Class: Selective Estrogen Receptor Degrader (SERD)
Therapeutic Indications
- Treatment of postmenopausal women with hormone receptor-positive, advanced or metastatic breast cancer, especially after progression on prior endocrine therapy (e.g., aromatase inhibitors).
- Used as monotherapy or in combination with targeted agents (e.g., CDK4/6 inhibitors).
Mechanism of Action
- Binds to estrogen receptors (ER) with high affinity, causing receptor downregulation and degradation.
- Completely blocks estrogen signaling, leading to inhibition of hormone-driven tumor growth in ER-positive breast cancer.
Dosing
- Administered as intramuscular injection, typically 500 mg on days 0, 14, 28, then monthly thereafter.
Common Adverse Effects
- Injection site reactions
- Hot flashes
- Fatigue
- Nausea
- Back pain
Pharmacist Considerations
- Counsel patients about the intramuscular injection schedule and possible injection site discomfort.
- Monitor for menopausal symptoms and manage accordingly.
- Be aware of drug interactions when combined with targeted therapies.
- Support adherence to scheduled dosing to maintain efficacy.