Women treated with tamoxifen (Nolvadex) had a 13% higher risk of
disease progression than those treated with anastrozole (Arimidex),
according to the North American and the European Tamoxifen or
Arimidex Randomized Group Efficacy and Tolerability (TARGET) study.
This finding suggests that anastrozole may be a more effective
treatment option for many postmenopausal women with advanced breast
cancer. The results from the TARGET study were reported at the 22nd
Annual San Antonio Breast Cancer Symposium.
These randomized, double-blind studies were designed to demonstrate
the efficacy of anastrozole and tamoxifen treatments in
postmenopausal women with advanced breast cancer. A total of 1,021
patients were included in the studies.
Aman Buzdar, MD, from The University of Texas M. D. Anderson Cancer
Center said, We know that tamoxifen and Arimidex are both
effective treatments for women with advanced breast cancer. But until
now, the two have never been compared directly in a clinical trial.
This is the first time that we have seen an aromatase inhibitor prove
to be as effective as tamoxifen.
Anastrozole, a selective, nonsteroidal aromatase inhibitor, differs
from tamoxifen because it inhibits a key step in the production of
estrogen. Anastrozole is currently available in most countries,
including the United States, for the treatment of advanced breast
cancer in postmenopausal women following disease progression during
treatment with tamoxifen or other antiestrogens. The Arimidex,
Tamoxifen Alone or in Combination (ATAC) trial for adjuvant use of
anastrozole is ongoing.