The Food and Drug Administration has approved eslicarbazepine acetate, a voltage-gated sodium channel inhibitor, as an add-on treatment for adults with partial-onset seizures.
The approval, announced Nov. 8, is based on three phase III, double-blind, randomized placebo-controlled clinical trials of eslicarbazepine at doses of 800 mg and 1,200 mg once daily involving more than 1,400 adults. All patients had partial seizures that were inadequately controlled on one to three concomitant antiepileptic drugs (including carbamazepine, lamotrigine, valproic acid, and levetiracetam). In the studies, 41% of patients taking eslicarbazepine had at least a 50% reduction from baseline in seizure frequency, compared with 22% of placebo-treated patients.
The most common side effects in the studies included dizziness, somnolence, nausea, headache, diplopia, vomiting, fatigue, vertigo, ataxia, blurred vision, and tremor, resulting in adverse event discontinuation rates of 14% for the 800-mg dose, 25% for the 1,200-mg dose, and 7% for placebo.
The manufacturer of eslicarbazepine, Sunovion Pharmaceuticals, will market the drug under the brand name Aptiom, an immediate-release formulation taken once daily.
The treatment dose should begin at 400 mg once daily and after 1 week can be increased to the recommended dose of 800 mg once daily, followed by a switch to the maximum recommended dose of 1,200 mg once daily if necessary. The 1,200-mg dose regimen is associated with an increase in adverse reactions and should be started only after a patient has tolerated 800 mg once daily for at least 1 week. However, it may be necessary for some patients to begin treatment at 800 mg once daily if the need for additional seizure reduction outweighs the risk of greater adverse reactions, according to Sunovion.
The company said it expects that Aptiom will be available in U.S. pharmacies in the second quarter of 2014.