PR-104

PR-104 is a novel hypoxia-activated DNA cross-linking agent with marked activity against human tumor xenografts, both as monotherapy and combined with radiotherapy and chemotherapy. Upon intravenous administration, PR-104 is converted by systemic phosphatases to the alcohol intermediate PR-104A, which is reduced to form the active DNA-crosslinking mustard species hydroxylamine PR-104H intracellularly under hypoxic conditions. PR-104H specifically crosslinks hypoxic tumor cell DNA, resulting in the inhibition of DNA repair and synthesis, cell-cycle arrest, and apoptosis in susceptible hypoxic tumor cell populations while sparing normoxic tissues.