"According to new research on epilepsy, zebrafish have certainly earned their stripes. Results of a study in Nature Communications suggest that zebrafish carrying a specific mutation may help researchers discover treatments for Dravet syndrome "...
Mechanism Of Action
Perampanel is a non-competitive antagonist of the ionotropic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor on post-synaptic neurons. Glutamate is the primary excitatory neurotransmitter in the central nervous system and is implicated in a number of neurological disorders caused by neuronal over excitation.
The precise mechanism by which FYCOMPA exerts its antiepileptic effects in humans is unknown.
In a healthy volunteer study to assess the effects of FYCOMPA on psychomotor performance using a standard battery of assessments including simulated driving, single and multiple daily doses of FYCOMPA 4 mg did not impair simple psychomotor tasks, driving performance, or sensorimotor coordination. Single and multiple doses of 8 mg and 12 mg impaired psychomotor performance in a dose-related manner. Car handling ability was impaired after dosing of FYCOMPA 12 mg, but postural stability was not significantly impaired. Performance testing returned to baseline within 2 weeks of cessation of FYCOMPA dosing.
Interactions with Alcohol
In the above study (see Psychomotor Performance), when administered to healthy subjects receiving alcohol to achieve a blood concentration of 80-100 mg/100 mL, FYCOMPA consistently impaired simple psychomotor performance after single doses of 4 to 12 mg, and after 21 days of multiple 12 mg/day doses. The effects of FYCOMPA on complex tasks such as driving ability were additive or supra-additive to the impairment effects of alcohol. FYCOMPA enhanced the effects of alcohol on vigilance and alertness, and increased levels of anger, confusion, and depression.
Potential to Prolong QT Interval
In a placebo-controlled thorough QT study of perampanel in healthy subjects, there was no evidence that perampanel caused QT interval prolongation of clinical significance at doses of 6 or 12 mg (i.e., the upper bound of the 95% confidence interval for the largest placebo-adjusted baseline-corrected QTc was below 10 msec). The exposures observed with the 12 mg dose in this study will not cover the exposures expected in patients with hepatic impairment taking doses over 6 mg/day. At the highest recommended dose (12 mg), perampanel did not prolong the QTc interval to any clinically relevant extent.
Pharmacokinetics of perampanel are similar in healthy subjects, patients with partial-onset seizures, and patients with primary generalized tonic-clonic seizures. The half-life of perampanel is about 105 hours, so that steady state is reached in about 2-3 weeks. AUC of perampanel increased in a dose-proportional manner after single-dose administration of 0.2-12 mg and after multiple-dose administration of 1-12 mg once daily.
Perampanel is rapidly and completely absorbed after oral administration with negligible first-pass metabolism. Median Tmax ranged from 0.5 to 2.5 hours under fasted condition. Food does not affect the extent of absorption (AUC), but slows the rate of absorption. Under fed conditions, Cmax of perampanel was decreased by 28-40% and Tmax was delayed by 2-3 hours compared to that under fasted conditions.
Data from in vitro studies indicate that, in the concentration range of 20 to 2000 ng/mL, perampanel is approximately 9596% bound to plasma proteins, mainly bound to albumin and α1-acid glycoprotein. Blood to plasma ratio of perampanel is 0.55-0.59.
Perampanel is extensively metabolized via primary oxidation and sequential glucuronidation. Oxidative metabolism is primarily mediated by CYP3A4/5 and to a lesser extent by CYP1A2 and CYP2B6, based on results of in vitro studies using recombinant human CYPs and human liver microsomes. Other CYP enzymes may also be involved.
Following administration of radiolabeled perampanel, unchanged perampanel accounted for 74-80% of total radioactivity in systemic circulation, whereas only trace amounts of individual perampanel metabolites were detected in plasma.
