Fulvestrant

Definition

Fulvestrant is a selective estrogen receptor downregulator (SERD) used in the treatment of hormone receptor-positive, advanced breast cancer. It works by binding to and degrading estrogen receptors, thereby reducing the growth-promoting effects of estrogen on breast cancer cells.

5 Must Know Facts For Your Next Test

1. Fulvestrant is administered as an intramuscular injection, typically given once a month.
2. It is approved for the treatment of hormone receptor-positive, advanced or metastatic breast cancer in postmenopausal women with disease progression following antiestrogen therapy.
3. Fulvestrant works by binding to the estrogen receptor, causing a conformational change that leads to its degradation and removal from the cell.
4. Unlike other antiestrogen therapies, such as tamoxifen, fulvestrant does not have any agonist (or partial agonist) activity, making it a pure antagonist of the estrogen receptor.
5. Fulvestrant has been shown to be effective in patients who have become resistant to other hormonal therapies, such as aromatase inhibitors or tamoxifen.

Review Questions

• Explain the mechanism of action of fulvestrant and how it differs from other antiestrogen therapies.
  • Fulvestrant is a selective estrogen receptor downregulator (SERD) that works by binding to the estrogen receptor and causing its degradation, rather than just blocking its activity like other antiestrogen therapies. This unique mechanism of action makes fulvestrant a pure antagonist of the estrogen receptor, without any agonist or partial agonist activity. As a result, fulvestrant is effective in treating hormone receptor-positive breast cancer, even in patients who have developed resistance to other hormonal therapies.
• Describe the clinical indications and patient population for which fulvestrant is approved.
  • Fulvestrant is approved for the treatment of hormone receptor-positive, advanced or metastatic breast cancer in postmenopausal women with disease progression following antiestrogen therapy. This includes patients who have previously received other hormonal therapies, such as tamoxifen or aromatase inhibitors, and have developed resistance to these treatments. Fulvestrant is administered as an intramuscular injection, typically given once a month, and has been shown to be effective in this patient population.
• Analyze the role of fulvestrant in the management of hormone receptor-positive breast cancer, particularly in the context of treatment resistance and disease progression.
  • Fulvestrant plays a critical role in the management of hormone receptor-positive breast cancer, especially in cases where the disease has progressed or become resistant to other hormonal therapies. By targeting and degrading the estrogen receptor, fulvestrant effectively reduces the growth-promoting effects of estrogen on breast cancer cells, even in patients who have developed resistance to other antiestrogen treatments. This makes fulvestrant a valuable therapeutic option for postmenopausal women with advanced or metastatic hormone receptor-positive breast cancer who have exhausted other hormonal therapy options. Its unique mechanism of action and proven efficacy in the setting of treatment resistance make fulvestrant an important component of the comprehensive approach to managing this challenging patient population.

Related terms

Selective Estrogen Receptor Downregulator (SERD): A class of drugs that bind to and degrade estrogen receptors, leading to a reduction in estrogen signaling and tumor growth.

Estrogen Receptor (ER): A protein found in certain cancer cells that binds to the hormone estrogen, promoting tumor growth and proliferation.

Hormone Receptor-Positive Breast Cancer: A type of breast cancer in which the cancer cells express receptors for hormones, such as estrogen and progesterone, and their growth is stimulated by these hormones.