Study to Assess the Short- and Long-term Efficacy of Certolizumab Pegol Plus Methotrexate Compared to Adalimumab Plus Methotrexate in Subjects With Moderate to Severe Rheumatoid Arthritis (RA) Inadequately Responding to Methotrexate

Inclusion Criteria:

- Subject must have a diagnosis of Rheumatoid Arthritis (RA) at Screening, as defined by
the 2010 European League Against Rheumatism (EULAR)/American College of Rheumatology
(ACR) classification criteria (Aletaha D et al, 2010)

- Subject must have a positive Rheumatoid Factor (RF) and/or a positive anti-Cyclic
Citrullinated Peptide antibody (anti-CCP) as determined by the central laboratory at
Screening

- Subject must have moderate to severe RA disease at Screening and Baseline defined as:

1. Screening (all criteria required)

- ≥ 4 swollen joints (of 28 prespecified joints)

- Disease Activity Score [Erythrocyte Sedimentation Rate] (DAS28[ESR]) > 3.2

- C-Reactive Protein (CRP) concentration ≥ 10 mg/L (or 1.0 mg/dL) or
Erythrocyte Sedimentation Rate (ESR) (Westergren) ≥ 28 mm/hr

2. Baseline (both criteria required)

- ≥ 4 swollen joints (of 28 prespecified joints)

- Disease Activity Score [Erythrocyte Sedimentation Rate] (DAS28[ESR]) > 3.2

- Subject must have inadequately responded previously to Methotrexate (MTX)

- Subject is using MTX 15 to 25 mg/week orally or subcutaneously at Screening and has
used the same MTX regimen for a minimum of 28 days prior to Baseline

Exclusion Criteria:

- Subject has previously received any biological Disease Modifying Antirheumatic Drug
(DMARD) or has received treatment with cyclophosphamide, chlorambucil, Janus Kinase,
phosphodiesterase 4 inhibitors or investigational agents such as spleen tyrosine
kinase

- Diagnosis of any other inflammatory arthritis

- Infected with Tuberculosis (TB) or high risk of acquiring TB infection

- Subjects with concurrent acute or chronic viral hepatitis B or C infection

- Subjects with a history of chronic or recurrent infections or subjects at high risk of
infection

- Use of prohibited medications like nonbiological DMARDs (excluding MTX), biological
DMARDs excluding study medications, experimental therapy, IA hyaluronic acid