Study to Evaluate Safety and Efficacy of Different Doses of Bimekizumab in Patients With Chronic Plaque Psoriasis

Inclusion Criteria:

- Subject has provided informed consent

- Chronic plaque psoriasis for at least 6 months prior to Screening

- PASI (Psoriasis Area and Severity Index) >=12 and BSA (body surface area) >=10% and
IGA (Investigator's Global Assessment) score 3 or greater on a 5-point scale

- Candidates for systemic psoriasis therapy and/or phototherapy and/or chemophototherapy

- Female subjects must be postmenopausal, permanently sterilized or, if of childbearing
potential, must be willing to use a highly effective method of contraception up till
20 weeks after last administration of study drug

- Male subjects with a partner of childbearing potential must be willing to use a condom
when sexually active, up till 20 weeks after the last administration of study
medication

Exclusion Criteria:

- Subjects with erythrodermic, guttate, pustular form of psoriasis, or drug-induced
psoriasis

- Subject has any severe, progressive and/or uncontrolled renal, hepatic, hematological,
endocrine, pulmonary, cardiac, gastrointestinal or neurological disease

- Subject has any significant concurrent medical condition or laboratory abnormalities,
as defined in the study protocol

- Subject taking prohibited psoriatic medications

- Subject receiving any live vaccines within 8 weeks prior to the Baseline and subjects
receiving Bacillus Calmette-Guerin (BCG) vaccination within 1 year prior to study drug
administration

- Subject has previously received treatment with any anti-interleukin-17 (anti-IL-17)
therapy or has been exposed to more than 1 biological response modifier (limited to
anti-tumor necrosis factor (TNF) or IL-12/23) for psoriatic arthritis or psoriasis
prior to the Baseline

- Subject has any current sign or symptom that may indicate an active infection (except
for common cold)