This past February, for example, Sugen, a division of Peapack, NJ-based Pharmacia, announced it was aborting its Phase III colorectal cancer clinical trial of SU5416, as no clinical benefit was found. SU5416 is a small-molecule angiogenesis inhibitor that blocks the action of vascular endothelial growth factor receptor (VEGF-R) in endothelial cells, which is critical for new blood vessel formation.1
Earlier this year, Joanne Yu and colleagues at the Sunnybrook and Women's College Health Sciences Centre in Toronto provided a possible, partial explanation for the disappointing clinical results of some antiangiogenic therapies.2 They demonstrated in mice that tumors with inactive p53 tumor suppressor genes, which account for 50% of human cancers, are relatively resistant to hypoxia. Cutting off the blood supply to such tumors, therefore, is of little clinical benefit.
Yet some clinical trials have produced promising results. In February, Judah Folkman's group at Children's Hospital in Boston reported successful treatment ...
