Assessment of the long-term efficacy and safety of adjunctive perampanel in adolescent patients with epilepsy: Post hoc analysis of open-label extension studies

OBJECTIVE

This post hoc analysis of four open-label extension (OLEx) studies evaluated the long-term efficacy and safety of adjunctive perampanel in adolescent patients (aged 12 to ≤17 years) with focal-onset seizures (FOS), with/without focal to bilateral tonic-clonic seizures (FBTCS), or generalized tonic-clonic seizures (GTCS).

METHODS

Patients who completed one of six double-blind, placebo-controlled studies could enter one of four OLEx studies comprising a blinded Conversion Period (6-16 weeks) followed by a Maintenance Phase (27 to ≤256 weeks; perampanel dose: ≤12 mg/day). Exposure, retention, seizure outcomes, and treatment-emergent adverse events (TEAEs) were analyzed. Efficacy outcomes were analyzed using observed case and last observation carried forward (LOCF) approaches; the latter was used to account for early dropouts.

RESULTS

The Full Analysis Set comprised 309 adolescents with FOS (FBTCS, n = 109) and 19 with GTCS, and the Safety Analysis Set comprised 311 with FOS (FBTCS, n = 110) and 19 with GTCS. Mean (standard deviation) cumulative duration of perampanel exposure (weeks) was: FOS, 77.7 (58.7); FBTCS, 88.7 (63.8); and GTCS, 97.0 (35.5). Retention rates were maintained for ≤2 years (FOS, 50.0 %; FBTCS, 57.1 %; GTCS, 41.7 %). Seizure control (median percent reduction in seizure frequency/28 days) was sustained for up to 2 years; FOS (59.4 %, n = 113), FBTCS (64.6 %, n = 53), and GTCS (86.5 %, n = 17). At Year 2, 50 % responder rates were: FOS, 58.4 % (n = 66); FBTCS, 54.7 % (n = 29); and GTCS, 82.4 % (n = 14); seizure-freedom rates were: FOS, 5.3 % (n = 6); FBTCS, 24.5 % (n = 13); and GTCS, 35.3 % (n = 6). Long-term seizure control was observed even in LOCF analyses. The incidence of TEAEs was highest during Year 1 (FOS, n = 269 [86.5 %]; FBTCS, n = 95 [86.4 %]; GTCS, n = 15 [78.9 %]), compared with Years 2-4; the most common (≥10 % of patients) were dizziness, somnolence, and nasopharyngitis. No new safety signals emerged with long-term treatment.

CONCLUSIONS

This post hoc analysis suggests that long-term (≤2 years) adjunctive perampanel (≤12 mg/day) is efficacious and generally well tolerated in adolescent patients with FOS, with or without FBTCS, or GTCS.

Efficacy and safety of adjunctive perampanel in adolescent patients with epilepsy: Post hoc analysis of six randomized studies

OBJECTIVE

This post hoc analysis of six randomized, double-blind, Phase II and III studies evaluated efficacy and safety of adjunctive perampanel (2-12 mg/day) in adolescent patients (aged ≥12 to ≤17 years) with uncontrolled partial-onset seizures, with or without secondarily generalized (SG) seizures, or primary generalized tonic-clonic (PGTC) seizures.

METHODS

Adolescent patients from Studies 304 (NCT00699972), 305 (NCT00699582), 306 (NCT00700310), 335 (NCT01618695), 235 (NCT01161524), and 332 (NCT01393743) were included. Efficacy assessments (split by seizure type) included median percent change in seizure frequency per 28 days from baseline and seizure-freedom rates. Safety assessments (all seizure types combined) included monitoring of treatment-emergent adverse events (TEAEs).

RESULTS

The Safety Analysis Set included 372 adolescent patients (placebo, n = 114; perampanel, n = 258); the Full Analysis Set included 346 patients with partial-onset seizures (placebo, n = 103; perampanel, n = 243), of whom 125 experienced SG seizures during baseline (placebo, n = 37; perampanel, n = 88), and 22 with PGTC seizures (placebo, n = 9; perampanel, n = 13). Compared with placebo, perampanel 8 and 12 mg/day conferred greater median percent reductions in seizure frequency per 28 days for partial-onset seizures (18.0% vs 35.9% and 53.8% [both P < 0.01]) and SG seizures (24.4% vs 72.8% [P < 0.001] and 57.8% [P < 0.01]), and greater seizure-freedom rates (partial-onset: 7.8% vs 13.2% and 11.8% [not statistically significant]; SG: 8.1% vs 40.7% [P < 0.001] and 41.7% [P < 0.01]). For PGTC seizures, and compared with placebo, perampanel 8 mg/day was also associated with greater median percent reductions in seizure frequency per 28 days (29.8% vs 88.0%) and greater seizure-freedom rates (11.1% vs 23.1%). Treatment-emergent adverse events were reported in 76 (66.7%) placebo- and 192 (74.4%) perampanel-treated patients (most common: dizziness, somnolence, headache, and nasopharyngitis). Serious TEAEs occurred in 5 (4.4%) placebo- and 11 (4.3%) perampanel-treated patients.

