Janus kinases (JAKs) are non-receptor kinases that mediate signaling through cytokine receptors, often to members of the signal transducer and activator of transcription family. CEP-33779 is a potent, orally available inhibitor of JAK2 (IC50 = 1.3 nM). It shows 65-fold selectivity for JAK2 over JAK3. In mouse models of systemic lupus erythematosus, CEP-33779 reduces the production of inflammatory cytokines, decreases splenomegaly and lymphomegaly, and extends survival. It also diminishes inflammatory signaling and improves clinical scores in mice during collagen antibody-induced arthritis and collagen type II-induced arthritis. CEP-33779 induces regression of established colorectal tumors in mice, reducing angiogenesis and proliferation of tumor cells.
