Efficacy and safety of neoadjuvant pyrotinib plus docetaxel/liposomal doxorubicin/cyclophosphamide for HER2-positive breast cancer

Pyrotinib is a novel EGFR/HER2 dual tyrosine kinase inhibitor developed in China, while its role in neoadjuvant therapy of HER2-positive (HER2+) breast cancer lacks evidence. The current study aimed to explore the efficacy and safety of neoadjuvant pyrotinib plus docetaxel/liposomal doxorubicin/cyclophosphamide (TAC) for HER2+ breast cancer.A total of 27 HER2+ breast cancer patients received neoadjuvant pyrotinib plus TAC for 6 cycles, then surgery was performed. The clinical and pathological responses, and adverse events were evaluated.Complete response rate, objective response rate, and disease control rate were 0.0%, 44.4% and 100.0% after 2 treatment cycles; 0.0%, 37.0%, and 100.0% after 4 treatment cycles; 37.0%, 37.0%, and 96.3% after 6 treatment cycles; as well as 37.0%, 44.4%, and 100.0% based on the best clinical response. Regarding pathological response, there were 1 (2.7%), 3 (11.1%), 8 (29.6%), 5 (18.5%), and 10 (37.0%) patients realizing Miller-Payne grade (G) 1, G2, G3, G4, and G5, respectively; besides, 10 (37.0%) patients achieved total pathological complete response (pCR), 10 (37.0%) patients realized pCR in breast, and 23 (85.2%) patients achieved pCR in lymph node. Additionally, adverse events included diarrhea (81.5%), dental ulcer (7.4%), and hand-foot syndrome (3.7%); meanwhile, grade 3-4 adverse event consisted of only diarrhea (11.1%).Neoadjuvant pyrotinib plus TAC treatment is efficient and safe in HER2+ breast cancer patients, while further validation is needed.