A Study to Test the Efficacy and Safety of Bimekizumab in the Treatment of Subjects With Active Psoriatic Arthritis

Inclusion Criteria: * An Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved written Informed Consent form is signed and dated by the subject * Subject is male or female at least 18 years of age * Female subject must be postmenopausal, permanently sterilized or willing to use a highly effective method of contraception * Documented diagnosis of adult-onset Psoriatic Arthritis (PsA) meeting the Classification Criteria for Psoriatic Arthritis (CASPAR) for at least 6 months prior to Screening with active PsA and must have at Baseline tender joint count (TJC) \>=3 out of 68 and swollen joint count (SJC) \>=3 out of 66 * Subject must be negative for rheumatoid factor and anti-cyclic citrullinated peptide (CCP) antibodies * Subject must have at least 1 active psoriatic lesion(s) and/or a documented history of psoriasis (PSO) * Subject must be a suitable candidate for treatment with adalimumab and has no contraindications to receive adalimumab as per the local label as assessed by the Investigator * Subjects currently taking NSAIDs, cyclooxygenase 2 (COX-2) inhibitors, analgesics (including mild opioids), corticosteroids, methotrexate (MTX), leflunomide (LEF), sulfasalazine (SSZ), hydroxychloroquine (HCQ) AND/OR apremilast can be allowed if they fulfill specific requirements prior to study entry Exclusion Criteria: * Female subjects who are breastfeeding, pregnant, or plan to become pregnant during the study * Subjects with current or prior exposure to any…