Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast Cancer

Introduction: CDK4/6 inhibitors in combination with aromatase inhibitors (AIs) are the standard first-line treatment for hormone receptor-positive (HR+), HER2-negative (HER2−) metastatic breast cancer. Landmark trials have demonstrated a comparable progression-free survival (PFS) across CDK4/6 inhib...

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Main Authors: Ram Patel, John Mathews, Caroline Hamm, Swati Kulkarni, Rasna Gupta, Tarquin Opperman, John Dean Chiong, Abdullah Nasser
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Current Oncology
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Online Access:https://www.mdpi.com/1718-7729/32/1/52
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author Ram Patel
John Mathews
Caroline Hamm
Swati Kulkarni
Rasna Gupta
Tarquin Opperman
John Dean Chiong
Abdullah Nasser
author_facet Ram Patel
John Mathews
Caroline Hamm
Swati Kulkarni
Rasna Gupta
Tarquin Opperman
John Dean Chiong
Abdullah Nasser
author_sort Ram Patel
collection DOAJ
description Introduction: CDK4/6 inhibitors in combination with aromatase inhibitors (AIs) are the standard first-line treatment for hormone receptor-positive (HR+), HER2-negative (HER2−) metastatic breast cancer. Landmark trials have demonstrated a comparable progression-free survival (PFS) across CDK4/6 inhibitors, but the overall survival (OS) outcomes have varied. This study aimed to evaluate the real-world PFS and OS for palbociclib and ribociclib when combined with AIs in patients with HR+/HER2− advanced breast cancer. Materials and Methods: This was a retrospective chart review of adult patients with HR+/HER2− metastatic breast cancer treated at a single academic center between 1 January 2015 and 1 December 2022. The baseline demographics, clinical characteristics, and treatment details were extracted. A Kaplan–Meier analysis was used to estimate the PFS and OS, and differences between the treatment groups were assessed using the log-rank test. Cox proportional hazards models were constructed to adjust for confounding factors. Results: Seventy-five patients were included in the final analysis. The cohort was predominantly female (98.7%) and postmenopausal (77.3%), with 52.0% having de novo stage IV disease. Palbociclib was prescribed to 74.7% of the patients, and ribociclib to 25.3%. The patients receiving ribociclib were significantly younger (57.6 vs. 67.5 years, <i>p</i> = 0.013) and more likely to be premenopausal (42.1% vs. 5.4%, <i>p</i> < 0.001). The real-world median PFS and OS for palbociclib were 20.3 months (95% CI: 14.8–46) and 37.2 months (95% CI: 20.3–not reached [NR]), respectively. For ribociclib, the median PFS and OS were not reached. The Cox proportional hazards models adjusting for age and menopausal status found no significant differences between ribociclib and palbociclib for the PFS (HR = 0.92, <i>p</i> = 0.86) or OS (HR = 0.95, <i>p</i> = 0.92). Conclusion: In this real-world analysis, palbociclib demonstrated a median PFS consistent with the results from landmark trials, although the observed OS was shorter. The ribociclib-treated patients had a numerically longer PFS and OS compared with those treated with palbociclib, but the differences were not statistically significant. The discontinuation rates were similar between the two groups.
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spelling doaj-art-5235a457ef924c4784b7c71ea532046b2025-01-24T13:28:30ZengMDPI AGCurrent Oncology1198-00521718-77292025-01-013215210.3390/curroncol32010052Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast CancerRam Patel0John Mathews1Caroline Hamm2Swati Kulkarni3Rasna Gupta4Tarquin Opperman5John Dean Chiong6Abdullah Nasser7Schulich School of Medicine and Dentistry, Western University, London, ON N6A 3K7, CanadaDepartment of Medical Oncology, Windsor Regional Hospital, Windsor, ON N8W 1L9, CanadaDepartment of Medical Oncology, Windsor Regional Hospital, Windsor, ON N8W 1L9, CanadaDepartment of Medical Oncology, Windsor Regional Hospital, Windsor, ON N8W 1L9, CanadaDepartment of Medical Oncology, Windsor Regional Hospital, Windsor, ON N8W 1L9, CanadaSchulich School of Medicine and Dentistry, Western University, London, ON N6A 3K7, CanadaSchulich School of Medicine and Dentistry, Western University, London, ON N6A 3K7, CanadaSchulich School of Medicine and Dentistry, Western University, London, ON N6A 3K7, CanadaIntroduction: CDK4/6 inhibitors in combination with aromatase inhibitors (AIs) are the standard first-line treatment for hormone receptor-positive (HR+), HER2-negative (HER2−) metastatic breast cancer. Landmark trials have demonstrated a comparable progression-free survival (PFS) across CDK4/6 inhibitors, but the overall survival (OS) outcomes have varied. This study aimed to evaluate the real-world PFS and OS for palbociclib and ribociclib when combined with AIs in patients with HR+/HER2− advanced breast cancer. Materials and Methods: This was a retrospective chart review of adult patients with HR+/HER2− metastatic breast cancer treated at a single academic center between 1 January 2015 and 1 December 2022. The baseline demographics, clinical characteristics, and treatment details were extracted. A Kaplan–Meier analysis was used to estimate the PFS and OS, and differences between the treatment groups were assessed using the log-rank test. Cox proportional hazards models were constructed to adjust for confounding factors. Results: Seventy-five patients were included in the final analysis. The cohort was predominantly female (98.7%) and postmenopausal (77.3%), with 52.0% having de novo stage IV disease. Palbociclib was prescribed to 74.7% of the patients, and ribociclib to 25.3%. The patients receiving ribociclib were significantly younger (57.6 vs. 67.5 years, <i>p</i> = 0.013) and more likely to be premenopausal (42.1% vs. 5.4%, <i>p</i> < 0.001). The real-world median PFS and OS for palbociclib were 20.3 months (95% CI: 14.8–46) and 37.2 months (95% CI: 20.3–not reached [NR]), respectively. For ribociclib, the median PFS and OS were not reached. The Cox proportional hazards models adjusting for age and menopausal status found no significant differences between ribociclib and palbociclib for the PFS (HR = 0.92, <i>p</i> = 0.86) or OS (HR = 0.95, <i>p</i> = 0.92). Conclusion: In this real-world analysis, palbociclib demonstrated a median PFS consistent with the results from landmark trials, although the observed OS was shorter. The ribociclib-treated patients had a numerically longer PFS and OS compared with those treated with palbociclib, but the differences were not statistically significant. The discontinuation rates were similar between the two groups.https://www.mdpi.com/1718-7729/32/1/52cyclin-dependent kinase inhibitorsaromatase inhibitorsmetastatic breast cancersurvival analysisreal-world evidence
spellingShingle Ram Patel
John Mathews
Caroline Hamm
Swati Kulkarni
Rasna Gupta
Tarquin Opperman
John Dean Chiong
Abdullah Nasser
Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast Cancer
Current Oncology
cyclin-dependent kinase inhibitors
aromatase inhibitors
metastatic breast cancer
survival analysis
real-world evidence
title Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast Cancer
title_full Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast Cancer
title_fullStr Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast Cancer
title_full_unstemmed Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast Cancer
title_short Real-World Experience with CDK4/6 Inhibitors in the First-Line Palliative Setting for HR+/HER2− Advanced Breast Cancer
title_sort real world experience with cdk4 6 inhibitors in the first line palliative setting for hr her2 advanced breast cancer
topic cyclin-dependent kinase inhibitors
aromatase inhibitors
metastatic breast cancer
survival analysis
real-world evidence
url https://www.mdpi.com/1718-7729/32/1/52
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