Phase 3 Randomized, Double-blind Study Of The Efficacy And Safety Of 2 Doses Of Cp-690,550 Compared To Methotrexate In Methotrexate Navie Patients With Rheumatoid Arthritis

This study is designed to compare the effectiveness of the experimental drug, CP-690,550, to methotrexate in preventing joint damage and improving symptoms of rheumatoid arthritis. This study will also compare the safety of CP-690,550 with methotrexate.