Tumor growth slowed considerably in trial patients who were given a high dose of bevacizumab, an antibody that neutralizes vascular endothelial growth factor. The time for measurable growth of tumor was two and a half times longer in these patients compared with growth in patients who did not receive the drug (approximately 5 versus 2 months). Although the difference was small, it was highly statistically significant. There was also a smaller, but still significant effect from the lower dose of bevacizumab.

Kidney cancer is diagnosed in more than 30,000 Americans each year. In this phase II trial, 116 patients with advanced cancer and no known effective treatment options were randomized to placebo, a low dose of the drug (3 mg/kg), or a high dose (10 mg/kg). Because only minimal side effects were associated with drug treatment, researchers were able to design a double-blind trial.

"The results of this trial are encouraging, demonstrating that anti-angiogenic drugs can inhibit tumor growth in patients," said James C.Yang, M.D., the lead investigator on the study. "This is an important first step toward validating, in patients with cancer, the exciting advances in angiogenesis we have seen in the laboratory. We must continue to build on this finding in order to meaningfully prolong the lives of patients with advanced cancer."

More than 20 additional clinical trials are currently underway to evaluate bevacizumab as a treatment for various types of cancer. The drug is being tested in phase III trials for breast and colorectal cancer. Phase II trials with bevacizumab include those for prostate, breast, colorectal, cervical, ovarian, pancreatic, and lung cancers, as well as for mesothelioma and several types of leukemia.