OBJECTIVE: This study was the first to evaluate the effect of CYP3A4 gene polymorphisms on the plasma concentration and effectiveness of perampanel (PER) in Chinese pediatric patients with epilepsy.
METHODS: We enrolled 102 patients for this investigation. The steady-state concentration was determined after patients maintained a consistent PER dosing regimen for at least 21 days. Plasma PER concentrations were measured using liquid chromatography-tandem mass spectrometry. Leftover samples from standard therapeutic drug monitoring were allocated for genotyping analysis. The primary measure of efficacy was the rate of seizure reduction with PER treatment at the final check-up.
RESULTS: The CYP3A4×10 GC phenotype exhibited the highest average plasma concentration of PER at 491.1 ± 328.1 ng/mL, in contrast to the CC phenotype at 334.0 ± 161.1 ng/mL. The incidence of adverse events was most prominent in the CYP3A4×1 G TT and CYP3A4×10 GC groups, with rates of 77.8 % (7 of 9 patients) and 50.0 % (46 of 92 patients), respectively. Moreover, the percentage of patients for whom PER was deemed ineffective was least in the CYP3A4×1 G TT and CYP3A4×10 CC groups, recorded at 11.1 % (1 of 9 patients) and 10.0 % (1 of 10 patients), respectively. There was a significant correlation between PER plasma concentration and either exposure or toxicity (both with p < 0.05). We suggest a plasma concentration range of 625-900 ng/mL as a suitable reference for PER in Chinese patients with epilepsy.
CONCLUSIONS: The CYP3A4×10 gene\'s genetic polymorphisms influence plasma concentrations of PER in Chinese pediatric patients with epilepsy. Given that both efficacy and potential toxicity are closely tied to plasma PER levels, the CYP3A4 genetic phenotype should be factored in when prescribing PER to patients with epilepsy.

Managing epilepsy in the context of intellectual disability can be complicated as this population is known to have higher rates of drug resistance and sensitivity to side effects of antiseizure medications (ASMs). Perampanel is a novel ASM recently approved as an adjunctive treatment for drug resistant focal seizures. It carries a black-box warning for serious psychiatric and behavioral adverse reactions of aggression, irritability, et cetera. However, psychosis is a seldom reported side effect of perampanel. We herein describe a case of a 15-year-old girl with moderate intellectual disability who presented with refractory seizures managed successfully after using perampanel. Around 2 months later, she developed psychosis and aggression. The patient\'s history lacked any significant family or personal history of mental illness. Managing psychotic symptoms was difficult in this case; as perampanel was needed for proper seizure control, and both psychosis and seizures were severe and significantly endangering the patient and people around her. Thus, symptoms were addressed by adding a low-dose risperidone, an atypical antipsychotic. This paper highlights the importance of pre-treatment counselling and monitoring for the emergence of psychiatric side effects including the rarely occurring psychosis while using perampanel, particularly in highly sensitive patients, e.g., those with intellectual disability. We also emphasize on the importance of accurate weighing of risks and benefits while managing psychosis as an adverse event to ASMs in the background of drug-resistant epilepsy.

OBJECTIVE: To examine the efficacy and safety of perampanel (PER) in patients with post-stroke epilepsy (PSE), brain tumor-related epilepsy (BTRE), and post-traumatic epilepsy (PTE) using Japanese real-world data.
METHODS: The prospective post-marketing observational study included patients with focal seizures with or without focal to bilateral tonic-clonic seizures who received PER combination therapy. The observation period was 24 or 52 weeks after the initial PER administration. The safety and efficacy analysis included 3716 and 3272 patients, respectively. This post hoc analysis examined responder rate (50% reduction in seizure frequency), seizure-free rate (proportion of patients who achieved seizure-free), and safety in patients included in the post-marketing study who had PSE, BTRE, and PTE in the 4 weeks prior to the last observation.
RESULTS: Overall, 402, 272, and 186 patients were included in the PSE, BTRE, and PTE subpopulations, and 2867 controls in the \"Other\" population (etiologies other than PSE, BTRE, or PTE). Mean modal dose (the most frequently administered dose) values at 52 weeks were 3.38, 3.36, 3.64, and 4.04 mg/day for PSE, BTRE, PTE, and \"Other,\" respectively; PER retention rates were 56.2%, 54.0%, 52.6%, and 59.7%, respectively. Responder rates (% [95% confidence interval]) were 82% (76.3%-86.5%), 78% (70.8%-83.7%), 67% (56.8%-75.6%), and 50% (47.9%-52.7%) for PSE, BTRE, PTE, and \"Other,\" respectively, and seizure-free rates were 71% (64.5%-76.5%), 62% (54.1%-69.0%), 50% (40.6%-60.4%), and 28% (25.8%-30.1%), respectively. Adverse drug reactions tended to occur less frequently in the PSE (14.7%), BTRE (16.5%), and PTE (16.7%) subpopulations than in the \"Other\" population (26.3%).
CONCLUSIONS: In real-world clinical conditions, efficacy and tolerability for PER combination therapy were observed at low PER doses for the PSE, BTRE, and PTE subpopulations.
CONCLUSIONS: To find out how well the medication perampanel works and whether it is safe for people who have epilepsy after having had a stroke, brain tumor, or head injury, we used information from real-life medical situations in Japan. We looked at the data of about 3700 Japanese patients with epilepsy who were treated with perampanel. We found that perampanel was used at lower doses and better at controlling seizures, and had fewer side effects for patients with epilepsy caused by these etiologies than the control group.

