The effects of mitoxantrone and bisantrene on angiogenic responses induced by tumor cell-conditioned media in the avascular cornea of rat eye have been evaluated. Both mitoxantrone and bisantrene effectively inhibited, in a concentration-dependent manner, angiogenesis induced by conditioned media obtained from either a hamster buccal pouch carcinoma cell line or P388D1 murine macrophage-like cells. Whereas vessel ingrowth in corneas containing tumor cell-conditioned media was detected as early as day 2 or 3 and was maximal by day 7, inclusion of mitoxantrone or bisantrene in the conditioned media at a 1:1 ratio (160 microM mitoxantrone or 32 microM bisantrene) resulted in complete inhibition of angiogenesis throughout the 14-day evaluation period. When concentrations of 64 and 32 microM mitoxantrone or 13 and 6.4 microM bisantrene were employed there was a marked delay in the appearance of capillary blood vessels (day 5 to 7) and a reduction in the intensity of angiogenic responses. No untoward toxicity to the tissue was observed at the concentrations of mitoxantrone or bisantrene employed.