Abstracts

Rationale: Perampanel is an anti-seizure medication (ASM) for focal-onset seizures (FOS) and generalized tonic-clonic seizures (GTCS). In the US and Europe, perampanel is approved for FOS, with/without focal to bilateral tonic-clonic seizures (FBTCS), in patients aged ≥ 4 years (US: monotherapy/adjunctive; Europe: adjunctive), and GTCS in patients aged ≥ 12 (≥ 7, Europe) years (adjunctive). The AMPA study (NCT04257604; Study 501) investigated the effectiveness of adjunctive perampanel in patients with FOS (with/without FBTCS) in a real-life clinical setting in Italy. Here, we report a post hoc analysis of efficacy and safety outcomes from the AMPA study stratified by age.

Methods: The AMPA study was a multicenter, prospective, real-life observational study of adjunctive perampanel. Adult and adolescent patients aged ≥ 12 years with insufficiently controlled FOS with/without FBTCS while receiving 1–3 ASMs were prescribed adjunctive perampanel as per the approved indication; the treating physician’s decision to prescribe perampanel was made before and independently of their decision to include the patient in the study. Seizure diaries and treatment-emergent adverse events (TEAEs) were verified at study visits (baseline and after 3, 6, and 12 months of treatment). The primary endpoint was percentage change from baseline in all-seizure frequency per 28 days at Month 6 (secondary endpoint, Month 12); other secondary efficacy and safety measures included 50% and 75% responder rates, seizure-freedom rates, retention rates, and monitoring of TEAEs up to 12 months.

Results: Of the 234 patients included in the analysis, 26 were adolescents aged 12–17 years (mean [range], 15.0 [12–17] years) and 208 were adults aged ≥ 18 years (mean [range], 41.5 [18–84] years). In total, 17/26 (65.4%) adolescents and 118/208 (56.7%) adults completed the study. Median reduction from baseline in all-seizure frequency at Month 6 was 85.3% (95% confidence interval [CI], 35.4, 100.0; n=25) in adolescents and 52.3% (95% CI, 44.0, 61.9; n=173) in adults; at Month 12, reductions were 87.0% (95% CI, 61.1, 98.8; n=25) and 66.7% (55.6, 73.3; n=175), respectively. The 50% and 75% responder rates increased throughout the study to 76.0% and 64.0%, respectively, for adolescents, and to 61.7% and 41.7%, respectively, for adults at Month 12 (Table 1). At Month 12, the seizure-freedom rate was 28.0% for adolescents and 17.5% for adults, and retention rates were 61.5% and 56.7%, respectively (Table 1). TEAE incidence was comparable between adolescents (15/26 [57.7%]) and adults (117/208 [56.3%]). The most common TEAEs were behavior disorder, dizziness/vertigo, and irritability in adolescents, and dizziness/vertigo, somnolence, and irritability in adults (Table 2). TEAEs leading to study drug withdrawal were reported by 5/26 (19.2%) adolescents and 40/208 (19.2%) adults.

Conclusions: Based on the findings of this analysis, adjunctive perampanel in a real-world clinical setting was efficacious and generally safe in both adolescent and adult patients with FOS (with/without FBTCS).

Funding: Please list any funding that was received in support of this abstract.: Eisai S.r.l.