Study shows AstraZeneca's new breast cancer drug works better.

Byline: Todd Ackerman

Dec. 9--A newer breast cancer drug that outperforms industry-standard tamoxifen should replace it as first-line therapy for postmenopausal patients, according to a new international study.

The University of Texas M.D. Anderson Cancer Center and other researchers reported Wednesday that women who took Arimidex were less likely to have their breast cancer come back, less likely to have it spread and less likely to have serious side effects.

"I hope with this new data doctors start using Arimidex as their new first choice," said Dr. Aman Buzdar, a professor in M.D. Anderson's department of breast medical oncology and the lead investigator for the North American portion of the study. "It's the better drug."

Buzdar, who presented the research Wednesday at the San Antonio Breast Cancer symposium, said he thought "the days of tamoxifen are gone." The findings of the study were also published online by the British medical journal The Lancet.

Tamoxifen, which revolutionized breast cancer treatment when it came out three decades ago, is taken by about three-quarters of postmenopausal women with breast cancer. The drug, which blunts estrogen's ability to fuel cancer growth, cuts in half the risk cancer will recur.

But the five-year study of more than 9,000 patients in 21 countries found Arimidex cut the risk of recurrence by 70 to 80 percent. In addition, women taking it had less bleeding and fewer blood clots, strokes and uterine cancers.