CONCLUSIONS

Adjunctive perampanel was efficacious and generally well tolerated in adolescent patients with partial-onset, SG, or PGTC seizures and represents a potentially beneficial treatment option for adolescents with uncontrolled epilepsy.

Assessment of treatment patterns and healthcare costs associated with probable Lennox-Gastaut syndrome

Lennox-Gastaut syndrome (LGS) is a chronic and severe form of epilepsy characterized by intractable seizures, cognitive impairment, and abnormal electroencephalogram findings with slow spike-wave complexes. It typically presents before age 8, but symptoms continue into adulthood and require lifelong treatment associated with significant clinical burden. Data on LGS-associated healthcare utilization and costs are limited. In this study we use a claims-based LGS classifier based on random forest methodology to identify patients with probable LGS from the a Medicaid multi-state database and assess its prevalence across the age spectrum, healthcare utilization, treatment patterns, costs, and comorbid conditions. The classifier identified patients with probable LGS across all ages, with up to 8% of 10-year-old patients with epilepsy identified as having probable LGS. The prevalence of probable LGS was lower in older age cohorts, indicating that it may be under-recognized in older patients. Our analysis showed that probable LGS is associated with considerably higher total healthcare and medical costs than non-LGS patients. The costs were generally consistent between age cohorts, suggesting that the cost burden extends beyond childhood and has a lifelong impact. Analysis of treatment patterns suggest that while the majority of probable LGS patients in this study received widest-spectrum AEDs, a considerable proportion did not and therefore may have been inadequately treated. Further, usage of clobazam and rufinamide was decreased in older compared to younger patient cohorts, indicating that older patient cohorts are less likely to be receiving optimum treatment for LGS. These findings indicate the need for increased clinical attention to LGS beyond pediatric years, with a focus on optimization of treatment for LGS patients of all ages with widest-spectrum AEDs. Timely recognition and adequate treatment of LGS are likely to result in improved outcomes and less costly management of this condition.

A pilot study of topiramate in childhood absence epilepsy

OBJECTIVE

Evaluate the antiepileptic effect of topiramate monotherapy in childhood absence epilepsy (CAE).

MATERIALS AND METHODS

Childhood absence epilepsy patients aged 4-9 years were initiated with topiramate 15 or 25 mg/day, which was titrated upwards until patients were free of absence seizures. The primary efficacy outcome was seizure-free rates after a 12-week maintenance period.

RESULTS

The study was terminated early due to lack of efficacy after enrollment of 12 patients. Four patients completed the study; two became clinically seizure-free, but without a significant reduction in the number of electrographic seizures. Six patients discontinued for lack of efficacy, none due to adverse events (AEs). Mean reduction in seizure count was seen on Days 22 (P = 0.0391) and 36 (P = 0.0156) and percentage of days with seizures decreased from baseline. Most AEs were mild.

CONCLUSIONS

Although well-tolerated, this pilot study did not demonstrate an antiepileptic effect of topiramate monotherapy for treatment of CAE.

Adjunctive lamotrigine for partial seizures in patients aged 1 to 24 months

OBJECTIVE

This randomized, double-blind, placebo-controlled trial was conducted to assess the efficacy and tolerability of adjunctive lamotrigine for the treatment of partial seizures in infants aged 1 to 24 months.

METHODS

The study used a responder-enriched design in which all patients received adjunctive lamotrigine during an open-label phase (n = 177; maximum maintenance dose 5.1 mg/kg/day for those on non-enzyme-inducing antiepileptic drugs [AEDs] or valproate and 15.6 mg/kg/day for those on enzyme-inducing AEDs). Patients meeting response criteria were randomly assigned to double-blind treatment for up to 8 weeks with continued lamotrigine (n = 19) or to withdrawal from lamotrigine (placebo; n = 19) while background AEDs were maintained.

