Long-term efficacy and safety of adjunctive perampanel in patients from the Asia-Pacific region with refractory focal-onset seizures in Study 335 open-label extension.

OBJECTIVE: To evaluate the long-term efficacy, safety, and tolerability of adjunctive perampanel for the treatment of patients with refractory focal-onset seizures (FOS), with or without focal to bilateral tonic-clonic seizures (FBTCS), from the Asia-Pacific region. METHODS: Study 335 (NCT01618695) was a randomized, double-blind, placebo-controlled, Phase III study. Patients aged ≥12 years with refractory FOS who completed the Core Study could enter an open-label extension (OLEx) Phase (6-week Conversion and ≥46-week Maintenance Period). Endpoints included median percent reduction in seizure frequency per 28 days, 50% responder and seizure-freedom rates, and treatment-emergent adverse events (TEAEs). RESULTS: The Intent-to-Treat Analysis Set included 704 patients (529 received perampanel and 175 received placebo during the Core Study; all patients received perampanel during OLEx). The median percent reduction in seizure frequency and 50% responder rates in patients who received perampanel during the Core Study were maintained throughout the OLEx Phase (Week 64-75: 55.9% and 54.3%, respectively). Seizure freedom for ≥12 consecutive months at any time during perampanel treatment was achieved by 4.1% of patients with FOS and 14.2% of patients with FBTCS. Among patients treated with perampanel 4 mg/day (n = 83), median reduction in seizure frequency was lower in those who received concomitant enzyme-inducing anti-seizure medications (EIASMs) than those who received non-EIASMs. The most common TEAE was dizziness (n = 318; 46.8%); 141 (20.8%) patients had TEAEs that led to study/drug withdrawal. SIGNIFICANCE: Overall, long-term seizure control was achieved with adjunctive perampanel in patients with refractory FOS, with or without FBTCS, in an Asia-Pacific population.

Status of epilepsy care delivery and referral in clinics, hospitals, and epilepsy centers in Japan: A nationwide survey.

OBJECTIVE: Collaboration among medical facilities is crucial to deliver comprehensive epilepsy care to a diverse and large population of people with epilepsy. We conducted a survey among medical facilities of various sizes throughout Japan to investigate the status of epilepsy care delivery, functioning, and referral. METHODS: With the cooperation of the Japan Neurological Society (1428 facilities), Japanese Neurosurgical Society (3489 specialists), and Epilepsy Care Network (948 facilities), a questionnaire was mailed to 5865 locations that provide epilepsy care in Japan. The facilities were classified into clinics (19 beds or less), small hospitals (SH, 20-199 beds), large hospitals (LH, 200 beds or more), and epilepsy centers (EC). The status of epilepsy care delivery, functioning, and referral was compared among the four groups. RESULTS: Responses were received from 1014 facilities (17.3% response rate). After excluding duplicate responses, 957 facilities were analyzed (394 clinics, 149 SH, 388 LH, 26 EC). EC responded "manageable" in more items of epilepsy care functions in general, especially those related to epilepsy surgery, compared to LH with similar facility size. However, EC responded being less manageable in psychiatric service (61.5%), dietary therapy (46.2%), rehabilitation (53.8%), and patient employment support (61.5%). The percentage of facilities that responded "always able to refer" was highest in clinics (67.6%) and the lowest in EC (40%). Referral difficulties were more commonly encountered in EC, and less common in clinics. In EC, the most common reason for inability to refer was patient or family refusal (64%). SIGNIFICANCE: We have clarified the epilepsy care delivery, functioning, and referral in facilities of various sizes in Japan. This study highlights the issues of downward referral and patient stagnation in EC, which have not received much attention. PLAIN LANGUAGE SUMMARY: A nationwide survey of healthcare facilities ranging in size from small clinics to large hospitals in Japan examined medical care delivery and patient referrals related to epilepsy. Compared to other facilities, epilepsy centers provided a variety of medical services to people with epilepsy but were inadequate in addressing psychiatric symptoms, providing dietary therapy, rehabilitation, and patient employment support. Referrals from epilepsy centers to other medical facilities were often refused by patients and their families. This results in patient crowding at epilepsy centers.

Localized focal cortical dysplasia type II: seizure freedom with lesionectomy guided by MRI and FDG-PET.

