Evaluation of perampanel as monotherapy for focal seizures: Experience from open-label extension studies

PERPRISE: A prospective non-interventional study of PERampanel as only adjunctive treatment in patients with PRImary or SEcondarily generalized tonic-clonic seizures: First interim analysis

OBJECTIVE

To report the interim results of the PERPRISE study (Study 509; NCT04202159), which is evaluating perampanel as the only adjunctive anti-seizure medication (ASM) in adults with focal to bilateral tonic-clonic seizures (FBTCS) or primary generalized tonic-clonic seizures (GTCS).

METHODS

PERPRISE is an ongoing 12-month multicenter, prospective, observational, non-interventional study of perampanel in a real-world setting in Germany. Patients are aged ≥18 years with FBTCS or GTCS due to focal or idiopathic generalized epilepsy. Perampanel, as an adjunctive therapy to ASM monotherapy ('add-on therapy') or as a substitute for one ASM in dual therapy ('substitution therapy'), is prescribed in line with its SmPC. The Interim Analysis Set comprises the first 100 patients who received ≥1 dose of perampanel and attended or discontinued prior to the ~6-month visit. Interim endpoints include retention rate, measures of effects on seizure frequency, and treatment-emergent adverse events (TEAEs).

RESULTS

One hundred patients were included in the Interim Analysis Set (add-on, n = 43 [43.0%]; substitution, n = 55 [55.0%]; unknown, n = 2). The 6-month retention rate was 78.0% (add-on, 83.7%; substitution, 72.7%). For the overall population with GTCS and/or FBTCS, seizure-freedom rate at 6 months was 58.8% (add-on, 72.2%; substitution, 47.9%) and 50% responder rate at 6 months was 82.6% (add-on, 89.2%; substitution, 76.6%). Retention rates and seizure outcomes were better with perampanel as an early-line treatment than as a late-line treatment. TEAEs were reported by 48 patients (48.0%), most commonly dizziness (n = 9), fatigue (n = 7), and irritability (n = 7). Sixteen patients (16.0%) withdrew from perampanel treatment due to TEAEs.

SIGNIFICANCE

The interim analysis of PERPRISE offers insight into the real-world use of perampanel in Germany, including for the first time, clinical practice data from patients with GTCS and switching ASMs within a dual therapy. Further data from PERPRISE will be of value to inform clinical decision-making in this patient cohort.

PLAIN LANGUAGE SUMMARY

Patients with epilepsy often take more than one medication for seizure control. This 12month study looked at patients in Germany receiving perampanel as only add-on medication. The interim analysis shows, that at 6 months, over 70% of the 100 patients continued to use perampanel; 59% experienced no seizures during treatment with perampanel, and in 83%, seizure frequency was reduced by half. Side effects occurred in 48% of patients (most commonly dizziness, fatigue, and irritability) and caused 16% to withdraw from the study. Overall, perampanel was a suitable as only add-on medication for patients with epilepsy.

Efficacy and safety of perampanel monotherapy in patients with focal-onset seizures:A real-world experience in eastern China

OBJECTIVE

To assess the effectiveness and tolerability of perampanel (PER) monotherapy in real-world practice for the treatment of focal-onset seizures (FOS) in eastern China.

METHOD

This is a single-center, retrospective study of patients with FOS, aged ≥ 4 years, who had been prescribed PER as monotherapy. Outcomes included retention, seizure-free, and responder rates at 3, 6 and 12 months and adverse events (AEs) throughout the follow-up period. The efficacy and AEs of PER monotherapy in patients with aged < 14 years old and ≥ 14 years old were also compared.

