ABSTRACT Objective Characterize safety of the Janus kinase-1 preferential inhibitor filgotinib (FIL) in Japanese patients with moderately to severely active rheumatoid arthritis (RA). Methods Data from three Phase 3 trials (NCT02889796, NCT02873936, and NCT02886728) and a long-term extension (NCT03025308) through September 2019 were integrated; patients received ≥1 dose of FIL 200 (FIL200) or 100 mg (FIL100) daily, or placebo (PBO). We calculated exposure-adjusted incidence rates (EAIRs) per 100 patient-years FIL exposure (100PYE) for treatment-emergent adverse events (TEAEs) and adverse events of special interest. Results Among 3691 total patients and 6080.7 PYE, 229 Japanese patients received FIL for 311.4 PYE (median 1.5, maximum 2.5 years). During the 12-week PBO-controlled period, serious TEAEs and TEAEs leading to study drug disruption were comparable between FIL and PBO. Serious infection rates were 1.9%, 0%, and 2% for FIL200, FIL100, and PBO during the PBO-controlled period; long-term FIL200 and FIL100 EAIRs were 3.8 and 2.1/100PYE. No herpes zoster (HZ) or major adverse cardiovascular events (MACEs) occurred during the PBO-controlled period; long-term FIL200 and FIL100 EAIRs were 3.0 and 2.1/100PYE (HZ) and 0.6 and 0/100PYE (MACE). Conclusion Long-term FIL treatment (median 1.5, maximum 2.5 years exposure) was well tolerated at 100- and 200-mg doses in Japanese patients with RA.