ASCO Says "Too Early" To Recommend Switch From Tamoxifen to Arimidex

The American Society of Clinical Oncology (ASCO) said its experts believe it would be premature to recommend switching from the use of tamoxifen to one of the new aromatese inhibitors as a follow-up therapy for women with hormone receptor-positive breast cancer.

The organization said it considered the results of the ATAC (Arimidex and Tamoxifen, Alone or in Combination) trial, in which patients on Arimidex (anastrozole) had a significantly lower rate of disease recurrence than those on Tamoxifen, "very promising" and encouraged physicians to discuss the data with their patients.

In the ATAC trial, the new AstraZeneca drug also was associated with significantly fewer reports of endometrial cancer, thromboembolic events (overall incidence and deep vein thromboses) and vaginal bleeding than tamoxifen.

But ASCO said its experts "felt that it was too early to recommend a wholesale switch from the standard use of tamoxifen in this setting and that physicians and patients need to come to their own conclusions after considering all available data."

The organization also made a point of stating that Arimidex "is the only aromatase inhibitor with clinical trial data in the adjuvant setting, and it should be considered the preferred agent if an aromatase inhibitor is used in this setting."

Novartis, manufacturer of another aromatase inhibitor, Femara, said more than 10,000 women are now participating in a new set of studies comparing Febara to a placebo in women who have remained disease free for five years of tamoxifen therapy; and to tamoxifen in various treatment sequences.

"The company is looking forward to the results of its ongoing Femara (letrozole) adjuvant studies that should provide data sufficiently robust to enable the (ASCO) Committee to move forward with its recommendations," a Novartis spokesperson said. Vitamin D May Pr

Other sources: ASCO