RESULTS

Sixty-seven patients with FOS who received PER monotherapy and completed a one-year follow-up were included in the analysis. The median maintenance dose was 4 mg. Modified intent-to-treat analysis demonstrated that the retention rates of PER monotherapy at follow-up of 3, 6 and 12months were 75%, 70% and 63%, respectively. At the same points, seizure-free rates of PER monotherapy were 69%, 63% and 52%, and responder rates were 69%, 66% and 61%, respectively. Patients with sleep-related seizures had higher seizure-free rates at 12 months of follow-up. No significant difference in seizure-free and responder rates was found between the aged < 14 years old and the aged ≥ 14 years old. Twenty-one patients (31.3%) had AEs and five patients discontinued using PER because of intolerant AEs. Common AEs were dizziness, irritability and somnolence. The AEs rate in patients < 14 years was 17.9%, significantly lower than patients ≥ 14 years.

CONCLUSIONS

Our findings revealed the real-world data of patients in eastern China with FOS using PER as monotherapy. Patients had good retention, seizure-free and responder rates, and relatively low AEs rate at a low dose of PER treatment.

Perampanel Monotherapy for Focal and Generalized Epilepsy in Clinical Practice

Objectives. To investigate the effectiveness, safety, and tolerability of perampanel (PER) when used as monotherapy to treat focal or generalized epilepsy in everyday clinical practice, using data from the PERMIT study. Methods. PERMIT was a pooled analysis of 44 real-world studies from 17 countries, in which people with focal and generalized epilepsy were treated with PER. This post hoc analysis included people with epilepsy (PWE) from PERMIT who were treated with PER monotherapy at baseline. Retention and effectiveness were assessed after 3, 6, and 12 months. Effectiveness assessments included ≥50% responder rate and seizure freedom rate (no seizures since at least the prior visit). Safety and tolerability were assessed by evaluating adverse events (AEs) and discontinuation due to AEs. Results. Overall, 268 PWE were treated with PER monotherapy at baseline. Retention was assessed for 168 PWE, effectiveness for 183 PWE, and safety and tolerability for 197 PWE. Retention rates were 91.1%, 87.3%, and 73.3% at 3, 6, and 12 months, respectively. At 12 months, responder rates were 84.2% overall, 82.9% in PWE with only focal-onset seizures at baseline, and 88.0% in those with only generalized-onset seizures at baseline; corresponding freedom rates were 62.9%, 57.7%, and 80.0%, respectively. AEs were reported for 45.2% of PWE. The most frequently reported AEs (≥5% of PWE) were dizziness/vertigo (16.8%), irritability (11.2%), somnolence (9.1%), and depression (6.6%). Over 12 months, 13.7% discontinued due to AEs. Conclusions. PER was effective when used as monotherapy in clinical practice, particularly in those with generalized-onset seizures, and was generally well tolerated.

Perampanel dosage in plasma samples: development and validation of a novel HPLC method with combined UV-Fluorescence detection

Therapeutic drug monitoring (TDM) is a recognized method to improve the quality of use of antiepileptic drugs, such as perampanel (PRP). It is the first compound in the class of selective non-competitive antagonists of AMPA receptors approved in 2012 in Europe and United States for adjunctive therapy of partial seizures. Although several studies have recently underlined that a general reference range for PRP plasmatic concentration might be difficult to propose, TDM of this drug is important in specific clinical situations, as hepatic or renal impairment or co-administration with enzyme-inducing antiepileptics. Several methods have been described in literature for the determination of PRP in different biological matrices, which include the use of liquid chromatography methods coupled with ultraviolet, fluorescence, mass or tandem-mass spectrometry detection. Here we describe the development and validation of a novel method for the measurement of PRP in plasma samples, based on a HPLC-UV/FL double detection approach and using ketoprofen as internal standard. PRP concentration in a small subset of plasma samples of treated patients was evaluated using both our approach and a commercially available CE-IVD LC-MS/MS method. The results obtained were compared, and confirmed the possibility to use our method as an alternative to LC-MS/MS in clinical routine.

