ESMO 2021: Neoadjuvant Giredestrant Versus Anastrozole in Postmenopausal Women With Early Breast Cancer
Posted: Monday, September 27, 2021
During the European Society for Medical Oncology (ESMO) Congress 2021, Sara A. Hurvitz, MD, of UCLA Jonsson Comprehensive Cancer Center, and colleagues presented data from an interim analysis of the phase II coopERA study comparing the kinase inhibitor palbociclib plus the selective estrogen receptor (ER) antagonist and degrader (SERD) giredestrant or anastrozole plus placebo in postmenopausal women with ER-positive, HER2-negative untreated early breast cancer (Abstract LBA14). Their results demonstrated “superior” antiproliferative activity with giredestrant plus palbociclib, with a consistent safety profile to that of giredestrant alone.
“Our results provide an early indication that giredestrant may reduce cancer cell division to a greater extent than our standard of care treatment,” commented Dr. Hurvitz in a UCLA press release. “These data provide solid rationale to further evaluate giredestrant in larger randomized trials in the curative or late-stage setting.”
The investigators assessed 83 patients with untreated ER-positive, HER2-negative breast cancer who had Ki67 scores of at least 5%. Before undergoing surgery, participants were randomly assigned to receive giredestrant or anastrozole followed by the neoadjuvant addition of palbociclib.
A greater 2-week relative reduction in Ki67 levels was observed with the giredestrant regimen (80%) than with the anastrozole regimen (67%; P = .0222). Notably, patients with a baseline Ki67 level of 20% or greater experienced an 83% reduction with the addition of giredestrant and a 71% reduction with anastrozole; those with a baseline Ki67 level less than 20% had reductions of 65% and 24%, respectively.
At week 2, the complete cell-cycle arrest rate was 25% for individuals who received the giredestrant regimen and 5% for those given the anastrozole regimen. Additionally, patients administered giredestrant reported fewer treatment-related adverse events compared with participants given anastrozole (28% vs. 38%), and no events of grade 3 or greater or serious adverse events were attributed to giredestrant.
Disclosure: For full disclosures of the study authors, visit oncologypro.esmo.org.
