Pyrotinib Combined With Trastuzumab and AI in the First-line Treatment of HER2 Positive/ HR Positive MBC

This is a randomized, two-arm, open-label, multicenter phase II trial. Our primary purpose is to compare that PFS of patients with trastuzumab, AI plus pyrotinib and trastuzumab plus an AI for HER2-positive and hormone receptor-positive MBC or locally advanced breast cancer (LABC). Eligible patients will randomized to a ratio of 1:1 to pyrotinib+ trastuzumab + aromatase inhibitor (experimental group) or trastuzumab+aromatase inhibitor (control group). Stratification factors were 1)time since adjuvant hormone therapy (\<=12 months/\>12 months/no prior hormone therapy); 2) lesion (visceral; non-visceral). In treatment period, patients will be administrated trastuzumab plus aromatase inhibitors, with or without pyrotinib, every 21 days for 1 cycle, until disease progression, toxicity intolerance, withdrawal of informed consent, patients judged must be terminated study termination. The imaging evaluation was performed according to the RECIST 1.1 criteria every 6 weeks.