Objectives: To investigate the long-term effectiveness, safety, and methotrexate (MTX) dose-tapering patterns in patients with rheumatoid arthritis (RA) receiving adalimumab plus high-dose MTX.Methods: In this prospective, postmarketing study (2012-2017), conducted at 128 sites in Japan, biologic-naïve patients with RA (duration ≤2 years) previously treated with MTX for ≥3 months, initiated treatment with adalimumab and MTX (≥12 mg/week). Effectiveness by Disease Activity Score in 28 joints using C-reactive protein (DAS28-CRP), safety, and MTX dose-tapering were assessed from baseline to 104 weeks.Results: In the effectiveness analysis set (n = 292), DAS28-CRP remission (<2.6) was achieved in 92.3% (n = 120/130) of patients at week 104. The proportions of patients receiving MTX dose <10 mg/week increased to 32.3% (n = 50/155) and ≥12 mg/week reduced to 52.9% (n = 82/155) by week 104. Per univariate regression analysis, MTX dose tapering was associated with longer adalimumab drug survival. Of 70 patients with joint X-rays available, 59 (84.3%) achieved Δ modified total Sharp score ≤1.0 at 104 weeks. In the safety analysis set (n = 300), 143 adverse drug reactions were reported in 92 patients (30.7%, non-serious; 24.7%, serious 8.7%).Conclusion: The long-term effectiveness and safety of adalimumab with high-dose MTX was confirmed in biologic-naïve patients with early RA in a real-world setting in Japan.Clinical Trial Registration: This study is registered at ClinicalTrials.gov (identifier: NCT01736189; retrospectively registered 29 November 2012, due to administrative reasons).
Keywords: Adalimumab; Japan; dose tapering; methotrexate; postmarketing.