From San Francisco, at the American Society of Hematology’s 42nd annual meeting.
When STI-571 first made news in 1999, it seemed almost too good to be true. In patients with low-grade chronic myelogenous leukemia (CML), it seemed to kill tumor cells like a heatseeking missile destroys a target (SN: 12/11/99, p. 372). Now, further testing of STI-571, called Glivec by Novartis Oncology of East Hanover, N.J., supports the early findings. The new research also indicates that the intravenous drug may help patients who’ve progressed to fullblown CML.
An international team led by researchers at the Jonsson Cancer Center of the University of California, Los Angeles gave STI-571 daily to 260 patients with full-blown CML. These patients had entered a stage of the disease in which immature white blood cells flood the bone marrow.
In this acute form, the disease usually proves fatal within 2 to 3 months. During the 6 months after treatment began, hematologist Charles Sawyers of UCLA reports, 161 of the patients improved. However, most of these patients subsequently relapsed, he says.
To counter this trend, various research teams are working on different regimens and drug combinations. STI-571 works by attacking the protein chiefly responsible for the uncontrolled cell growth in CML, says Brian J. Druker, a hematologist at the Oregon Heath Sciences University in Portland, who is also testing the drug. It also presents a valuable option for CML patients with chronic disease that hasn’t responded to interferon alpha, the best drug now available, he says.
The other current treatment for CML is a bone marrow transplant. However, Druker says, “many patients don’t want to accept the 20 percent mortality rate in the first 6 months that comes with a bone marrow transplant.”