Following administration of a radiolabeled perampanel dose to 8 healthy elderly subjects, 22% of administered radioactivity was recovered in the urine and 48% in the feces. In urine and feces, recovered radioactivity was primarily composed of a mixture of oxidative and conjugated metabolites. Population pharmacokinetic analysis of pooled data from 19 Phase 1 studies reported that t½ of perampanel was 105 hours on average. Apparent clearance of perampanel in healthy subjects and patients was approximately 12 mL/min.
The pharmacokinetics of perampanel following a single 1 mg dose were evaluated in 12 subjects with mild and moderate hepatic impairment (Child-Pugh A and B, respectively) compared with 12 demographically matched healthy subjects. The total (free and protein bound) exposure (AUC0-inf) of perampanel was 50% greater in subjects with mild hepatic impairment and more than doubled (2.55-fold) in subjects with moderate hepatic impairment compared to their healthy controls. The AUC0-inf of free perampanel in subjects with mild and moderate hepatic impairment was 1.8-fold and 3.3fold, respectively, of those in matched healthy controls. The t½ was prolonged in subjects with mild impairment (306 vs. 125 hours) and moderate impairment (295 vs. 139 hours). Perampanel has not been studied in subjects with severe hepatic impairment [see DOSAGE AND ADMINISTRATION, Use In Specific Populations].
A dedicated study has not been conducted to evaluate the pharmacokinetics of perampanel in patients with renal impairment. Population pharmacokinetic analysis was performed on pooled data from patients with partial-onset seizures and receiving FYCOMPA up to 12 mg/day in placebo-controlled clinical trials. Results showed that perampanel apparent clearance was decreased by 27% in patients with mild renal impairment (creatinine clearance 50-80 mL/min) compared to patients with normal renal function (creatinine clearance > 80 mL/min), with a corresponding 37% increase in AUC. Considering the substantial overlap in the exposure between normal and mildly impaired patients, no dosage adjustment is necessary for patients with mild renal impairment. Perampanel has not been studied in patients with severe renal impairment and patients undergoing hemodialysis [see DOSAGE AND ADMINISTRATION, Use In Specific Populations].
In a population pharmacokinetic analysis of patients with partial-onset and primary generalized tonic-clonic seizures receiving FYCOMPA in placebo-controlled clinical trials, perampanel apparent clearance in females (0.54 L/hr) was 18% lower than in males (0.66 L/hr). No dosage adjustment is necessary based on sex.
FYCOMPA has not been studied in patients less than 12 years of age. In a population pharmacokinetic analysis of pediatric patients 12 to 17 years of age with partial-onset seizures receiving FYCOMPA in placebo-controlled trials, apparent clearance of perampanel was 0.729 L/hr, slightly higher than that in adults. Pediatric patients 12 years of age and older can be dosed similarly to adults.
In a population pharmacokinetic analysis of patients with partial-onset seizures and primary generalized tonic-clonic seizures ranging in age from 12 to 74 years receiving FYCOMPA in placebo-controlled trials, no significant effect of age on perampanel apparent clearance was found [see DOSAGE AND ADMINISTRATION, Use In Specific Populations].
In a population pharmacokinetic analysis of patients with partial-onset seizures and primary generalized tonic-clonic seizures, which included 614 Caucasians, 15 Blacks, 4 Japanese, 4 American Indians/Alaska Natives, 79 Chinese and 108 other Asians receiving FYCOMPA in placebo-controlled trials, no significant effect of race on perampanel apparent clearance was found. No dosage adjustment is necessary.
Drug Interaction Studies
In Vitro Assessment of Drug Interactions
Drug Metabolizing Enzymes
In human liver microsomes, perampanel at a concentration of 30 μmol/L, about 10 fold the steady state Cmax at a 12 mg dose, had a weak inhibitory effect on CYP2C8, CYP3A4, UGT1A9, and UGT2B7. Perampanel did not inhibit CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, UGT1A1, UGT1A4, and UGT1A6 up to a concentration of 30 μmol/L.
Compared with positive controls (including phenobarbital and rifampin), perampanel was found to weakly induce CYP2B6 (30 μmol/L) and CYP3A4/5 ( ≥ 3 μmol/L) in cultured human hepatocytes. Perampanel also induced UGT1A1 ( ≥ 3 μmol/L) and UGT1A4 (30 μmol/L). Perampanel did not induce CYP1A2 at concentrations up to 30 μmol/L.