OBJECTIVE: The authors perform thorough, noninvasive presurgical evaluations for intractable epilepsy at their center and avoid unnecessary intracranial EEG when possible. The purpose of this study was to clarify the appropriateness of their lesion-oriented surgical strategy for localized focal cortical dysplasia (FCD) type II. METHODS: Fifty-one patients with pathologically proven localized FCD type II who were followed for at least 1 year after surgery were included. Patients with FCD type II with lobar or multilobar distribution were excluded. The results of presurgical evaluations, including thin-slice 3-T MRI, FDG-PET, and ictal SPECT, as well as surgical procedures and postoperative seizure and functional outcomes, were examined retrospectively. RESULTS: MRI was positive in 46 (90%) of 51 patients, and FDG-PET revealed localized hypo- or hypermetabolism in 47 (92%) of 51 patients. Ictal SPECT revealed concordant hyperperfusion in 37 of 42 patients examined. Intracranial EEG was used in only 13 patients (25%), including 5 with negative MRI results and 4 with subtle MRI findings. Of the 15 patients with FCD in the vicinity of eloquent (sensorimotor and language) areas, intracranial EEG was used in 4. Lesionectomy was performed in all 51 patients. Intraoperative electrocorticography (ECoG) was performed in 8 patients, but the findings were not used to tailor the extent of resection. Postoperative seizure outcomes were Engel class I in 47 patients (92%) and Ia in 45 (88%). In the 15 patients with FCD in the vicinity of eloquent areas, 13 (87%) achieved a class I outcome. Predictive factors for favorable seizure outcome were complete resection of the MRI lesion (p = 0.006) and frontal lobe surgery (p = 0.012). Postoperative neurological deficits were noted in only 4 (27%) of 15 patients with FCD in the vicinity of eloquent areas. All 5 MRI-negative patients achieved an Engel class I outcome. CONCLUSIONS: In most of the patients with localized FCD type II, MRI and/or FDG-PET detected the localized abnormality. Lesionectomy without intracranial EEG led to seizure freedom in most cases. Even when lesions were in the vicinity of eloquent areas, seizure and functional outcomes were favorable. Intraoperative ECoG may thus be unnecessary. Complete resection of the lesion is essential for favorable seizure outcome in MRI-positive patients. In MRI-negative patients, surgery with intracranial EEG guided by FDG-PET provided seizure-free outcomes.

Effects of low-dose titration on the tolerability and safety of perampanel.

PURPOSE: To evaluate the effects of low-dose titration on the tolerability and safety of perampanel. METHODS: We retrospectively reviewed the records of 1065 patients who started perampanel therapy and compared the incidence of adverse events after standard titration (Group A: starting dose, 2 mg/day; titration speed, 2 mg/2 weeks or longer) and low-dose titration (Group B: starting dose, < 1 mg/day; titration speed, < 1 mg/2 weeks or longer). RESULTS: Adverse events were reported in 158 patients (14.8%) within the initial first 90 days of starting perampanel (mean concentration, 331 ng/mL). At 90 days, the cumulative incidence of adverse events was significantly higher in Group A than in Group B (24.5% vs. 16.3%, respectively; log-rank test p < 0.001). A Cox proportional hazards model also showed that low-dose titration decreased the incidence risk of adverse events (adjusted hazard ratio, 0.49; 95% confidence interval, 0.35-0.69). When the groups were stratified by use of enzyme-inducing antiseizure medications (inducers), Group A patients without inducers had a significantly higher cumulative incidence of adverse events than the other three subgroups (26.7%, p < 0.001). In patients taking 2 mg of perampanel, median concentrations in patients with or without inducers were 43 ng/mL and 204 ng/mL, respectively. CONCLUSION: Perampanel is generally initiated at 2 mg, but serum perampanel concentrations show substantial interindividual variation. Our study suggests that care must be taken when setting the starting dose of perampanel. In particular, low-dose titration is recommended in patients not taking inducers.

[Psychiatric Symptoms of Patients With Epilepsy: Characteristics of Psychiatric Adverse Events by Novel Antiepileptic Medications].

