Long―term safety and efficacy of vigabatrin in Japanese patients with infantile spasms: A multicenter open―label study

This clinical study is to evaluate the long―term safety and efficacy of vigabatrin (VGB) in Japanese patients with infantile spasms. A total of 17 patients were treated (maximum treatment duration: 1,380 days), including 7 patients transitioned from the preceding phase III study, 2 patients administered VGB outside of clinical trials, and 8 patients who initiated VGB in this study. In these 8 patients, the daily dose was set during a dose adjustment phase. In the other patients, the daily dose was the same as at the start of the study (150 mg/kg/day). Nine patients discontinued the study because of treatment change (7 patients) and adverse drug reactions (2 patients). Adverse drug reactions occurred in 76.5% (13/17 patients) of patients. Notable adverse drug reactions included mild retinal abnormalities (2 patients, unrecovered), asymptomatic magnetic resonance imaging abnormality (1 patient, recovering), and encephalopathy (1 patient, recovered). However, the long―term administration of VGB was generally well tolerated. Spasms disappeared in 6 of 8 patients who completed the study. Follow―up including periodic ophthalmic examination is necessary to address adverse drug reactions such as retinal disorder observed in long―term administration of VGB in patients with infantile spasms.