This is a 2-part (6 weeks duration for each part), randomized, double-blind, placebo-controlled study in participants with rheumatoid arthritis. The hypothesis is that etoricoxib (60 mg and 90 mg) administration will demonstrate superior efficacy compared to placebo after 6 weeks of treatment, as measured by the greater mean improvement from baseline in the Disease Activity Score C-Reactive Protein (DAS-28 CRP), and by the greater mean improvement in Patient Global Assessment of Pain (PGAP) from baseline over 6 weeks of treatment. Additionally, the added benefit of increasing the dose of etoricoxib from 60 mg to 90 mg will be assessed in the second part of the study.