Antibody-drug conjugates (ADCs), such as trastuzumab deruxtecan (T-DXd) and sacituzumab govitecan (SG) offer new and potent options for curing for curing hormone receptor-positive (HR+)/human epidermal growth factor receptor 2 (HER2)-low advanced breast cancer; however, comparisons in terms of their relative effectiveness and safety concerns are lacking. Compared with other ADC drugs, T-DXd showed relatively better treatment characteristics, better PFS benefit, and relatively low incidence of serious AEs (SAEs). Combined with RCTs and real-world data, T-DXd has potential advantages in this population.

ADCs against TROP2 (Sacituzumab govitecan) or HER2 (T-DXd) have demonstrated efficacy in metastatic breast cancer, yet paradoxically, outside of HER2-amplified breast cancers, expression levels of these breast cancer-enriched epitopes in tumor biopsies have not been strongly correlated with clinical response. Thus, while CTC burden is correlated with response to these ADCs, the level of TROP2 or HER2 expression is poorly predictive. These findings point to sensitivity to the drug payload as a potential driver of clinical response to currently approved ADCs in breast cancer.

With the expanding use of trastuzumab deruxtecan (T-DXd), sacituzumab govitecan (SG), and datopotamab deruxtecan (Dato-DXd) across HER2-positive, HER2-low, and hormone-receptor-positive disease, management of treatment-related toxicities has become a critical determinant of outcomes. Integrating these findings, we propose practical algorithms for managing pulmonary, gastrointestinal, hematologic, ocular, and mucosal adverse events. This review consolidates evidence into a clinician-oriented reference for ADC toxicity management, emphasizing multidisciplinary coordination, early recognition, and system-specific mitigation strategies to enhance treatment safety and adherence.

P3, N=740, Active, not recruiting, Daiichi Sankyo | Recruiting --> Active, not recruiting | Trial completion date: Apr 2028 --> Mar 2032 | Trial primary completion date: Feb 2028 --> Mar 2030

P1/2, N=102, Not yet recruiting, Dualitybio Inc. | N=57 --> 102

P2, N=20, Not yet recruiting, Virginia Commonwealth University

P2, N=132, Not yet recruiting, Akeso

P=N/A, N=60, Recruiting, Regina Elena Cancer Institute | Trial completion date: Jun 2025 --> Jun 2027

P3, N=420, Not yet recruiting, Fudan University

In multivariable analysis, Eastern Cooperative Oncology Group (ECOG) performance status was the only independent predictor of poorer survival (hazard ratio 1.97, 95% CI 1.42-2.74, p < 0.01), while gBRCA1/2 status showed no independent association. In this large retrospective cohort of mTNBC patients treated with SG, the presence of gBRCA1/2 was not associated with statistically significant differences in PFS or OS.

P2, N=24, Recruiting, Fudan University