Key clinical point: Giredestrant demonstrated stronger anti-proliferative activity than anastrozole and was well-tolerated in patients with estrogen receptor-positive (ER+ ), human epidermal growth factor receptor 2-negative (HER2−), untreated early breast cancer (BC).
Major finding: At week 2, giredestrant vs anastrozole had a stronger anti-proliferative effect as indicated by greater relative geometric mean reduction of Ki67 scores (−75% vs −67%; P = .043). Neutropenia (26% and 27%, respectively) and decreased neutrophil count (15% and 15%, respectively) were the most common grade 3-4 adverse events observed in the giredestrant + palbociclib and anastrozole + palbociclib treatment arms.
Study details: Findings are from the phase 2 coopERA Breast Cancer trial including 221 postmenopausal patients with clinical T stage (cT)1c to cT4a-c, ER+ /HER2− early BC who were randomly assigned to receive giredestrant or anastrozole in combination with palbociclib.
Disclosures: This study was funded by F Hoffmann-La Roche. Seven authors declared being employees or stockholders of F Hoffmann-La Roche, and the other authors declared ties with various sources.
Source: Hurvitz SA et al on behalf of thecoopERA Breast Cancer study group. Neoadjuvant palbociclib plus either giredestrant or anastrozole in oestrogen receptor-positive, HER2-negative, early breast cancer (coopERA Breast Cancer): An open-label, randomised, controlled, phase 2 study. Lancet Oncol. 2023;24(9):1029-1041 (Aug 29). doi: 10.1016/S1470-2045(23)00268-1