Study to Evaluate Tulisokibart in Adults With Psoriatic Arthritis (MK-7240-015)

Researchers are looking for new ways to treat Psoriatic Arthritis (PsA). This study will help find out if a study medicine called tulisokibart (MK-7240) can treat symptoms of active PsA. This study assesses the efficacy, safety, and tolerability of tulisokibart in adult participants with active PsA. 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 PsA 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.

Inclusion Criteria: The main inclusion criteria include but are not limited to the following: * Has a clinical diagnosis of PsA and fulfillment of the Classification Criteria for Psoriatic Arthritis (CASPAR) criteria at Screening, with symptom onset ≥6 months before Screening. * Has a diagnosis of active plaque psoriasis or documented history of plaque psoriasis. * Has history of biologic disease-modifying antirheumatic drug (bDMARD)-naïve or bDMARD-inadequate response/intolerant. 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 PsA (such as, but not limited to, rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, myositis, etc), or any other conditions that may, in the judgment of the investigator, interfere with the assessment of PsA. * Has a skin condition diagnosis, other than psoriasis that may, in the judgment of the investigator, interfere with the assessment of psoriasis. * 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 \