FDA Approves New Use for Breast Cancer Drug
Aromasin May Now Treat Early Breast Cancer in Postmenopausal Women
WebMD News Archive
According to a Pfizer news release, the FDA approved Aromasin's new use
based on a study of more than 4,700 postmenopausal women with estrogen
receptor-positive breast cancer.
That study was published in The New England Journal of Medicine in
All of the women had taken tamoxifen for two to three years. About half were
then switched to Aromasin; others kept taking tamoxifen. Each woman got a
combined total of five years of drug therapy. They didn't know which drug they
Those who were switched to Aromasin had 32% more protection from cancer's
"[Aromasin] therapy after two to three years of tamoxifen therapy
significantly improved disease-free survival as compared with the standard five
years of tamoxifen treatment," the researchers wrote.
Severe side effects were rare in their study.
Aromasin is part of a newer family of breast cancer drugs called aromatase
inhibitors. Those drugs also include
Arimidex was recently compared to tamoxifen in a similar Austrian study. The
results, published in The Lancet in August, showed fewer cancer recurrences in
women who were switched to Aromasin after taking tamoxifen for about two years,
instead of continuing with tamoxifen.
in yet another study, which was presented in May
at the annual meeting of the American Society of Clinical Oncology.
None of those studies did a head-to-head comparison of aromatase
Aromatase inhibitors are generally known for a lower risk of blood clots
compared with tamoxifen, yet they appear to have a higher risk of bone loss and
fracture. As relatively new drugs, there is still more to learn about them.
Aromatase inhibitors are also more costly than tamoxifen, which is now
available as a generic drug.
Different From Tamoxifen
Like tamoxifen, aromatase inhibitors target estrogen, which fuels some (but
not all) breast cancers.
Tamoxifen blocks estrogen receptors on cells. It acts like your car's gas
cap, preventing the "fuel" (estrogen) from getting into the
"tank" (the cell).
Aromatase inhibitors work differently. They curb estrogen production. That
way, there's no "gas" to go in the "tank."
Tamoxifen has been a major part of breast cancer treatment for more than 20
years. It's typically taken for five years after surgery, chemotherapy, and
radiation to try to prevent cancer's return.