Efforts to optimize selectivity and in vivo properties of IRAK4 inhibitors have, however, proven successful, and two such selective inhibitors, Pf-06650833 (Pfizer) and CA-4948 (Curis/Aurigene) have reached clinical development, the former for rheumatoid arthritis (NCT02996500) and the latter for non-Hodgkin lymphoma (NHL; [NCT03328078]). Here, IRAK4 is linked to rheumatoid arthritis.