MADRID – The investigational antiepileptic lacosamide is well tolerated and reduced seizures by more than 50% in almost half of patients who took it as adjunctive therapy for medication-refractory partial seizures.
“This study, with more than 5 years of follow-up, showed that lacosamide controls these seizures very well,” Dr. William Rosenfeld said at the annual congress of the European Federation of Neurological Societies.
Lacosamide is also being investigated for neuropathic pain, said Dr. Rosenfeld, medical director of the Comprehensive Epilepsy Care Center for Children and Adults in St. Louis. The drugmaker, UCB Inc. of Brussels, received a not approvable letter from the Food and Drug Administration for this indication in late July, although the agency is still considering the drug's use as an add-on therapy for partial-onset seizures.
The phase III trial was an open-label extension study that comprised 370 adults (mean age 40 years) who had previously participated in placebo-controlled studies of the drug. The mean follow-up time was 5.5 years. At baseline, all patients had partial seizures that remained uncontrolled despite numerous medication trials; more than half of the cohort had tried seven or more drugs during their lifetime.
Study protocol allowed titration of up to 800 mg/day; lacosamide could be used as either add-on therapy or monotherapy at the clinicians' discretion. The most commonly used dosage was 400 mg/day (24%).
Overall, 46% of patients taking the drug experienced a reduction in seizures of at least 50%. This response rate was apparent by 6 months and continued to improve, with 65% responding by 30 months.
“This doesn't mean, however, that the drug was getting more effective as time went on,” Dr. Rosenfeld said. “It's a function of adjusting the dose and having nonresponders drop out.”
Adverse events were dizziness (37%), which was transient and usually ceased as patients adjusted to the medication; headache (18%), fatigue, and nasopharyngitis (14% each); and diplopia, abnormal vision, and upper respiratory tract infection (13% each). There were no significant cognitive side effects, Dr. Rosenfeld said.
According to the company Web site, lacosamide has a novel dual method of action, selectively enhancing slow inactivation of voltage-gated sodium channels, and modulating collapsin response mediator protein 2 (CRMP-2).
Dr. Rosenfeld has been a principal investigator in several of the company-sponsored lacosamide studies.