Peficitinib is primarily used in the treatment of autoimmune and inflammatory conditions, particularly rheumatoid arthritis. It functions as a Janus kinase (JAK) inhibitor, modulating intracellular signaling pathways involved in immune responses and inflammation. By inhibiting JAK enzymes, it helps reduce the production of pro-inflammatory cytokines, thereby alleviating joint pain, swelling, and stiffness. Its oral bioavailability makes it a convenient option for long-term management of chronic inflammatory diseases. Research has also explored its potential in other immune-mediated disorders, including psoriasis and inflammatory bowel disease, due to its broad impact on immune cell activity.