Atacicept in Anti-Tumor Necrosis Factor Alpha-naïve Subjects With Rheumatoid Arthritis (AUGUST II)

Inclusion Criteria:

- Male or female subjects greater than or equal to (>=) 18 years of age at the time of
informed consent who have RA satisfying American College of Rheumatology (ACR)
criteria with a disease history of at least 6 months

- Subjects must have active disease, defined by >=8 swollen joints (out of 66), >=8
tender joints (out of 68) and CRP >=10 milligram per liter (mg/L) and/or erythrocyte
sedimentation rate (ESR) >=28 millimeter per hour (mm/hr), despite treatment with MTX
at a dose of >=15 milligram per week (mg/week) for greater than (>) 3 months

- Other protocol-defined inclusion criteria could apply

Exclusion Criteria:

- Inflammatory joint disease other than RA

- Previous or concurrent treatment with any approved or investigational biological
compound for RA, including but not restricted to any anti-TNFalpha agents, rituximab,
abatacept, tocilizumab, interleukin-1 receptor antagonist (IL-1Ra) and belimumab

- Treatment with disease-modifying anti-rheumatic drug (DMARDs) other than MTX

- Participation in any interventional clinical trial within 1 month before study Day 1

- MTX dose >25 mg/week, prednisone dose >10 mg/day (or equivalent), or change in
steroid or non-steroidal anti-inflammatory drug (NSAID) dosing regimen within 28 days
before study Day 1

- Immunization with live vaccine or immunoglobulin (Ig) treatment within 28 days before
study Day 1 or need for such treatment during the study (including follow-up)

- Any history or presence of active or latent tuberculosis, major infection requiring
hospitalization or intravenous anti-infectives within 28 days before study Day 1

- Other major concurrent illness or organ dysfunction as specified in the protocol

- Serum IgG below 6 gram per liter (g/L)

- Known hypersensitivity to atacicept or to any of the components of the formulated
atacicept

- Other protocol-defined exclusion criteria could apply