Abstracts

Rationale: Lacosamide is approved for the adjunctive treatment of adults with partial-onset seizures (POS), and the safety and efficacy of long-term, open-label lacosamide treatment up to 8 years have been reported previously. The prevalence of new-onset seizures in the elderly is the highest among any age group and approximately twice that of younger adults. As the elderly often take concomitant drugs for other chronic conditions, treatment decisions for epilepsy in this patient population can be challenging. To determine any potential differences in lacosamide treatment effect or safety profile among the elderly compared with the overall OLE lacosamide pool, a subgroup analysis was performed. In this analysis, the safety and efficacy of lacosamide was examined in patients ≥65 years who participated in a lacosamide open-label extension (OLE) trial. Methods: Patients entered one of three OLEs (SP615, SP756, SP774) following completion of a corresponding phase II or III trial of adjunctive lacosamide for POS. Safety and efficacy data for patients who were ≥65 years at OLE study entry or by OLE study end were pooled from the three trials. Results: Of 1,054 patients who initiated OL lacosamide treatment, 13 were ≥65 years at study entry and 33 were ≥65 years by study end. Of the 33 elderly patients by study end, 21 (63.6%) completed the trial and 18 of the 21 (85.7%) continued to commercial lacosamide use. The mean and maximum duration of lacosamide treatment was 1563.2 and 2790.0 days, respectively, and the median modal lacosamide dose was 400 mg/day. At >1, >3, and >5 years OL treatment, 90.9%, 75.8%, and 42.4% of the elderly patients remained in the trial. As all patients had an opportunity to complete approximately 3 years of exposure, the lower rates of exposure after 3 years is attributed to premature discontinuations and study closure. The primary reasons for discontinuation were adverse events (n = 4, 12.1%), lack of efficacy (n = 3, 9.1%), and consent withdrawal (n = 2, 6.1%). Common treatment-emergent adverse events (TEAEs; n ≥ 5 [≥15%]) were dizziness (n = 12, 36.4%), fall (n = 9, 27.3%), contusion or sinusitis (n = 7 each, 21.2%), cognitive disorder, tremor, headache, depression, or cough (n = 6 each, 18.2%), and urinary tract infection, nausea, diplopia, vision blurred, convulsion, balance disorder, or pain in extremity (n = 5 each, 15.2%). The median percent reduction in seizure frequency from Baseline for 1-, 3- and 5-year completers was 62.5%, 58.2% and 66.6%. The ≥50% responder rate was 63.3%, 68.0% and 64.3% for 1-, 3- and 5-year completers. Conclusions: In this small population of elderly patients with POS, long-term OL treatment with lacosamide up to 8 years was generally well tolerated and was associated with a reduction in seizure frequency and maintenance of efficacy similar to the overall OLE patient pool. Sponsored by UCB