INCB23843

INCB23843 is a **small molecule inhibitor** of **indoleamine 2,3-dioxygenase 1 (IDO1)**, an intracellular enzyme involved in tryptophan metabolism and immunomodulation. INCB23843 has been studied primarily in preclinical cancer models, where it demonstrated the ability to inhibit IDO1 activity, restore antitumor T-cell responses, and control tumor growth. The molecule is an analog of epacadostat (INCB024360), with a similar mechanism of action targeting the immunosuppressive tumor microenvironment by blocking kynurenine pathway activation[1][3][5][7]. Combination studies in animal models show that INCB23843 can enhance the efficacy of immune checkpoint inhibitors such as anti-PD-L1 and anti-CTLA-4 antibodies[3][7]. One of its key differentiating characteristics is its use in preclinical research to further explore IDO1 inhibition as a strategy in cancer immunotherapy.