Pyrotinib, Trastuzumab And Abraxane in HER2-positive MBC With Brain Metastasis

Inclusion Criteria:

* Aged \>18 years.
* ECOG performance status ≤2.
* Histologically or cytologic confirmed HER2 positive advanced breast cancer.
* MRI confirmed brain metastases. According to RECIST 1.1, at least one measurable lesion exists.
* No limit of previous chemotherapy lines.
* Previously have not reveived capecitabine or disease progression of capecitabine after 6 months, or progression of capecitabine adjuvant therapy after one year;
* Life expectancy of more than 3 months.
* Required laboratory values including following parameters: ANC: ≥ 1.5 x 10\^9/L;Platelet count: ≥ 100 x 10\^9/L;Hemoglobin: ≥ 9.0 g/dL;Total bilirubin: ≤ 1.5 x upper limit of normal (ULN);ALT and AST: ≤ 1.5 x ULN (or ≤ 5×ULN in patients with liver metastases);BUN and creatine clearance rate: ≥ 50 mL/min;LVEF: ≥ 50%;QTcF: \< 470 ms for female and \< 450 ms for male.
* Signed the informed consent form prior to patient entry.

Exclusion Criteria:

* Patients with brain metastases who have extensive meningeal metastases and are treated with hormone dehydration.
* Subjects with third space fluid(such as a large amount of pleural effusion and ascites) that can not be controled by drainage or other methods. (such as pleural effusion and ascites).
* Received whole brain radiotherapy, chemotherapy, surgery or target therapy within 2 weeks prior to randomization. Received hormone therapy within 1 weeks prior to randomization, Received the nitrosoureas or mitomycin chemotherapy within 6 weeks prior to randomization.
* Participated in other clinical trial within 4 weeks prior to randomization.
* Treated or treating with HER2 tyrosine kinase inhibitors (TKIs) (including Lapatinib, Neratinib and Pyrotinib).
* Second malignancies within 5 years, except for cured carcinoma in-situ of uterine cervix, skin basal cell carcinomaand squamous-cell carcinoma.
* Receiving any other anti-tumor therapies at time of study screening visit.
* There are no other serious and/or uncontrolled diseases that may affect research participation, including any of the following: (1) unable to swallow, chronic diarrhea and intestinal obstruction and factors influencing the usage of oral administration; (2) has allergies or a known history of hypersensitivity to the drug components of this program; History of Immunodeficiency, acquired or congenital immunodeficiency (HIV positive) ,history of organ transplantation; (3) History of any kind of Heart disease, including 1) Myocardial infarction; 2) Heart failure; 3) Any other heart disease judged by researcher as not suitable for participating in this study, etc; (4) Infection.
* All female patients in breastfeeding period or in child-bearing period or with positive pregnancy test result or refusing to take a reliable method of birth control during the study.
* Any other situations judged by investigator as not suitable for participating in this study.