Perampanel belongs to a novel class of antiseizure medications (ASMs). Studies examining the effect of hemodialysis on perampanel serum levels in clinical settings are lacking. We aimed to evaluate the changes in serum perampanel levels during hemodialysis. We studied patients with seizures who received oral perampanel between April 2020 and March 2023 and whose serum concentration of perampanel was measured before and after hemodialysis. We analyzed the serum concentrations of levetiracetam and lacosamide for comparison. Fourteen patients, with a mean age of 76.1 ± 7.88 years, were included. The dose of perampanel was 2.14 ± 1.27 mg. The hemodialysis clearance rate of perampanel, levetiracetam, and lacosamide was 0 ± 13%, 69 ± 11%, and 59.6 ± 8.2%, respectively. The post-dialysis CD ratio decreased significantly with levetiracetam but not with perampanel. Adverse but acceptable effects of perampanel were observed in two patients. The serum concentrations of several ASMs have been shown to be reduced during hemodialysis. Our study revealed that the serum perampanel concentration does not decrease during hemodialysis. Owing to the low rate of adverse effects and the stability of perampanel serum concentration during hemodialysis, perampanel could be a favorable choice as an ASM for patients with seizures undergoing hemodialysis. PLAIN LANGUAGE SUMMARY: Our study looked at how hemodialysis affects the serum levels of perampanel, a new type of medication for seizures. In 14 patients who started treatment between April 2020 and March 2023, perampanel serum levels did not decrease during hemodialysis, unlike other seizure medications. This shows that perampanel can be a good option for patients with seizures who need hemodialysis, with fewer side effects compared to other medications.

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.

OBJECTIVE: Giant somatosensory evoked potentials (SEPs) are observed in patients with cortical myoclonus. Short-latency components (SLC), are regarded as evoked epileptic activities or paroxysmal depolarization shifts (PDSs). This study aimed to reveal the electrophysiological significance of the middle-latency component (MLC) P50 of the SEPs.
METHODS: Twenty-two patients with cortical myoclonus having giant SEPs (patient group) and 15 healthy controls were included in this study. Waveform changes in SEPs before and after perampanel (PER) treatment were evaluated in the patient group. The wide range, time-frequency properties underlying the waveforms were compared between the groups.
RESULTS: After PER treatment, SLC was prolonged and positively correlated with PER concentration, whereas MLC showed no correlation with PER concentration. Time-frequency analysis showed a power increase (156 Hz in all patients, 624 Hz in benign adult familial myoclonus epilepsy patients) underlying SLC and a power decrease (156 Hz, 624 Hz) underlying MLC in the patient group.
CONCLUSIONS: The high-frequency power increase in SLCs and decrease in MLCs clearly reflected PDS and subsequent hyperpolarization, respectively. This relationship was similar to that of interictal epileptiform discharges, suggesting that giant SEPs evoke epileptic complexes of excitatory and inhibitory components.
CONCLUSIONS: MLCs of giant SEPs reflected inhibitory components.

OBJECTIVE: We aimed to identify factors that contribute to the discontinuation of perampanel.
METHODS: We retrospectively analyzed patients with epilepsy at the Department of Psychiatry, Hokkaido University Hospital. We evaluated the factors contributing to perampanel discontinuation as primary outcomes using Cox proportional hazards regression. Then, we explored the components contributing to the primary outcomes using logistic regression analysis.
RESULTS: A total of 118 patients were included, 44.9% of whom discontinued participation, 22.0% had intellectual disability, and 23.7% had a psychiatric disorder other than intellectual disability. Adverse effects occurred in 65% of the patients, 23.7% had psychiatric adverse effects (PAE), and 49.2% had common adverse effects (CAE). The effect of PER to suppress seizures was confirmed in 65.3% of them. Discontinuation was influenced by non-response (Hazard Ratio (HR) 6.70, 95% Confidence Interval (CI) 3.42-13.1), the occurrence of PAE (HR 3.68, 95% CI 1.89-7.16), CAE (HR 1.90, 95% CI 1.06-3.41), and comorbid psychiatric disorders (HR 2.35, 95% CI 1.21-4.59). Moreover, comorbid intellectual disability correlated with a low risk of PAE (OR 0.19, 95% CI 0.04-0.89).
CONCLUSIONS: The discontinuation of perampanel is influenced by poor efficacy and the occurrence of common/psychiatric adverse effects. The discontinuation of perampanel is influenced by poor efficacy and the occurrence of common/psychiatric adverse effects. Consideration of factors contributing to perampanel discontinuation may assist in determining the indication for perampanel treatment.

