A Study to Assess the Safety, Tolerability and Efficacy of Bimekizumab in Adult Subjects With Moderate to Severe Chronic Plaque Psoriasis

Inclusion Criteria:

- Subject is considered reliable and capable of adhering to the protocol (eg, able to
understand and complete diaries), visit schedule, and medication intake according to
the judgment of the Investigator

- Subject completes the feeder study (PS0008 [NCT03412747], PS0009 [NCT03370133], PS0013
[NCT03410992]) without meeting any withdrawal criteria

- Female subjects of childbearing potential must continue to use an acceptable method of
contraception (as detailed in the feeder study) for up to 20 weeks after the last dose
of bimekizumab in PS0014

Exclusion Criteria:

- Subject has previously participated in this study

- Female subjects who plan to become pregnant during the study or within 20 weeks
following last dose of study medication

- Subject has any medical or psychiatric condition that, in the opinion of the
Investigator, could jeopardize or would compromise the subject's ability to
participate in this study. Note: For any subject with an ongoing Serious Adverse Event
(SAE), or a history of serious infections in the feeder study, the Medical Monitor
must be consulted prior to the subject's entry into PS0014

- Subject must have a negative interferon gamma release assay (IGRA) as measured at the
final dosing visit of the feeder study

- Subject may not participate in another study of a medicinal product or device under
investigation other than the substudy

- Subject has a history of chronic alcohol or drug abuse within 6 months prior to
Baseline as assessed by medical history, site interview, and/or results of the
specified urine drug screen