TH-302 is a highly potent and selective hypoxia-activated pro-drug targeting hypoxic regions of solid tumors with an IC50 of 19 nM. It is stable to liver microsomes. However, under hypoxic conditions, it is selectively and irreversibly converted to its active phosphoramidate-based, DNA-crosslinking, bis-alkylator. TH-302 inhibits H460 cells and HT29 cells with IC90 of 0.1 μM and 0.2 μM, respectively. It shows much enhanced potency in H460 spheroids compared to H460 monolayer cells under normoxia. TH-302 exhibits potent cytotoxicity to both human and murine MM cells with hypoxic selectivity and dose dependency, and induces G0/G1 cell-cycle arrest under hypoxic conditions. It inhibits primary tumor growth in multiple xenograft models. TH-302 is currently in a phase II clinical trial for the treatment of soft tissue sarcoma.