Patients with epilepsy often show treatment-related psychiatric symptoms. Among the novel antiseizure medications (ASM), Perampanel (PER), Levetiracetam (LEV), and Topiramate (TPM) have been reported to have a relatively high frequency of psychiatric adverse events. However, these psychiatric symptoms are not identical; PER and LEV show adverse events of irritability and aggression, while TPM shows typical symptoms of depression and schizophrenia. It is important to understand the characteristics of these psychiatric adverse events to design appropriate treatment regimens for epileptic patients. (Received August 1, 2022; Accepted December 24, 2022; Published April 1, 2023).

Periictal water drinking revisited: Occurrence and lateralizing value in surgically confirmed patients with focal epilepsy.

OBJECTIVE: Periictal water drinking (PIWD), which is a rare seizure-related autonomic behavior, has been reported in temporal lobe epilepsy (TLE) but only rarely in extra-TLE. Additionally, the lateralizing value of PIWD is controversial. We aimed to clarify the occurrence and lateralizing value of PIWD in patients with focal epilepsy. METHODS: This retrospective study included 240 focal epilepsy patients aged >10 years with a favorable postoperative seizure outcome (Engel class I). PIWD was defined as water drinking behavior during a seizure or within 2 min in the postictal phase. The occurrence of PIWD documented on video-electroencephalogram monitoring was assessed. The lateralizing value of PIWD was analyzed among patients whose language dominant hemisphere was identified. RESULTS: Twenty-three (9.5%) patients exhibited PIWD. PIWD occurred more frequently in frontal lobe epilepsy (FLE; eight of 41 patients, 19.5%) than in TLE (15 of 188 patients, 8%). The occurrence of PIWD was significantly different between FLE and extra-FLE (P = 0.035), with a low positive predictive value (34.8%). In FLE with PIWD, all but one patient underwent resective surgery involving the medial frontal lobe. In 194 patients whose language dominant hemisphere was determined, the lateralizing value of PIWD in FLE and TLE showed no statistical significance (P = 0.69 and P = 0.27, respectively). SIGNIFICANCE: Periictal water drinking occurred more often in FLE than TLE. Thus, PIWD might not be a specific periictal symptom in TLE. There was no evidence for the lateralizing value of PIWD in FLE and TLE. These findings can provide useful clinical clues for preoperative evaluations to estimate the epileptogenic zone based on seizure semiology and allow for a better understanding of pathophysiological insights into PIWD.

A Single-center Analysis of Three Japanese Patients with Mahjong-related Seizures.

Mahjong is one of the most popular Chinese tile games played in Japan. Mahjong-related seizures (MRS) are rare praxis-induced seizures. We identified three patients with MRS from February 2000 to February 2021. All cases were men, with a middle-age onset, generalized convulsive seizures, and lack of non-provoked, myoclonic, and absence seizures. All patients had no or non-specific neuroimaging or electroencephalogram abnormalities. They did not have features linked to idiopathic generalized epilepsy. All patients were seizure-free after behavioral adjustments, although one patient required anti-seizure medication and avoided long duration games. These changes may help other patients with MRS continue playing Mahjong.

Impact of COVID-19 pandemic on epilepsy care in Japan: A national-level multicenter retrospective cohort study.

OBJECTIVE: The impact of the coronavirus disease 2019 (COVID-19) pandemic on epilepsy care across Japan was investigated by conducting a multicenter retrospective cohort study. METHODS: This study included monthly data on the frequency of (1) visits by outpatients with epilepsy, (2) outpatient electroencephalography (EEG) studies, (3) telemedicine for epilepsy, (4) admissions for epilepsy, (5) EEG monitoring, and (6) epilepsy surgery in epilepsy centers and clinics across Japan between January 2019 and December 2020. We defined the primary outcome as epilepsy-center-specific monthly data divided by the 12-month average in 2019 for each facility. We determined whether the COVID-19 pandemic-related factors (such as year [2019 or 2020], COVID-19 cases in each prefecture in the previous month, and the state of emergency) were independently associated with these outcomes. RESULTS: In 2020, the frequency of outpatient EEG studies (-10.7%, p<0.001) and cases with telemedicine (+2,608%, p=0.031) were affected. The number of COVID-19 cases was an independent associated factor for epilepsy admission (-3.75*10-3 % per case, p<0.001) and EEG monitoring (-3.81*10-3 % per case, p = 0.004). Further, the state of emergency was an independent factor associated with outpatient with epilepsy (-11.9%, p<0.001), outpatient EEG (-32.3%, p<0.001), telemedicine for epilepsy (+12,915%, p<0.001), epilepsy admissions (-35.3%; p<0.001), EEG monitoring (-24.7%: p<0.001), and epilepsy surgery (-50.3%, p<0.001). SIGNIFICANCE: We demonstrated the significant impact that the COVID-19 pandemic had on epilepsy care. These results support those of previous studies and clarify the effect size of each pandemic-related factor on epilepsy care.

