The regulatory decision follows data from the Phase 3 EMBER-3 trial, which demonstrated that the combination therapy effectively doubled median progression-free survival compared to Inluriyo monotherapy. Patients receiving the dual regimen achieved a median progression-free survival of 11.1 months, compared to 5.5 months for those on the single drug.

Jacob Van Naarden, executive vice president of Lilly Oncology, stated that the approval validates a clinical strategy of switching therapies at the point of disease progression, avoiding unnecessary side effects and costs associated with early, aggressive interventions. For patients with ESR1-mutated tumors—a genetic change that often emerges after treatment with aromatase inhibitors—the combination works by simultaneously degrading estrogen receptors and inhibiting proteins that drive cell division. The most frequent adverse reactions observed in the study included diarrhea, neutropenia, and fatigue, though the majority were classified as Grade 1 or 2.