Advances in the treatment of human epidermal growth factor receptor 2-positive gastric cancer.

Human epidermal growth factor receptor 2 has been a pivotal biomarker for gastric cancer treatment strategies for many years. However, more than a decade after the ToGA trial demonstrated the efficacy of trastuzumab in improving survival, the development of treatments targeting human epidermal growth factor receptor 2 remains challenging. Several large-scale clinical trials of tyrosine kinase inhibitors, non-trastuzumab anti-human epidermal growth factor receptor 2 antibodies, and antibody-drug conjugates have failed to meet the primary endpoints. The concept of trastuzumab beyond progression and the complexity of resistance mechanisms to anti-human epidermal growth factor receptor 2 therapy after trastuzumab treatment presented significant obstacles, leading to trastuzumab being the sole therapy for human epidermal growth factor receptor 2-positive gastric cancer for some time. Nevertheless, the landscape has shifted in recent years, especially since the introduction of the antibody-drug conjugate trastuzumab deruxtecan in 2020. This has rekindled the interest in developing treatments targeting human epidermal growth factor receptor 2 in gastric cancer.