N Engl J Med

Next-generation SERD plus abemaciclib shows promise in advanced breast cancer

December 16, 2024

Study design: The phase 3, multicenter, randomized EMBER-3 trial involved 874 patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer. Participants were assigned to receive either imlunestrant alone, standard endocrine therapy (fulvestrant or exemestane), or imlunestrant plus abemaciclib.

Results: The combination of imlunestrant and abemaciclib significantly improved progression-free survival (PFS) compared with imlunestrant monotherapy, with median PFS of 9.4 months vs. 5.5 months (HR, 0.57, P < 0.001). Imlunestrant monotherapy also showed superior PFS compared with standard endocrine therapy in patients with ESR1 mutations but not in the overall population. Imlunestrant-abemaciclib was associated with a higher incidence of grade 3 or higher adverse events (48.6%) compared with imlunestrant monotherapy (17.1%) or standard endocrine therapy (20.7%).

Impact on clinical practice: These findings suggest that imlunestrant plus abemaciclib could be a valuable second-line treatment for ER+/HER2- advanced breast cancer, particularly for patients previously treated with CDK4/6 inhibitors. The oral administration of imlunestrant offers a more convenient option compared with existing SERDs, potentially improving patient adherence and outcomes. However, clinicians should consider the balance between efficacy and potential adverse effects when selecting treatment.

Source:

Jhaveri KL, et al. (2024, December 11). N Engl J Med. Imlunestrant with or without Abemaciclib in Advanced Breast Cancer. https://pubmed.ncbi.nlm.nih.gov/39660834/