Evaluation of Effectiveness of Two Dosing Regimens of Fostamatinib Compared to Placebo in Patients With Rheumatoid Arthritis (RA) Who Are Taking Methotrexate But Not Responding.

Inclusion Criteria:

• Active rheumatoid arthritis (RA) diagnosed after the age of 16

• Currently taking methotrexate

• 6 or more swollen joints and 6 or more tender/painful joints (from 28 joint count) andeither Erythrocyte Sedimentation Rate (ESR) blood result of 28mm/h or more, orC-Reactive Protein (CRP) blood result of 10mg/L or more

• At least one of the following: documented history of positive rheumatoid factor (bloodtest), current presence of rheumatoid factor (blood test), radiographic erosion within 12 months prior to study enrolment, presence of serum anti-cyclic citrullinatedpeptide antibodies (blood test)

Exclusion Criteria:

• Females who are pregnant or breast feeding

• Poorly controlled hypertension

• Liver disease or significant liver function test abnormalities

• Certain inflammatory conditions (other than rheumatoid arthritis), connective tissuediseases or chronic pain disorders

• Recent or significant cardiovascular disease

• Significant active or recent infection including tuberculosis

• Previous failure to respond to a TNF alpha antagonist, anakinra or previous treatmentwith other biological agent

• Severe renal impairment

• Neutropenia