Study to Evaluate SC Route of Administration of Ofatumumab in RA Patients

Key Inclusion Criteria: * Male or female aged ≥ 18 years * A diagnosis of rheumatoid arthritis according to the American College of Rheumatology (ACR1987 classification) of at least six months prior to screening * Subjects must be treated with MTX, 7.5-25 mg/week, for at least 12 weeks prior to Visit 2, with the last 4 weeks prior to Day 2 at a stable dosage * Patient must be willing to receive folic acid ≥5mg/wk 4 weeks prior to baseline administered according to locally accepted practice * Body mass index (BMI) \< 35kg/m2 (inclusive) * Capable of giving written informed consent, which includes compliance with the requirements and restrictions listed in the consent form Key Exclusion Criteria: * Subjects with a history of a rheumatic autoimmune disease other than RA (except secondary Sjögren's syndrome), or with significant systemic involvement secondary to RA (vasculitis, pulmonary fibrosis or Felty's syndrome) * Previous exposure to biologic cell depleting anti-rheumatic therapies, including investigational compounds (e.g. anti-CD11a, anti-CD19, anti-CD20, anti-CD22, anti-BLyS/BAFF, anti-CD3, anti-CD4, anti-CD5, anti-CD52) * Exposure to etanercept \< 4 weeks, infliximab or adalimumab \< 8 weeks, or abatacept or anakinra \< 12 weeks prior to visit 2 * Received any of the following treatments within 4 weeks prior to Visit 2: * Anti-cancer therapy (e.g. alkylating agents, anti-metabolites, purine analogues, monoclonal antibodies) * Glucocorticoid unless given in doses equivalent to ≤ 10 mg of prednisolone /day * Intra-articular, i.m. or IV corticosteroids * Live/attenuated vaccinations * Cyclosporine * Azathioprine * Penicillamine * Sulfasalazine * Bucillamine * Hydroxychloroquine * Chloroquine * Exposure to leflunomide within 12 weeks prior to visit 2 unless the subject has completed peroral cholestyramine treatment * Exposure to gold therapy ≤ 12 weeks prior to Visit 2 * Exposure to IV immunogammaglobulins ≤ 24 weeks prior to Visit 2 * Past or current malignant melanoma * Chronic or ongoing active infectious disease requiring systemic treatment such as, but not limited to, renal infection, chest infection with bronchiectasis, tuberculosis and active hepatitis B and C * History of significant cerebrovascular disease * Positive plasma / white cell JC Virus (JCV) PCR (either compartment)