In total, 6.4% of those with intellectual disability achieved seizure freedom and 37.5% had at least a 50% responder rate after treatment with perampanel.
Results from a post-hoc analysis of the PERMIT study (NCT04252846), a pooled analysis of 44 real-world studies, showed that perampanel (Fycompa; Eisai) is effective in treating patients with epilepsy who have comorbid intellectual disability (ID), although the data was not as pronounced compared with those without ID.1
The findings also showed that the antiseizure medication (ASM) was generally well-tolerated in both groups, with the incidence of psychiatric adverse events (AEs) higher among those with ID. Lead author Paola De Liso, MD, PhD, Department of Neuroscience, Bambino Gesu Children’s Hospital, presented these data at the 2021 American Epilepsy Society (AES) Annual Meeting, December 3-7, in Chicago, Illinois.
PERMIT originally included more than 5000 patients with focal-onset and/or generalized-onset seizures treated with perampanel in everyday clinical practice, however, this analysis included 735 patients with ID and 1890 patients without ID. Mean time on perampanel treatment was similar for patients with versus without ID (10.5 vs 10.6 months; P = not significant). At last visit or 12 months, responder rate, defined as at least 50% seizure reduction from baseline, was observed in 37.5% (209 of 558) of those with ID and in 48.5% (581 of 1197) of those without ID (P <.001).
Seizure freedom, defined as no seizures since at least the prior visit, was achieved by 6.4% (39 of 614) of patients with ID and 18.9% (274 of 1447) of those without ID (P <.001). No change in seizure frequency was observed in 31% (173 of 558) and 24.5% (293 of 1195) of patients with and without ID (P = .004). In total, 9.3% (52 of 558) of patients with ID had worsening of seizure frequency compared to 10.9% (130 of 1195) of those without, which was nonsignificant.
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The incidence of AEs was similar between the 2 groups, with 51.5% of patients with ID reporting at least 1 AE compared to 54.7% of those without (P = not significant). The most common AEs, occurring in at least 5% of patients with ID, were dizziness/vertigo (10.4%), irritability (10.2%), somnolence (9.3%), and behavioral disorders (7.5%). One noticeable difference was in the incidence of psychiatric AEs, which were significantly higher in those with ID (27.1%) compared to those without (21.2%; P = .003).
Discontinuation of the study drug at 12 months was similar between the 2 groups, with 19.5% and 19.4% of those with and without ID stopping perampanel. Retention rates were non-significant between groups. In total, 90.8%, 79.9% and 62.1% of those without ID stayed on perampanel at months 3, 6, and 12, respectively, compared with 88.9%, 78.4%, and 60.4% of those with ID, respectively, during the same time points.
Additional data from PERMIT presented at AES 2021 confirmed the treatment’s safety and efficacy overall. A total of 3644 and 3817 patients, respectively, made up the efficacy and safety analysis populations. At the conclusion of the 12-month period, 52% of patients with generalized-onset seizures achieved seizure freedom, while 73.3% reported at least a 50% reduction in seizure frequency from baseline. For patients with focal-onset seizures, 14.5% demonstrated complete seizure freedom, whereas 44.6% of the group had at least 50% response to treatment with perampanel.2
Perampanel was initially approved in 2012 as an adjunctive therapy for partial-onset seizures, and the indication was later expanded to include patients 12 years of age or older with primary generalized tonic-clonic seizures. In 2017, perampanel received a monotherapy indication for POS with or without secondary generalized seizures in those with epilepsy 12 years of age and older. The FDA then expanded the indication of perampanel for monotherapy and adjunctive use in pediatric patients 4 years of age and older for the treatment of POS with or without SGS in September 2018. Notably, the approval included both tablet and oral suspension formulations.
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