A Study to Compare ABT-494 Monotherapy to Methotrexate Monotherapy in Subjects With Rheumatoid Arthritis (RA) Who Have Not Previously Taken Methotrexate

Inclusion Criteria:

- Duration of symptoms consistent with RA for ≥ 6 weeks who also fulfill the 2010
ACR/EULAR classification criteria for RA.

- Naïve to Methotrexate (MTX) or, if already on MTX, have received no more than 3 weekly
MTX doses with requirement to complete a 4-week MTX washout before the first dose of
study drug.

- Subjects with prior exposure to conventional synthetic disease-modifying
anti-rheumatic drugs(csDMARDs) other than MTX may be enrolled if completed the washout
period.

- Subject meets the following minimum disease activity criteria: greater than or equal
to 6 swollen joints (based on 66 joint counts) and greater than or equal to 6 tender
joints (based on 68 joint counts) at Screening and Baseline Visits.

- Greater than or equal to 1 bone erosion on x-ray (by local reading) OR in the absence
of documented bone erosion, both positive rheumatoid factor and positive anti-cyclic
citrullinated peptide autoantibodies are required at Screening.

Exclusion Criteria:

- Intolerant to Methotrexate (MTX).

- Prior exposure to any Janus kinase (JAK) inhibitor (including but not limited to
tofacitinib, baricitinib, and filgotinib).

- Prior exposure to any biologic disease-modifying anti-rheumatic drugs (bDMARDs).

- History of any arthritis with onset prior to age 17 years or current diagnosis,
inflammatory joint disease other than RA (including but not limited to gout, systemic
lupus erythematosus, psoriatic arthritis, axial spondyloarthritis including ankylosing
spondylitis and non-radiographic axial SpA, reactive arthritis, overlap connective
tissue diseases, scleroderma, polymyositis, dermatomyositis, fibromyalgia [currently
with active symptoms]. Current diagnosis of secondary Sjogren's Syndrome is permitted.