In vitro studies showed that perampanel is not a substrate or significant inhibitor of the following: organic anion transporting polypeptides 1B1 and 1B3; organic anion transporters 1, 2, 3, and 4; organic cation transporters 1, 2, and 3; efflux transporters P-glycoprotein and Breast Cancer Resistance Protein.
In Vivo Assessment of Drug Interactions
Drug Interactions with AEDs
Effect of Concomitant AEDs on FYCOMPA:
Carbamazepine. As an inducer of CYP enzymes, carbamazepine increases perampanel clearance. Steady state administration of carbamazepine at 300 mg BID in healthy subjects reduced the Cmax and AUC0-inf of a single 2 mg dose of perampanel by 26% and 67%, respectively. The t½ of perampanel was shortened from 56.8 hours to 25 hours. In clinical studies examining partial-onset and primary generalized tonic-clonic seizures, a population pharmacokinetic analysis showed that perampanel AUC was reduced by 64% in patients on carbamazepine compared to the AUC in patients not on enzyme-inducing AEDs [see DOSAGE AND ADMINISTRATION, DRUG INTERACTIONS].
Oxcarbazepine. In clinical studies examining partial-onset and primary generalized tonic-clonic seizures, a population pharmacokinetic analysis showed that perampanel AUC was reduced by 48% in patients on oxcarbazepine compared to patients not on enzyme-inducing AEDs [see DOSAGE AND ADMINISTRATION, DRUG INTERACTIONS].
Eslicarbazepine. Eslicarbazepine is structurally similar to oxcarbazepine and thus may also reduce perampanel plasma concentrations when used concomitantly.
Phenytoin. In clinical studies examining partial-onset and primary generalized tonic-clonic seizures, a population pharmacokinetic analysis showed that perampanel AUC was reduced by 43% in patients on phenytoin compared to patients not on enzyme-inducing AEDs [see DOSAGE AND ADMINISTRATION, DRUG INTERACTIONS].
Phenobarbital and Primidone: In a population pharmacokinetic analysis of patients with partial-onset and primary generalized tonic-clonic seizures in clinical trials (40 patients co-administered phenobarbital and 9 patients coadministered primidone), no significant effect on perampanel AUC was found. A modest effect of phenobarbital and primidone on perampanel concentrations cannot be excluded.
Topiramate: Population pharmacokinetic analysis of patients with partial-onset and primary generalized tonic-clonic seizures in clinical trials showed that perampanel AUC was reduced by approximately 19% in patients on topiramate compared to patients not on enzyme-inducing AEDs.
Other AEDs: Population pharmacokinetic analysis of patients with partial-onset and primary generalized tonic-clonic seizures in clinical trials showed that clobazam, clonazepam, lamotrigine, levetiracetam, valproate, and zonisamide did not have an effect on perampanel clearance.
Other strong CYP3A inducers (e.g., rifampin, St. John's wort) may also greatly increase clearance of perampanel and reduce perampanel plasma concentrations [see DRUG INTERACTIONS].
Effect of FYCOMPA on Concomitant AEDs
FYCOMPA up to 12 mg/day did not significantly affect the clearance of clonazepam, levetiracetam, phenobarbital, phenytoin, topiramate, or zonisamide based on a population pharmacokinetic analysis of patients with partial-onset seizures in clinical trials. FYCOMPA had a statistically significant effect on the clearance of carbamazepine, clobazam, lamotrigine, and valproic acid, but the increases in clearance of these drugs were each less than 10% at the highest perampanel dose evaluated (12 mg/day). FYCOMPA co-administration resulted in a 26% decrease in oxcarbazepine clearance and increased its concentrations. The concentrations of 10-monohydroxy metabolite (MHD), the active metabolite of oxcarbazepine, were not measured.
