Pyrotinib Maleate, Trastuzumab, SHR6390 and Letrozole in Combination for Stage II-III TPBC

NOAH study confirmed that trastuzumab combined with chemotherapy can significantly improve PCR compared with chemotherapy alone, and established the status of trastuzumab as a new adjuvant targeted therapy. The emergence of CDK4/6 inhibitors has brought hope to breast cancer patients resistant to endocrine therapy. studies have shown that pyrotinib maleate combined with CDK4/6 inhibitor can significantly inhibit the proliferation of HER2 positive breast cancer cell lines, reduce the activation of pAKT and pHER3, inhibit cell arrest in G0-G1 phase, and increase cell apoptosis. In the mouse model, pyrotinib maleate combined with CDK4/6 inhibitor exhibits higher anti-tumor activity than any anti-tumor drug alone. Moreover, the toxicity of the combined therapy does not increase compared with monotherapy. This provides a good preclinical model for the treatment of breast cancer by pyrotinib maleate combined with CDK4/6 inhibitor. In addition, NeoALTTO study、CALGB 40601 study、NSABP B-41 study confirmed that the clinical efficacy of lapatinib combined with trastuzumab combined chemotherapy was better than that of lapatinib or trastuzumab single target treatment group. Therefore, it is envisaged that the combination of pyrotinib maleate and dalpiciclib combined with letrozole on the basis of adding new trastuzumab to treat triple positive breast cancer will further improve the curative effect. In conclusion, we believe that pyrotinib maleate combined with trastuzumab, dalpiciclib and letrozole can provide better strategies for neoadjuvant therapy in patients with II-III three positive breast cancer.