Electroclinical features of seizures in myelin oligodendrocyte glycoprotein antibody-associated cerebral cortical encephalitis: A case report and literature review.

PURPOSE: Myelin oligodendrocyte glycoprotein (MOG) antibodies (Abs) are associated with various central nervous system demyelinating disorders. Recently, they were detected in cerebral cortical encephalitis (CCE), which often causes seizures. We performed a literature review to elucidate the electroclinical features of CCE. In addition to the published cases, we describe a new, illustrative case of MOG-Ab-associated CCE (MOG-CCE) with multifocal seizures documented by video electroencephalograph (EEG). METHODS: We searched PubMed with the keywords "[MOG] AND [encephalitis]" and reviewed relevant articles. The articles included reports of patients with CCE (as demonstrated by magnetic resonance imaging) and serum MOG Ab positivity. Cases were excluded if no epileptic seizures were reported or if details of the seizures were unavailable. RESULTS: Our literature review identified 34 patients with MOG-CCE. An analysis of these 34 cases and the new case showed that 20 patients were male (57.1%), and the median age at presentation was 23 years (range, 6 to 46 years). Focal to bilateral tonic-clonic seizure was the most common seizure type, followed by focal motor seizure in the face or an arm or leg. EEG findings were available for 26 patients. Interictal epileptiform discharges (IEDs) and ictal EEG patterns were seen in 10 (38.5%) and 5 (19.2%) patients, respectively. Focal EEG abnormalities, including slow waves and IEDs, were observed in the central, parietal, occipital, or posterior temporal region. CONCLUSION: MOG-CCE has distinctive electroclinical features that differ from those of other autoimmune encephalitides. Careful electroclinical analysis of seizures can be helpful for diagnosing MOG-CCE.

Risk factors for psychiatric adverse effects associated with perampanel therapy.

PURPOSE: To identify the risk factors for psychiatric adverse effects associated with perampanel therapy. METHODS: We retrospectively evaluated the adverse effects of perampanel by reviewing clinical records from 895 Japanese patients with epilepsy (aged 1-86 years) who started perampanel therapy at National Epilepsy Center, Shizuoka, Japan, between June 2016 and December 2019. Patients were classified into 3 groups: those without adverse effects (Group I), those with psychiatric adverse effects (Group II), and those with common adverse effects (Group III). RESULTS: The number of patients assigned to each group was as follows: Group I, n = 641; Group II, n = 93; and Group III, n = 161. The mean follow-up period was 458 ±â€¯265 days (median, 511 days). Kaplan-Meier survival estimates showed that the median time to treatment failure was shorter in Group II than in Group III (294 vs. 392 days, respectively; log-rank test, p < 0.001). According to polytomous logistic regression, younger age (<16 years) was associated with a lower risk of common and psychiatric adverse effects. The risk factors for psychiatric adverse effects (Group II) were intellectual disability (adjusted odds ratio [AOR], 2.6; 95% confidence interval (CI), 1.5-4.5) and psychiatric comorbidity (AOR, 3.8; 95% CI, 2.3-6.3); in patients with intellectual disability, the occurrence of psychiatric adverse effects was concentration dependent. Patients with lamotrigine use had a 0.54-fold lower risk of psychiatric adverse effects. In Group III, concomitant use of inducers was associated with a decreased risk of common adverse effects (AOR, 0.68; 95% CI, 0.46-0.99). SIGNIFICANCE: We found clear differences in the risk factors for psychiatric adverse effects. In patients with intellectual disability, care must be taken when titrating perampanel, and therapeutic drug monitoring should be performed.

Psychiatric outcome of temporal lobe epilepsy surgery: A prospective, 2-year follow-up study.

