Lacosamide Significantly Reduced Seizures In Refractory Epilepsy Patients
Investigational drug lacosamide, with the proposed brand name Vimpat, administered as oral, adjunctive therapy, significantly reduced the frequency of seizures and was generally well-tolerated in patients with uncontrolled partial-onset seizures, for up to 5.5 years. The results of the two Phase II trials (Abstracts 3.197 and 3.191) were presented today at the 61st annual meeting of the American Epilepsy Society.
"These findings are encouraging because they show lacosamide significantly reduced seizure frequency in this refractory patient population over a long-term period," said Steve S. Chung, Director of Clinical Epilepsy Research at the Barrow Neurological Institute in Phoenix. "Approximately one third of people with epilepsy are resistant to current antiepileptic drugs. These data show lacosamide's potential to fill an unmet need in this patient population."
The first presentation (SP754) was a double-blind, randomized, parallel-group, placebo-controlled Phase II trial involving 405 patients with refractory partial onset seizures, which were uncontrolled despite treatment with one to three AEDs. The patients were randomized to receive lacosamide 400 mg/day or 600 mg/day (given in 2 doses), or placebo over the 12-week treatment period.
The median reduction in seizure frequency from baseline was significantly greater for lacosamide than placebo: 37.3%, 37.8% and 20.8% for lacosamide 400 mg/day, 600 mg/day, and placebo, respectively. Significantly more patients achieved a 50% or greater reduction in seizure frequency with lacosamide than placebo: 38.3%, 41.2% and 18.3% for lacosamide 400 mg/day, 600 mg/day, and placebo, respectively. Nine subjects who completed the Maintenance Phase were seizure free throughout the entire 12-weeks: 4 of 160 completers in the 400 mg/day group (2.5%) and 5 of 62 completers in the 600 mg/day group (8.1%).
The most common adverse events associated with lacosamide, occurring in 10% or more of patients, included dizziness, nausea, diplopia, blurred vision, vomiting, headache, tremor, abnormal coordination, sleepiness, and nystagmus. A small increase in mean PR interval (4-6 msec) was associated with 400-600mg/day lacosamide treatment.
Patients in the SP754 trial had the option to transition to an open-label extension trial (SP615). The presentation of the SP615 data included an interim analysis of long-term efficacy and safety findings with lacosamide in 370 patients. The patients received lacosamide 100-800 mg/day based on the investigator's clinical judgment (median dose 400 mg/day). Of the 370 patients enrolled, 284 (76.8%) were exposed to lacosamide for more than 12 months, 224 (60.5%) for more than 24 months, and 140 (37.8%) for more than 36 months.
The study supported the long-term use (up to 5.5 years) of lacosamide as an adjunctive treatment in epilepsy patients with partial onset seizures, finding that the median percent reduction in seizure frequency across all prior treatment groups was 45.9%. Additionally, 46.6% of patients had at least a 50% reduction in seizure frequency with lacosamide.
The most common adverse events associated with lacosamide, occurring in 10% or more of patients, were dizziness, headache, fatigue, nasopharyngitis, diplopia, upper respiratory tract infection, nausea, abnormal coordination, contusion, vision blurred, vomiting, skin laceration, and sinusitis. Long-term lacosamide treatment was not associated with any pattern of change in hematology, clinical chemistry, vital sign, and body weight measurements with increasing duration of exposure. A small increase in median PR interval (5 to 9 msec) across all subjects (all modal doses) was observed on the ECG.