Evaluating everolimus for the treatment of breast cancer.

Introduction: Everolimus is an oral drug that inhibits mTOR with immunosuppressive and antiproliferative characteristics. It is commonly used in association with exemestane in hormone receptor (HR)-positive advanced breast cancer (ABC).

Areas Covered: The current review summarizes the publications relating to everolimus from clinical research in breast cancer. Everolimus showed treatment efficacy and an acceptable safety tolerance with the prevention of side effects in Phase II/III studies. BOLERO-2 study showed a progression-free survival improvement in patients with HR - positive ABC previously treated with aromatase inhibitors (AI) and leading to its acceptance in this indication. The absence of a post-CDK4/6 inhibitor (CDK4/6i.) study and the arrival of new drugs may raise questions about its current place in the therapeutic strategy.

Expert Opinion: Everolimus is relevant in the management of HR - positive ABC. Because of its efficacy, acceptable tolerability and the absence of drugs that have shown a greater benefit, it remains a second-line treatment option in HR-positive, HER2 negative (score 0) patients without BRCA mutation or visceral crisis and can be discussed with fulvestrant in second line after CDK4-6i. It is likely that within 5 years this treatment will be replaced in second-line HR-positive breast cancer by new emerging treatments: drug-conjugated antibodies, tyrosine kinase inhibitors or immunotherapy in combination with chemotherapy.