Advances in HER2-Targeted Treatment for Advanced/Metastatic Urothelial Carcinoma.

Urothelial carcinoma (UC) represents a common malignancy of the urinary system that can involve the kidneys, ureter, bladder, and urethra. Advanced/metastatic UC (mUC) tends to have a poor prognosis. UC ranks third in terms of human epidermal growth factor receptor 2 (HER2) overexpression among all tumors. However, multiple studies found that, unlike breast cancer, variable degrees of HER2 positivity and poor consistency between HER2 protein overexpression and gene amplification have been found. Trials involving trastuzumab, pertuzumab, lapatinib, afatinib, and neratinib have failed to prove their beneficial effect in patients with HER2-positive mUC, and a clinical trial on T-DM1 (trastuzumab emtansine) was terminated prematurely because of the adverse reactions. However, a phase II trial showed that RC48-ADC was effective. In this review, we provided an in-depth overview of the advances in the research regarding HER2-targeted therapy and the role of HER2 in mUC. Furthermore, we also discussed the prospects of potential strategies aimed at overcoming anti-HER2 resistance, and summarize the novel anti-HER2 approaches for the management of mUC used in recent clinical trials.