New Leukemia Drug Works for Incurable Stomach Tumors, Too
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Blanke tells WebMD that Gleevec hones in on c-kit, a gene that sends a
signal that tells cells to grow. This gene is present in many cancer cells, he
says. If c-kit is abnormal it causes uncontrolled cell growth and
multiplication, which forms a tumor. The drug blocks the signal. Oncologist
Michael Gordon, MD, of the Arizona Cancer Center in Tucson, says that Gleevec
works like a circuit breaker to shut down the power to the cell.
In his study of 139 patients with GIST, more than half of the patients
responded to treatment, says Blanke. Hendrickson was patient No. 1.
"They rushed the study because I was so near death," Hendrickson
says. "I knew the drug was working right away because in seven days I went
from severe pain to moderate pain and after 40 days my first CT scan showed
that the tumor was reduced by 47%."
Allan T. van Oosterom, MD, professor of medicine at the University of Leuven
in Belgium, says that a smaller study of 36 patients with GIST suggests that
the most effective dose is actually 800 mg or twice what Hendrickson takes.
"I have two patients who didn't respond at 400 mg; we increased to 800 mg
and now they are responding," van Oosterom tells WebMD.
At a press conference Sunday where the Gleevec results were presented at the
American Society of Clinical Oncologists meeting held here, he said "I have
been waiting 30 years to report results like these."
Although the buzz among the 26,000 cancer specialists attending this meeting
is definitely Gleevec, Blanke and van Oosterom both say they are worried that
oncologists will try the drug on the wrong patients. The drug is approved for
leukemia and "demonstrated efficacy in GIST", but this targeted therapy
only works if the target is present. In solid tumors, that means that the tumor
must test positive for c-kit and have the mutation that causes
overproduction of cells.
Cancer experts worry, too, that patients will demand treatment with the new
drug, which has received almost as much publicity about its ease of use as it
has about its effectiveness. Unlike other cancer treatments, Gleevec is a pill.
Patients should take it after meals, says van Oosterom.
Moreover, the side effects of the drug are minimal. "Sleep disturbances,
puffiness around the eyes, a slight rash," says Hendrickson. And the side
effects "usually disappear after eight weeks," says van Oosterom.
Blanke says that several other types of cancers express c-kit, and his
center is beginning a trial in terminal lung cancer patients while other
researchers are testing the drug in pancreatic cancers and brain tumors.
Meanwhile, in Minnesota, Hendrickson celebrated yet another holiday,
Mothers' Day, with his wife and three sons. He observed, "I was knocking on
death's door until this drug. This stuff is absolutely a miracle."