Abstracts

Rationale: Eslicarbazepine acetate (ESL) is a once-daily antiepileptic drug (AED) that is approved in Europe and the USA as an adjunctive therapy for adults with partial-onset seizures. The prospective, non-interventional Eslicarbazepine acetate in Partial-Onset Seizures (EPOS) study assessed the effectiveness and safety/tolerability of ESL as add-on to antiepileptic monotherapy in everyday clinical practice across eight European countries, in order to provide ‘real-world’ data to complement evidence from clinical trials. ESL may be effective in patients who are non-responsive to carbamazepine (CBZ), since the agents differ in their modes of action, particularly in their effects on voltage-gated sodium channels (Hebeisen S et al. Neuropharmacology 2015;89:122–35). Therefore, a post hoc subgroup analysis of EPOS data was conducted in patients with documented non-response to historic CBZ treatment, results of which are presented here.Methods: EPOS included adult patients with uncontrolled partial-onset seizures under antiepileptic monotherapy, whose clinician had previously and independently decided to initiate ESL add-on therapy, and who provided informed consent. Primary endpoint was retention rate after 6 months. Other assessments (all assessed after 6 months) included responder rate (response defined as ≥50% seizure frequency reduction from baseline), seizure freedom rate, patient-rated quality of life (Quality of Life in Epilepsy Inventory-10; QOLIE-10) and physician-rated global improvement (Clinical Global Impressions-Global Improvement scale; CGI-GI). Safety/tolerability was assessed by evaluating adverse events (AEs).Results: Overall, 45 patients in EPOS had documented non-response to historic CBZ treatment. Two (4.4%) patients discontinued ESL treatment due to AEs and one (2.2%) due to lack of efficacy (n=1). Mean time to ESL discontinuation was 99.8 days (Figure 1). After 6 months, retention, responder and seizure freedom rates were 88.9% (95% confidence interval [CI] 75.9–96.3%; n=45), 95.1% (95% CI 83.5–99.4%; n=41) and 33.3% (95% CI 19.6–49.5%; n=42; Figure 2), respectively. Mean QOLIE-10 score decreased from 2.8 (n=21) at baseline to 2.2 (-13.0%; n=18) after 6 months. The majority of patients were shown to have ‘much improved’ or ‘very much improved’ on the CGI-GI after 6 months (‘much improved’, 48.8%; ‘very much improved’, 27.9%; n=43). Two AEs were reported for two (4.4%) patients; both AEs were hyponatremia.Conclusions: When ESL was used as add-on to antiepileptic monotherapy in patients with documented non-response to historic CBZ treatment in a real-world setting, the vast majority (>95%) responded to treatment and one third achieved seizure freedom after 6 months. ESL was well tolerated. Study supported by Eisai