Objectives: To evaluate the efficacy and safety of methotrexate (MTX) discontinuation in Japanese rheumatoid arthritis (RA) patients with sustained low disease activity undergoing combination therapy with tocilizumab (TCZ) plus MTX.Methods: This multicenter, open-label, uncontrolled, prospective study included RA patients maintaining low disease activity (Clinical Disease Activity Index (CDAI) ≤10) for ≥12 weeks with TCZ plus MTX. Methotrexate was discontinued following 12 weeks of biweekly administration while continuing TCZ therapy. The primary endpoint was the proportion of patients maintaining low disease activity with no flare at week 36.Results: A total of 49 patients completed 36 weeks of therapy. The proportion of patients maintaining low disease activity at week 36 was 75.5%. The lower limit of the 95% confidence interval exceeded the assumed threshold response rate of 60%, demonstrating the clinical feasibility of MTX discontinuation. The prevalence of gastroesophageal reflux disease, defined as a Frequency Scale for Symptoms of Gastroesophageal reflux disease score ≥8, significantly decreased from week 0 to 12 (27.1-18.4%; p= .025).Conclusion: Discontinuation of concomitant MTX is clinically feasible for maintaining low disease activity, and may be beneficial from the perspective of reducing gastrointestinal symptoms in Japanese RA patients treated with TCZ. Trial registration number: UMIN000021247.
Keywords: Rheumatoid arthritis; clinical trial; gastroesophageal reflux; methotrexate; tocilizumab.