Original Source
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Success Halts Tests of Novartis
Breast Cancer Drug
Thu Oct 9, 6:37 PM ET
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By Rajiv Sekhri
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TORONTO (Reuters) - One of a new class of breast cancer drugs was so successful
in a major international trial that scientists stopped the test half way
through to allow all the patients to take advantage of the stunning success
rate, the lead author of a new medical report said on Thursday.
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The five-year study of about 5,200 women with the most common form of breast
cancer was halted midway because Femara, made by Swiss drugmaker Novartis, cut
by 43 percent the risk of the disease's recurrence, compared with the risk for
patients taking a placebo, scientists said.
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"This is a sea change in the treatment of the disease," Dr. Paul Goss of
Princess Margaret Hospital in Toronto, who led the research, told a news
conference.
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The New England Journal of Medicine released the findings ahead of its Nov. 6
print issue because of their significance.
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Goss said the "dramatic results" prompted doctors to halt the trial so that
nearly 2,600 women in the placebo group could start taking the once-daily
Femara pill immediately.
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Doctors said the study offers a new direction to treat patients who have the
hormone-receptor positive form of breast cancer in which estrogen fuels the
cancer. But the report also raises questions.
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"How long should one take (Femara)? What are the long-term toxicities," said
Dr. James Ingles, with the Mayo Clinic in Rochester, Minnesota, another major
participant in the study, which was conducted in nine countries, including
Canada, the United States, England and Belgium.
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Stopping the trial meant researchers were unable to study Femara's effect over
the trial's full five-year period.
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The most widely used treatment for breast cancer now is a drug called
tamoxifen. But tamoxifen loses its effectiveness after five years, a cause of
worry for patients with the disease, which strikes again in one out of two
women five or more years after diagnosis.
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The trial offered Femara, whose generic name is letrozole, to women who had
been off tamoxifen for less than three months after taking tamoxifen for an
average of five years.
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The question of the effectiveness of the new drug for women who have been off
tamoxifen for more than three months is still unanswered. Also, the study
offered no definitive answers for women who have recently been diagnosed with
breast cancer and might want to take letrozole.
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"There are studies looking at taking (letrozole) right away (when you are
diagnosed)," said Goss. "I would argue 'take letrozole' to any woman who has
previously been exposed to tamoxifen."
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Letrozole is one of a class of cancer drugs called aromatase inhibitors, which
suppress the production of estrogen. AstraZeneca has a drug of the same type
called Arimidex.
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Half of the women in the blind trial got letrozole and half got a placebo, but
neither group knew what they were getting.
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After a little more than two years, the cancer returned in 75 of the women who
took letrozole, compared with 132 in group taking the placebo. The researchers
said 42 women who took the placebo died and 31 women who got letrozole died.
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Of these deaths, however, only 17 women in the placebo group died of breast
cancer, and nine taking letrozole died from the disease. The remaining deaths
were from other causes, such as old age.
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After lung cancer, breast cancer is the most common cancer killer in women
across the industrialized world. The World Health Organization says more than
1.2 million people will be diagnosed with breast cancer this year.
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Tamoxifen works by blocking the estrogen receptor on cells -- the molecular
doorway that estrogen uses to get into cells. But it can also, paradoxically,
stimulate this receptor.
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Scientists believe that over time, this stimulation becomes greater,
interfering with tamoxifen's ability to prevent cancer.
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Aromatase inhibitors such as letrozole suppress the production of estrogen.
Side effects include increased risk of osteoporosis, hot flashes, night sweats
and pain in the bones, joints or back.
Sales of Femara, which totaled $108 million in the first half of
2003, are expected to reach $417 million by 2007, according to
Merrill Lynch.
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In Switzerland, Novartis shares closed up 2.4 percent, or 1.25
Swiss francs, at 52.65 Swiss francs on Thursday.
(Additional reporting by Maggie Fox in Washington)