ARIMIDEX AND CARDIOVASCULAR RISK

Anastrozole (Arimidex) Contraindicated in Pregnancy, Linked to Cardiovascular Risk in Women With Preexisting Ischemic Disease

On December 10, 2008, the FDA approved safety labeling revisions for anastrozole (Arimidex tablets; AstraZeneca) to warn against its use in pregnancy and of the risk for ischemic cardiovascular events.

Anastrozole may cause fetal harm when administered to a pregnant woman and offers no clinical benefit to premenopausal women with breast cancer, the FDA warned. In animal studies, anastrozole caused pregnancy failure, increased pregnancy loss (increased preimplantation and/or postimplantation loss, increased resorption, and decreased numbers of live fetuses), and signs of delayed fetal development (incomplete ossification and depressed fetal body weights). Women who become pregnant during treatment should be advised of the potential harm to the fetus and risk for fetal loss.

Citing new data from the Arimidex, Tamoxifen, Alone or in Combination study (n = 6186), the FDA also warned that anastrozole therapy may be linked to an increased risk for ischemic cardiovascular events in women with preexisting ischemic heart disease (17% vs tamoxifen, 10%). This factor should be considered when weighing risks and benefits of anastrozole therapy.

Anastrozole tablets are indicated for the adjuvant treatment of hormone receptor–positive early breast cancer in postmenopausal women, as first-line therapy for postmenopausal women with hormone receptor–positive or unknown locally advanced or metastatic breast cancer, and as second-line treatment of advanced breast cancer in postmenopausal women with disease progression after tamoxifen therapy.