Immunotherapy Targeting HER2-positive Breast Cancer

Breast cancer with HER2-positive status is highly invasive and susceptible to recurrence and metastasis, and its targeted immunotherapies mAb (e.g., trastuzumab, pertuzumab), ADCs (e.g., T-DM1, T-DXd), and ICIs have enhance the prognosis; however, their drug-resistance and adverse effects still limit their long-term efficacy. Despite advances in immunotherapy targeting HER2+, the indications for ICIs in HER2-positive breast cancer are unclear, the selection of biomarkers for combination therapy remains controversial. This article systematically summarizes several immunotherapeutic strategies for HER2-positive breast cancer and their research progress, including the mechanism of action,resistance management of mAb, the clinical advantages and toxicity risks of ADC , and the potential and challenges of ICI combination targeted therapy. Trastuzumab plus pertuzumab combination chemotherapy can enhance the survival of early-stage patients, while T-DM1 demonstrates safety advantages in drug-resistant second-line therapy; ICI combined with targeted therapy has preliminary efficacy in PD-L1-positive patients, and the specific applicability of the population needs to be further screened. This review provides a theoretical basis for optimizing the precision treatment of HER2-positive breast cancer, and in the future, in-depth exploration of drug resistance mechanisms, development of novel ADC, and combination therapy strategies based on the immune microenvironment are needed to break through the bottleneck.