A Study With a Initial Treatment Period Followed by a Randomized-withdrawal Period to Evaluate the Efficacy and Safety of Bimekizumab in Adult Subjects With Moderate to Severe Chronic Plaque Psoriasis

Inclusion Criteria:

Must be at least 18 years of age
Chronic plaque psoriasis (PSO) for at least 6 months prior to the Screening Visit
Psoriasis Area Severity Index (PASI) >=12 and body surface area (BSA) affected by PSO >=10% and Investigator's Global Assessment (IGA) score >=3 on a 5-point scale
Subject is a candidate for systemic PSO therapy and/or phototherapy
Female subject of child bearing potential must be willing to use highly effective method of contraception

Exclusion Criteria:

Subject has an active infection (except common cold), a recent serious infection, or a history of opportunistic, recurrent, or chronic infections
Subject has concurrent acute or chronic viral hepatitis B or C or human immunodeficiency virus (HIV) infection
Subject has known tuberculosis (TB) infection, is at high risk of acquiring TB infection, or has current or history of nontuberculous mycobacterium (NTMB) infection
Subject has any other condition, including medical or psychiatric, which, in the Investigator's judgment, would make the subject unsuitable for inclusion in the study
Presence of active suicidal ideation or positive suicide behavior
Presence of moderately severe major depression or severe major depression
Subject has any active malignancy or history of malignancy within 5 years prior to the Screening Visit EXCEPT treated and considered cured cutaneous squamous or basal cell carcinoma, or in situ cervical cancer