Study to Evaluate the Long-term Safety, Tolerability and Efficacy of Bimekizumab in Patients With Chronic Plaque Psoriasis.

Inclusion Criteria:

- Subject has provided informed consent

- Subject completes all dosing requirements in feeder study and completes PS0010 study
without meeting any withdrawal criteria

- Female subjects of childbearing potential and male subjects with a partner of
childbearing potential must continue to use an acceptable method of contraception (as
detailed in PS0010) for up to 20 weeks after the last dose of study treatment in
PS0011

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. Male subjects who are planning a partner
pregnancy during the study or within 20 weeks following the last dose

- 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.

- Subject must have a negative interferon gamma release assay (IGRA) as measured at Week
8 of PS0010