Dr. Carey on the Updated Results of the PALOMA-3 Trial in HR+/HER2- Breast Cancer

Lisa A. Carey, MD, FASCO, The Richardson and Marilyn Jacobs Preyer Distinguished Professor in Breast Cancer Research, deputy director of clinical sciences, division chief, Hematology and Oncology, UNC Lineberger Comprehensive Cancer Center, discusses the updated results of the phase 3 PALOMA-3 trial (NCT01942135) in hormone receptor (HR)–positive, HER2-positive breast cancer.

The PALOMA-3 trial enrolled patients with pretreated HR-positive, HER2-negative metastatic breast cancer, and randomized to palbociclib (Ibrance) plus fulvestrant (Faslodex) vs placebo plus fulvestrant, Carey explains. During the 2021 ASCO Annual Meeting, updated findings from the study were presented. The final protocol-specified median overall survival (OS) at a median follow-up of 44.8 months was 34.9 months with the addition of palbociclib vs 28.0 months with placebo. 

OS favored the addition of palbociclib in the majority of subgroups analyzed; however, it proved slightly less effective in patients who had short disease-free intervals prior to disease metastasis, as well as those who had prior chemotherapy, Carey continues. Additionally, OS generally favored the palbociclib plus fulvestrant combination compared with the fulvestrant alone regimen across patient subgroups irrespective of ESR1, PIK3CA, and TP53 mutation status, Carey concludes.