A Clinical Study of Increased Dose of TA-650 in Patients With Psoriasis

* Patients with plaque psoriasis or psoriatic arthritis: 1. Screening Period: TA-650 at 5 mg per kg body weight is administered on the day of TA-650 administration at the start (week 0) and week 8 (if efficacy is not judged as decreased or maintained at week 8 of the screening period) , respectively, by intravenous infusion slowly over at least 2 hours. 2. Increased Dose Period: If efficacy is judged as decreased in the screening period, TA-650 at 10 mg per kg body weight is administered on the day of TA-650 administration at the start (week 0) and at every 8 weeks up to week 32 in the increased dose period , respectively, as one dose by intravenous infusion slowly over at least 2 hours. * Patients with pustular psoriasis or psoriatic erythroderma: TA-650 at 10 mg per kg body weight is administered on the day of TA-650 administration at the start (week 0) and at every 8 weeks up to week 32, respectively, as one dose by intravenous infusion slowly over at least 2 hours.