Review of zonisamide development in Japan.

Zonisamide is a benzisoxazole-based compound first synthesized in the early 1970s by the research laboratories of Dainippon Pharmaceutical Company in Osaka, Japan. Identified as an anticonvulsant during exploratory research, zonisamide has since been characterized as having broad-spectrum antiepilepsy and neuroprotective effects. Early clinical studies in Japan demonstrated that zonisamide has a long elimination half-life and is well tolerated; Phase II and III clinical trials established the drug's efficacy and safety for the treatment of partial and generalized seizures.

Overview of Japanese experience-controlled and uncontrolled trials.

Zonisamide is a new type of benzisoxazole derivative, first marketed in Japan in 1989. This study analyzed: (1) the drug's efficacy by seizure and epilepsy type in a total of 1008 patients treated during the development of zonisamide in Japan; (2) the effectiveness of zonisamide for 726 newly-diagnosed patients treated with zonisamide postmarketing; and (3) 50 patients with generalized epilepsies and epileptic syndromes (idiopathic generalized epilepsies, symptomatic generalized epilepsies, Lennox-Gastaut syndrome, Doose syndrome, and West syndrome), and 19 patients with undetermined epilepsies and specific syndromes (refractory grand mal in childhood, severe myoclonic epilepsy in infancy, other undetermined epilepsy, familial essential myoclonic epilepsy, and mitochondrial encephalomyopathy with ragged-red fibers). Analysis of study results showed that among all patients treated, zonisamide was highly effective for the treatment of idiopathic generalized epilepsy, temporal lobe epilepsy, and other partial epilepsies.