When treating cancer, it's often not enough to target the tumor as cancer cells can retreat and form new tumors in different parts of the body. But now, an experimental drug described recently in the journal Cancer Discovery purports to cut off the cells' "escape route," says New Scientist's Andy Coghlan. The drug, called cabozantinib, inhibits VEGFR and cuts off the tumor's blood suppl and it blocks the c-MET receptor, which helps cancer cells spread, Coghlan says. Researchers at the University of California, San Francisco, tested the drug on mice that had developed human cancers. Mice treated with cabozantinib survived longer than the mice given a placebo. And in a study of men with metastatic prostate cancer, treatment with cabozantinib caused bone metastases in 82 out of 108 patients to shrink or vanish, he adds. Three-quarters of the men also saw their primary tumors shrink.
"The broader implication of [this] research is that existing drugs which cut the blood supply to tumors could be improved by giving patients a second drug that blocks the c-MET receptor as well," Coghlan says. "It may be that choking off the cancer's blood supply makes them more aggressive and more likely to spread. If so, giving a c-MET blocker as well might make treatment more successful." Some drugs, like Roche's Avastin, which work by cutting off a tumor's blood supply, are currently being tested in conjunction with c-MET inhibitors like onartuzumab, he adds.