An Adaptive Phase 2a/2b Study of LY3871801 in Adult Participants With Rheumatoid Arthritis

Inclusion criteria

• Have a diagnosis of adult-onset RA for at least 3 months prior to screening as defined by the 2010 ACR/European League Against Rheumatism (EULAR) classification criteria.
• Have moderately-to-severely active RA at screening and baseline, defined by the presence of

• ≥6 swollen joints based on 66 joint count, and
• ≥6 tender joints based on 68 joint count.
• Have had a history of failure (an inadequate response, intolerance, or loss of response) to at least 1 conventional synthetic disease modifying anti rheumatic drug (csDMARD) and either 1 biologic (bDMARD), or targeted synthetic (tsDMARD) treatment.

Exclusion criteria

• Have Class IV RA according to ACR revised criteria
• Have presence of 1 or more significant concurrent medical conditions per investigator judgment, including but not limited to

• poorly controlled diabetes or hypertension
• chronic kidney disease stage IIIa or IIIb, IV, or V
• symptomatic heart failure according to New York Heart Association class II, III, or IV
• myocardial infarction,unstable angina pectoris, stroke, or transient ischemic attack within the past 12 months before randomization
• severe chronic pulmonary disease, for example, requiring oxygen therapy
• major chronic inflammatory disease or connective tissue disease other than RA, including but not limited to

• systemic lupus erythematosus
• psoriatic arthritis
• axial spondyloarthritis,including ankylosing spondylitis and non-radiographic axial spondyloarthritis
• reactive arthritis
• gout
• scleroderma
• polymyositis
• dermatomyositis
• active fibromyalgia, or
• multiple sclerosis