A drug that
targets only diseased cells has proved astonishingly
effective against an aggressive form of early breast
cancer—a long-sought breakthrough that has
doctors talking about curing thousands of women each
year in this country alone. The drug, Herceptin, is already
used for advanced cancer. But in three studies
involving thousands of women with early-stage disease,
it cut the risk of a relapse in half.
used words like "revolutionary," "stunning," and
"jaw-dropping" to describe the findings.
"In 1991, I
didn't know that we would cure breast cancer, and in
2005, I'm convinced we have," exulted Jo Anne Zujewski, head
of breast cancer therapeutics at the government's
National Cancer Institute.
generically as trastuzumab, does not help everyone. For
one thing, it is only for the estimated 20% of breast cancer
cases in which tumors churn out too much of a protein
known as HER2. In the recent studies, the drug was
used along with standard treatments, including surgery
could be the biggest thing in cancer drugs since
research a decade ago demonstrated the extraordinary
effectiveness of tamoxifen, another medicine that
transformed the treatment of the disease by homing in
on cancer cells but sparing healthy ones.
by Genentech, appears to have "changed one of the most
worrisome kinds of cancers into one that may have a
relatively good prognosis," said Ed Romond of the
University of Kentucky.
He was one of the
researchers who reported findings from three Herceptin
studies Thursday in The New England Journal of
Medicine.One was an international study sponsored by
Herceptin's European marketer, Roche. The others were
North American studies sponsored by the National
Cancer Institute. The researchers followed a total of
more than 6,500 women with early-stage breast cancer.
In the first
study, 220 women taking standard therapy for a year either
developed breast cancer again, showed other kinds of tumors,
or died. Only 127 did when Herceptin was added.
The two other
studies, partly funded by Genentech, reached similar
findings in their combined results. At three years, patients
on Herceptin showed a disease-free survival rate that
was 12% points higher than without it.
approved the drug in 1998 for advanced breast cancer that
has already spread within the body. But early-stage cases
are much more common.
Many doctors are
already embracing the drug for such women, cancer
experts say, because details of the three studies were first
publicized last spring at a medical conference.
"The strength of
the evidence is so overwhelming at this point that it
would be almost impossible to withhold this drug from the
appropriate group of patients," said Gabriel
Hortobagyi, of the University of Texas, who is
president-elect of the American Society of Clinical
to apply to the U.S. government to add early-stage
cancer use to Herceptin's label, spokeswoman Colleen Wilson
said. But doctors are already freely prescribing the
drug for early breast cancer on their own authority.
women are diagnosed with breast cancer each year in this
country, and 40,000 die. About 30,000 American women will
probably be taking Herceptin for breast cancer within
a couple of years, curing perhaps 7,000 who would
otherwise relapse, some doctors predicted.
cautioned that some women get better without Herceptin,
especially when there is little evidence that the cancer is
spreading within the breast. Also, a small number
taking the drug suffer heart failure.
A year of
Herceptin could cost $48,000 even at wholesale prices.
Tamoxifen has the
same kind of benefit as Herceptin—a 50% reduction in
risk—but works against another large class of cancer
cases known as estrogen-positive.
director of the breast cancer section of the American
Cancer Society, said she was impressed by the Herceptin
findings but wants to watch such patients for years.
"I think it's way too soon to talk about a cure," she
It is also
unclear whether Herceptin should be taken with chemotherapy
drugs, soon afterward, or even years later. Herceptin
appears so potent, some researchers said, that
patients might someday be able to skip chemotherapy,
radiation, and surgery, which destroy both healthy and
diseased tissue. (AP)