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

Inclusion Criteria: * Patients who have already been diagnosed as having plaque psoriasis, psoriatic arthritis, pustular psoriasis (excluding a localized), or psoriatic erythroderma. * Patients in whom effect of the treatment was confirmed for a certain period after the start of administration of Remicade® at 5 mg/kg at every 8 weeks but decreased thereafter. Exclusion Criteria: * Patients who have guttate psoriasis. * Patients who have drug-induced psoriasis * Patients who have previously used any other biological products than infliximab. * Patients who have a concomitant diagnosis, or a history within 6 months prior to provisional enrollment, of serious infections that need hospitalization. * Patients who have a concomitant diagnosis, or a history within 6 months prior to provisional enrollment, of opportunistic infections * Female patients who are pregnant, breast-feeding, or possibly pregnant.