Zimlovisertib (PF-06650833) is a drug which acts as a selective inhibitor of the enzyme Interleukin-1 receptor-associated kinase 4 (IRAK-4). It has antiinflammatory effects and has been trialed for various indications including hidradenitis suppurativa and treatment of COVID-19 infection, and while it has not been adopted into clinical use it continues to be used for research in this area.[1][2][3]