A significant breakthrough in breast cancer treatment has been announced with the investigational oral selective estrogen receptor degrader (SERD), giredestrant. New data from the Phase III lidERA Breast Cancer study, presented in December 2025 at the San Antonio Breast Cancer Symposium, demonstrated that adjuvant giredestrant significantly reduced the risk of invasive disease recurrence or death by 30% when compared to standard-of-care endocrine therapy. This finding is particularly impactful as it targets hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative early-stage breast cancer, which accounts for approximately 70% of all breast cancer cases. The lidERA trial results also showed a 31% reduction in the risk of distant recurrence-free interval. Experts highlight this as the first major advancement in endocrine therapy in over two decades for this specific patient population, for whom recurrence remains a concern despite current treatments. Giredestrant works by blocking estrogen from binding to the estrogen receptor, leading to the receptor's degradation and inhibiting cancer cell growth. Preliminary overall survival data from the study showed a positive trend, and the therapy was reported to be well-tolerated with a manageable safety profile. This novel treatment offers new hope for patients globally, including in India, by potentially establishing a new standard of care to prevent disease recurrence in high-risk early breast cancer.