Dose-ranging Study With GLPG0634 in Methotrexate-refractory Active Rheumatoid Arthritis Patients

Inclusion Criteria: * Have active RA as shown by five or more swollen joints (from the 66-joint count), five or more tender joints (from 68-joint count), and a serum CRP ≥1.0 mg/dL; * Have received methotrexate for 12 weeks or longer and at a stable dose of 7.5 to 25 mg/week for at least 4 weeks prior to screening and willing to continue on this regimen for the duration of the study; * If taking oral steroids, these should be at a dose ≤10 mg/day of prednisone or prednisone equivalent and stable for at least 4 weeks prior to screening; * If taking non-steroidal anti-inflammatory drugs (NSAIDs), these must be at a stable dose for at least 2 weeks prior to screening; * Female subjects must have a negative pregnancy test unless they are surgically sterile or have been post-menopausal for at least one year; * Women of childbearing potential must use a medically acceptable means of birth control and agree to continue its use during the study and for at least 12 weeks after the last dose of study drug. * Sexually active men must agree to use a medically acceptable form of contraception during the study and continue its use for at least 3 months after the last dose of study drug; and * Able and willing to sign the informed consent prior to screening evaluations and agree to schedule of assessments. Exclusion Criteria: * Treatment with disease-modifying antirheumatic drugs (DMARDs), other than background methotrexate; * Current or previous RA treatment with a biological agent, with the exception of biologics administered in a clinical study setting more than six months prior to screening (12 months for rituximab or other B cell depleting agents); * Previous treatment at any time with a cytotoxic agent, other than methotrexate, before screening; * Previous use of the study drug GLPG0634; * Receipt of an intra-articular or parenteral corticosteroid injection within 4 weeks prior to screening; * Known hypersensitivity to study drug ingredients or a significant allergic reaction to any drug as determined by the Investigator; * Positive serology for HIV1 or 2 or hepatitis B or C, or any history of hepatitis from any cause with the exception of hepatitis A; * History of any inflammatory rheumatological disorders other than RA; * History of tuberculosis (TB) infection