Title: Neoadjuvant Chemotherapy and Immunotherapy for Estrogen Receptor–Positive Human Epidermal Growth Factor 2–Negative Breast Cancer

Publication: Journal of Clinical Oncology, April 9, 2024

Author:Alejandro R´ıos-Hoyo, MD ; Erin Cobain, MD; Laura A. Huppert, MD; Peter D. Beitsch, MD; Thomas A. Buchholz, MD; Laura Esserman, MD; Laura J. van ’t Veer, PhD; Hope S. Rugo, MD; and Lajos Pusztai, MD, DPhil


Clinical trial results presented at the 2023 European Society of Medical Oncology (ESMO) annual meeting and at the 2023 San Antonio Breast Cancer Symposium (SABCS) combined with earlier reports from the I-SPY2 clinical trial are building evidence that immune checkpoint inhibitors added to neoadjuvant chemotherapy might improve outcome in high-risk stage II-III estrogen receptor–positive (ER1) human epidermal growth factor receptor 2–negative (HER2–) breast cancer. These studies showed improved pathologic complete response (pCR) rates, but the impact on event-free survival (EFS) is yet unknown. If improvement in EFS is seen with longer follow-up, these results will make treatment decisions more complex for patients with highrisk ER1/HER2– cancers and will pose new management questions about who the right patient population is, and how to integrate immune checkpoint inhibitor therapy with adjuvant CDK4/6 inhibitors.