Anticancer effects of chemoembolization using microspheres of an angiogenesis inhibitor (TNP-470) in rabbits bearing VX-2 carcinoma

Chemoembolization is a useful cancer treatment which combines chemotherapy and tumor devascularization using an anticancer drug and transcatheter embolization of the arteries running to the tumor. TNP-470 is a new type of anticancer durg which prevents tumor neovascularization thereby blocking nutrient supply. We expected that the chemoembolization using microspheres containing this angiogenesis inhibitor would produce strong anticancer activity attributed to sitespecific inhibition of the tumor neovascularization, especially the development of collateral circulation. We examined the anticancer effects of chemoembolization using TNP-470 microspheres prepared with poly(DL-lactic/glycolic acid) in rabbits bearing VX-2 carcinoma. It is assumed that microspheres of 53-125 μm in diameter persistently embolized the arterial capillaries surrounding the tumor for 2∼3weeks and released the drug over 5 days. When TNP-470 was injected s. c. 5 times at a dose of 5 mg at 2-or 3-day intervals, tumor growth was found to be significantly inhibited after the 3rd injection(P