INCB024360 potently inhibits kynurenine production in IFN-γ–treated human HeLa cells. HeLa cells were treated with 25 ng/mL IFN-γ and INCB024360 or L-1MT at various concentrations for 2 days. The kyn levels in culture supernatants were measured spectrophotometrically. The data from a composite curve derived from multiple independent assays is presented. Mean values are shown with error bars representing SD.