A Study of Tildrakizumab in Pediatric Subjects With Chronic Plaque Psoriasis

Inclusion Criteria: * Subject must be 6 to \< 18 years of age, of either sex, of any race/ ethnicity, must weight greater than or equal to 15Kg. * Diagnosis of predominantly plaque psoriasis for ≥6 months (as determined by subject interview and confirmation of diagnosis through physical examination by investigator). * Moderate to severe psoriasis at baseline defined as: at least 10% Body Surface Area (BSA) involvement, PGA score ≥ 3, and PASI score ≥ 12 * Subject must be considered a candidate for systemic therapy and/or phototherapy. * Subject is considered to be eligible according to tuberculosis (TB) screening criteria * A maximum of 2 QuantiFERON tests will be allowed. A re-test is only permitted if the first is indeterminate; the result of the second test will then be used. Exclusion Criteria: * Subject has predominantly non-plaque forms of psoriasis specifically erythrodermic psoriasis, predominantly pustular psoriasis, medication-induced or medication-exacerbated psoriasis, or new-onset guttate psoriasis * Subject has laboratory abnormalities at screening including any of the following: Alanine transaminase (ALT) or aspartate transaminase, (AST) ≥2X the upper limit of normal, Creatinine ≥1.5X the upper limit of normal serum direct bilirubin ≥ 1.5 mg/dL, white blood cell count \< 3.0 x 103/μL, and any other laboratory abnormality, which, in the opinion of the Investigator, will prevent the subject from completing the study or will interfere with the interpretation of the study results * Subject who is expected to require topical therapy, phototherapy, or additional systemic therapy for psoriasis during the trial * Female subjects of childbearing potential who are pregnant, intend to become pregnant (within 6 months of completing the trial), or are lactating. (Sexually active adolescent girls will be required to use contraception) * Subject with presence of any infection or history of recurrent infection requiring treatment with systemic antibiotics within 2 weeks prior to Screening, or severe infection (e.g. pneumonia, cellulitis, bone or joint infections) requiring hospitalization or treatment with IV antibiotics within 8 weeks prior to Screening * Positive human immunodeficiency virus (HIV) test result, hepatitis B Virus (HBV) test results, or hepatitis C virus (HCV) test result * Subjects who have a high risk of suicidality at the Screening assessment as indicated by the C-SSRS (Columbia Suicide Severity Rating Scale), or based on the Investigator's judgment. * Subject who has received any of the prohibited medications, supplements or substances during the study.