rilzabrutinib

Rilzabrutinib is an investigational **oral small-molecule, reversible covalent Bruton's tyrosine kinase inhibitor** being developed by Sanofi, originally from Principia Biopharma. It is designed to selectively inhibit BTK in immune cells including B cells and macrophages, with the goal of reducing pathogenic autoantibody production and Fc receptor-mediated inflammatory signaling while potentially limiting off-target toxicities seen with earlier BTK inhibitors. The most advanced program is in **immune thrombocytopenia**, where phase 3 LUNA 3 data showed durable platelet responses and improvements in bleeding and fatigue; the drug has also been studied in other immune-mediated diseases including **asthma**, **chronic spontaneous urticaria**, **warm autoimmune hemolytic anemia**, **atopic dermatitis**, **prurigo nodularis**, and **IgG4-related disease**. In published and trial data, common adverse events have included diarrhea, nausea, and headache, with an overall safety profile generally described as favorable for the BTK class.

Brand names

Wayrilz

Other names

1575591-66-0SAR-444671SAR444671SAR 444671