Giredestrant showed consistent invasive disease-free survival benefits across menopausal subgroups in ER+/HER2− early breast cancer, according to results from the lidERA trial presented at ASCO. The investigational oral selective estrogen receptor degrader reduced iDFS risk versus standard-of-care endocrine therapy in both premenopausal and postmenopausal groups. For premenopausal patients, giredestrant achieved a 35% iDFS risk reduction (HR 0.65) and improved distant relapse-free interval outcomes, with benefits reported across comparator components including AI plus ovarian function suppression and tamoxifen plus ovarian function suppression. In postmenopausal patients, the hazard ratio was 0.74 with 3-year iDFS rates of 91.3% versus 88.3%. Investigators also pointed to tolerability differences: musculoskeletal-pain-driven discontinuations were less than half as common on giredestrant compared with standard therapy in both menopausal categories. The results add to the oral SERD competition as developers seek alternatives to existing endocrine backbones in high-risk adjuvant settings.