Dataset from A Phase 3, Multi-Center, Randomized, Double-Blind, Placebo-Controlled Study and Open-Label Study to Evaluate the Efficacy and Safety of Abatacept in Combination Therapy With Methotrexate Versus Methotrexate Alone in Subjects With Active Rheumatoid Arthritis and Inadequate Response to Methotrexate

Short Term: The purpose of this clinical research study is to learn if abatacept (BMS-188667) in combination with methotrexate is better than methotrexate alone in participants that have active rheumatoid arthritis and are not responding to methotrexate. The safety of this treatment will also be studied.Long Term Extension: The purpose of this amendment is to provide participants who have completed the initial 12-month double-blind treatment period the opportunity to receive open label treatment with active drug treatment until abatacept is approved in the local country or until clinical development has been discontinued.