Margetuximab Plus Tucatinib and Capecitabine in HER2-positive Metastatic Breast Cancer

Margetuximab (15 mg/kg) will be administrated by intravenous infusion on Day 1 of each cycle.

Tucatinib (300 mg) will be administrated orally twice daily (every 12 hours) continuously in 21-day cycles.

Capecitabine (1000 mg per square meter of body-surface area) will be administrated orally twice daily on days 1 to 14 of each 21-day cycle