Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors play a key role in mediating glutamatergic transmission in the cortex. Perampanel (2-[2-oxo-1-phenyl-5-pyridin-2-yl-1,2-dihydropyridin-3-yl] benzonitrile) is a potent, orally active, highly selective, non-competitive AMPA-type glutamate receptor antagonist, identified via a focused discovery program at Eisai Research Laboratories. Development of perampanel as adjunctive therapy for the treatment of partial-onset seizures was planned in keeping with regulatory guidance and guidelines on antiepileptic drug (AED) development. This is the first AED with a specific action on glutamate-mediated excitatory neurotransmission to show evidence of efficacy and tolerability in reducing treatment-refractory partial-onset seizures in Phase III clinical trials. Perampanel (Fycompa®) has been approved in the EU and the United States for adjunctive treatment of partial-onset seizures.