||Conquer Cancer Health News
Drug offers hope in battle against leukemia, other cancers
LOS ANGELES (CNN)
experimental drug designed to
combat chronic myelogenous
leukemia, a common form of the
adult cancer, has produced dramatic
results in early clinical trials,
according to a preliminary report
Unlike traditional, toxic chemotherapy remedies, which kill both cancerous
and healthy cells, the drug STI-571 specifically targets an enzyme found
only in leukemia cells, meaning patients suffer minimal side effects. Some
experts think the new approach could work for other cancers as well.
"This is a real home run," said principal researcher Dr. Charles Sawyers of
the Jonsson Cancer Center at the University of California in Los Angeles.
"Six or eight months ago, I would never have believed this."
In fighting chronic myelogenous leukemia, STI-571 attacks the common
adult cancer by altering abnormal cell structure and reducing the white
blood cell count.
In the Phase I trial, CML patients with early stages of the disease who
failed to respond to traditional interferon treatment received STI-571 in pill
form once a day. Patients experienced little or no toxicity, and most of
those receiving doses at 200 mg or higher had white blood counts come
down to normal.
Leukemia patient Virginia Garner, who did not respond to interferon, is
enthusiastic about the experimental treatment. "I just have a feeling about
this new drug that it's going to turn out to be something that everyone is
going to be amazed at," she said.
Her physician agrees. "With this new therapy, I've seen re-growth of
healthy cells and that's the first step toward achieving remission," said Dr.
Douglas Blayney of the Wilshire Oncology Medical Group.
Perhaps most remarkable, at doses of 300 mg or more, researchers have
seen the molecular cause of CML begin to disappear. CML is linked to a
particular fusion protein created when two chromosomes switch pieces with
the other, Sawyer said. The chromosome responsible for the fusion protein
was undetectable after several months of STI-571 treatment.
Some Phase I subjects are still being treated, and Phase 2 trials are
underway for CML patients with more advanced phases of the disease.
Novartis Pharmaceuticals Corporation is supporting the trials. The drug
manufacturer is waiting Phase 2 results before deciding whether to seek
approval from the U.S. Food and Drug Administration.
Other medical experts are optimistic about the preliminary results. "It's rare
to see a real response" in early trials, said Dr. Harmon Eyre, chief medical
officer of the American Cancer Society. "In this case, seeing very good
responses early on with minimal toxicity is very exciting."
Eyre thinks the new treatment could extend beyond leukemia: "The concept
of specifically approaching the cancer cells compared to a normal cell is
very important and will have applications to other cancers."
Sawyer, who presented his findings at the American Medical Association's
annual Science Reporters Conference in Los Angeles, declined to provide
details on the preliminary data. Yet he plans to present formal results of the
STI-571 clinical trials in early December.
CML most often occurs among middle-aged men and women. In the
chronic phase, usually from three to five years, patients have a high white
blood cell count, but generally have few symptoms. Afterwards the disease
advances to the accelerated phase, characterized by rapid white blood cell
growth. The end stage of the disease, known as the blast crisis, can be fatal
within several months.
Medical Correspondent Rhonda Rowland contributed this report, written by Richard