The FDA has granted tentative approval to a supplemental new drug application (sNDA) requesting a label expansion for Trokendi XR (extended-release topiramate, Supernus Pharmaceuticals) to include the prophylaxis of migraine headache in adults.
The approval of the sNDA is tentative because the FDA has determined that the drug meets all of the required quality, safety, and efficacy standards for approval but is subject to pediatric exclusivity, which expires in March 2017. Final approval may not be made effective until this exclusivity period has expired.
In addition, the FDA has granted final approval to expand the label for Trokendi XR for monotherapy of partial-onset seizures to include adults and pediatric patients 6 years of age and older, rather than 10 years of age and older.
Trokendi XR is the first approved once-daily, extended-release formulation of topiramate for the treatment of epilepsy. It is indicated for initial monotherapy in patients 6 years of age and older with partial-onset or primary generalized tonic-clonic seizures; for adjunctive therapy in patients 6 years of age and older with partial-onset or primary generalized tonic-clonic seizures; and for adjunctive therapy in patients 6 years of age and older with seizures associated with Lennox–Gastaut syndrome. The product is available in 25-mg, 50-mg, 100-mg, and 200-mg extended-release capsules.
Topiramate is a sulfamate-substituted monosaccharide. The precise mechanisms by which topiramate exerts its anticonvulsant effects are unknown; however, preclinical studies have indicated that four properties may contribute to the drug’s efficacy in epilepsy. Electrophysiological and biochemical evidence suggests that topiramate, at pharmacologically relevant concentrations, blocks voltage-dependent sodium channels; augments the activity of the neurotransmitter gamma-aminobutyrate at some subtypes of the gamma-aminobutyric acid A (GABA-A) receptor; antagonizes the AMPA/kainate subtype of the glutamate receptor; and inhibits the carbonic anhydrase enzyme, particularly isozymes II and IV.