Discontinuation of methotrexate in rheumatoid arthritis patients achieving clinical remission by treatment with upadacitinib plus methotrexate (DOPPLER study): A study protocol for an interventional, multicenter, open-label and single-arm clinical trial with clinical, ultrasound and biomarker assessments

BACKGROUND: The administration of Janus kinase inhibitors as well as biological disease-modifying anti-rheumatic drugs has dramatically improved the clinical outcomes of patients with rheumatoid arthritis (RA). Previous trials have shown that upadacitinib, a Janus kinase inhibitor, can effectively improve disease activity and prevent progression of joint destruction in RA patients with inadequate responses to methotrexate (MTX). It remains unclear whether reduced disease activity can be maintained after discontinuation of MTX in patients treated with upadacitinib plus MTX. Thus, the aim of this study is to evaluate changes in disease activity after administration of upadacitinib plus MTX in RA patients who failed to achieve an adequate response to MTX and to determine whether clinical relapse can be avoided after discontinuation of MTX in those who achieved clinical remission. METHODS/DESIGN: The proposed study is an interventional, multicenter, open-label, single-arm clinical trial with a 48-week follow-up. The cohort will include 155 RA patients with at least moderate disease activity during treatment with MTX. Patients will receive upadacitinib and MTX will be discontinued for those who achieve clinical remission. Disease activity will be evaluated longitudinally by measuring clinical disease activity indices and with musculoskeletal ultrasound (MSUS). The primary endpoint is the proportion of patients who sustain a disease activity score-28- C reactive protein score of ≤3.2 from week 24 to 48 after a disease activity score-28- C reactive protein score of <2.6 at week 24. Important secondary endpoints are changes from baseline MSUS scores. Serum levels of multiple biomarkers, including cytokines and chemokines, will be comprehensively analyzed. DISCUSSION: The study results are expected to show the clinical benefit of the discontinuation of MTX after achieving clinical remission by treatment with upadacitinib plus MTX combination therapy. The strength of this study is the prospective evaluation of therapeutic efficacy using clinical disease activity indices and standardized MSUS, which can accurately and objectively evaluate disease activity at the joint level among patients drawn from multiple centers. Furthermore, parameters to predict clinical remission after administration of upadacitinib plus MTX combination therapy and nonclinical relapse after discontinuation of MTX will be screened by integrated multilateral assessments (i.e., clinical disease activity indices, MSUS findings, and serum biomarkers).