Abstracts

Rationale: Lacosamide (LCM) is licensed across Europe and in the USA as add-on therapy for the treatment of adults with partial-onset seizures. The drug may exert its effect by enhancing sodium channel slow inactivation and by binding to collapsin-response mediator protein 2. This prospective audit aims to ascertain outcomes with this new antiepileptic drug (AED) in everyday clinical practice. Methods: To date, 76 patients (35M; 41F, aged 21-71 years [median 40 years]) with uncontrolled partial-onset seizures with or without secondary generalisation (monthly frequency range 1-300; [median 4]) have been started on LCM. Patients were taking a median of 1 AED (range 1-4), having previously tried 1-12 AEDs (median 2). After 12 weeks on stable AED doses, LCM was added with initial target dosing of 200-400mg/day. Review occurred every 6-8 weeks until 1 of 4 end-points was reached: seizure freedom for ?6 months on a given LCM dose; ?50% (responder) or <50% (marginal benefit) seizure reduction over 6 months compared with baseline on the highest tolerated LCM dose; withdrawal of LCM due to lack of efficacy, adverse effects, or both. Results: An end-point has been reached by 50 (65.8%) of the 76 patients. Of these, 25 (50%) also took other sodium channel blocking drugs (sodium blockers; 14 carbamazepine, 5 oxcarbazepine, 4 lamotrigine, 2 phenytoin); 25 (50%) were taking AEDs with different mechanisms of action (see Table). Seizure freedom was achieved in 14 (28%), with a median LCM dose of 100mg/day (range 50-400mg/day). Of the seizure-free patients, 8 (57.1%) took other sodium blockers, with the remaining 6 (42.9%) taking different AEDs. Patients were more likely to become seizure-free when LCM was used as a first add-on (11 of 21, 52.4%), compared to a later treatment schedule (3 of 29, 10.3%; p=0.001). Fourteen (28%) patients could be classified as responders with a further 14 (28%) showing marginal benefit. LCM was withdrawn in 8 (10.5%) patients (3 lack of efficacy, 5 side effects), 4 of whom took concomitant sodium blockers. Problems leading to withdrawal in the 5 patients comprised sedation, ataxia, dizziness, agitation, tremor and headache. Only 2 (1 dizziness, 1 headache) were treated with other sodium blockers. Conclusions: These preliminary data suggest that LCM appears an effective and well-tolerated adjunctive AED in patients with partial-onset seizures. Outcomes were no different when the drug was combined with other sodium blockers compared with patients taking AEDs with different mechanisms of action. Seizure freedom was more likely when LCM was used a first add-on compared to later in the treatment schedule.