Pyrotinib Combined With Trastuzumab for Maintenance Therapy After First-line TH (P) Therapy for HER2+ABC

This study tests whether combining pyrotinib (a targeted HER2-blocking drug taken as a pill) with trastuzumab (a HER2-targeting antibody) as maintenance therapy can prevent or delay cancer recurrence in women with HER2-positive metastatic breast cancer who responded to prior treatment. **You may be eligible if...** - You are female, aged 18–70 - You have HER2-positive invasive breast cancer that has spread (recurrent or metastatic) - You had a recurrence more than 1 year after trastuzumab treatment, or you were newly diagnosed with stage IV disease - You are in good health (ECOG 0–1) with expected survival of at least 6 months - Your blood counts, liver, kidney, and heart function are within required ranges **You may NOT be eligible if...** - You have brain metastases (cancer spread to the brain) - You have had gastrointestinal surgery or have difficulty swallowing pills - You are pregnant or breastfeeding - You have a known allergy to the study drugs - You have severe mental illness Talk to your doctor to see if this trial is right for you.