (4) Conclusions: Our data support the efficacy of PER in treating SE when first- and second-line ASMs have failed and suggest a possible earlier use in SE cases that are due to inflammatory/autoimmune etiology.

The broad-spectrum activity of perampanel: state of the art and future perspective of AMPA antagonism beyond epilepsy

Glutamate is the brain's main excitatory neurotransmitter. Glutamatergic neurons primarily compose basic neuronal networks, especially in the cortex. An imbalance of excitatory and inhibitory activities may result in epilepsy or other neurological and psychiatric conditions. Among glutamate receptors, AMPA receptors are the predominant mediator of glutamate-induced excitatory neurotransmission and dictate synaptic efficiency and plasticity by their numbers and/or properties. Therefore, they appear to be a major drug target for modulating several brain functions. Perampanel (PER) is a highly selective, noncompetitive AMPA antagonist approved in several countries worldwide for treating different types of seizures in various epileptic conditions. However, recent data show that PER can potentially address many other conditions within epilepsy and beyond. From this perspective, this review aims to examine the new preclinical and clinical studies-especially those produced from 2017 onwards-on AMPA antagonism and PER in conditions such as mesial temporal lobe epilepsy, idiopathic and genetic generalized epilepsy, brain tumor-related epilepsy, status epilepticus, rare epileptic syndromes, stroke, sleep, epilepsy-related migraine, cognitive impairment, autism, dementia, and other neurodegenerative diseases, as well as provide suggestions on future research agenda aimed at probing the possibility of treating these conditions with PER and/or other AMPA receptor antagonists.

Perampanel in achieving status epilepticus cessation: A systematic review

BACKGROUND

Status epilepticus (SE) is a neurological emergency necessitating rapid seizure control to prevent long-term consequences. Perampanel (PER) is a novel selective, noncompetitive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor antagonist that demonstrated efficacy and safety in lithium-pilocarpine models of SE; however, data in humans are limited. This systematic review was performed to assess the efficacy and safety of PER in patients with SE, RSE, and SRSE.

METHODS

We searched MEDLINE (accessed through PubMed), Embase, Scopus, Cochrane Library, and ClinicalTrials.gov from inception until May 30, 2021 to identify all human studies on PER for the treatment of SE of any type and etiology. An additional search was performed on DANS Easy Archive, in which OpenGrey data were stored, from inception until January 10, 2022 and conference proceedings by the International League Against Epilepsy from 2011 onward. The GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach was used to assess the overall certainty of the body of evidence.

RESULTS

Twenty-one studies (7 case reports, 9 case series, and 5 retrospective cohort studies) were included with a total of 369 cases of SE in 368 patients aged 11 months to 99 years, of which 56.2% were female. Seizures of the majority were refractory (n = 220), super refractory SE (n = 70), or either (n = 81) with prominent motor symptoms (n = 284) and are associated with a structural etiology (n = 218). The number of antiseizure medications and/or anesthetics used prior to PER ranged from 1 to 13. PER was administered in 324 cases and was initiated at a dose of 2-36 mg between 30 min to 59 days from SE onset. SE cessation ranged from 1 h to 4 weeks from PER initiation. A total of 119 cases (36.6%) were considered PER responders. According to the GRADE approach, there is very low certainty of evidence for all outcomes.

CONCLUSIONS

The real-world data of PER as a possible therapeutic option in SE of any type are increasing. However, there is very low certainty of evidence for its use and this requires further clinical studies to establish the appropriate timing, dosing, and titration that are efficacious and safe for SE cessation.

PERMIT study: a global pooled analysis study of the effectiveness and tolerability of perampanel in routine clinical practice

The PERaMpanel pooled analysIs of effecTiveness and tolerability (PERMIT) study was a pooled analysis of data from 44 real-world studies from 17 countries, in which people with epilepsy (PWE; focal and generalized) were treated with perampanel (PER). Retention and effectiveness were assessed after 3, 6, and 12 months, and at the last visit (last observation carried forward). Effectiveness assessments included 50% responder rate (≥ 50% reduction in seizure frequency from baseline) and seizure freedom rate (no seizures since at least the prior visit); in PWE with status epilepticus, response was defined as seizures under control. Safety and tolerability were assessed by evaluating adverse events (AEs) and discontinuation due to AEs. The Full Analysis Set included 5193 PWE. Retention, effectiveness and safety/tolerability were assessed in 4721, 4392 and 4617, respectively. Retention on PER treatment at 3, 6, and 12 months was 90.5%, 79.8%, and 64.2%, respectively. Mean retention time on PER treatment was 10.8 months. The 50% responder rate was 58.3% at 12 months and 50.0% at the last visit, and the corresponding seizure freedom rates were 23.2% and 20.5%, respectively; 52.7% of PWE with status epilepticus responded to PER treatment. Overall, 49.9% of PWE reported AEs and the most frequently reported AEs (≥ 5% of PWE) were dizziness/vertigo (15.2%), somnolence (10.6%), irritability (8.4%), and behavioral disorders (5.4%). At 12 months, 17.6% of PWEs had discontinued due to AEs. PERMIT demonstrated that PER is effective and generally well tolerated when used to treat people with focal and/or generalized epilepsy in everyday clinical practice.