A open-label, single-arm, phase II trial to study was designed to evaluate the effectiveness and safety of trastuzumab and pyrotinib in treating HER2 positive patients who have previously treated, locally advanced, or metastatic urothelial carcinoma.

Inclusion Criteria:

• Sign the informed consent form
• Locally advanced or metastatic histologically confirmed transitional cell carcinoma of the urothelium, including the bladder, urethra, ureter, or renal pelvis
• 18 years and older
• HER2 expression (3+ or 2+) as determined by immunohistochemistry or gene amplification by fluorescent in situ hybridization
• Relapsed from or failed at least one prior standard systemic chemotherapy regimen, including immunotherapy, HER2 ADC durgs, and chemothearpy containing cisplatin, carboplatin, paclitaxel, docetaxel, or gemcitabine
• At least 1 measurable lesion could be evaluated by RECIST v1.1
• Performance status: ECOG 0-1
• Life expectancy more than 12 weeks
• Ejection fraction at least 50% (or lower limit of normal) by echocardiogram
• Good organ function:

Blood routine: hemoglobin ≥80g/L, neutrophil ≥1.5×10^9/L, platelet ≥75×10^9/L; Renal function: creatinine≤1.5×upper limit of normal (UNL) or creatinine clearance ≥50ml/min; Liver function: total bilirubin (TBIL)≤1.5×upper limit of normal (UNL); ALT≤2.5×UNL, AST≤2.5×UNL, ALT≤5×UNL and AST≤5×UNL for patients with liver metastasis

Exclusion Criteria:

• Have received trastuzumab or pyrotinib treatment in the past
• Known to have allergic reactions to any ingredients or excipients of experimental drugs
• Radiotherapy, RFA, interventional therapy or surgery were performed within 28 days before the first medication (except for previous diagnostic biopsy)
• Other active malignant tumors, excluding those who have been disease free for more than 5 years or in situ cancer considered to have been cured by adequate treatment
• Clinically significant ascites
• Brain metastasis or meningeal metastasis with neurological symptoms
• Diabetes was not controlled, defined as HbA1c > 7.5% after anti-diabetic drugs or hypertension was not controlled, defined as systolic / diastolic blood pressure > 140 / 90 mmHg after antihypertensive drug
• Myocardial infarction, severe/unstable angina, New York Heart Association (NYHA) class III or IV congestive heart failure in the past 12 months
• Known to be infected with human immunodeficiency virus (HIV), have acquired immunodeficiency syndrome (AIDS) related diseases, have active hepatitis B or hepatitis C
• Pregnant or nursing
• May increase the risk associated with participation in the study or administration of the study drug or mental illness that may interfere with the interpretation of research results
• There are other serious diseases that the researchers believe patients cannot be included in the study