CHZ868

CHZ868 is a potent small molecule type II inhibitor of Janus kinase 2 (JAK2), specifically designed to target the inactive conformation of JAK2. Unlike type I JAK inhibitors, which bind to the active conformation of JAK2, CHZ868 demonstrates efficacy in both wild-type and mutant JAK2-driven malignancies, including JAK2 and MPL-mutant myeloproliferative neoplasms (MPN) and CRLF2-rearranged B-cell acute lymphoblastic leukemia (B-ALL)[1][3][7][9]. In cellular and preclinical animal models, CHZ868 abrogates pathological JAK2 signaling, reduces disease burden, and reverses resistance to type I JAK inhibitors[1][3][5]. Its mechanism involves selective inhibition of JAK2 kinase activity, leading to disruption of downstream JAK-STAT signaling, with minimal effects on physiological hematopoiesis at effective doses[3][10]. The drug was originally developed by Novartis for anti-neoplastic indications, primarily hematological malignancies such as B-ALL, leukemia with JAK2 fusions or rearrangements, and myeloproliferative neoplasms[1][7][9]. CHZ868 remains investigational and has not reached clinical approval; however, it is widely used as a research tool in cancer biology and pharmacology[7][9].