Phototherapy of cancer and atheromatous plaque with texaphyrins

Cancer and cardiovascular disease are the leading causes of death in the western world. Photodynamic therapy (PDT) has demonstrated activity in the treatment of superficial cancerous lesions and as an intraoperative adjunct during surgical debulking. Texaphyrins are pure, synthetic water-soluble macrocycles that localize in both cancerous lesions and atheromatous plaque. Lutetium texaphyrin (PCI-0123) is activated by tissue-penetrating far red light (720-760 nm). Patient diagnosis and treatment planning is possible via magnetic resonance imaging (MRI) with the paramagnetic gadolinium texaphyrin (PCI-0120) or via fluorescence imaging using the diamagnetic PCI-0123. In this study it is shown that texaphyrins localize selectively in cancer and atheromatous plaque. PDT with PCI-0123 is found to cause selective photodamage to the diseased tissue. Specifically, PCI-0123 acts to eradicate the SMT-F murine mammary tumors and diet-induced atheromatous plaque in rabbits.