Abstracts

Rationale: Lacosamide is a new antiepileptic drug for add-on-treatment of focal epilepsies, which is available in Germany since 2008. The aim of this study was the evaluation of patients under treatment up to 12 month with Lacosamide with regard to seizure control, side effects and co-medication with sodium channel blockers.Methods: 107 consecutive patients suffering from focal epilepsies who started add-on-therapy with Lacosamide before June 2010 were analysed. Maximum evaluation period was 12 months of treatment. Patients suffering from a progressive disease or psychogenic seizures, taking part in another treatment study or undergoing epilepsy-surgery including implantaion of a vagal nerve stimulator during the evaluated period were not included. Demographic data, aetiology of epilepsy, retention rates, treatment response, co-medication and side-effects were recorded. Influence of co-medication with sodium channel blockers on the 12 month retention rate, the main side effects and the treatment response was evaluated by applying the chi-square test.Results: 53 men and 54 women of median age 43 (21-72) were included. Titration: first week: 100mg/day, second week: 200mg/day, third week: 300mg/day. Main aetiologies: 30.8% cryptogenic, 17.8% cerebral malformation, 13,1% hippocampal sclerosis, 9.3% focal cortical dysplasia and 7.5% encephalitis. 10% of the patients underwent unsuccesful epilepsy surgery before treatment with Lacosamide. Retention rates: 63.6%/59.8% after 11/12 months. Responder rates (ITT): 4.7% seizure free, 13.1% seizure reduction (SR) between 75% and 99%, 17.8% SR between 50% and 74%, 59.7% SR below 50%, worsening in 3.8%. Main co-medications: 36.4% Levetiracetam, 26.2% Lamotrigine, 24.3% Oxcarbazepine. Main side effects: 23.3% dizziness, 15% tiredness, 2.8% nausea. Temporary or persistent side effects were found in 35.5% of the patients. We found a significant difference in the 12-month retention rate and the responder rates (seizure reduction >= 50%) for patients with versus without co-medication with sodium channel blockers: 31.7% versus 68.3% (p=0,004) and 25,5% versus 45% (p=0,04). No significant difference was found for the side effects.Conclusions: Due to the main aetiologies most of our patients suffered from a difficult to treat epilepsy. They showed a responder rate (ITT, seizure reduction >= 50%) of 35.6% and a 12-month retention rate of 59,8%. Over all tolerability was good. Our results from a naturalistic treatment setting are well compareable to other add-on studies and confirm that Lacosamide is a good therapeutic option in focal epilepsies. Interestingly 12-month retention rate and seizure response were significantly better in patients without co-medication with sodium channel blockers. This finding is concordant to prior studies and up to now not well understood.