Efficacy of Palbociclib Combinations in Hormone Receptor–Positive Metastatic Breast Cancer Patients After Prior Everolimus Treatment

Ajay Dhakal, Christina M. Matthews, Ellis Glenn Levine, Kilian Elizabeth Salerno, Fan Zhang, Kazuaki Takabe, Amy P. Early, Stephen B. Edge, Tracy O'Connor, Thaer Khoury, Jessica S. Young, Mateusz Opyrchal

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20 Scopus citations

Abstract

This retrospective study examined outcomes of hormone receptor-positive (HR + ) human epidermal growth factor receptor 2 nonamplified (HER2 ) metastatic breast cancer (MBC) in patients with prior exposure to everolimus on palbociclib-based therapy. Twenty-three eligible patients with HR + HER2 MBC were assessed. Median progression-free survival (PFS) was 2.9 months (95% confidence interval, 2.1-4.2), objective response rate (ORR) 0 (0%) of 23 and clinical benefit rate (CBR) of 4 (17.4%) of 23. We found a limited clinical activity of palbociclib combinations after progression of disease in patients receiving everolimus combination. Purpose: Outcome data on hormone receptor positive (HR + ), human epidermal growth factor receptor 2 (HER2) nonamplified (HER2 ) metastatic breast cancer (MBC) treated with palbociclib after treatment with everolimus are lacking. The PALOMA-3 trial, showing benefit of palbociclib plus fulvestrant compared to fulvestrant alone in HR + HER2 MBC after progression while receiving endocrine therapy excluded women previously treated with everolimus. The objective of this study was to examine outcomes of HR + HER2 MBC with prior exposure to everolimus while receiving palbociclib-based therapy. Patients and Methods: A retrospective, single-institute review was conducted of HR + HER2 MBC from January 2014 to November 2016 in patients treated with palbociclib after prior treatment with everolimus. Progression-free survival (PFS) was defined as the time from initiation of palbociclib to the date of progression as determined by the treating physician based on radiologic, biochemical, and/or clinical criteria. Response rates were determined on the basis of available radiologic data. Objective response rate (ORR) was defined as the rate of any complete or partial responses; clinical benefit rate (CBR) was the rate of complete response, partial response, or stable disease for at least 24 weeks. Results: Twenty-three patients with a mean (range) age of 68 (42-81) years were identified. Kaplan-Meier estimate showed median PFS of 2.9 months (95% confidence interval, 2.1-4.2); ORR was 0 of 23 and CBR was 4 (17.4%) of 23. In the PALOMA-3 trial, median PFS, ORR, and CBR of palbociclib cohort were 9.5 months (95% confidence interval, 9.2-11.0), 19%, and 67%, respectively. Conclusion: There is a limited clinical activity of palbociclib combinations after progression with everolimus combination therapy. Further studies are necessary to confirm these findings.

Original languageEnglish
Pages (from-to)e1401-e1405
JournalClinical breast cancer
Volume18
Issue number6
DOIs
StatePublished - Dec 2018

Keywords

  • CDK 4/6 inhibitor
  • Endocrine therapy
  • Resistance to endocrine therapy
  • Sequential endocrine therapy
  • mTOR inhibitor

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