Giredestrant, an oral selective estrogen receptor degrader (SERD), reduced recurrence risk across menopausal subgroups in ER+/HER2− early breast cancer in the lidERA Phase 3 trial results presented at ASCO. The company reported improved invasive disease-free survival and better tolerability signals tied to fewer musculoskeletal-pain-driven discontinuations versus standard endocrine therapy. In premenopausal participants, giredestrant reduced the risk of invasive disease or death (HR 0.65), while postmenopausal results similarly favored the investigational SERD with an HR of 0.74. The trial evaluated giredestrant for five years compared with tamoxifen or aromatase inhibitor therapy (with or without ovarian function suppression). Lead investigator Peter Schmid of Queen Mary University of London said the iDFS benefit held irrespective of menopausal status, positioning giredestrant as a contender for expanded adjuvant endocrine use if confirmatory evidence supports durability and safety across broader populations.