Data from the PHILA study, for example, demonstrated that pyrotinib significantly improved progression-free survival in patients with metastatic HER2-positive breast cancer who had previously been treated with adjuvant trastuzumab.11 Additionally, preclinical models, including those conducted by our research team, have shown that pyrotinib can enhance the effectiveness of trastuzumab in trastuzumab-resistant cell lines. This evidence concerns the gene ERBB2 and breast cancer.