This single arm study will evaluate the safety and efficacy of MabThera in patients with active rheumatoid arthritis who are receiving methotrexate treatment, and who have had an inadequate response to one anti-TNF alpha therapy. All patients will receive MabThera 1000mg i.v. on days 1 and 15, in addition to concomitant methotrexate. Patients who achieve a clinically relevant response to the first course of treatment may be eligible to receive one re-treatment course of MabThera between weeks 24 and 48. The anticipated time on study treatment is 3-12 months, and the target sample size is 100 individuals.

Inclusion Criteria:

• adult patients, 18-80 years of age;
• moderate to severe active rheumatoid arthritis;
• inadequate response to previous or current treatment with 1 anti-TNF agent;
• receiving methotrexate at a dose of 10-25mg/week for 12 weeks prior to start of study, at a stable dose for >=4 weeks.

Exclusion Criteria:

• previous treatment with MabThera;
• use of an anti-TNF alpha agent within 8 weeks of study start;
• concurrent treatment with any DMARD other than methotrexate;
• active infection, or history of serious recurrent or chronic infection.