LW106

LW106 is an indoleamine 2,3-dioxygenase 1 (IDO; IDO1) inhibitor (IC50 = 13 nM) that effectively inhibits kynurenine production upon cellular IDO1 upregulation by IFNγ induction (50 ng/mL, 48 h) in HeLa cultures (IC50 = 1.57 μM) and prevents the antiproliferation activity of IDO1-positive DCs against co-cultured CD8+ T-cells (proliferation suppression = 67% with vehicle vs. 33% with 20 μM LW106). LW106 exhibits antitumor activity only in immunocompetent, but not athymic or IDO1-/-, mice, displaying better in vivo efficacy than Epacadostat (Lewis lung carcinoma/B16-F10 tumor suppression = 68%/65% with LW106 vs. 51%/50% with Epacadostat; 80 mg/kg/day i.p.).