RO7790121 for Moderate to Severe Rheumatoid Arthritis

Inclusion Criteria: * Has moderate to severe active RA defined by the presence of \>=6 swollen joints and \>=6 tender joints at screening and baseline (based on 66/68-joint count) * Diagnosis of RA for \>=3 months and also fulfills the 2010 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) classification criteria for RA * Demonstrated an inadequate response or loss of response to or intolerance to \>=1 conventional synthetic disease-modifying antirheumatic drug (csDMARD) Exclusion Criteria: * Have failed more than two TNF inhibitors or JAK inhibitors * Class IV RA according to ACR revised response criteria (Hochberg et al. 1992) * Past or current use of other biologic disease-modifying antirheumatic drugs (bDMARDs) (excluding TNF inhibitors) or rituximab * Treatment with investigational therapy within 4 weeks or within 5 half-lives of the investigational therapy, whichever is longer, prior to initiation of study treatment. * History of any arthritis with onset prior to age 17 years or current diagnosis of inflammatory joint disease other than RA * Has been treated with intra-articular, intramuscular, intravenous, trigger point or tender point, intra-bursa, or intra-tendon sheath corticosteroids in the preceding 8 weeks prior to the first dose of study drug * History of a severe allergic reaction or anaphylactic reaction or known hypersensitivity to any component of the study drug (or its excipients) and/or other products in the same class * Any major surgery within 6 weeks prior to screening or a major surgery planned during the study * Any serious, chronic and/or unstable pre-existing medical, psychiatric, or other- condition * History of malignancy, with the exception non-metastatic basal cell or cutaneous squamous cell cancer adequately treated with electrodesiccation and curettage or resection or in situ cervical cancer adequately treated and cured * Participants with severe chronic or recurrent viral, bacterial, parasitic, or fungal infections * History of active hepatitis B virus (HBV), hepatitis C virus (HCV), or human immunodeficiency virus (HIV) infection * History of organ transplant * Any identified confirmed congenital or acquired immunodeficiency * Abnormal laboratory values and liver function test