International Breast Cancer Prevention Study
Launches In The United States And Canada
ExCel research study seeks 4,500 women
to participate in clinical trial
March 30, 2005 – Today, a new clinical trial
evaluating a novel approach to breast cancer prevention launched in
the United States and Canada. Called the ExCel research study, this
is the first North American clinical trial to evaluate the role of
an aromatase inhibitor in the prevention of breast cancer.
Coordinated by the National Cancer Institute of Canada
Clinical Trials Group (NCIC CTG), the ExCel research study will examine
the potential benefit of exemestane and its ability to prevent breast
cancer in women who are at increased risk for the disease.
Exemestane – part of a class of drugs called
aromatase inhibitors – suppresses estrogen production, a key
component in the development of some types of breast cancer. Exemestane
could provide women with an alternative option to tamoxifen, the only
drug FDA approved for prevention of breast cancer.
"Breast cancer is a major public health issue
– every 30 seconds somewhere in the world a woman is diagnosed
with this disease," says Dr. Paul Goss, the ExCel research study
chair.
"Thousands of women have already beat breast
cancer thanks to recent research on aromatase inhibitors. As a result,
we think this could be an effective approach to preventing it from
developing in the first place."
The ExCel research study will follow more than 4,500
postmenopausal women from the U.S., Canada and Spain over a five year
period. To be eligible, women must be 35 years of age or older and
have an increased risk of developing breast cancer. Risk factors can
include a woman's age, her family history of breast cancer, her age
at first menstrual period and her age at first live birth.
Initial results of the trial could be available within
four years and study investigators hope to see as much as a two-thirds
reduction in the incidence of breast cancer among women in the treatment
group.
Aromatase inhibitors are currently being used to treat
breast cancer in women around the world and results from a study published
in a March 2004 issue of the New England Journal of Medicine demonstrated
that exemestane can prevent the occurrence of new cancers in the opposite
breast of women who have already had breast cancer, suggesting that
it may also be able to prevent the disease in healthy women.
Clinical studies have also shown that aromatase inhibitors
are associated with fewer serious side effects than tamoxifen, the
only other drug available to women for primary breast cancer prevention.
"While tamoxifen has already been shown to reduce
the incidence of primary breast cancer, many women choose not to take
this drug because of its known side effects," says Dr. Goss,
also Director of Breast Cancer Research at the Massachusetts General
Hospital and Professor of Medicine at Harvard Medical School. "Results
of this study will provide women with important information about
another potentially effective tool for breast cancer prevention."
Women enrolled in the ExCel research study will be
randomized to one of two groups and all will take one pill per day
for five years. Group A will take exemestane and Group B will take
a placebo. Women will participate in two follow-up visits during the
first year – at six and 12 months – and then an annual
follow-up visit during years two through five.
Women will have a screening visit with a member of
the study's clinical staff to see if they are eligible for the trial.
If eligible, they will undergo a routine health examination, routine
blood tests, a mammogram and a bone mineral density test.
The National Cancer Institute of Canada Clinical Trials
Group (NCIC CTG), based at Queen's University in Kingston Ontario,
is working in cooperation with physicians in Canada, the U.S. and
Spain to coordinate the ExCel research study.
Founded in 1971 and funded by the Canadian Cancer
Society, the NCIC CTG develops, conducts and analyzes national and
international trials of cancer therapy, including trials for new cancer
drugs, cancer prevention and supportive care to improve quality of
life for people with cancer. Since its inception, the NCIC CTG has
enrolled more than 40,000 patients from Canada and around the world
in over 300 clinical trials.
Pfizer, Inc. manufactures exemestane under the brand
name Aromasin® and is providing the drug for the trial.
Women looking for more information about the ExCel
research study and participating study centers in their community
can visit www.excelstudy.com or call toll-free:
In the U.S. 1-800-4-CANCER
In Canada 1 888 939-3333
About Exemestane
Exemestane (Aromasin) was approved in the United States
late in 1999 for the treatment of advanced breast cancer in postmenopausal
women whose tumors have stopped responding to tamoxifen. Exemestane
is approved by the FDA and Health Canada and is marketed by Pfizer,
Inc. as Aromasin®. It is also approved for use in Europe, Japan,
and South America. It is currently used for the treatment of advanced
breast cancer in postmenopausal women whose disease has progressed
following tamoxifen therapy.
Results of the Intergroup Exemestane Study, published
in the New England Journal of Medicine, revealed that 32 percent fewer
women had a recurrence in their breast cancer when they switched to
exemestane after two to three years of tamoxifen compared to those
who continued on tamoxifen for a total of five years, the current
standard of care. Additionally, twice as many women receiving tamoxifen
developed second (or new) breast cancers than those treated with exemestane.
Unlike other aromatase inhibitors, exemestane is a
steroidal aromatase inactivator, which means it selectively targets
and irreversibly binds to the aromatase enzyme, which is required
to produce estrogen. Without estrogen, breast cancer cells cannot
survive. Exemestane is well tolerated and the side effects associated
with the treatment are generally predictable and manageable. Given
its potent suppression of estrogen, exemestane has been associated
with low instances of mild nausea and hot flashes.
