A recently published study on Pfizer’s CP-690,550 looked at its efficacy 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 tumor necrosis factor alpha inhibitor. CP-690 is a Jak-3 inhibitor designed to block enzymes that play a key role in inflammatory disease.

In the study, patients were randomized equally to placebo, CP-690,550 5, 15 or 30 mg twice daily for 6 weeks, with 6 weeks' follow-up. The patients’ assessment of arthritis pain, assessment of disease activity, Health Assessment Questionnaire-Disability Index (HAQ-DI), and Short Form-36 (SF-36) were recorded. The study results showed that at week 6, significantly more patients in the CP-690,550 twice-daily groups (all doses) experienced a 50% improvement in pain compared with placebo, along with clinically meaningful reductions in HAQ-DI and improvements in SF-36 domains and physical and mental components. This demonstrates that CP-690,550 is efficacious in improving the pain, function, and health status of patients with RA, from week 1 to week 6.

Reference:

1. Coombs JH, Bloom BJ, Breedveld FC, et al. Improved pain, physical functioning and health status in patients with rheumatoid arthritis treated with CP-690,550, an orally active Janus kinase (JAK) inhibitor: results from a randomised, double-blind, placebo-controlled trial. Ann Rheum Dis. 2010;69(2):413-6. Epub 2009 Jul 8.