OBJECTIVE: We performed a prospective, longitudinal, 2-year follow-up study to clarify psychiatric courses and outcomes after temporal lobe epilepsy surgery. METHODS: We assessed 141 patients (68 men, 73 women) aged 16 or older with structured interviews and psychiatric rating scales before surgery and 3 months, 1 year, and 2 years afterward. RESULTS: Fifty-two patients (36.9%) had a psychiatric condition before surgery or during the follow-up period or both. The number of patients with a psychiatric condition decreased from 31 (22.0%) before surgery to 14 (9.9%) at 2 years. On the basis of our results, we defined 5 courses of psychiatric conditions: course 0, no psychopathology (n = 89, 63.1%); course 1, remission or resolution of a presurgical psychiatric condition after surgery (n = 19, 13.5%); course 2, new onset, transient psychiatric condition after surgery (n = 19, 13.5%); course 3, new onset, persistent psychiatric condition after surgery (n = 2, 1.4%); and course 4, chronic psychiatric condition before and after surgery (n = 12, 8.5%). In 14/25 (56.0%) patients with a mood or anxiety disorder before surgery, the condition remitted or resolved after surgery (course 1). Eighteen of 110 patients (16.4%) without any psychopathology before surgery developed mood or anxiety disorders afterward, including major depressive disorder in 13 patients (courses 2 and 3); in more than half of these patients, the disorder manifested within 1 year. More patients with a past history of psychiatric conditions were found in course 2 than in course 0. The duration of epilepsy was longer in course 4 than in course 0, and age at epilepsy onset was lower in course 4 than in course 0. SIGNIFICANCE: Most patients with a psychiatric condition show a favorable outcome 2 years after surgery; however, some show a transient worsening or new onset of psychiatric conditions, in particular depression.

Pharmacokinetics, tolerability, and clinical effectiveness of perampanel in Japanese patients with epilepsy.

OBJECTIVE: We aimed to evaluate the influence of concomitant antiepileptic drugs (AEDs) on serum perampanel concentration and to correlate the concentration with clinical response and tolerability. METHODS: A total of 4224 serum samples were obtained from 763 pediatric, adolescent, and adult patients for routine therapeutic drug monitoring. We compared the extent of enzyme induction between cytochrome P450 3A4 (CYP3A4) inducer regimens and built a statistical model to estimate the serum perampanel concentration that considered use of CYP3A4 inducers and inhibitors. To assess the tolerability and clinical effectiveness of perampanel therapy, we used the nested case-control approach. The case group was matched with the control group for age, sex, epilepsy type, and perampanel exposure periods. RESULTS: Concomitant use of the inducers phenytoin, carbamazepine, and phenobarbital dose-dependently reduced the perampanel concentration by 51 %, 67 %, and 37 %, respectively. The estimate model showed a good correlation between the predicted and measured concentrations (r2 = 0.62, p < 0.001). In 206 patients, the seizure reduction from baseline was > 50 % and the median perampanel concentration was 351 ng/mL (interquartile range, 191-603 ng/mL). Adverse events, such as somnolence, dizziness, and irritability, were experienced by 185 patients. The responder odds ratio was 5.1-fold higher in patients with a serum concentration > 600 ng/mL than in those with a serum concentration < 200 ng/mL; however, the former group had a 7.9-fold higher incidence of adverse events. CONCLUSION: Therapeutic drug monitoring is clinically useful to assess drug interactions between perampanel and CYP3A4 inducers and inhibitors. We recommend that the target concentration of perampanel is initially set at 200-600 ng/mL. Serum concentrations > 600 ng/mL were associated with greater anti-seizure effects but had an increased risk of adverse events.

Nurse teachers' knowledge about epilepsy and communication issues between schools and medical institutions: A nationwide questionnaire survey in Japan.