Clinical experience on the use of perampanel in epilepsy among child neurologists in the Philippines

BACKGROUND

Perampanel is the latest anti-seizure medication introduced in the Philippines in 2015. This was initially approved as an adjunctive treatment for focal seizures and those with secondary generalization among individuals 12 years old and above. By March 2020, it has been approved also for generalized seizures and in children 4 years and above. The general objective of this research is to describe the clinical experience of Filipino child neurologists on the use of perampanel in children.

METHODS

This is a cross-sectional descriptive study that surveyed child neurologists with review of medical records of children who have received perampanel as either an adjunctive therapy or monotherapy for epilepsy.

RESULTS

There were 65 patients included in the study aged 1 to 18 years with a mean age of 10.0 ± 5.2 years and a median of 10 years. Follow-up duration were between 2 weeks to more than a year. Perampanel was started in 98.5% as an add-on treatment between 5 months and 18 years of age. The responder rate is 69.2% (45/65), seizure-free rate is 29.2% (19/65), seizure-aggravation rate is 9.2% (6/65), and perampanel retention rate is 83.1% (54/65). Treatment emergent adverse events were noted in 53.8% of the children with somnolence (20.0%), gait problems (12.3%), weight gain (10.8%) and dizziness (9.2%) as the most common events experienced. Dizziness was experienced significantly more among children 12 to 18 years of age.

CONCLUSION

Perampanel is seen to be effective and relatively safe to use among Filipino children.

Changes in perampanel levels during de-induction: Simulations following carbamazepine discontinuation

Objective

To evaluate the time course of changes in perampanel levels when co‐administered with carbamazepine, and following carbamazepine discontinuation, using a physiologically based pharmacokinetic (PBPK) model.

Methods

The PBPK model was developed, verified using clinical PK data, and used to simulate the effect of abrupt discontinuation and down‐titration (75 mg twice daily [bid]/wk) of co‐administered carbamazepine 300 mg bid on the PK of perampanel once daily (qd). Perampanel dose tapering (8‐4 mg) and up‐titration (2‐6 mg) were simulated during abrupt carbamazepine 300 mg bid discontinuation to identify a titration schedule that minimizes changes in perampanel plasma concentrations.

Results

The PBPK model accurately reproduced perampanel plasma concentration‐time profiles from clinical studies in single‐ and multiple‐dose regimen simulations, including multiple‐dose carbamazepine co‐administration. The time course of return to pre‐induced perampanel levels occurred more slowly following carbamazepine down‐titration (~48 days after first down‐titration) vs abrupt discontinuation (~25 days). Perampanel dose tapering (8‐4 mg) at abrupt carbamazepine discontinuation produced minimal changes in steady‐state concentrations, which returned to the levels observed during carbamazepine co‐administration in ~15 days from the time of carbamazepine discontinuation. When perampanel was up‐titrated in the presence of carbamazepine, return to steady state occurred more slowly when carbamazepine was down‐titrated weekly (~45 days) vs abrupt discontinuation (~24 days).

Conclusion

This PBPK model simulated and predicted optimal perampanel dose tapering and up‐titration schedules for maintaining perampanel levels during conversion to monotherapy. These results may guide physicians when managing conversion from perampanel polytherapy with concomitant enzyme‐inducing anti‐seizure medications to monotherapy.

Effectiveness and safety of perampanel monotherapy for focal and generalized tonic-clonic seizures: Experience from a national multicenter registry

OBJECTIVE

To assess the effectiveness and tolerability of perampanel (PER) monotherapy in routine clinical practice for the treatment of focal onset and generalized tonic-clonic seizures (GTCS).

METHODS

This multicenter, retrospective, observational study was conducted in patients aged ≥12 years treated with PER as primary monotherapy or converted to PER monotherapy by progressive reduction of background antiepileptic drugs. Outcomes included retention, responder, and seizure-free rate after 3, 6, and 12 months and tolerability throughout the follow-up.

