TUESDAY, Dec. 16, 2025 (HealthDay News) – Giredestrant, a selective estrogen receptor antagonist and degrader given as an adjuvant therapy, shows significant improvement in invasive disease-free survival (iDFS) in patients with early-stage, hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer, according to a study presented at the annual San Antonio Breast Cancer Symposium, held from Dec. 9 to 12 in San Antonio. Aditya Bardia, M.D., M.P.H., from the University of California Los Angeles, and colleagues conducted a global, randomized, open-label trial in which 4,170 patients with HR-positive, HER2-negative early breast cancer (stages I to III) were assigned (1:1) to receive either 30 mg of oral giredestrant daily or one of four standard-of-care endocrine therapies (tamoxifen, letrozole, anastrozole, or exemestane). All patients received surgery and, if indicated, completed adjuvant or neoadjuvant chemotherapy.The researchers report that after a median follow-up of 32.3 months, patients who received giredestrant had significantly better iDFS than those receiving standard-of-care endocrine therapy and were 30 percent less likely to develop invasive disease progression at follow-up. Additionally, patients who received giredestrant were 31 percent less likely than those in the standard-of-care arm to experience distant recurrence at follow-up. Overall survival data were immature but showed a positive trend in favor of giredestrant."Giredestrant demonstrated clinically meaningful superiority to currently well-established standard-of-care endocrine agents: aromatase inhibitors and tamoxifen," Bardia said in a statement. "What is particularly striking and relevant is early separation of [the overall survival] curves."Several authors disclosed financial ties to pharmaceutical companies, including F. Hoffmann-La Roche, which manufactures giredestrant and funded the study.Press ReleaseMore Information.Sign up for our weekly HealthDay newsletter