Advances in Immunotherapy for Breast Cancer

Immunotherapy has transformed the treatment of a variety of malignancies, including breast cancer. Given the unmet clinical need, immunotherapy was first studied in advanced-stage, triple-negative breast cancer (TNBC). The anti-PD-1 agent pembrolizumab plus chemotherapy is approved for both advanced and early TNBC, and data from randomized phase 3 trials in high-risk, early-stage, hormone receptor-positive breast cancer have demonstrated promising efficacy. Ongoing trials aim to identify the most appropriate patients for treatment, amount and timing of immunotherapy needed for optimal outcomes, and ideal combination of therapies to maximize survival while minimizing toxicity. The future of immunotherapy in breast cancer will continue to evolve with the advent of novel immunologic agents. In this review, we highlight pivotal trials that have informed current practice and ongoing trials that may inform the therapeutic landscape in the coming years.