Abstracts

Rationale: Conversion to monotherapy is a rational therapeutic approach to minimize the likelihood of treatment-related adverse events (AEs) associated with antiepileptic drug (AED) polypharmacy. Withdrawal to monotherapy clinical trials do not necessarily reflect real-world clinical practice conditions, since the protocols employed are not specifically tailored to each individual patient’s needs. Real-world clinical practice studies therefore complement evidence from such clinical trials. The Euro-Esli study investigated the real-world effectiveness, safety and tolerability of eslicarbazepine acetate (ESL) when used in everyday clinical practice in Europe. We present a subanalysis of data from patients who withdrew to ESL monotherapy during Euro-Esli, compared with patients who received ESL adjunctive therapy at the end of the study.    Methods: Euro-Esli was a pooled analysis of 14 European clinical practice studies. Effectiveness assessments included responder rate (=50% seizure frequency reduction) and seizure freedom rate (seizure freedom at least since prior visit). Effectiveness data from the last visit were compared for patients who withdrew to ESL monotherapy versus those who were receiving ESL adjunctive therapy at the last visit. Safety and tolerability were assessed throughout follow-up by evaluating AEs and ESL discontinuation due to AEs, respectively.  Results: Euro-Esli included a total of 2058 patients, of whom 199 (9.7%) started treatment with ESL as adjunctive therapy and subsequently withdrew to ESL monotherapy by the end of the study. Of 1340 patients for whom the number of AEDs received at the last visit was known, 1111 (82.9%) were being treated with ESL adjunctive therapy. Patients who withdrew to monotherapy, compared with those who received ESL adjunctive therapy at the last visit, had a later onset of epilepsy, shorter duration of epilepsy, lower baseline seizure frequency across all seizure types, and had been treated with fewer previous AEDs (Table). Responder and seizure rates were statistically higher in patients who withdrew to monotherapy versus those who received ESL adjunctive therapy at the last visit (Figure). The proportions of patients who experienced AEs were 28.6% (57/199) for those who withdrew to monotherapy versus 30.8% (342/1109) for those who received ESL adjunctive therapy at the last visit (?² = 0.38; p=0.536). The proportions of patients who discontinued ESL due to AEs were 4.5% (9/199) for those who withdrew to monotherapy versus 14.4% (158/1096) for those who received ESL adjunctive therapy at the last visit (?² = 14.68; p<0.001). Conclusions: These findings from Euro-Esli suggest that there is a subgroup of patients who may benefit from withdrawing to ESL monotherapy from adjunctive therapy. Such patients appear to be less refractory and/or earlier in their disease course than those who require adjunctive therapy. Such findings may help identify patients most suitable for withdrawal to ESL monotherapy. Funding: Study supported by Eisai.