Inclusion Criteria:  Patients must meet all of the following requirements to be considered for entry into the study:  ≥20 years old with the diagnosis of RA based on the American College of Rheumatology (ACR) /EULAR 2010 RA Classification Criteria with at least moderate DAS28-CRP >3.2 at the eligibility evaluation with at least one PD score positive joint of 22 joints examined MSUS at the eligibility evaluation treated with MTX for ≥8 weeks prior to the providing consent, including 4 weeks or more at the same doses of 6 to 16 mg per week ability and willingness to provide written informed consent and comply with the requirements of the study protocol.  Exclusion Criteria:  The exclusion criteria are as follows:  (1) concurrent use of a corticosteroid equivalent to >7.5 mg/day of prednisolone (2) applicable an item for the contraindication of upadacitinib (3) a previous use of a JAK inhibitor (4) treatment with a corticosteroid and change of dose within 4 weeks prior to the providing consent (5) treatment with a csDMARD except MTX within 2 weeks prior to the providing consent; (6) treatment with a biologic DMARD or a biosimilar DMARD (ie, infliximab, biosimilar of infliximab, adalimumab, golimumab, certolizumab pegol, tocilizumab, sarilumab or abatacept) within 8 weeks prior to the providing consent (7) treatment with a TNF inhibitor (ie, etanercept or biosimilar of etanercept) within 4 weeks prior to the providing consent (8) use of a prohibited drug or therapy, other than the agents noted above, within 4 weeks prior to the providing consent (9) a complication causing musculoskeletal disorders other than RA (ie, ankylosing spondyloarthritis, reactive arthritis, psoriatic arthritis, crystal-induced arthritis, systemic lupus erythematosus, systemic scleroderma, inflammatory myopathy, or mixed connective tissue disease) (10) current pregnancy, breastfeeding, or noncompliant with a medically approved contraceptive regimen during and 12 months after the study period (11) inappropriateness for inclusion in this study as determined by the investigator