Tofacitinib (CP-690,550) in Patients with Rheumatoid Arthritis Receiving Methotrexate: Twelve-month Data from a Twenty-four-month Phase III Randomized Radiographic Study

Objective: The purpose of this 24-month phase III study was to examine structural preservation with tofacitinib in patients with rheumatoid arthritis (RA) with an inadequate response to methotrexate (MTX). Data from a planned 12-month interim analysis are reported.

Methods: In this double-blind, parallel-group, placebo-controlled study, patients receiving background MTX were randomized 4:4:1:1 to tofacitinib at 5 mg twice daily, tofacitinib at 10 mg twice daily, placebo to tofacitinib at 5 mg twice daily, and placebo to tofacitinib at 10 mg twice daily. At month 3, nonresponder placebo-treated patients were advanced in a blinded manner to receive tofacitinib as indicated above; remaining placebo-treated patients were advanced at 6 months. Four primary efficacy end points were all analyzed in a step-down procedure.

Results: At month 6, response rates according to the American College of Rheumatology 20% improvement criteria for tofacitinib at 5 mg and 10 mg twice daily were higher than those for placebo (51.5% and 61.8%, respectively, versus 25.3%; both P < 0.0001). At month 6, least squares mean (LSM) changes in total modified Sharp/van der Heijde score for tofacitinib at 5 mg and 10 mg twice daily were 0.12 and 0.06, respectively, versus 0.47 for placebo (P = 0.0792 and P ≤ 0.05, respectively). At month 3, LSM changes in the Health Assessment Questionnaire disability index score for tofacitinib at 5 mg and 10 mg twice daily were -0.40 (significance not declared due to step-down procedure) and -0.54 (P < 0.0001), respectively, versus -0.15 for placebo. At month 6, rates of remission (defined as a value <2.6 for the 4-variable Disease Activity Score in 28 joints using the erythrocyte sedimentation rate) for tofacitinib at 5 mg and 10 mg twice daily were 7.2% (significance not declared due to step-down procedure) and 16.0% (P < 0.0001), respectively, versus 1.6% for placebo. The safety profile was consistent with findings in previous studies.

Conclusion: Data from this 12-month interim analysis demonstrate that tofacitinib inhibits progression of structural damage and improves disease activity in patients with RA who are receiving MTX.