Abstracts

Rationale: Data from regulatory randomised controlled trials do not provide information to help guide best use of new antiepileptic drugs (AED). Long term observational studies in a real life setting can help identify strategies for the optimal use of new AED, as well as provide more realistic picture of adverse effects. We analysed outcomes in patients treated with lacosamide (LCM) in a regional epilepsy clinic over a period of 7 years. Methods: All patients prescribed lacosamide (LCM) were identified from the clinical database. Data regarding seizure type and frequency, epilepsy classification, number of previous AED, concomitant AED, dose of lacosamide used, responder rates for each seizure types, adverse effects and retention on treatment were analysed Results: 74 patients, median age 40 (range21-86 years), 45 (61%) of whom were male were included in the analysis. Epilepsy was classified as cryptogenic or symptomatic focal in 62 (84%), Idiopathic Generalised in 6 (8%), Symptomatic Generalised in 2 (3%) and was unclassified in 4 (5%). Over the study period 32 (43%) of patients discontinued LCM, 17 (23%) due to adverse effects, and 15 (20%) due to lack of efficacy. The median duration of treatment with LCM was 42 months (range 1-144). Kaplan-Meier analysis of retention on treatment is shown in figure 1. Adverse effects leading to discontinuation are listed in table 1. 32 patients could be classed as responders, 11 of 61 (18%) patients with GTCS, 16 of 59 (27%) patients with complex partial seizures and 5 of 27 (19%) with simple partial seizures. No patients with absence (n=11), tonic (n=5) atonic (n=5) or myoclonic (n=6) seizures could be classed as responders The median daily dose of LCM was 200 mg (range 50-500) in patients withdrawing due to side effects, and 400 mg in both responders and those withdrawing due to lack of efficacy. The mean number of concomitant AED were higher in patients withdrawing due adverse effects (2.6) compared to responders (mean 1.6, p=0.02). Those withdrawing due to adverse effects were also more likely to have been co-prescribed sodium channel blocking AED compared to responders (31% v/s 84 %, chi square 7.05, p = 0.002) Compared to responders, those withdrawing due to adverse effects had on average longer duration of epilepsy (22 years versus 31 years) and had received more AED (6.6 versus 8.06) prior to initiation of LCM, but these differences were not statistically significant. Conclusions: LCM produced responder rates comparable to those seen in the regulatory clinical trials in patients with refractory partial and generalised tonic clonic seizures, but was ineffective in patients with absence, myoclonic and tonic seizures. Withdrawal due to side effects was more commonly seen in patients co-prescribed other sodium channel blocking drugs and those who were on a higher number of concomitant AED. Funding: No funding has been received in support of the work presented in this abstract