Real-World Analysis of the Efficacy and Safety of a Novel Irreversible HER2 Tyrosine Kinase Inhibitor Pyrotinib in Patients with HER2-Positive Metastatic Breast Cancer.

Pyrotinib is highly beneficial to HER2-positive metastatic breast cancer patients, even in patients with previous lapatinib exposure. Pyrotinib is a feasible replacement of lapatinib in combination with chemotherapeutic drugs or as a monotherapy. Adverse effects are tolerable and easily manageable.