Femara More Effective Than Tamoxifen at Preventing Breast Cancer’s Return

The breast cancer drug letrozole, marketed as Femara, may be more effective than tamoxifen at preventing the return of breast cancer and improving survival among older women with hormone-sensitive breast cancers, a new study reports.

In the study, published online Oct. 21 in The Lancet Oncology, the researchers updated data from an ongoing study of about 8,000 women, which compares the two drugs alone as well as the use of both Femara and tamoxifen sequentially.

Femara outperformed tamoxifen in terms of breast cancer recurrence and survival, the study found. The new study was partially funded by Novartis, the drug company that makes Femara.

Femara is part of a class of breast cancer drugs known as aromatase inhibitors. These drugs block the body’s production of estrogen via the enzyme aromatase. Tamoxifen is a selective estrogen receptor modulator, which means that it acts like estrogen in certain tissues, but not in others, namely the breast. Aromatase inhibitors are given alone or in combination with tamoxifen.

Breast cancer survivors who are being treated with tamoxifen should discuss their options with their doctor. “Talk to your doctor about switching to an aromatase inhibitor,” said Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City. “Tamoxifen is still an excellent drug, but the aromatase inhibitors are better. If the plan was to switch drugs, you may want to talk to [your] doctor about going straight to the aromatase inhibitor,” she added.

Dr. Maura N. Dickler, a breast cancer medical oncologist at the Memorial Sloan-Kettering Cancer Center in New York City, said cost may be an issue for some women, but the gap in price between the two drugs is narrowing. Femara is now available as a generic, which helps reduce its costs, but tamoxifen is still probably less expensive, she said.