(564) Long-term Seizure Freedom with Adjunctive Perampanel in Pediatric Patients (Aged 4–<12 years) with Partial-Onset Seizures or Primary Generalized Tonic-Clonic Seizures: Post Hoc Analysis of Study 311
Pediatric Neurologist & Epilepsy Specialist Pediatric and Adolescent Neurodevelopmental Associates, Atlanta, GA, USA Atlanta, Georgia
Rationale: In the U.S., perampanel is approved for partial-onset seizures (POS; adjunctive and monotherapy) in patients aged ≥ 4 years, and adjunctive treatment of primary generalized tonic-clonic seizures (PGTCS) in patients aged ≥ 12 years. Previous analyses have shown long-term seizure-freedom rates with adjunctive perampanel are maintained in adolescents/adults (aged ≥ 12 years) with secondarily generalized seizures (SGS) or PGTCS. We assessed if seizure-freedom rates with adjunctive perampanel during the 311 Core Study (NCT02849626) are maintained during long-term (1-year) treatment in pediatric patients (aged 4–< 12 years) with POS (with/without SGS) or PGTCS who participated in the Extension A Phase. Methods: The Core Study comprised 4-week Pretreatment, 23-week Treatment (11-week Titration; 12-week Maintenance), and 4-week Follow-up Periods (for those not entering Extension A). Extension A comprised 29-week Maintenance and 4-week Follow-up Periods. For this post hoc analysis, seizure-freedom rates (POS, SGS, PGTCS) were assessed in pediatric patients (aged 4–< 12 years) who achieved seizure freedom during the Core Study Maintenance Period and then remained seizure free for six and/or 12 months (calculated from the start of their seizure-free period). Data were stratified by concomitant enzyme-inducing anti-seizure medications (EIASMs) (with/without) and age (4–< 7 and 7–< 12 years). Results: Overall, 180 patients (POS, n=149 [of which 54 had SGS]; PGTCS, n=31) were enrolled and treated in the Core Study. Of these, 136 patients (POS, n=116; SGS, n=43; PGTCS, n=20) entered Extension A. During the Core Study, seizure freedom was achieved by 17/148 (11.5%) patients with POS, 10/54 (18.5%) patients with SGS, and 12/22 (54.5%) patients with PGTCS. Figure 1 shows the proportions of patients who achieved seizure freedom during the Core Study and then remained seizure free for six and 12 months during Extension A. Seizure-freedom rates by EIASM use and age group at six and 12 months are presented in Table 1. Patients without concomitant EIASMs reported higher seizure-freedom rates compared with patients receiving concomitant EIASMs at six and 12 months across all seizure types. This may be attributable to decreased perampanel plasma concentrations in patients receiving EIASMs; however, the small patient numbers in these groups, particularly the EIASM group, should be taken into consideration when interpreting these data. Across seizure types, >60% of patients remained seizure free for up to six months and >30% remained seizure free for up to 12 months in the aged 7–< 12 years group; patient numbers for the aged 4–< 7 years group at six and 12 months were too small to draw conclusions across seizure types. Conclusions: Despite small patient numbers, these data suggest seizure-freedom rates are maintained during long-term (one-year) perampanel treatment in pediatric patients, which is consistent with previous analyses in adolescent and adult patients. Funding: Please list any funding that was received in support of this abstract.:
