First-Line Treatment with a Cyclin-Dependent Kinase 4/6 Inhibitor Plus an Aromatase Inhibitor for Metastatic Breast Cancer in Alberta.

Carla P Amaro,Sasha Lupichuk,Atul Batra

doi:10.3390/curroncol28030209

Carla P Amaro, Sasha Lupichuk + Show 1 more

Open Access

https://doi.org/10.3390/curroncol28030209

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Abstract

In this analysis, we describe population-based outcomes for first-line treatment with a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) combined with an aromatase inhibitor (AI). All patients who were prescribed CDK4/6i + AI from January 2016 through June 2019 were included. Patient demographics, tumour and treatment characteristics were collected and described. Survival distributions were estimated using the Kaplan–Meier method. Multivariate analysis (MVA) was constructed to examine associations between potentially prognostic clinical variables and progression-free survival (PFS). In total, 316 patients were included. The median age was 61 years. After a median follow-up of 28.1 months, the median PFS was 37.9 months (95% CI, 26.7–NR). In the MVA, PR-negative tumour (HR, 2.37; 95% CI, 1.45–3.88; p = 0.001) and CDK4/6i dose reduction (HR, 1.51; 95% CI, 1.06–2.16; p = 0.022) predicted worse PFS. Median overall survival (OS) was not reached. The 30-month and 36-month OS rates were 74% and 68%, respectively. Of patients who progressed, 89% received second-line treatment. Median time to progression on second-line chemotherapy was 9.0 (5.8–17.6) months, and median time to progression on second-line hormonal therapy +/− targeted agent was 4.0 (3.4–8.6) months (p = 0.012). CDK4/6i + AI as first-line treatment for HR-positive, HER2-negative MBC in Alberta is justified based on favourable PFS and early OS outcomes.

Highlights

Breast cancer is the most commonly diagnosed malignancy and a major cause of death among women worldwide [1]
Palbociclib was the first CDK4/6 inhibitor (CDK4/6i) to be approved in combination with an aromatase inhibitor (AI) after the PALOMA-2 trial showed an improvement in progressionfree survival (PFS) for the experimental arm compared with an AI alone [4]
We present population-based outcomes for first-line treatment with a CDK4/6 inhibitor combined with an AI amongst patients with Hormone receptor (HR)-positive, human epidermal growth factor receptor-2 (HER2)-negative metastatic breast cancer (MBC) in the province of Alberta, Canada

Summary

Introduction

Breast cancer is the most commonly diagnosed malignancy and a major cause of death among women worldwide [1]. In Canada, approximately 27,400 women were diagnosed and 5100 died of breast cancer in 2020 [2]. The treatment of HR-positive, HER2-negative metastatic breast cancer (MBC) has undergone a paradigm shift in recent years. The combination of a cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) with an aromatase inhibitor (AI) has emerged as the standard first-line treatment in patients with de novo stage IV disease and in those with recurrent metastatic disease who completed adjuvant antiestrogen therapy with an AI at least 12 months prior. CDK4/6 inhibitors are oral medications, well-tolerated, and do not negatively impact quality of life [10,11,12]

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