Roche reported positive Phase III adjuvant results for its oral selective estrogen receptor degrader (SERD) giredestrant, showing a statistically significant improvement in invasive disease‑free survival versus standard endocrine therapy at a planned interim analysis. The Lidera study’s outcome positions Roche to pursue regulatory filings for use after surgery in ER‑positive, HER2‑negative early breast cancer. Roche and Genentech framed the result as a potential paradigm shift—giredestrant could become the first oral SERD to displace established injectable endocrine therapies in the adjuvant setting if regulators concur. Competitors and investors reacted quickly: shares of rival companies developing SERDs moved on the news, and market watchers noted implications for ongoing trials by AstraZeneca, Lilly and others testing oral SERDs in similar indications.