Word: tumors
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...Some of these therapies prevent a class of chemicals called growth factors from reaching a tumor, blocking signals that would otherwise instruct the cell to grow out of control. Others tip the delicate balance that every cell maintains between life and death, driving cancerous cells to self-destruct. Still others block enzymes that cancer cells use to chew openings in normal tissues and give themselves room to expand. And, most famously, the class of compounds known as angiogenesis inhibitors keep tumors from building new blood vessels to supply themselves with food and oxygen. Three years ago, Nobel laureate James Watson...
...Then just this year researchers at Sloan-Kettering showed that the drug could dramatically boost the effectiveness of standard colorectal-cancer chemotherapy, shrinking tumors in more than a fifth of otherwise hopeless cases. Says Sloan-Kettering's Saltz: "The fact that we got a 20% response rate is staggering." What is happening, he surmises, is that the growth-factor inhibitor weakens the tumor enough for chemotherapy to finish...
...Another reason cancers grow inexorably is that unlike normal cells, which die a natural death after a fixed number of divisions, cancer cells live forever. Scientists have been looking for compounds that will rewire tumor cells so they will know when it's time to go. The research is still in its early stages, but scientists in several labs have started looking at a group of enzymes called caspaces; inhibiting these enzymes disrupts the process of DNA repair that occurs each time a cell divides...
...promise was this: by cutting off the blood supply of a tumor, you can kill it before it spreads. This is called antiangiogenesis (the prevention of new blood-vessel growth). The concept, first championed by Dr. Judah Folkman of Children's Hospital in Boston, launched thousands of research studies. But the concept of antiangiogenesis hasn't gone well lately. Major pharmaceutical firms have stopped work on their favorite antiangiogenesis candidates, and not one of the 50 other compounds under study has yet been approved by the FDA--despite three decades of research and an investment of some $4 billion...
...trial design to give the new drugs more time to work. As a second step, the panel also wants to change the criteria by which a drug's success is measured. The group proposed that with the newer, better-targeted medications, success should be determined not by whether a tumor shrinks in size but by whether it can be confined, or by how long a patient can put off chemotherapy...