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Brand name(s): Aromasin®

• Approved for breast cancer

Full prescribing information ³ is available, including clinical trial information, safety, dosing, drug-drug interactions and contraindications.

Safety and efficacy were evaluated in the Intergroup Exemestane Study (IES), a double-blind, multicenter, international clinical trial in postmenopausal women with early stage breast cancer who had received two to three years of adjuvant tamoxifen. Four thousand seven hundred and twenty four patients in the intention-to-treat population were randomly assigned to either continue tamoxifen (20-30 mg/day) or switch to exemestane (25 mg/day) to complete a total of five years of adjuvant hormonal therapy.

Approval was based on an analysis of disease-free survival (DFS), defined as the time from randomization to the development of local or distant recurrence, contralateral breast cancer (cancer in the other breast), or death from any cause. After a median duration of randomized therapy of 27 months and with a median duration of follow-up of 34.5 months, DFS was significantly improved in patients who switched to exemestane compared to those who continued tamoxifen (HR=0.69, 95 percent CI: 0.58-0.82, p<0.0001).

In the hormone receptor-positive subpopulation representing about 85 percent of the trial patients, DFS was significantly improved (HR=0.65, 95 percent CI: 0.53-0.79, p=0.00001) in the exemestane arm compared to the tamoxifen arm. Overall survival was not significantly different in the two arms.

The most common adverse events on the IES that occurred more frequently on the exemestane arm included hot flashes, fatigue, arthralgia (joint pain), headache, insomnia (difficulty sleeping), increased sweating, hypertension (high blood pressure), and dizziness. Cardiac ischemic events (heart problems) occurred in 1.6 percent of patients in the exemestane arm of the IES compared to 0.6 percent of patients in the tamoxifen arm.

Changes in bone mineral density (BMD) were evaluated in a substudy of the IES and in a supporting safety study (027), which compared the effects of two years of exemestane to placebo. Mean decreases in BMD of the lumbar spine and femoral neck were more pronounced with exemestane than with either tamoxifen or placebo. On the IES, osteoporosis was reported in 4.6 percent of patients treated with exemestane compared to 2.8 percent of patients receiving tamoxifen.

Glossary Terms

Additional cancer treatment given after the primary treatment to lower the risk that the cancer will come back. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, targeted therapy, or biological therapy.

An unexpected medical problem that happens during treatment with a drug or other therapy. Adverse effects do not have to be caused by the drug or therapy, and they may be mild, moderate, or severe. Also called adverse event.

The length of time after treatment for a specific disease during which a patient survives with no sign of the disease. Disease-free survival may be used in a clinical study or trial to help measure how well a new treatment works. Also called DFS and disease-free survival time.

A clinical trial in which the medical staff, the patient, and the people who analyze the results do not know the specific type of treatment the patient receives until after the clinical trial is over.

Describes cells that have a receptor protein that binds the hormone estrogen. Cancer cells that are estrogen receptor positive may need estrogen to grow, and may stop growing or die when treated with substances that block the binding and actions of estrogen. Also called ER+.

A drug used to treat advanced breast cancer and to prevent recurrent breast cancer in postmenopausal women who have already been treated with tamoxifen. It is also being studied in the treatment of other types of cancer. Exemestane causes a decrease in the amount of estrogen made by the body. It is a type of aromatase inhibitor. Also called Aromasin.

A statistics term. The middle value in a set of measurements.

An inactive substance or treatment that looks the same as, and is given the same way as, an active drug or treatment being tested. The effects of the active drug or treatment are compared to the effects of the placebo.

Having to do with the time after menopause. Menopause (“change of life”) is the time in a woman's life when menstrual periods stop permanently.

A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.

Describes a mathematical measure of difference between groups. The difference is said to be statistically significant if it is greater than what might be expected to happen by chance alone. Also called significant.

A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and in women who are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate.