A Clinical Study of Tulisokibart (MK-7240) to Treat Rheumatoid Arthritis (RA) (MK-7240-014)

Researchers are looking for new ways to treat rheumatoid arthritis (RA). Methotrexate (MTX) is a standard (usual) treatment for RA. However, MTX and other current treatments may not work well to treat RA symptoms for many people. This study will help find out if a study medicine called tulisokibart can treat symptoms of active RA in people who are taking MTX. In this study, researchers will look at different doses of tulisokibart. Researchers want to learn if at least one of the study doses of tulisokibart works better than a placebo to lessen RA symptoms. A placebo looks like the study medicine but has no study medicine in it. Using a placebo helps researchers better understand the effects of the study medicine.

This study consists of a 12-week Placebo-controlled Period and a 116-week Long-term Extension (LTE), which is composed of a 44-week Main Extension and an 72-week Optional Extension

Inclusion Criteria: The main inclusion criteria include but are not limited to the following: * Has a clinical diagnosis of rheumatoid arthritis (RA) and fulfillment of 2010 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria * Has active disease defined as ≥6 tender joints (based on 68 joints) and ≥6 swollen joints (based on 66 joints) * Has current treatment with oral or parenteral methotrexate (MTX) therapy * Has history of one of the following: a) biologic disease-modifying antirheumatic drug (bDMARD) naïve, or b) bDMARD-Inadequate Response (IR)/intolerant up to a maximum of 2 classes of bDMARDS Exclusion Criteria: The main exclusion criteria include but are not limited to the following: * Has any arthritis with onset before age 17 years or current diagnosis of inflammatory joint disease other than RA (such as, but not limited to, psoriatic arthritis, systemic lupus erythematosus, gout, systemic sclerosis, myositis, pseudogout, etc) or any other condition that may, in the judgment of the investigator, interfere with the assessment of RA * Has a history of cancer (except fully treated nonmelanoma skin cancers or cervical carcinoma in situ after complete surgical removal) and is disease free for \<5 years before randomization * Has any active infection * Has known allergies, hypersensitivity, or intolerance to tulisokibart or its excipients