10/21 16:06 U.S. to compare breast cancer prevention drugs
By Maggie Fox, Health and Science Correspondent
WASHINGTON, Oct 21 (Reuters) - The U.S. government said on
Wednesday it is preparing to launch the biggest-ever trial comparing two drugs
-- tamoxifen and raloxifene -- to see which one works better to prevent breast
cancer.
Health and Human Services Secretary (HHS) Donna Shalala made the
announcement as part of a report on progress her department and the
government have made into fighting cancer, and of a new push to get women
over the age of 40 to get regular mammograms.
"This will be the single most important legacy of the Clinton Administration."
Shalala told reporters. "It will be the largest clinical trial ever into breast cancer."
Earlier this year doctors said tamoxifen, marketed as a cancer drug under the
name Nolvadex by Zeneca Group Plc <ZEN.L>, reduced the risk of breast
cancer by nearly 50 percent in healthy women who took it.
They had been testing the drug, long used against breast cancer, to see if it
could prevent the disease in women considered at high risk.
But rival drug raloxifene, sold under the name Evista by Eli Lilly & Co.
<LLY.N>, has also been found to prevent breast cancer, at least in preliminary
trials. Evista is prescribed against osteoporosis, a thinning of the bones that
affects many older people, especially women.
Dr. Leslie Ford of the National Cancer Institute (NCI), who will direct the
comparative trial, says it has yet to be approved by the Food and Drug
Administration (FDA). But she expects a decision soon.
Ford said her team would recruit 20,000 post-menopausal women for the trial.
"They also have to be at elevated risk (of breast cancer)," she said.
Any woman over the age of 60, or who has a family history of breast cancer or
who has had several pre-cancerous lumps removed is considered to have a high
risk of breast cancer.
"We know tamoxifen works and now the question is, is there another drug, like
raloxifene, that works just as well but perhaps without the side-effects," she
said.
One reason doctors would like to have an alternative to tamoxifen is that it
seems to raise the risk of cancer of the uterus, known as endometrial cancer, by
two to three times. Endometrial cancer is very rare, and is usually detected early
and treatable by hysterectomy, but is nonetheless best avoided.
Ford said tamoxifen's effects on endometrial cancer were not known until about
15 years after it was first used, and it may be the same for raloxifene, which has
been tested just a few years.
The drugs are similar in other risks such as deep vein thrombosis, a blood clot
in the leg that can travel to the lungs, and pulmonary embolism, an air bubble
that blocks the arteries to the lungs.
Ford said Zeneca and Lilly were providing the drugs for free.
She said it is still not clear whether tamoxifen prevents cancer altogether, or just
delays it.
"There is no evidence that once tamoxifen is stopped, that there is a rebound in
... cancers," she said. In the tamoxifen versus raloxifene trial, volunteers wil be
taken off the drugs completely after five years.
Shalala said the Clinton administration made breast cancer research a priority in
part because of lobbying by activist groups. "They didn't say please," she said.
But she said it is also a worthy subject of study. Breast cancer is the
second-biggest cancer killer of women, after lung cancer. Heart disease is the
biggest killer of all Americans, men and women.
Shalala said HHS and other government agencies will continue to press for
better cancer prevention, detection and treatment. "We are in a golden age of
biomedical research," Shalala said.
"No longer are we searching for therapies -- we are comparing therapies. The
question is which one works better and in what groups."
Shalala said Clinton's new budget for 1999 includes $605 million for breast
cancer research and education. |
