Epacadostat

Epacadostat, also known as INCB024360 or INCB24360, is an orally available hydroxyamidine and inhibitor of indoleamine 2,3-dioxygenase (IDO1), with potential immunomodulating and antineoplastic activities. INCB024360 targets and binds to IDO1, an enzyme responsible for the oxidation of tryptophan into kynurenine. By inhibiting IDO1 and decreasing kynurenine in tumor cells, INCB024360 increases and restores the proliferation and activation of various immune cells, including dendritic cells (DCs), NK cells, and T-lymphocytes, as well as interferon (IFN) production, and a reduction in tumor-associated regulatory T cells (Tregs) . (In Vitro) :In cellular assays, Epacadostat (INCB 024360) selectively inhibits human IDO1 with IC50 values of approximately 10 nM, demonstrating little activity against other related enzymes such as IDO2 or tryptophan 2,3-dioxygenase (TDO) . Epacadostat (INCB 024360) also exhibits significant activity toward mouse IDO1, with an IC50 value of 52.4 nM±15.7 nM, in a similar assay using mouse IDO1-transfected HEK293/MSR cells. (In Vivo) :Female Balb/c mice bearing CT26 tumors are treated orally twice daily for 12 d with Epacadostat at 100 mg/kg. Epacadostat (INCB 024360) suppresses kynurenine equivalently in plasma, tumors, and lymph nodes. In na ve C57BL/6 mice, 50 mg/kg Epacadostat (INCB 024360) decreases plasma kynurenine levels within 1 hour and those levels stay at least 50% suppressed through the 8-hour time course.