OBJECTIVE: The importance of school teachers' knowledge of and attitudes toward epilepsy and the communication between educational and medical systems is widely appreciated, but exploration of these factors in Japan has been extremely limited. In order to identify issues in support systems for students with epilepsy and bridge the gaps in communication between schools and medical institutions in Japan, we performed a nationwide questionnaire survey of nurse teachers (nurses in charge of health education/care at schools). METHODS: We mailed a questionnaire to 900 nurse teachers all over Japan. It included six items on general epilepsy knowledge and 15 items on information about each student with epilepsy in their schools. We used a modified grounded theory approach (M-GTA) to analyze open-ended questions. RESULTS: We received responses from 640 (71.1%) nurse teachers. In their schools, there were 237 253 students, of whom 1565 had epilepsy. Most nurse teachers (84.7%) understood that epilepsy is a neurological disease. When performing first aid for a seizure, they would observe the seizure calmly (85.9%) and/or secure the airway (75.3%). There were 1398 responses about individual students with epilepsy (89.3%). Nurse teachers knew the seizure type in 70.0% of these students, seizure frequency in 76.8%, triggers in 38.9%, and appropriate first aid for 79.0%. Some nurse teachers (30.2%) obtained information on students with epilepsy from medical institutions. They knew more about their students' seizures than those without medical information. Existing forms for communicating information on students with epilepsy between schools and physicians were not actively utilized. Responses to open questions converged on safety at school. SIGNIFICANCE: Japanese nurse teachers understand epilepsy relatively well, but do not fully grasp the condition of each student with epilepsy. Better information flow from medical institutions is needed. Active communication is necessary to support the safety of students with epilepsy at school.

Seizures, accidental injuries at work, and reasons for resignation in people with epilepsy.

OBJECTIVE: Few studies have examined seizures, accidental injuries at work, and reasons for resignation in people with epilepsy (PWE). We performed a questionnaire survey of PWE to identify the risk of injury at work, its relationship to different seizure characteristics, and reasons for resignation. METHODS: We distributed a questionnaire survey in the outpatient clinic of a single epilepsy center. Medical information was obtained retrospectively from medical records. RESULTS: Of 200 patients who received the questionnaire, 172 responded. Two-fifths of PWE had experienced seizures at work, but the risk of accidental injuries due to epileptic seizures was only 0.01 person/year (1.0%) and 0.018 injuries/year, whereas the risk of accidental injuries not related to seizures was 0.039 person/year (3.9%) and 0.083 injuries/year. All accidental injuries due to seizures at work were caused by seizures characterized by a fall and inappropriate behavior with impaired awareness. Most accidental injuries due to seizures at work were caused by seizures that occurred at least once a year. The types of injuries reported were bruising, abrasion, laceration, fracture, burn, and submersion injuries. A quarter of PWE had left previous jobs because of epilepsy, of these, about four-fifths reported that seizures at the workplace had interfered with their own or others' tasks. SIGNIFICANCE: The risk of seizure-related injury is not high compared to the risk of injury not related to seizures, and most injuries due to seizures are not severe. The features of seizures with a fall, impaired awareness, and inappropriate behavior, as well as seizure frequency, should be considered when evaluating the risks associated with seizures in the workplace. Most PWE who had left their previous job because of epilepsy had experienced seizures at the workplace interfering with their own or others' tasks.

Risks of seizure with fatal traffic crash at wheel in people with epilepsy.

PURPOSE: The Japanese authorities require a 2-year seizure-free period for a driver's license in people with epilepsy. To evaluate the stringency of the criteria, we calculated the risk of fatal traffic crashes by epileptic seizure and compared that to the risk of fatal traffic crashes among the general population. METHODS: Nation-wide questionnaire surveys to physicians and their patients with epilepsy were conducted to determine the rate of seizure recurrence after given seizure-free periods, average driving time and the rate of traffic crashes by epileptic seizures. The risk of fatal traffic crashes by epileptic seizures was calculated using the method proposed by the Driving License Committee of the EU. The risk of fatal traffic crashes among subgroups of the general population was calculated using the national statistics available. RESULTS: Valid answers were obtained from a total of 548 patients of 138 epilepsy-specialists and 102 non epilepsy-specialist physicians. The relative risks of fatal traffic crashes in people with epilepsy with 1-year and 2-year seizure-free periods were 1.22 and 1.15, compared to the general population, while the ones in males in their twenties, people aged 60 and over, people aged 65 and over, and people aged 75 and over among the general population were 1.71, 1.31, 1.52 and 2.69, respectively. CONCLUSION: The risk of fatal traffic crashes in people with epilepsy for 1-year and 2-year seizure-free periods was estimated to be lower than that of some age groups in the general population. The increased risk in 1-year seizure freedom from that in 2-year seizure freedom was relatively small.