OBJECTIVE: To determine if insomnia-related factors differ depending on the presence of depression in patients with epilepsy.
METHODS: This cross-sectional multicenter study collected data on depressive symptoms, insomnia symptoms, and excessive daytime sleepiness, which were defined as a Patient Health Questionnaire-9 (PHQ-9) score of ≥ 10, an Insomnia Severity Index (ISI) score of ≥ 15, and an Epworth Sleepiness Scale (ESS) of ≥ 11, respectively. Further, uncontrolled seizures were defined as one or more seizures per month during antiseizure medications treatment. A stepwise logistic regression analysis was conducted, with a logistic regression with interaction terms performed to identify differences in insomnia-related factors depending on depressive symptoms.
RESULTS: Of 282 adults with epilepsy (men, 58 %; mean age, 40.4 ± 13.9 years), a PHQ-9 score ≥ 10, an ISI score ≥ 15, an ESS score ≥ 11 were noted in 23.4 % (n = 66), 20.2 % (n = 57), and 12.8 % (n = 36), respectively. More patients with depressive symptoms had an ISI score ≥ 15 (56.1 % vs. 9.3 %; p < 0.001) than those without. In multiple logistic regression, uncontrolled seizures (odds ratio [OR], 4.896; p < 0.01), daytime sleepiness (OR, 5.369; p < 0.05), and a history of psychiatric disorders (OR, 3.971; p < 0.05) were identified as significant factors that were more likely to be associated with an ISI score ≥ 15; however, this was only true in patients without depressive symptoms. In contrast, use of perampanel (OR, 0.282; p < 0.05) was less likely associated, while female sex (OR, 3.178; p < 0.05) was more likely associated with an ISI score ≥ 15 only in patients with depressive symptoms.
CONCLUSIONS: Insomnia-related factors in patients with epilepsy may differ between patients with and without depression. Our findings of different insomnia-related factors based on the presence of depression may facilitate the management of patients with epilepsy.

BACKGROUND: Status epilepticus (SE) is a medical emergency associated with a significant risk of disability and death. The treatment of SE follows a step-wise approach, with limited data on ideal antiseizure medications (ASMs) for refractory and super refractory SE (RSE/SRSE). Perampanel (PER), an AMPA receptor antagonist, has shown promise in animal models but still has limited data in humans. This study tried to evaluate optimal dosage and safety of PER in RSE and SRSE patients.
METHODS: We retrospectively analysed 17 adult patients with RSE (1) or SRSE (16) treated with PER. Demographic and clinical data, including EEG patterns, ASMs administered, PER dosages, and PER plasma concentrations, were collected. For patients receiving a 24 mg PER loading dose (full dose group), the following treatment regimen was applied: 24 mg per day for 48 h following by 16 mg per day. The response to PER was assessed based on electroencephalographic (EEG) improvement from high to low epileptiform activity or from low to the absence of epileptiform activities. Safety was evaluated monitoring hepatic and renal function.
RESULTS: A response rate of 58.82 % was observed, with significantly higher responses in the full dose group (81.82 %) compared to those receiving PER doses below 24 mg (low dose group) (16.67 %) (p-value = 0.004; OR 0.044, 95 % CI 0.003 to 0.621, p = 0.021). No other clinical factors significantly influenced treatment response. Hepatic enzymes become elevated in most patients (70.59 %) but spontaneously decreased.
CONCLUSIONS: Our findings suggest that a 24 mg PER dose administered for 48 h may be more effective in managing RSE and SRSE compared to doses below 24 mg, potentially due to pharmacokinetic factors.
CONCLUSIONS: More robust data on PER in RSE and SRSE, including standardized dosing procedures and plasma level monitoring are needed. PER\'s potential benefits should be explored further, particularly in patients with RSE and SRSE.

Perampanel (PER) is an antiseizure medication (ASM) with a unique mechanism of action, which was approved in Japan for use in combination therapy in 2016 and as a monotherapy in 2020. It has exerted antitumor effects against several types of tumors in vitro. However, the efficacy of PER monotherapy for seizure control is not well-established in patients with brain tumor. In the present study, 25 patients with brain tumor treated using PER monotherapy at our institution were analyzed and compared with 45 patients treated using the most commonly prescribed ASM, levetiracetam (LEV). The PER group was younger and had a higher frequency of glioma cases. During drug administration, seizures were observed in two patients from the PER group (8.0%) and five patients from the LEV group (11.1%); however, the difference was not significant. The incidence of adverse effects did not significantly differ between the groups (12.0 and 2.2%, respectively). In the PER group, mild liver dysfunction was observed in two patients and drug rash in one. In the LEV group, a drug-induced rash was observed in one patient. PER monotherapy may be safe and effective for seizure treatment or prophylaxis in patients with brain tumor. Further large-scale clinical studies are warranted.