OBJECTIVES: To determine the efficacy of CP-690,550 in improving pain, function 
and health status in patients with moderate to severe active rheumatoid 
arthritis (RA) and an inadequate response to methotrexate or a tumour necrosis 
factor alpha inhibitor.
METHODS: Patients were randomised equally to placebo, CP-690,550 5, 15 or 30 mg 
twice daily for 6 weeks, with 6 weeks' follow-up. The patient's assessment of 
arthritis pain (pain), patient's assessment of disease activity, Health 
Assessment Questionnaire-Disability Index (HAQ-DI) and Short Form-36 (SF-36) 
were recorded.
RESULTS: At week 6, significantly more patients in the CP-690,550 5, 15 and 30 
mg twice-daily groups experienced a 50% improvement in pain compared with 
placebo (44%, 66%, 78% and 14%, respectively), clinically meaningful reductions 
in HAQ-DI (> or =0.3 units) (57%, 75%, 76% and 36%, respectively) and clinically 
meaningful improvements in SF-36 domains and physical and mental components.
CONCLUSIONS: CP-690,550 was efficacious in improving the pain, function and 
health status of patients with RA, from week 1 to week 6.