New agents may extend survival more than old ones

Here we go again. A better drug? It always goes back to that, which will line the pockets of the drug manufacturers and pill pushers. Why can’t they just reapproach this dreaded dis-ease with natural, alternative methods? They couldn’t possibly do worse than they are doing now – in fact – they might just improve on their record! That would be a shame – people might just live a long time.

A new class of breast cancer drug seems to work even better than the standard tamoxifen in fighting the disease, researchers said on Monday. They said it was too soon to say if the new drugs, called aromatase inhibitors, should replace tamoxifen as a favored drug, but they shrank tumors better and helped more women survive.

ABOUT 80 percent of women with breast cancer, like Michelle Henderson, have tumors that need estrogen to grow. That is why hormone therapy plays such a big role in breast cancer treatment – and the new drugs should bring a major improvement.

“I think these results … are going to make us re-think the whole area of hormone therapy for breast cancer,” said Dr. Larry Norton, a cancer specialist at Memorial Sloan-Kettering Cancer Center (the same folks who conducted the study on the work of Dr. Kelley) in New York.

For 20 years, doctors have been using tamoxifen, which blocks estrogen from getting into the cancer cells, to try to slow tumor growth.

Monday’s findings shows that the aromatase inhibitors, which cut the body’s production of estrogen, work at least 17 percent better than tamoxifen – and with fewer side effects. And unlike tamoxifen, aromatase inhibitors do not increase the risk of uterine cancer or blood clots.

“It is the first time we have ever had a drug that has improved upon tamoxifen in terms of survival,” said Duke University’s Dr. Matthew Ellis, who led one of three studies on the drugs presented at a breast cancer conference in San Antonio.

The latest studies show that the new drugs work better in both advanced and early stage breast cancer. One even suggested that they might do a better job than tamoxifen in reducing the odds of getting cancer for healthy women at high risk.

“If the aromatase inhibitors work even better than tamoxifen this gives us a very important lead toward the prevention of breast cancer which is our ultimate goal,” Norton said.
Breast cancer is the second biggest cancer killer of women in the industrialized world, after lung cancer. It kills 40,000 women each year in the United States.

~ STUDY DETAILS ~
In one of the new studies, an aromatase inhibitor called Femara, made by Swiss drugmaker Novartis under the generic name letrozole, worked in a wider range of women than tamoxifen.

“Letrozole is associated with a higher rate of tumor shrinkage … and a better one – and two-year survival than tamoxifen,” Ellis said.

Ellis, working with researchers in Germany, Spain, France and Britain, followed 324 women taking either tamoxifen or Femara. They saw tumors shrink in 60 percent of women taking Femara for four months, compared to 41 percent of women taking tamoxifen.

“Although our results are preliminary, letrozole appears to block estrogen more effectively than does tamoxifen, suggesting that letrozole may work for women whose tumors are relatively resistant to tamoxifen,” Ellis, who is a paid consultant to Novartis, which also funded the study, said in a statement.

In a second study, Dr. Martine Piccart of the Jules Bodet Institute in Brussels, Belgium, and colleagues followed 453 women taking Femara and 454 taking tamoxifen.

Overall median survival was 34 months with Femara and 30 months with tamoxifen. Piccart said 64 percent of patients were alive two years after starting Femara, compared to 58 percent of tamoxifen patients.

Ellis’ team worked with women whose breast cancer had progressed to the late stages, but another study presented at the conference showed a related drug, Arimidex, could help women with early breast cancer.

Made by AstraZeneca under the generic name anastrozole, Arimidex also reduced breast cancer deaths. After a median of 30 months’ treatment and 33 months of follow-up, 317 of 3,125 women given Arimidex suffered relapses, compared to 379 of 3,116 women taking tamoxifen – a 17 percent reduction.

“This advance is as important for women fighting early breast cancer as the advent of tamoxifen was 20 years ago,” Michael Baum of University College Hospital in London, who presented the results, said.

“The results of the (latest) study … may support the use of anastrozole, rather than tamoxifen, as the future treatment of choice,” he added.

A third company, Pharmacia, makes an aromatase inhibitor called Aromasin.

~ HOW THEY WORK ~
Tamoxifen mimics some of the action of estrogen and by doing so blocks its cancer-causing effects – usually. But sometimes it does not, and tamoxifen can increase the risk of a very rare form of cancer of the uterus.

Femara and related drugs stop the action of an enzyme called aromatase, which converts androgen, a precursor hormone, into the female hormone estrogen.

As for Henderson, despite several rounds of treatment including tamoxifen, her cancer spread to her lungs. With one of new drugs, the tumors shrank.

“To know that I can survive this cancer for so many years is a wonderful thing,” Henderson said.

Written by Robert Bazell for the NBC News, and Reuters and published on DrKelley.info, December 11, 2001. Embedded links may no longer be active (Ed. 12.28.10)

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