Trastuzumab Deruxtecan vs Endocrine Therapy in Low-HER2 HR+ Advanced Breast Cancer

"Trastuzumab deruxtecan (T-DXd) 5.4mg/kg intravenous infusion every 3 weeks.~(1 cycle = 3 weeks)"

"1. Fulvestrant intramuscular injection of two 250mg injection every 4 weeks (every 2 weeks for the first cycle, 1 cycle = 4 weeks)~2. Fulvestrant (administered same as above) + alpelisib 300mg oral administration every day~ (1 cycle = 4 weeks)\*~3. Exemestane 25mg oral administration every day (1 cycle = 4 weeks)~4. Exemestane 25mg + everolimus 10mg oral administration every day (1 cycle = 4 weeks)~5. Tamoxifen 20mg oral administration every day (1 cycle = 4 weeks)~6. Fulvestrant (administered same as above) + Capivasertib 400mg oral administration twice a day(dosed on Days 1 to 4 in each week of a 28-day treatment cycle)~ * fulvestrant + alpelisib can be selected in PIK3CA activating mutation positive patients~ * Fulvestrant + Capivasertib can be selected in 1 or More mutation positive of PIK3CA/AKT1/PTEN"