A Study in Moderate to Severe Rheumatoid Arthritis Participants

The purpose of this study is to determine whether baricitinib 4 milligram (mg) once daily (QD) is superior to placebo in the treatment of participants with moderately to severely active Rheumatoid Arthritis (RA) who have had inadequate response to or are intolerant to at least 1 conventional disease-modifying antirheumatic drug (cDMARD)(cDMARD-IR \[inadequate response\] participants) and who have not received a biologic disease-modifying antirheumatic drug (DMARD).