RESULTS

A total of 98 patients (mean age = 49.6 ± 21.7 years, 51% female) with focal seizures and/or GTCS were treated with PER monotherapy for a median exposure of 14 months (range = 1-57) with a median dose of 4 mg (range = 2-10). The retention rates at 3, 6, and 12 months and last follow-up were 93.8%, 89.3%, 80.9%, and 71.4%, respectively. The retention rates according to the type of monotherapy (primary vs conversion) did not differ (log-rank P value = .57). Among the 98 patients, 61.2% patients had seizures throughout the baseline period, with a median seizure frequency of 0.6 seizures per month (range = 0.3-26). Responder rates at 3, 6, and 12 months were 79.6%, 70.1%, and 52.8%, respectively, and seizure freedom rates at the same points were 62.7%, 56.1%, and 41.5%. Regarding the 33 patients who had GTCS in the baseline period, 87.8% were seizure-free at 3 months, 78.1% at 6 months, and 55.1% at 12 months. Over the entire follow-up, PER monotherapy was generally well tolerated, and only 16% of patients discontinued PER due to adverse events (AEs). Female patients were found to be at a higher risk of psychiatric AEs (female vs male odds ratio = 2.85, 95% confidence interval = 1-8.33, P = .046).

SIGNIFICANCE

PER demonstrated good effectiveness and a good safety profile when used as primary therapy or conversion to monotherapy at relatively low doses, in a clinical setting with patients with focal seizures and GTCS.

Efficacy and safety of perampanel monotherapy in patients with focal-onset seizures with newly diagnosed epilepsy or recurrence of epilepsy after a period of remission: The open-label Study 342 (FREEDOM Study)

Objective

Our study assessed perampanel monotherapy in patients (aged ≥12 years) with focal‐onset seizures (FOS) with or without focal to bilateral tonic‐clonic seizures (FBTCS) in Japan and South Korea.

Methods

Study 342 (NCT03201900; FREEDOM) is a single‐arm, open‐label, Phase III study. Patients initially received perampanel in a 32‐week 4‐mg/d Treatment Phase (6‐week Titration; 26‐week Maintenance Periods). If they experienced a seizure during the 4‐mg/d Maintenance Period, they could be up‐titrated to 8 mg/d across an additional 30‐week Treatment Phase (4‐week Titration; 26‐week Maintenance Periods). Primary endpoint was the seizure‐freedom rate during the Maintenance Period (4 mg/d and last evaluated dose [4 or 8 mg/d]). Secondary endpoints included time to first seizure onset and to withdrawal during Maintenance. Treatment‐emergent adverse events (TEAEs) were monitored.

Results

At data cutoff (February 28, 2019), 89 patients with FOS (84 [94.4%] with newly diagnosed epilepsy and 5 [5.6%] with recurrence of epilepsy after a period of remission) had received ≥1 perampanel dose; 16 patients discontinued during the 4‐mg/d Titration Period, meaning 73 patients entered the 4‐mg/d Maintenance Period and were included in the primary analysis set for efficacy. Seizure‐freedom rate in the 26‐week Maintenance Period was 46/73 (63.0%; 95% confidence interval [CI]: 50.9‐74.0) at 4 mg/d and 54/73 (74.0%; 95% CI: 62.4‐83.5) at 4 or 8 mg/d. Cumulative probability of seizure‐onset and withdrawal rates during Maintenance was 30.8% (95% CI: 21.5‐43.0) and 23.7% (95% CI: 15.4‐35.3) at 4 mg/d, and 18.2% (95% CI: 11.0‐29.3) and 23.3% (95% CI: 15.2‐34.8) at 4 or 8 mg/d. Perampanel was generally well tolerated, and the most common TEAE was dizziness.

Significance

Perampanel monotherapy (4 to 8 mg/d) was efficacious and consistent with the known safety profile up to 26 weeks in patients (≥12 years) with primarily newly diagnosed FOS with or without FBTCS.