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Nor will angiogenesis inhibitors necessarily work equally well against all cancers. The Angiogenesis Foundation has analyzed 29 kinds of solid tumors and discovered that some rely much more heavily on blood-vessel networks than others.
Armed with such knowledge, younger researchers think they can improve on Folkman's techniques. They prefer a more targeted approach: selectively attacking the various molecules and biochemical signals involved in building a new blood vessel. For instance, researchers at Ixsys, a biotech company in San Diego, have developed an artificial antibody that dissolves the biochemical glue that holds a tumor's capillaries together. Indeed, one of the patients in their safety study exceeded all expectations when two of the tumors in his abdomen shrank 70%. "I've been on the drug now for over a year," says Barry Riccio, a college professor from Illinois who is suffering from a rare sarcoma. "I have more energy than I did just nine months ago, and I've gained back a lot of weight."
Other researchers are zeroing in on different targets. Some are looking at a specialized growth factor called VEGF (for vascular endothelial growth factor) that so far has been found only in the blood vessels that feed tumors. One synthetic molecule being tested at UCLA prevents VEGF from stimulating new growth by elbowing it aside and taking its place in the cell's receptors. Safety studies in more than 30 patients have so far not revealed any major side effects, although their tumors' growth was only slowed, not halted. Dr. Joseph Sparano, at Montefiore Medical Center in New York City, who is pursuing still another approach to anti-angiogenesis, says he doesn't need to stop tumor growth completely to judge his experiment a success: "If we can make patients with metastatic breast cancer live 20 years and not have symptoms, that may be as good as a cure."
But it may not be good enough for those millions of cancer patients whose hopes were stirred last week. Hope, for them, is a precious commodity, not something to be rationed or trifled with. Just ask Renee Smith of Dripping Springs, Texas, who three years ago found she has non-Hodgkin's lymphoma. She has a four-year-old daughter she'd like to see grow up and a husband with whom she'd like to grow old. When friends started calling excitedly last week with news of a possible cure, she resolved to maintain a philosophical calm. "I try to live in the moment because that helps level out the emotional roller coaster," she says. Still, the moment sometimes escapes her. "I am not perfect," she says. "I am not the Dalai Lama." Ironically, it's patients like Smith, the people most in need of a breakthrough, who were the most vulnerable to last week's false hopes.
--Reported by William Dowell and Alice Park/New York