Drug-drug Interaction Studies with Other Drugs
Effect of Other Drugs on FYCOMPA
Ketoconazole. Co-administration of single 1-mg dose of perampanel with 400 mg once daily doses of ketoconazole, a strong CYP3A4 inhibitor, for 8 days in healthy subjects prolonged perampanel t½ by 15% (67.8 vs. 58.4 hours) and increased AUC0-inf by 20%.
Oral Contraceptives. Perampanel Cmax and AUC0-72h were not altered when a single 6-mg dose of perampanel was administered to healthy female subjects following a 21-day course of oral contraceptives containing ethinylestradiol 30 μg and levonorgestrel 150 μg.
Effect of FYCOMPA on Other Drugs
Midazolam. Perampanel administered as 6 mg once daily doses for 20 days decreased AUC0-inf and Cmax of midazolam (a CYP3A4 substrate) by 13% and 15%, respectively, in healthy subjects.
Oral Contraceptives. Co-administration of perampanel 4 mg once daily with an oral contraceptive containing ethinylestradiol 30 μg and levonorgestrel 150 μg for 21 days did not alter Cmax or AUC0-24h of either ethinylestradiol or levonorgestrel in healthy female subjects. In another study, a single dose of the oral contraceptive was administered following 21-day once daily dosing of FYCOMPA 12 mg or 8 mg in healthy females. FYCOMPA at 12 mg did not alter AUC0-24h of ethinylestradiol but decreased its Cmax by 18%, and also decreased Cmax and AUC0-24h of levonorgestrel by 42% and 40%, respectively. FYCOMPA at 8 mg did not have significant effect on Cmax or AUC0-24h of either ethinylestradiol or levonorgestrel, with a small decrease in AUC0-24h of levonorgestrel (9%) [see DRUG INTERACTIONS].
Levodopa. Perampanel administered as 4 mg once daily doses for 19 days had no effect on Cmax and AUC0-inf of levodopa in healthy subjects.
The efficacy of FYCOMPA in partial-onset seizures, with or without secondary generalization, was studied in patients who were not adequately controlled with 1 to 3 concomitant AEDs in 3 randomized, double-blind, placebo-controlled, multicenter trials (Studies 1, 2, and 3) in adult and pediatric patients (12 years of age and older). All trials had an initial 6week Baseline Period, during which patients were required to have more than five seizures in order to be randomized. The
Baseline Period was followed by a 19-week Treatment Period consisting of a 6-week Titration Phase and a 13-week Maintenance Phase. Patients in these 3 trials had a mean duration of epilepsy of approximately 21 years and a median baseline seizure frequency ranging from 9 to 14 seizures per 28 days. During the trials, more than 85% of patients were taking 2 to 3 concomitant AEDs with or without concurrent vagal nerve stimulation, and approximately 50% were on at least one AED known to induce CYP3A4, an enzyme critical to the metabolism of FYCOMPA (i.e., carbamazepine, oxcarbazepine, or phenytoin), resulting in a significant reduction in FYCOMPA's serum concentration [see DRUG INTERACTIONS, CLINICAL PHARMACOLOGY].
Each study evaluated placebo and multiple FYCOMPA dosages (see Figure 1). During the Titration period in all 3 trials, patients on FYCOMPA received an initial 2 mg once daily dose, which was subsequently increased in weekly increments of 2 mg per day to the final dose. Patients experiencing intolerable adverse reactions were permitted to have their dose reduced to the previously tolerated dose.
The primary endpoint in Studies 1, 2, and 3 was the percent change in seizure frequency per 28 days during the Treatment Period as compared to the Baseline Period. The criterion for statistical significance was p < 0.05. A statistically significant decrease in seizure rate was observed at doses of 4 to 12 mg per day. Dose response was apparent at 4 to 8 mg with little additional reduction in frequency at 12 mg per day.
