A new drug shows hope of conquering a form of leukemia by targeting the misbehaving cells two summers ago Douglas Jenson was so wiped out from battling chronic myelogenous(骨髓性的) leukemia(白血病) (CML) that he could do little more than sit by his window; watching the numbers on a thermometer rise and fall with the sun. Today thanks to an experimental drug called STI571 (brand name: Glivec), Jenson 67, is biking in Oregon and planning a trip to the Caribbean. "I feel wonderful," he says.
2. So do his doctors. STI571, a "smart bomb" drug that targets leukemia cells without harming healthy ions, first made headlines last year when researchers announced that white blood counts had returned to normal in 31 out of 31 patients who had taken the pill. Last week scientists were hack reporting new data on just over 1000 patients. In one trial, more than 90 % of 532 people on the drug saw counts return to normal. And under microscopic examination, 28 percent showed no evidence of cancer left in their bone marrow.
3. The drug even helped, although not as dramatically, some patients in the final "blast" phase of the disease, when survival is measured in months. STI571"has ignited the cancer-research field", says Dr Brian Druker, an Oregan Health Sciences University researcher who developed the drug with manufacturer Novartis.
4. CML, diagnosed in 5100 Americans every year, is triggered when two chromosomes swap fragments of genetic information. CML starts with the mistaken swap of genes between two chromosomes. The resulting "Philadelphia chromosome" produces the mutant Bcr-Abl protein. Bcr-Abl transfers a phosphate from the chemical messenger ATP to other proteins. They initiate a flawed signal to white blood cells to replicate incessantly.
5. STI571 returns blood counts back to normal for those patients with chronic myelogenous leukemia(CML) in a "smart bomb way" by targeting the protein that sends the message to make the white blood cells. Bone marrow transplants can work extremely well, but they' re applicable only for a minority of patients; otherwise, standard treatment is the injectable drug interferon. Many patients, however, cannot tolerate the adverse effects, which include severe fatigue, weight loss and depression. The new pill works by deactivating the cancer cells' growth signal. Side effects- nausea, eye puffiness, muscle aches have been relatively mild so far.