JAK1 and rheumatoid arthritis: Filgotinib is an oral preferential JAK-1 inhibitor that is used in the treatment of moderate to severe RA; lanraplenib is an oral inhibitor of SYK and in development for the treatment of inflammatory and autoimmune diseases; tirabrutinib, a selective inhibitor of BTK, is also under development for the treatment of B-cell malignancies and inflammatory diseases.