Adjuvant therapy for postmenopausal women with estrogen receptor–positive early breast cancer who have completed two to three years of Tamoxifen treatment and are transitioned to Exemestane to complete a total of five continuous years of adjuvant hormonal therapy. Management of advanced breast cancer in postmenopausal women whose condition has worsened after treatment with tamoxifen.

Exemestane is an irreversible steroidal aromatase inhibitor that is structurally similar to the natural substrate androstenedione. It acts as a false substrate for the aromatase enzyme and is converted into an intermediate that binds permanently to the enzyme’s active site, leading to its inactivation—a process also called suicide inhibition. Exemestane significantly reduces circulating estrogen levels in postmenopausal women. However, it does not affect adrenal production of corticosteroids or aldosterone. Additionally, Exemestane does not impact other enzymes in the steroid synthesis pathway, even at concentrations up to 600 times higher than those needed to inhibit aromatase.

The recommended dose of Exemestane in early and advanced breast cancer is one 25 mg tablet once daily after a meal.

• Adjuvant treatment of postmenopausal women with estrogen-receptor positive early breast cancer who have received two to three years of tamoxifen and are switched to Exemestane for completion of a total of five consecutive years of adjuvant hormonal therapy.
• The treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy.

Dose Modifications: Concomitant use of strong CYP 3A4 inducers decreases exemestane exposure, For patients receiving Exemestane with a strong CYP 3A4 inducer such as rifampicin or phenytoin, the recommended dose of Exemestane is 50 mg once daily after a meal.

Co-medications that act as CYP3A4 inducers (such as rifampicin, phenytoin, carbamazepine, phenobarbital, or St. John’s wort) can significantly reduce the blood levels of Exemestane. For patients taking a strong CYP3A4 inducer, a dose adjustment of Exemestane is recommended to maintain effectiveness.

Exemestane should not be used in patients with a known hypersensitivity to the drug itself or to any of its inactive ingredients (excipients).

• Hot flashes
• Fatigue (tiredness or lack of energy)
• Arthralgia (joint pain)
• Headache
• Insomnia (difficulty sleeping)
• Increased sweating

Based on animal studies and its mechanism of action, Exemestane may cause fetal harm if administered to a pregnant woman. Limited human data from case reports are insufficient to clearly define the risk.

In animal reproduction studies, administration of Exemestane to pregnant rats and rabbits resulted in: Increased abortions, Embryo-fetal toxicity,Prolonged gestation with abnormal or difficult labor. Pregnant women should be advised about the potential risk to the fetus. The background risk of major birth defects or miscarriage in the indicated population is unknown. For reference, in the US general population, the estimated background risk of major birth defects is 2–4%, and miscarriage is 15–20% in clinically recognized pregnancies.

There is no data on the presence of Exemestane in human milk or its effects on the breastfed infant or milk production. Exemestane is detected in rat milk at levels similar to maternal plasma. Due to the potential for serious adverse effects in breastfed infants, women should not breastfeed during Exemestane treatment and for 1 month after the final dose.

• Bone Mineral Density (BMD): Long-term use of Exemestane may lead to reductions in bone mineral density.
• Vitamin D Assessment: Before starting aromatase inhibitor therapy, it is recommended to routinely check 25-hydroxy vitamin D levels.
• Embryo-Fetal Toxicity: Exemestane can cause fetal harm. Women of reproductive potential should be informed of the risk to a fetus and advised to use effective contraception during treatment.

Aromatase inhibitor

Store below 30°C, protected from light and moisture. Keep out of reach of children.