Saphnelo (anifrolumab) is a monoclonal antibody used for the treatment of systemic lupus erythematosus (SLE) in adult patients. The medication targets the type I interferon receptor subunit 1 (IFNAR1) and is administered intravenously every four weeks. Saphnelo works by blocking the activity of type I interferons, which are involved in the abnormal immune activation in SLE.