Japan’s Ministry of Health, Labour and Welfare has granted orphan drug designation to Sanofi’s rilzabrutinib for treating IgG4-related disease, marking the third global orphan drug designation for the oral reversible Bruton’s tyrosine kinase inhibitor. The designation was supported by positive Phase 2 study results showing that treatment over 52 weeks reduced disease flares and disease markers while minimizing glucocorticoid requirements.
Common adverse events in the study included diarrhea, COVID-19, dizziness, dry mouth, and nausea, with no new safety concerns identified. A Phase 3 trial called RILIEF is currently evaluating the drug for this indication.
Rilzabrutinib, marketed as Wayrilz, has accumulated a broad set of regulatory designations and approvals globally. It received approval in the U.S., European Union, and UAE for immune thrombocytopenia in 2025, and holds additional orphan and fast track designations across multiple rare autoimmune conditions.