Immunotherapy Approaches for Breast Cancer Patients in 2023

Immunotherapy, particularly agents targeting the immunoregulatory PD-1/PD-L1 axis, harnesses the power of the immune system to treat cancer, with unique potential for a durable treatment effect due to immunologic memory. The PD-1 inhibitor pembrolizumab combined with neoadjuvant chemotherapy followed by adjuvant pembrolizumab improves event-free survival and is a new standard of care for high-risk, early-stage triple-negative breast cancer (TNBC), regardless of tumor PD-L1 expression. For metastatic TNBC, pembrolizumab combined with chemotherapy is a new standard of care for the first-line therapy of PD-L1⁺ metastatic TNBC, with improvement in overall survival. The PD-L1 inhibitor atezolizumab combined with nab-paclitaxel is also approved outside the United States for the first-line treatment of metastatic PD-L1⁺ TNBC. Current research focuses on refining the use of immunotherapy in TNBC by defining informative predictive biomarkers, developing immunotherapy in early and advanced HER2-driven and luminal breast cancers, and overcoming primary and secondary resistance to immunotherapy through unique immune-based strategies.