CB-668

CB-668 is an **oral small-molecule inhibitor of interleukin 4 induced 1** designed for oncology. It was developed by Calithera Biosciences as a potent and selective inhibitor of IL4I1, an amino acid oxidase that suppresses anti-tumor immunity through production of hydrogen peroxide and aryl hydrocarbon receptor activating metabolites. By blocking IL4I1, CB-668 is intended to restore cytotoxic T-cell function and counter tumor-promoting immune suppression, with particular rationale in cancers such as ovarian tumors and B-cell lymphomas where IL4I1 is reported to be overexpressed. Publicly described development was at the preclinical stage with IND-enabling studies ongoing.