RESULTS

The proportion of treatment failures (patients who met escape criteria or withdrew before completing the double-blind phase) was lower with lamotrigine (58%) than with placebo (84%). This finding was not significant in the primary analysis (two-sided chi(2) test [primary endpoint]). A post hoc sensitivity analysis of the primary endpoint was also performed (p = 0.045 by one-sided, mid-p corrected Fisher exact test). The median time to meet escape criteria was longer with lamotrigine (42 days) than with placebo (22 days) (p = 0.059). During the last 28 days of the open-label phase, 53% of the patients had a >or=50% reduction in frequency of partial seizures with lamotrigine. Additional reduction in partial seizure frequency was observed during the double-blind phase compared with the last 4 weeks of the open-label phase among those randomly assigned to lamotrigine (32% with a >or=25% reduction) but not those randomly assigned to placebo (5% with a >or=25% reduction). Lamotrigine was well tolerated, with an adverse event profile comparable to that observed in older pediatric patients.

CONCLUSION

Lamotrigine was well tolerated, and the data indicate that it may be efficacious in the treatment of partial seizures in infants aged 1 to 24 months.

Oxcarbazepine adjunctive therapy in infants and young children with partial seizures

OBJECTIVE

To evaluate the efficacy, safety, and pharmacokinetics of oxcarbazepine as adjunctive therapy in infants and young children (1 month to < 4 years).

METHODS

Children 1 month to < 4 years of age with inadequately controlled partial seizures taking up to two concomitant antiepileptic drugs (AEDs) were enrolled in this rater-blind, randomized, parallel-group study. Patients received either high-dose (60 mg/kg/day) or low-dose (10 mg/kg/day) oxcarbazepine as oral suspension. The primary efficacy variable was the absolute change in electrographic partial seizures with a behavioral correlate (type 1 seizure) frequency per 24 hours during the last 72 hours of continuous video-EEG monitoring in the treatment phase compared with baseline seizure frequency.

RESULTS

Of 191 patients screened, 128 were randomized: 64 to both oxcarbazepine dose groups. The median absolute change in type 1 seizure frequency per 24 hours was more effective for the high-dose group (-2.00) compared with the low-dose group (-1.37; p = 0.043). The median percentage reduction in type 1 seizure frequency per 24 hours was also greater in the high-dose group (83.33%) than in the low-dose group (46.18%; p = 0.047). The most frequent adverse events (> or = 10%) were somnolence and pyrexia, and most were mild in severity.

CONCLUSIONS

In this study, high-dose oxcarbazepine was significantly more effective than low-dose oxcarbazepine in controlling partial seizures in infants and very young children.

Analgesic-induced headaches in a 17-month-old infant

This is a case report of a 17-month-old infant with 8 weeks of constant headache, which resulted from the daily ingestion of analgesics.

Pediatric manifestations of Hashimoto's encephalopathy

Hashimoto's encephalopathy is a steroid-responsive encephalopathy associated with elevated blood concentrations of antithyroid antibodies. The patients are usually euthyroid or mildly hypothyroid. The authors report two pediatric patients with Hashimoto's encephalopathy and review the literature. The clinical picture in adolescents, as with adults, is pleomorphic but frequently associated with seizures, confusion, and hallucinations. Alternatively, progressive cognitive decline manifested by a drop in school performance can be observed. The diagnosis of Hashimoto's thyroiditis is often overlooked at presentation and a high degree of suspicion is necessary for proper diagnosis.

Analgesic rebound headache in children and adolescents

For more than a decade, the frequent use of analgesics has been recognized to lead to daily headaches in adults. To date, no studies on the occurrence of analgesic rebound headache have been done on the pediatric population. We retrospectively reviewed all charts of patients with the diagnosis of headache seen in our pediatric headache clinic between January 1996 and May 1997. Among the 98 patients seen, 46 (47%) suffered from daily or near daily headaches; 30 of them were consuming daily analgesics. Twenty-four patients (mean age 12.1 years, and mean follow-up 6.2 months) successfully discontinued their analgesics. Twenty-two patients were also placed on amitriptyline. A significant reduction in the frequency (80%), severity (47%), and number of school days missed (74%) were seen. In conclusion, this data is comparable to previous observations reported in adults, and suggests that the daily use of analgesics might result in daily or near daily headaches in the pediatric population. Discontinuing daily analgesics, with the concomitant use of amitriptyline, is an effective treatment for analgesic rebound headache in this population.