PRRT2 mutations in Japanese patients with benign infantile epilepsy and paroxysmal kinesigenic dyskinesia.

PURPOSE: This study was performed to clarify the clinical features of Japanese patients with PRRT2 mutations. METHODS: The PRRT2 gene was analyzed in 135 patients with benign infantile epilepsy (BIE) or paroxysmal kinesigenic dyskinesia (PKD) using a direct sequencing method: 92 patients had BIE alone, 25 had both BIE and PKD, and 18 had PKD alone. Of the cases, 105 were familial, and 30 were sporadic. Clinical information was collected using a structured questionnaire. RESULTS: PRRT2 mutations were identified in 104 patients. Among the familial cases, PRRT2 mutations were found in at least one individual in 21 of 28 families with BIE alone, in 26 of 27 families with infantile convulsions and choreoathetosis, and in 2 of 3 families with PKD alone. Among the sporadic cases, PRRT2 mutations were observed in 7 of 25 patients with BIE alone, in 1 of 1 patient with BIE and PKD, and in 3 of 4 patients with PKD alone. The c.649dupC mutation was the most frequent, followed by the c.981C > G mutation. Among the patients with epilepsy, the median age at BIE onset was 5 months, the median age at the last seizure was 6 months, and the median number of seizures was 5. CONCLUSION: PRRT2 mutations were found in 68% of Japanese probands with BIE or PKD. The phenotypes of BIE associated with PRRT2 mutations were consistent with those of BIE diagnosed clinically.

Efficacy and safety of perampanel in generalized and focal to bilateral tonic-clonic seizures: A comparative study of Asian and non-Asian populations.

Perampanel is an approved adjunctive treatment for focal seizures with or without focal to bilateral tonic-clonic (FBTC) seizures and generalized tonic-clonic (GTC) seizures. We compared efficacy and safety of perampanel vs placebo in Asian and non-Asian populations in a post hoc analysis of pooled data from 5 randomized phase 3 studies. Patients (≥12 years old) with focal + FBTC seizures received perampanel 2, 4, 8, or 12 mg or placebo; patients with GTC seizures received perampanel 8 mg or placebo (titration: 4-6 weeks; maintenance: 13 weeks). Efficacy endpoints included median percentage change in FBTC or GTC seizure frequency per 28 days and 50% responder rate relative to baseline. Median percentage change in FBTC seizure frequency was significantly greater for perampanel 8 and 12 mg than placebo in the Asian population (median difference from placebo: -30.32%, P = 0.0017; -30.06%, P = 0.0008, respectively) and perampanel 4, 8, and 12 mg in the non-Asian population (-35.07%, P = 0.0001; -37.78%, P < 0.0001; -34.53%, P < 0.0001, respectively). In both populations, median percentage change in GTC seizure frequency was significantly greater for perampanel 8 mg than placebo (median difference from placebo: Asian, -37.37%, P = 0.0139; non-Asian, -27.04%, P = 0.0006). The 50% responder rates were significantly greater than placebo for perampanel 8 and 12 mg for FBTC seizures (Asian: 58.0%, P = 0.0017 and 58.6%, P = 0.0013, respectively; non-Asian: 59.3%, P < 0.0001 and 54.3%, P = 0.0050, respectively) and perampanel 8 mg for GTC seizures (Asian: 57.6%, P = 0.0209; non-Asian: 68.8%, P = 0.0329). Pooled FBTC/GTC seizure data showed generally similar patterns of response to perampanel in both populations. The most frequent treatment-related adverse events were fatigue, irritability, dizziness, somnolence, and headache. Perampanel was effective, well tolerated, and can be considered a therapeutic option for FBTC/GTC seizures in Asian populations.

Influence of Inflammation on the Pharmacokinetics of Perampanel.

