Take aim
6/8/2007 London, England staff Economist.com Drugs directed at precise molecular targets are helping cancer patients live longer. They have yet, however, to fulfil all expectations. Researchers have been promising a revolution in cancer treatment for a long time. More effective and less toxic drugs are expected to replace old-fashioned chemotherapies. The approach is called targeted molecular medicine and the idea is to substitute the blunderbuss of chemotherapy with the sharp-shooting of a chemical that interrupts a single molecular pathway—one that is crucial for the survival of cancer cells, but not normal cells. The problem is that this pathway will vary from cancer to cancer. You therefore have to find out which pathway is crucial in a cancer before you can make the drug. And once armed with the drug, you have to devise tests that reveal what type of cancer someone has, in order to find out whether the drug will work in his case. Even then, there is no guarantee it will work well—as three large clinical trials unveiled at this week's meeting of the American Society of Clinical Oncology, in Chicago, sadly demonstrate. It is not that any of the trials failed, exactly: all added weeks or months to the lives of those taking the new therapies. It is rather that physicians were hoping for years of extra life. There are useful lessons to be learned from these trials. Unfortunately, the main one is that molecular medicine is harder than it looks. The tumours treated in the three [...]