Study of Single Doses of SBT777101 in Subjects With Rheumatoid Arthritis

Inclusion Criteria: * Body mass index (BMI) \<35 kg/m\^2, inclusive * Adult-onset, moderate-to-severe rheumatoid arthritis (RA) * Moderate-to-severe active disease * Clinical and/or ultrasound evidence of synovitis * Prior inadequate response to or unable to tolerate available RA therapies * Stable doses of RA medications for at least 30 days * Use of highly effective methods of contraception Exclusion Criteria: * Major surgery within 12 weeks prior to screening or planned within 12 months after dosing * Uncontrolled cardiovascular, pulmonary, renal, hepatic, endocrine, or gastrointestinal disease * Recurrent infections or active infection * Active or untreated latent tuberculosis * Primary or secondary immunodeficiency * History of or current inflammatory joint disease other than RA