Roche reported positive Phase III results showing its oral selective estrogen receptor degrader (SERD) extended invasive disease-free survival versus standard hormone therapy in patients with ER-positive, HER2-negative early breast cancer when used after surgery. The trial met its primary endpoint at an interim analysis, marking a potential first for an oral SERD in the adjuvant setting. Roche’s giredestrant therefore challenges decades of injectable endocrine standards and could broaden the use of oral SERDs into earlier-stage disease. Company commentary highlighted a “clear positive trend” on survival while cautioning that follow-up is ongoing to confirm overall survival benefit. The outcome could reshape adjuvant endocrine therapy and intensify late-stage competition from other oral SERDs—AstraZeneca and Lilly among peers with rival programs in late-stage testing—by establishing an oral option for many patients previously treated with standard hormone modulators. SERDs degrade the estrogen receptor to block signaling and tumor growth; adjuvant success would expand their market beyond advanced disease.