A Study of Pyrotinib Plus Vinorelbine in Comparison With Treatment of Physician's Choice in Participants With HER2-positive Locally Advanced or Metastatic Breast Cancer

The purpose of this study is to identify the highest tolerable dose of pyrotinib in combination with vinorelbine and to assess the safety and efficacy of the combination in Patients With HER2-Positive Locally Advanced or Metastatic Breast Cancer. The study will be conducted in two parts. In the first part, testing will be done on up to 12 subjects to determine the highest tolerable dose of pyrotinib and vinorelbine in patients with advanced solid tumors. In the second part of the study, we will compare the safety and efficacy of Pyrotinib + vinorelbine vs. Treatment of Physician\'s Choice in Patients With HER2-Positive Locally Advanced or Metastatic Breast Cancer Who Have Received Prior Trastuzumab-Based Therapy.Participants will be treated until disease progression (PD), unmanageable toxicity, or study termination.