Figure 1: Median Percent Reduction in Seizure
Frequency per 28 Days from Baseline to Treatment Period
Tables 4 and 5 present an analysis combining data from all 3 studies, grouping patients based upon whether or not concomitant enzyme-inducing AEDs (carbamazepine, oxcarbazepine, or phenytoin) were used. The analysis revealed a substantially reduced effect in the presence of inducers.
Table 4: Median Percent
Reduction for Combined Studies (Study 1, 2 and 3) Based on the Presence or
Absence of Concomitant Enzyme-Inducing AEDs (carbamazepine, oxcarbazepine,
|Without Enzyme-Inducing AEDs||With Enzyme-Inducing AEDs|
|Placebo %||FYCOMPA %||Placebo %||FYCOMPA %|
|aPatients from Latin American region are excluded because of a significant treatment-by-region interaction due to high placebo response|
Table 5: Responder Rate for
Combined Studies (Study 1, 2 and 3) Based on the Presence or Absence of
Concomitant Enzyme-Inducing AEDs (carbamazepine, oxcarbazepine, phenytoin)a,b
|Without Enzyme-Inducing AEDs||With Enzyme-||nducing AEDs|
|Placebo %||FYCOMPA %||Placebo %||FYCOMPA %|
|aPatients from Latin American region are
excluded because of a significant treatment-by-region interaction due to high
bThe proportion of patients with at least a 50% decrease in seizure frequency
Figure 2 shows the proportion of patients with different percent reductions during the maintenance phase over baseline across all three trials. Patients in whom the seizure frequency increased are shown at left as “worse.” Patients in whom the seizure frequency decreased are shown in the remaining four categories.
Figure 2: Proportion of
Patients Exhibiting Different Percent Reductions During the Maintenance Phase
Over Baseline Across All Three Trials.
The percentages of patients with a 50% or greater reduction in seizure frequency were 19%, 29%, 35%, 35% for placebo, 4, 8, and 12 mg, respectively.
Primary Generalized Tonic-Clonic (PGTC) Seizures
The efficacy of FYCOMPA as adjunctive therapy in patients 12 years of age and older with idiopathic generalized epilepsy experiencing primary generalized tonic-clonic seizures was established in one multicenter, randomized, double-blind, placebo-controlled study (Study 4), conducted at 78 sites in 16 countries. Eligible patients on a stable dose of 1 to 3 AEDs experiencing at least 3 primary generalized tonic-clonic seizures during the 8-week baseline period were randomized to either FYCOMPA or placebo. Efficacy was analyzed in 162 patients (FYCOMPA N=81, placebo N=81) who received medication and at least one post-treatment seizure assessment. Patients were titrated over 4 weeks up to a dose of 8 mg per day or the highest tolerated dose and treated for an additional 13 weeks on the last dose level achieved at the end of the titration period. The total treatment period was 17 weeks. Study drug was given once per day.
The primary endpoint was the percent change from baseline in primary generalized tonic-clonic seizure frequency per 28 days during the treatment period as compared to the baseline period. The criterion for statistical significance was p < 0.05. Table 6 shows the results of this study. A statistically significant decrease in seizure rate was observed with FYCOMPA compared to placebo.
Table 6: Median Percent
Reduction from Baseline in Primary Generalized Tonic-Clonic Seizure Frequency
in Study 4
|FYCOMPA 8 mg
|Percent Reduction During Treatment||38||76a|
|aP-value compared to placebo: < 0.0001. Statistically significant as compared to placebo based on ANCOVA with treatment and pooled country as factors and the ranked baseline seizure frequency per 28 days as a covariate.|
Figure 3 shows the proportion of patients with different percent reductions during the maintenance phase over baseline in primary generalized tonic-clonic seizure frequency. Patients in whom the seizure frequency increased are shown at left as “worse.” Patients in whom the seizure frequency decreased are shown in the remaining four categories.
Figure 3: Proportion of
Patients Exhibiting Different Percent Reductions During the Maintenance Phase
Over Baseline in Primary Generalized Tonic-Clonic Seizure Frequency.
Last reviewed on RxList: 7/14/2015
This monograph has been modified to include the generic and brand name in many instances.
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