2nd drug better at fighting breast cancer

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ASSOCIATED PRESS

A second member of a new class of drugs has proved more effective than 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 in the early stages of breast cancer. It is already approved for treating advanced cases of the disease.

Femara and Arimidex, a similar drug 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.

The challenge is figuring out how long women should take these drugs, which drug is best and whether switching drugs at some point is helpful.

Tamoxifen remains the gold standard 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 often are advised to take supplements or other medications to maintain bone density.

A third aromatase inhibitor, Pfizer Inc.'s Aromasin, also has shown promise for preventing recurrence when given after several years of tamoxifen. But unlike Femara and AstraZeneca PLC's Arimidex, Aromasin has not been tested against tamoxifen as initial therapy.

A study reported earlier this year in Europe and published in today's New England Journal of Medicine estimated that 84 percent of women given Femara compared with 81 percent of those on tamoxifen would be alive without any signs of cancer five years after starting treatment.

The estimates were based on about two years of data on relapses among the 8,000 women in the study, conducted in the United States, Europe and Australia.

The research 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," Dr. Sandra Swain of the National Cancer Institute wrote in an editorial in the journal.

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