Can Everolimus/Afinitor treat triple-negative breast cancer?

Everolimus is a targeted drug commonly used to treat advanced breast cancer, renal cell carcinoma and other diseases. It inhibits cell proliferation and slows down tumor growth by inhibiting the mTOR signaling pathway. However, everolimus is not effective against all types of breast cancer, especially in the treatment of triple-negative breast cancer (TNBC), and its efficacy is controversial.

Triple-negative breast cancer (TNBC) is a subtype of breast cancer characterized by the lack of estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor 2 (HER2). The lack of these markers makes traditional targeted therapy, hormone therapy, and HER2-targeted therapy less effective in triple-negative breast cancer. Therefore, the treatment strategy for triple-negative breast cancer mainly relies on chemotherapy, immunotherapy and some new targeted therapies.

Everolimus exerts its anti-tumor effects primarily by inhibiting themTOR (mammalian target of rapamycin) pathway, which is overactivated in many types of cancer. For hormone receptor-positive, HER2-negative breast cancer, everolimus is often used in combination with other drugs, such as exemestane, especially after failure of letrozole or anastrozole. However, research on triple-negative breast cancer is limited, and its effects are far less dramatic than those in hormone receptor-positive or HER2-positive breast cancer.

Current research shows that the effect of everolimus in triple-negative breast cancer is not ideal. Although the mTOR pathway plays a key role in a variety of tumors, the treatment of triple-negative breast cancer is more complex, and its driving mechanism does not entirely rely on the mTOR pathway. Therefore, everolimus is not a standard treatment option for triple-negative breast cancer. More common treatments include chemotherapy, immune checkpoint inhibitors (such as PD-1/PD-L1 inhibitors) and, in some cases, emerging therapies such as PARP inhibitors.

Reference materials:https://www.bccancer.bc.ca/drug-database-site/Drug%20Index/Everolimus_monograph.pdf