Abstracts

Rationale: Lacosamide (LCM) is approved as adjunctive therapy in adults 17 years and older for partial onset seizures. LCM may benefit children who have failed to respond to previous antiepileptic drugs (AEDs). However, little is known about the use of LCM in children. We have reviewed our records and report our experience on dose, efficacy and adverse effects of LCM in children. Methods: Following IRB approval, patients < 17 years old who had been treated with LCM between May 2009 and May 2010 were identified. Medical records were audited for demographics, EEG/MRI, seizure type/frequency, previous/current treatments for seizures, and information regarding treatment with LCM, dosing regimen, efficacy and adverse effects (AEs). Results: Thirty patients (15 female, 15 male), median age 8 years (range: 17 months-16 years), were treated with LCM. 22/30 (73%) have a significant related structural abnormality identified on MRI and 21 (70%) have severe/profound cognitive impairment. Median failed past AED trials 10(range 5-18). LCM was added to 1-5 concomitant AEDs (90% ? 2 AEDs). The mean starting dose was 2.2 (range: 0.54-8.64) and maximum dose 8.4 (range: 2.74-18.8) mg/kg/day. 7/30 (23%) had a ? 50% reduction of seizures from baseline (mean dose 7.8 mg/kg/day) with 2 (6.6%) seizure free for 52 and 37 weeks. 18/30 (60%) continue LCM with duration of therapy at last contact of 4-52 weeks. 16/30 (53.3%) reported 26 total AEs regardless of association to LCM (mean dose 8 mg/kg/day) compared to 14/30 without AEs (9 mg/kg/day). Most frequently reported: ataxia (23.3%), sedation (23.3%), vomiting (10%) at mean doses of 10, 9 and 15 mg/kg/day respectively. 16/30 (53%) had LCM added to a regimen containing an AED with a primary mechanism of voltage-gated Na channel blocker. 10/16 (62.5%) reported AEs (7/10 LTG, 1/3 OXC, 1/2 CBZ, 1/1 RUF): mean dose 5.24 mg/kg/day (LTG group) and 13.73 mg/kg/day (others combined). 14/30 patients whose LCM was added to non-primary Na channel blocker AEDs, 6 reported AEs (mean dose 8.2 mg/kg/day). No significant abnormal lab values or serious AEs were reported. EKG was not routinely performed. 12/30 (40%) discontinued LCM. 9/30 (30%) due to lack of acceptable benefit and 3 (10%) due to AEs (mean maximum dose 8.9 and 3.3 mg/kg/day respectively). 7/30 had 9 random LCM levels drawn. Levels of 1.8-8.3 mg/L were documented on 3.67 - 14.2 mg/kg/day and not clearly associated with efficacy or tolerability. Conclusions: Lacosamide demonstrated efficacy and tolerability as adjunctive therapy in children with refractory epilepsy. Almost one in every 4 patients had a ? 50% improvement in seizure control with 2 patients (6.6%) seizure free. There were no serious adverse effects; no clinically significant abnormal lab values. In this very small group, more AEs were observed at relatively lower doses when LCM was added to LTG. When LCM is added as adjunctive therapy to multi-AED therapy, in general, an initial starting dose of 2 mg/kg/day to a maintenance dose of up to 8 mg/kg/day is tolerated.