In this study, we identified an unclassified RIPK1 inhibitor (18), KW2449, and evaluated its therapeutic effects on RA using collagen-induced arthritis (CIA) rats, a classical RA animal model, and an in vitro necroptosis model induced by lipopolysaccharide (LPS) with the pancaspase inhibitor zVAD (19) in RAW 264.7 cells. The gene discussed is RIPK1; the disease is rheumatoid arthritis.