To men with advanced prostate cancer who could benefit from antiangiogenic drugs — designed to stop cancer from growing, by thwarting its supply of new blood vessels — the wait for new drugs seems interminable. Scientist John T. Isaacs, Ph.D., is trying to speed up the process. He is studying an antiangiogenic drug (also called an angiogenesis inhibitor) known simply as ABR-2I5050, which has just entered the drug pipeline. It's in Phase I trials in prostate cancer patients; these trials are mainly to make certain that the drug can be safely tolerated.

Before these tests can even begin to see whether it works, Isaacs and colleagues are investigating the drug's mechanism of action, trying to figure out how it works — specifically, looking to see whether it stimulates the body to make growth-regulating chemicals. They also want to find ways to measure the drug's progress — perhaps even in skin biopsies. "We hope that we'll be able to predict whether the drug is working in men with prostate cancer without the long time that usually is involved in these types of clinical trials," says Isaacs. In other studies, he and colleagues are combining ABR-2I5050 with other agents, including interferon gamma, and with hormonal therapy, to see if they can make it even more effective.