A Study to Assess the Pharmacokinetics, Safety, and Efficacy of Two Doses of Bimekizumab in Adolescent Study Participants With Moderate to Severe Plaque Psoriasis

Inclusion Criteria:

Participant must be ≥12 to less than 18 years of age at the time of signing the informed consent/assent according to local regulation

Participant has had a diagnosis of moderate to severe plaque psoriasis (PSO) for at least 3 months prior to the Screening Visit and:

Body surface area (BSA) affected by PSO ≥10%
Investigator's Global Assessment (IGA) score ≥3 (on a scale from 0 to 4)
Psoriasis Area and Severity Index (PASI) score ≥12 OR
PASI score ≥10 plus at least 1 of the following:

i. Clinically relevant facial involvement ii. Clinically relevant genital involvement iii. Clinically relevant hand and foot involvement

Participant must be candidate for systemic PSO therapy and/or photo/chemotherapy
Body weight ≥30 kg and body mass index for age percentile of ≥5 at Baseline
Male or female A female participant will be eligible to participate if she is not pregnant, not breastfeeding, and a woman of childbearing potential (WOCBP) agrees to follow the contraceptive guidance
Capable of giving/having parent(s) or legal representative provide signed informed consent/assent (where appropriate)

Exclusion Criteria:

Participant has a presence of guttate, inverse, pustular, or erythrodermic PSO or other dermatological condition that may impact the clinical assessment of PSO
Participant has a history of inflammatory bowel disease (IBD) or symptoms suggestive of IBD
History of active tuberculosis unless successfully treated, latent TB unless prophylactically treated
Participant has an active infection or history of infections (such as serious infection, chronic infections, opportunistic infections, unusually severe infections)
Participant has laboratory abnormalities at Screening
Participant has experienced primary failure to one or more interleukin-17 (IL-17) biologic response modifier OR primary failure to more than 1 biologic response modifier other than an IL-17 biologic response modifier
Presence of active suicidal ideation, or positive suicide behavior
Participant has been diagnosed with severe depression in the past 6 months