Neoadjuvant pyrotinib plus trastuzumab and vinorelbine for HER2-positive locally advanced breast cancer patient who was initially resistant to HP therapy: a case report and literature review.

Background: Trastuzumab (H) and pertuzumab (P) plus chemotherapy is the standard guideline-recommended neoadjuvant therapy recommended for patients with human epidermal growth factor receptor 2 (HER2)-positive locally advanced breast cancer (BC), which has dramatically improved patient prognosis. However, over 10% of patients develop primary drug resistance to HP and did not respond to treatment. There is no standard second-line neoadjuvant therapy approach for these individuals at the present. Pyrotinib and vinorelbine have shown promising efficacy in HER2-positive metastatic breast cancer, but their usage in neoadjuvant therapy has not been reported so far. Case Description: Here, we present a case of a 58-year-old female patient with locally advanced HER2-positive BC who was initially resistant to HP neoadjuvant therapy. Following the failure of the treatment, this patient was given pyrotinib plus trastuzumab and vinorelbine as second-line neoadjuvant therapy. The patient tolerated this treatment well, with mild symptoms of diarrhea. After 6 cycles of neoadjuvant therapy, the efficacy was assessed to be partial remission (PR), and a modified radical mastectomy was finally conducted. This patient remained disease-free for 23 months after surgery. Conclusions: This is the first report to present a case of neoadjuvant pyrotinib plus trastuzumab and vinorelbine in a patient with HER2-positive locally advanced BC, suggesting that the combination could be a new option for patients who have developed resistance to HP neoadjuvant treatment.