An Open-label, Non-controlled Study of KHK4827 in Subjects With Psoriasis

Inclusion Criteria: * Subject has signed voluntarily the written informed consent form to participate in this study. * Subject has been diagnosed as pustular psoriasis or psoriatic erythroderma. * Subject has received at least one previous phototherapy or systemic psoriasis therapy or has been a candidate to receive phototherapy or systemic psoriasis therapy in the opinion of the investigator. Exclusion Criteria: * Subject with psoriatic erythroderma has involved Body surface area (BSA) of lesion \< 80% at baseline. * Subject diagnosed with guttate psoriasis, medication-induced or medication-exacerbated psoriasis. * Evidence of skin conditions at the time of the screening visit (eg, eczema) that would interfere with evaluations of the effect of KHK4827 on psoriasis. * Subject has any active Common Terminology Criteria for Adverse Events (CTCAE) grade 2 or higher infection * Subject has a significant concurrent medical condition or laboratory abnormalities, as defined in the study protocol. * Subject has used Ultra Violet B (UVB) therapy within 14 days of the first dose or Ultra Violet A (UVA) (with or without psoralen) within 28 days of the first dose. * Subject has used etanercept, adalimumab, infliximab or ustekinumab within 1 week, 2 weeks, 8 weeks or 12 weeks of the first dose, respectively. * Subject has stopped ustekinumab or other anti-Interleukin (IL)-23 biologics therapy due to lack of efficacy * Subject has used live vaccine within 3 months of the first dose * Subject has previously used an anti-IL-17 biologic therapy