Phase II study of pembrolizumab plus nab-paclitaxel in Hormone Receptor–positive, HER2- negative metastatic breast cancer: clinical and molecular insights into response
This phase II study demonstrates that combining pembrolizumab with nab-paclitaxel yields a manageable toxicity profile and clinical efficacy in HR+/HER2- metastatic breast cancer, including in patients previously treated with CDK4/6 inhibitors, while revealing that adaptive immune activation alone is insufficient for response and highlighting the prognostic value of baseline T-cell fraction.