Retrospective Analysis Provides Insight into Treatment-Emergent Neutropenia Among Patients with Metastatic Breast Cancer Treated with Ribociclib or Palbociclib

2020 Year in Review - Breast Cancer - Breast Cancer

Real-world data showed that patients with metastatic breast cancer receiving palbociclib had a numerically higher rate of neutropenia than patients receiving ribociclib.

After the administration of CDK4/6 inhibitors ribociclib and palbociclib for hormone receptor–positive metastatic breast cancer, neutropenia is the most common adverse event.

In patients receiving these therapies, data are lacking to compare the incidences of treatment-emergent neutropenia. Lee Schwartzberg, MD, FACP, Medical Oncologist, Breast Cancer, West Cancer Center & Research Institute, Germantown, TN, and colleagues presented real-world data exploring the incidence, duration, and severity of treatment-emergent neutropenia, based on a retrospective analysis of administrative claims and electronic health records.

Two mutually exclusive cohorts of patients with metastatic breast cancer were treated with ribociclib or palbociclib. Patients were matched 1:1 based on year of treatment start and age. Previous baseline activity was required for ≥6 months.

To evaluate incidence rates of treatment-emergent neutropenia from January 1, 2015, to December 31, 2018, in patients receiving ribociclib or palbociclib, the MarketScan claims databases were used. From the Optum deidentified Electronic Health Record Dataset, data on neutropenia severity and duration were acquired. Neutrophil counts from lab tests (grade 1/2, 1000-1500/µL; grade 3, 500-1000/µL; grade 4< 500/µL) within the first 180 days of treatment were used to grade neutropenia severity. Kaplan-Meier analysis was used to estimate the duration of neutropenia, characterized as the period of time between first aberrant laboratory result and those showing resolution. One hundred fifty-two patients from the MarketScan database were included in the ribociclib and palbociclib groups after 1:1 matching, and 168 matched patients from the Optum database were also included.

In 38 (25%) patients in the palbociclib group and 25 (17%) patients in the ribociclib group, neutropenia was reported. The rate of neutropenia per person-treatment year was higher in the palbociclib group at 0.5 (95% confidence interval [CI], 0.4-0.7) when compared with the ribociclib group at 0.4 (95% CI, 0.3-0.6).

Although statistical significance was not demonstrated due most likely to small sample size, neutropenia rate ratio between treatments (palbociclib vs ribociclib) was 1.4 (95% CI, 0.8-2.3). Whereas the severity of neutropenia with palbociclib and ribociclib was similar at 32% for grade 1/2 and 4% for grade 4, it differed at grade 3, which was 35% for palbociclib and 26% for ribociclib. For grade 3 or 4 neutropenia (palbociclib vs ribociclib), the rate ratio was 1.3 (95% CI, 0.9-1.8). For palbociclib compared with ribociclib, the median neutropenia duration was significant, at 29 days compared with 20 days (P <.01).

Considering best possible practices for the management of neutropenia is an integral component of the treatment of hormone receptor–positive metastatic breast cancer. Clinicians may want to consider the impact of treatment and real-world data regarding rates of neutropenia, especially a higher rate of grade 3 neutropenia and a longer duration of neutropenia in patients receiving palbociclib therapy.

Source: Schwartzberg LS, Zarate JP, Chandiwana D, et al. Real-world incidence, duration, and severity of treatment-emergent (TE) neutropenia among patients (pts) with metastatic breast cancer (MBC) treated with ribociclib (RIB) or palbociclib (PAL). J Clin Oncol. 2020;38(15_suppl). Abstract e13048.

Related Items
The Pharmacist and Patients With HER2-Positive or HER2-Low Metastatic Breast Cancer: Navigating the Treatment Landscape
The Pharmacist and Patients With HER2-Positive or HER2-Low Metastatic Breast Cancer: Navigating the Treatment Landscape published on January 11, 2024 in Breast Cancer
Ovarian Function Suppression in Premenopausal Women with HR+ Breast Cancer
Emily M. Beard, RN, BSN, OCN, CBCN, Abbey J. Kaler, MS, APRN, FNP-C, Mohammed A. Jaloudi, MD
Best Practices in Ovarian Function Suppression in Breast Cancer published on December 21, 2023 in Breast Cancer
Enhertu Received Regular FDA Approval for Patients with Unresectable or Metastatic Breast Cancer
JHOP - June 2022 Vol 12, No 3 published on June 16, 2022 in FDA Oncology Update, Breast Cancer
Pembrolizumab plus Chemotherapy for Neoadjuvant and Adjuvant Therapy in Early Triple-Negative Breast Cancer: KEYNOTE-522
Robert J. Ignoffo, PharmD, FASHP, FCSHP, FHOPA
JHOP - April 2022 Vol 12, No 2 published on May 3, 2022 in From the Literature, Breast Cancer, Checkpoint Inhibitors
Lynparza Receives FDA Approval for Adjuvant Treatment of High-Risk Early Breast Cancer with BRCA Mutation
JHOP - April 2022 Vol 12, No 2 published on May 3, 2022 in FDA Oncology Update, Breast Cancer
Evaluating Adverse Events in Patients with Breast Cancer and HIV Infection Receiving Concomitant Antiretroviral Therapy and Chemotherapy with Curative Intent
Donyika Joseph, PharmD, BCOP, Farnaz Foolad, PharmD, BCPS, Neelam K. Patel, PharmD, BCOP, Meghan Karuturi, MD, MSc, Jaime Kaushik, PharmD, BCOP
JHOP - April 2022 Vol 12, No 2 published on May 2, 2022 in Original Article, Adverse Events, Breast Cancer, Infections
Advances in Breast Cancer Treatments: Are We Extending Patients’ Survival?
Meg Barbor, MPH
JHOP - June 2019 Vol 9, No 2 published on April 28, 2022 in HOPA Highlights, Breast Cancer
Development and Implementation of a Pharmacist-Led Virtual Clinic Improve the Management of Patients with Metastatic Breast Cancer Receiving CDK4/6 Inhibitors
JHOP - March 2022 Vol 12 Special Feature published on March 22, 2022 in HOPA Abstracts, Breast Cancer
Time to Treatment Initiation and Outcomes for Patients with Nonmetastatic Breast Cancer Before and During the COVID-19 Pandemic at Community Cancer Centers
JHOP - March 2022 Vol 12 Special Feature published on March 22, 2022 in HOPA Abstracts, Breast Cancer
Spontaneous Tumor Lysis Syndrome in a Patient with Stage IV HER2-Positive Breast Cancer: Case Report
Blake T. Robbins, PharmD, MBA , Alexander M. Kreimer, PharmD, BCPS , Reema A. Patel, MD, Allison R. Butts, PharmD, BCOP
JHOP - February 2022 Vol 12, No 1 published on March 1, 2022 in Case Reports, Tumor Lysis Syndrome, Breast Cancer
© Amplity Health. All rights reserved.

Subscribe Today!

To sign up for our newsletter or print publications, please enter your contact information below.

I'd like to receive: