Ruxolitinib-d 9 (INCB18424-d 9 ) is deuterium labeled Ruxolitinib. Ruxolitinib (INCB18424) is an orally active and selective JAK1/2 inhibitor with IC 50 s of 3.3 nM and 2.8 nM in cell-free assays, and has 130-fold selectivity for JAK1/2 over JAK3. Ruxolitinib induces autophagy and kills tumor cells through toxic mitophagy.