Treatment persistence and clinical outcomes following subcutaneous methotrexate initiation in patients with rheumatoid arthritis: a real-world observational study

Objectives This study aimed to evaluate treatment persistence and safety following subcutaneous methotrexate (MTX) initiation in Japanese patients with RA and to assess clinical outcomes among patients who directly switched from oral to subcutaneous MTX. Methods This retrospective study included 101 patients with RA who initiated subcutaneous MTX at our institution. Efficacy and safety were analysed in patients who switched from oral MTX due to adverse events. The primary endpoint was the 26-week retention rate of subcutaneous MTX. Results Gastrointestinal intolerance was the commonest reason for switching from oral to subcutaneous MTX. The overall retention rate was 87.1% (88/101). Among 88 patients who switched, the 26-week retention rate was 92.0% (81/88). During 26 weeks after switching, MTX dose increased in 46.6% (41/88). In patients not receiving biologic or targeted synthetic disease-modifying anti-rheumatic drugs at switching (n=50), the 26-week retention rate was 96.0% (48/50), and mean MTX dose increased (10.3±2.8 to 12.0±2.8 mg/week; p<0.0001). The Clinical Disease Activity Index improved by week 26 (13.2±10.1 to 8.2±7.8; p<0.0001), with 30.0% (15/50) achieving remission. Conclusions Switching from oral to subcutaneous MTX in patients with RA who are intolerant to oral MTX may enable continued treatment and dose optimization and be associated with improved disease activity.