BACKGROUND: It is well-known that the pharmacokinetics of various drugs are influenced by inflammation. This study evaluated the relationship between C-reactive protein (CRP; an inflammation marker) and the pharmacokinetics of perampanel. METHODS: Among 111 patients who underwent measurement of both CRP and perampanel, 23 patients had a serum CRP level exceeding 1.5 mg/dL (CRP-positive). We compared the concentration/dose ratio (CD ratio) of perampanel in these 23 patients between the times when they were CRP-positive and CRP-negative. To evaluate the effect of CRP on the CD ratio, multiple regression analysis was performed with the following covariates: CRP-positive status, body weight, and use of phenytoin, carbamazepine, or phenobarbital, and combinations of these drugs. RESULTS: In 10 patients using enzyme-inducing antiepileptic drugs (AEDs), the mean CD ratio increased by 53.5% [from 1389 to 2132 (ng/mL)/(mg/kg)] when they were CRP-positive. In 13 patients without enzyme-inducing AEDs, the mean CD ratio increased by 100.8% [from 3826 ng/mL to 7683 (ng/mL)/(mg/kg)] when they were CRP-positive. By multiple regression analysis, the CRP level was a significant independent determinant of the CD ratio of perampanel. Despite a marked increase of the CD ratio, no adverse events were reported. CONCLUSIONS: Irrespective of concomitant administration of enzyme-inducing AEDs, the serum perampanel concentration showed a marked increase in patients with inflammation. However, this increase was not associated with central nervous system toxicity. Although it is unknown whether the concentration of free and/or bound perampanel was increased, it seems likely that dose reduction is unnecessary for elevation of the serum perampanel level in patients with inflammation.

Influence of Renal Function on Pharmacokinetics of Antiepileptic Drugs Metabolized by CYP3A4 in a Patient With Renal Impairment.

BACKGROUND: Several studies have demonstrated that renal impairment not only decreases renal clearance but also hepatic clearance of medications that are CYP3A4 substrates. We evaluated the influence of renal function on the pharmacokinetics of antiepileptic drugs metabolized by CYP3A4. METHODS: We retrospectively calculated the concentration/dose ratio (CD ratio) for topiramate and clobazam in an epilepsy patient with renal impairment. In addition, we determined the CD ratio of perampanel in 17 patients with normal renal function and compared it with that in the patient with renal impairment. RESULTS: A patient with frontal lobe epilepsy and mild renal impairment [creatinine clearance (CCr): 67.7 mL/min] was taking phenytoin and 3 CYP3A4 substrates (topiramate, clobazam, and perampanel). With progression of renal impairment (CCr: 28.1 mL/min), the CD ratios of topiramate and clobazam increased by about 2-fold. The mean CD ratio of perampanel was 1740 ± 966 ng·mL·mg·kg in the 17 patients with normal renal function using phenytoin. By contrast, the CD ratio of perampanel was markedly higher (range: 5327-9113 ng·mL·mg·kg) in the patient with renal impairment (CCr: <20 mL/min). CONCLUSIONS: These findings suggest that dose adjustment based on therapeutic drug monitoring is probably necessary when topiramate, clobazam, or perampanel is prescribed for patients with moderate-to-severe renal impairment.

Therapeutic Drug Monitoring for Perampanel in Japanese Epilepsy Patients: Influence of Concomitant Antiepileptic Drugs.

BACKGROUND: Perampanel is a new antiepileptic drug (AED) that acts as a noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor antagonist and is mainly metabolized by cytochrome P450 (CYP) 3A4. This study evaluated the influence of concomitant AEDs on the serum concentration profile of perampanel. METHODS: A total of 215 serum samples obtained from 76 patients aged 12 years or older were analyzed for routine therapeutic drug monitoring, and the concentration-to-dose ratio (CD ratio) of perampanel was compared among patients on various AED regimens. RESULTS: In patients not taking concomitant enzyme-inducing AEDs, the mean CD ratio was 3963 ng·mL·mg·kg (range: 1793-13,299). By contrast, the mean CD ratio was lower in patients using enzyme-inducing AEDs [1760 (range: 892-3090), 2256 (range: 700-4703), and 1120 (range: 473-1853) ng·mL·mg·kg in patients taking phenytoin, phenobarbital, and carbamazepine, respectively], and carbamazepine had a significantly greater reduction in the CD ratio compared with phenytoin or phenobarbital (P < 0.001). Twenty-one patients responded with ≥50% reduction of seizure frequency from baseline, and their mean serum perampanel concentration was 450 ng/mL (range: 85-1500). CONCLUSIONS: There is a large interindividual variation in CD ratio of perampanel because its metabolism is highly susceptible to interactions with enzyme-inducing AEDs. Therapeutic drug monitoring could be clinically useful for determining the influence of AED CYP3A4 inducers on perampanel concentrations.