HR-positive breast cancer: Entinostat fails phase 3 trial

Key clinical point: Adding entinostat to exemestane does not improve survival in aromatase inhibitor (AI)-resistant advanced hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative breast cancer.

Major finding: There were no differences between the entinostat and placebo groups in median progression-free survival (3.3 months vs. 3.1 months; P = 0.30) and median overall survival (23.4 months vs. 21.7 months; P = 0.94). The most common grade 3-4 adverse events in the entinostat group were neutropenia (20%) and hypophosphatemia (14%).

Study details: This was a multicenter, randomized, double-blind, placebo-controlled phase 3 E2112 study of 608 patients with AI-resistant, HR-positive, HER2-negative breast cancer, randomly assigned to entinostat plus exemestane or placebo plus exemestane.

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Disclosures: The study was supported by the National Cancer Institute of the National Institutes of Health. The authors reported receiving consulting/advisory/speaker fees, research funding, accommodation/travel/expenses, and royalties from and/or stock ownership and/or other relationship in companies or patents owned/filed.

Source: Connoly RM et al. J Clin Oncol. 2021 Aug 6 (in press). doi: 10.1200/JCO.21.00944.