LAUSR

OBJECTIVE To present safety and efficacy of the JAK1 preferential inhibitor filgotinib in Japanese patients with prior inadequate response (IR) to methotrexate (MTX) from a 52-week randomised controlled parent study (PS) and long-term extension (LTE) through June 2020. METHODS The PS (NCT02889796) randomised MTX-IR patients to filgotinib 200 (FIL200) or 100 mg (FIL100), adalimumab (ADA) 40 mg, or placebo; all took stable background MTX. At week (W) 24, placebo patients were rerandomised to FIL200 or FIL100. The primary endpoint was W12 American College of Rheumatology 20% improvement (ACR20); safety was assessed by adverse event (AE) reporting. For the LTE (NCT03025308), eligible filgotinib patients continued FIL200/FIL100; ADA patients were rerandomised (blinded) to FIL200 or FIL100; all continued MTX. RESULTS 114/147 Japanese patients completed the PS; 115 enrolled in LTE; 103 remained on study in June 2020. In the PS, AEs were consistent with the overall population, and W24 efficacy was maintained or improved through W52, comparable with the overall population. LTE AE incidences were similar between doses; filgotinib efficacy was consistent from baseline to W48 and similar between PS ADA and filgotinib patients. CONCLUSION Among MTX-IR Japanese patients, filgotinib maintained efficacy over 1 year; LTE safety was consistent with the PS.