FDA Approves Extended-Release Oxcarbazepine for Epilepsy

Emma Hitt, PhD


October 23, 2012

The US Food and Drug Administration (FDA) has approved a novel once-daily extended-release formulation of oxcarbazepine (Oxtellar XR, Supernus Pharmaceuticals Inc) for use as adjunctive therapy for partial seizures in adults and in children 6 to 17 years of age.

The formulation, formerly known as SPN-804, is recommended at a daily dose of 1200 to 2400 mg once per day for adults and 900 to 1800 mg for children 6 to 17 years of age depending on weight. The product will be available in 150-mg, 300-mg, and 600-mg extended-release tablets.

The FDA approval letter, dated October 19, indicates that the FDA granted a waiver for the pediatric study requirement for ages birth to 1 month and a deferral for submission of postmarketing assessments for children 1 month to 6 years of age. The postmarketing pharmacokinetic assessments are due in 2016, to be followed by clinical assessments in 2021.

The company states that they will launch the new therapy in the first quarter of 2013.

Approval of the new formulation was based on the results of a multicenter, randomized, double-blind, 3-group study of adults aged 18 to 65 years with refractory partial epilepsy. A total of 369 patients were randomly assigned; 366 of these were included in the intention-to-treat population.

Compared with placebo, SPN-804 at a dose of 2400 mg/d resulted in a significant increase in response rate (P = .018) and seizure-free periods during treatment (P = .013) and maintenance (P = .008).

Adverse events occurred in 69.1%, 56.6%, and 54.5% of those receiving SPN-804 2400 mg/d, SPN-804 1200 mg/d, and placebo, respectively; the most frequently reported adverse events with SPN-804 were dizziness, somnolence, headache, nausea, diplopia, and vomiting.

Serious adverse events occurred in 9.8%, 6.6%, and 6.6% of those taking SPN-804 2400 mg/d, SPN-804 1200 mg/d, and placebo, respectively, although no deaths were reported in the treatment groups.