Femara Prevents Breast Cancer Recurrence
Drug Picks Up Where Tamoxifen Leaves Off in Reducing Cancer Risks
Oct. 9, 2003 -- Women who survived their first battle with
breast cancer may now have a powerful new tool to prevent the dreaded disease
from coming back, even years after other treatments have lost their edge.
A major new study announced today shows that the drug Femara
picks up where the breast cancer drug tamoxifen leaves off and cuts the risk of
breast cancer recurrence nearly in half among postmenopausal women with
hormone-dependent breast cancers.
The benefits of this therapy were so significant that
researchers stopped their study short in order to make the drug available to
more women. The results of the study were announced today at a news conference
in Toronto and released in advance of the scheduled Nov. 6 publication date in
TheNew England Journal of Medicine.
About two-thirds of all breast cancers depend on hormones such
as estrogen to grow, and researchers say hundreds of thousands of
postmenopausal women worldwide who have had estrogen-sensitive breast cancers
may benefit from this new treatment option.
Femara Fights Breast Cancer in the Long Run
Tamoxifen is a commonly used drug for preventing breast cancer
recurrence among postmenopausal women who had hormone-dependent breast cancers.
It works by binding to estrogen receptors and depriving breast cancer cells of
the estrogen they need.
But the benefits of tamoxifen therapy taper off after five
years. After that, there has been little doctors could do to reduce the risk of
cancer recurrence among these women.
"For many years, we have lacked the tools to address the
ongoing substantial risk of breast cancer after five years," says
researcher Paul Goss, MD, PhD, of Princess Margaret Hospital in Toronto, who
spoke at the briefing.
"What is unrecognized by many doctors and patients is that
over 50% of recurrences that occur from breast cancer unfortunately occur over
the long term, beyond five years after diagnosis," says Goss. "It
becomes a dark cloud that hangs over patients and their families for many years
after the primary diagnosis."
The study involved 5,187 postmenopausal women who had completed
an average of five years of tamoxifen therapy and compared the effects of a
once-a-day Femara pill vs. placebo in preventing breast cancer recurrence.
After about two and a half years of follow-up, researchers
found Femara appeared to reduce the risk of breast cancer recurrence by nearly
half (43%) compared with placebo.
Overall, 75 women in the Femara group and 132 in the placebo
group developed new breast cancers or other new cancers. Researchers also found
a significant difference in the estimated four-year disease-free survival rates
between the Femara and placebo users, 93% and 87%, respectively.
Goss says that 6% reduction in breast cancer recurrence risk
may also continue to grow with longer duration of treatment with Femara and may
have a significant impact on reducing deaths due to breast cancer. But he says
the number of breast cancer-related deaths in the study was too small to draw
any firm conclusions about that yet.
Although the study was designed to go on for five years, an
independent monitoring committee recommended halting the study so as not to
endanger the lives of the women on placebo.