Since July 2000, Harvard and Dana-Farber Cancer Institute researcher George Demetri and his colleagues have treated 148 patients with a rare, lethal stomach cancer known as GIST (Gastrointestinal Stromal Tumor). Eighty-six of them have been taking the drug long enough to evaluate its results, and half of these patients showed a 50 percent or greater shrinkage of their tumors. In the other half, all but seven have enjoyed a halt to their tumor growth. Demetri and his colleagues described the successful use of the drug, called Gleevec, on May 14, 2001. Gleevec, first known as STI571, was not developed for GIST, but to treat an often-fatal type of leukemia known as chronic myelogenous leukemia or CML. In one study, 53 out of 54 patients in the early stage of CML saw their cancer go into remission. Cancerous cells in seven of the patients disappeared completely. The U.S. Food and Drug Administration approved the drug on May 10, 2001, following the shortest review on record, a scant two-and-a-half months. Tests have been expanded to include more than 3,000 patients worldwide, and researchers have begun testing Gleevec on brain, lung, and prostate tumors.