Motexafin lutetium is pentadentate aromatic metallotexaphyrin with photosensitizing properties patented by Pharmacyclics, Inc. as anticancer agent that enhances the cytotoxic potential of photodynamic therapy through several mechanisms, including depleting intracellular reducing metabolites that are necessary for repairing the oxidative damage induced by irradiation. Motexafin lutetium catalyzes the oxidation of intracellular reducing metabolites such as ascorbate, glutathione, nicotinamide adenine dinucleotide phosphate, and protein thiols, generating reactive oxygen species in a process known as futile redox cycling. The depletion (through oxidation) of these reducing metabolites removes the substrate necessary in a cell to repair oxidative damage induced by photodynamic therapy and, left unrepaired, such oxidative DNA damage is converted into lethal double-stranded breaks. Motexafin lutetium has the potential to combine the features of selective localization, ability to be activated by deeply penetrating far-red light, low incidence of skin photosensitization and water solubility. The product was in clinical development as a treatment for several types of solid tumors (as Lutrin), age-related macular degeneration (as Optrin), atherosclerosis and prevention of restenosis (as Antrin).