A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called sulfonamides. OR An orally bioavailable antimitotic sulfonamide. ABT-751 binds to the colchicine-binding site on beta-tubulin and inhibits the polymerization of microtubules, thereby preventing tumor cell replication. This agent also disrupts tumor neovascularization, reducing tumor blood flow and so inducing a cytotoxic effect.