Comparative analysis of the safety and tolerability of eslicarbazepine acetate in older (≥60 years) and younger (18-59 years) adults.

Objective: To investigate the safety and tolerability of eslicarbazepine acetate (ESL), a once-daily oral anti-seizure drug (ASD), in older and younger adult patient populations.

Methods: Two post-hoc pooled data analyses were performed: one from three Phase III studies in patients with focal (partial-onset) seizures who were taking 1-3 concomitant ASDs; the other from five Phase II studies in patients from non-epilepsy populations not taking other ASDs chronically and/or at a clinically-effective anti-seizure dose. The frequencies of treatment-emergent adverse events (TEAEs) were calculated for the older (≥60 years) and younger (18-59 years) adults separately.

Results: In the focal seizures study pool, 4.1 % of patients (58/1431) were aged ≥60 years. The overall frequency of TEAEs was 77.5 % in older ESL-treated patients and 72.6 % in younger ESL-treated patients (p = 0.495). For patients who received placebo, the overall frequency of TEAEs was 50.0 % in the older adults and 57.5 % in the younger adults (p = 0.531). The overall placebo-adjusted frequency of TEAEs was 27.5 % in older adults and 15.1 % in younger adults. The placebo-adjusted frequencies of the TEAEs dizziness, somnolence, headache, nausea, diplopia, blurred vision, and ataxia were ≥5 % higher, and frequencies of vomiting and vertigo were ≥2 % higher in older than younger adults. The overall frequency of TEAEs leading to discontinuation was 15.0 % in older ESL-treated patients and 17.6 % in younger ESL-treated patients (p = 0.647); the frequency increased with increasing ESL dose. For patients who received placebo, the overall frequency of TEAEs leading to discontinuation was 5.6 % in older adults and 6.6 % in younger adults (p = 0.847). In the non-epilepsy study pool, 30.2 % of patients (515/1705) were aged ≥60 years. The overall frequency of TEAEs was 56.9 % in older ESL-treated patients and 58.8 % in younger ESL-treated patients. The placebo-adjusted frequencies were 14.9 % in older and 15.1 % in younger ESL-treated patients. The placebo-adjusted frequencies of the TEAEs nausea, vomiting, fatigue, and vertigo were ≥2 % higher in older adults, whereas somnolence was ≥2 % higher in younger adults. The overall frequency of TEAEs leading to discontinuation was 18.3 % in older ESL-treated patients and 12.1 % in younger ESL-treated patients (p = 0.003); frequencies were not related to ESL dose. For patients who received placebo, the overall frequency of TEAEs leading to discontinuation was 8.0 % in older adults and 5.6 % in younger adults (p = 0.407).

Conclusion: Analyses of adverse event data support the safety and tolerability of ESL in adults aged ≥60 years. In the limited number of older patients with focal seizures taking ESL plus concomitant ASDs (n = 40), the frequency of TEAEs was generally higher than in younger adults. However, in the non-epilepsy patient group (in which the number of older patients was ten times larger; 427 patients taking ESL without concomitant ASDs), no marked age-related TEAE differences were observed, suggesting that increased ASD load associated with adjunctive therapy may complicate treatment selection in older patients, due to risk of increased adverse events. As is common practice for all ASDs, balancing clinical response and tolerability is needed in this vulnerable group of patients.