A Randomized, Placebo-controlled, Double-blind, Phase 3 Clinical Study to Investigate the Efficacy and Safety of or Treatment of Moderate to Severe Vasomotor Symptoms (Hot Flashes) in Women with Stage 0 to 3 Hormone Receptor-positive Breast Cancer Who Are Receiving Adjuvant Endocrine Therapy (ASTELLAS 2693-CL-1303 (Highlight 1))

Hundreds of women with breast cancer suffer severe hot flashes from their hormone-blocking drugs, and a new clinical trial is testing whether a drug already approved for menopausal hot flashes can help them too. The problem is that tamoxifen and aromatase inhibitors, which are essential for preventing cancer recurrence in women with hormone receptor-positive breast cancer, often trigger debilitating hot flashes and night sweats. Existing treatments for these symptoms are limited, and fezolinetant—which works by blocking a brain chemical involved in temperature regulation—has never been formally tested in this specific patient group. This phase 3 trial will randomly assign 540 women across 12 countries to receive either fezolinetant or a placebo for 52 weeks, tracking both symptom relief and safety. If fezolinetant proves effective and safe, it could give thousands of breast cancer patients a new option to manage treatment side effects without compromising their cancer therapy. Better symptom control could improve quality of life and help women stay on their prescribed endocrine therapy, potentially reducing cancer recurrence rates. The results would also provide regulators with the evidence needed to approve fezolinetant for this new use.