Newer breast cancer drug better than the gold standard

BY Matthew Van Atta

December 30 2005 1:00 AM ET

A second member
of a new class of drugs has proved more effective than
the gold standard, tamoxifen, at preventing breast cancer
from recurring in women who received the medicine as
initial therapy right after surgery.

The drug, Femara,
is expected to win Food and Drug Administration
approval soon for women who are past menopause and have
early breast cancer. It is already approved for
treating advanced cases of the disease.

Femara and
Arimidex, a similar drug already licensed for early breast
cancer, are aromatase inhibitors, which block production of
estrogen, a hormone that fuels the growth of most
tumors that develop after menopause. Tamoxifen works
differently, by blunting the ability of estrogen to
enter cells.

A study reported
earlier this year in Europe and published in
Thursday’s New England Journal of
Medicine
estimated that 84% of women given Femara
versus 81% of those on tamoxifen would be alive without any
signs of cancer five years after starting treatment.
The estimates were based on roughly two years of
information on relapses among the 8,000 women in the
study done by researchers in the United States, Europe, and
Australia.

The study was
financed by Femara’s maker, Novartis. Many of the
researchers own stock in or are consultants for Novartis or
companies with rival drugs.

Several other
studies have shown Femara or Arimidex to be better either
as initial treatment or after a couple years of tamoxifen.

“These
trials, with close to 30,000 participants, consistently
demonstrate that treatment with an aromatase inhibitor alone
or after tamoxifen treatment is beneficial,”
Sandra Swain of the National Cancer Institute wrote in
an editorial in the journal. The challenge now is
figuring out how long women should take these drugs, which
drug is best, and whether switching drugs at some
point is helpful, she wrote.

Tamoxifen remains
the top choice for women who get breast cancer before
menopause because aromatase inhibitors aren’t thought
to be effective then. Aromatase inhibitors do not
raise the risk of blood clots or endometrial cancer as
tamoxifen does, but they do increase the chances of
bone problems such as osteoporosis. Women are often advised
to take supplements or other medications to maintain
bone density.

A third aromatase
inhibitor, Pfizer’s Aromasin, also has shown promise
for preventing recurrence when given after several years of
tamoxifen. But it has not yet been tested against
tamoxifen as an initial therapy, as Femara and
AstraZeneca’s Arimidex have been.

Each year, about
800,000 women around the world are diagnosed with early
breast cancer and about three-fourths of them might
benefit from these drugs. (AP)

Tags: Health

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