Pooled analyses of randomized controlled trials onpyrotinib plus capecitabine and a rethink of the first-line options for HER2-positive relapsed or metastatic breast cancer

Human epidermal growth factor receptor 2(HER2)-positive breast cancer,which accounts for 15%-20% of breast cancers,is associated with aggressive tumor behavior and conferred a poor outcome before the era of HER2-targeted therapy.The advent of anti-HER2 antibodies(trastuzumab and pertuzumab),antibody-drug conjugates(ADCs,ado-trastuzumab emtansine and trastuzumab deruxtecan),and HER2‐tyrosine kinase inhibitors(TKIs,neratinib and lapatinib),have dramatically improved the treatment response and survival of this aggressive subtype.