How to Optimise Extended Adjuvant Treatment with Neratinib for Patients with Early HER2+ Breast Cancer

Over the last 20 years, treatment of patients with human epidermal growth factor receptor 2-positive (HER2+) early breast cancer has considerably improved. The development and addition of (neo)adjuvant trastuzumab to chemotherapy in patients with early HER2+ breast cancer (EHBC) has been shown to provide improvements in both disease-free survival (DFS) and overall survival, with some patients having a good prognosis being candidates for chemotherapy de-escalation strategies. However, despite such promising clinical outcomes, a significant proportion of patients still recur calling for the development of new preventive approaches. To this aim, the use of (neo)adjuvant trastuzumab for longer than one year or followed by lapatinib were tested without additional clinical improvement. Based on more recent advances, therapeutic strategies for patients with HER2+ tumours are now incorporating the use of newer (neo)adjuvant treatments, such as pertuzumab and trastuzumab emtansine, which have shown to further improve the invasive DFS (iDFS) benefit gained with trastuzumab. In this context, the tyrosine kinase inhibitor neratinib is approved in Europe for the extended adjuvant treatment of adult patients with early-stage hormone receptorpositive HER2+ breast cancer who completed adjuvant trastuzumab-based therapy less than one year ago. Clinical data have demonstrated that neratinib significantly improves iDFS when used for the total recommended duration of 12 months. This review paper provides an overview of the treatment of patients with EHBC, with a focus on the post-trastuzumab use of neratinib.