Early Real-World Treatment Patterns and Clinical Outcomes in Patients with Metastatic Breast Cancer Treated with Eribulin After Prior Immuno-Oncology or Antibody–Drug Conjugate Therapy

Abstract

Introduction

Eribulin was approved by the FDA in 2010 for the treatment of metastatic breast cancer (MBC) in the United States (US). More recently, several immuno-oncology (IO) and antibody–drug conjugate (ADC) regimens have been approved for MBC. We assessed the treatment patterns and clinical outcomes in MBC patients treated with eribulin following treatment with an IO or ADC in US clinical practice.

Materials and Methods

In a retrospective patient medical chart review study, patients with MBC, aged ≥18 years, who initiated eribulin therapy between March 1, 2019, and September 30, 2020, treated with either prior IO or ADC in the metastatic setting were included. Patient demographics, treatment characteristics, and clinical outcomes were analyzed descriptively. Real-world progression-free survival (rwPFS) and overall survival (OS) were estimated using Kaplan–Meier analyses.

Results

In the study population (N=143), median age at eribulin initiation was 62 years; 64% were Caucasian, and 67% had triple-negative MBC (TNBC). Eribulin therapy was used in the second to fifth line of therapy in the metastatic setting; median treatment duration was 7.2 months. The overall response rate for eribulin was 59.4%. Median rwPFS and OS from eribulin initiation were 21.4 months (95% CI, 12.9-not estimable [NE]) and 24.2 months (95% CI, 17.5-NE), respectively. In patients with TNBC, median rwPFS and OS from eribulin initiation were 12.0 months (95% CI, 8.8-NE) and 18.3 months (95% CI, 14.9-NE), respectively.

Conclusion

These real-world data provide evidence for the clinical effectiveness outcomes of eribulin treatment among MBC patients previously treated with an IO or ADC.

Keywords:

• real world evidence
• metastatic breast cancer
• immuno-oncology
• antibody drug conjugates
• eribulin
• patient medical chart review

Data Sharing Statement

The data for this study will not be available.

Ethical Approval

The RTI Institutional Review Board (IRB) waived full IRB review or informed consent from patients because of the use of deidentified patient data.

Acknowledgments

The authors thank Sara Musetti Jenkins, PhD, and Brian Samsell, PhD, of RTI Health Solutions for medical writing assistance.

An abstract from this study was presented at the Miami Breast Cancer Conference as a poster presentation with interim findings. The poster’s abstract was published in “Poster Abstracts” in 39th Annual Miami Breast Cancer Conference Abstracts, Volume 36, Issue suppl 3, Page 13; https://www.cancernetwork.com/view/real-world-treatment-patterns-and-clinical-outcomes-in-patients-treated-with-eribulin-after-prior-immunotherapy-io-or-antibody-drug-conjugate-adc-for-metastatic-breast-cancer.

Disclosure

RKG, KLD, and MSO are full-time employees of RTI Health Solutions, an independent nonprofit research organization, which was retained by Eisai Inc. to conduct the research, which is the subject of this manuscript. Their compensation is unconnected to the studies on which they work. JZ is an employee of Eisai Inc. PAK received research support and/or served as a consultant/advisor for the following: Eisai, Inc., Roche/Genentech Amgen, Novartis, Macrogenics, Polyphor, Lilly, Pfizer, Sanofi, Seagen, Bristol-Myer Squibb, H3 BioMedicine, Zymeworks Therapeutics, and AstraZeneca. The authors report no other conflicts of interest in this work.

Additional information

Funding

Eisai Inc. provided financial support for the study. RTI Health Solutions, an independent nonprofit research organization, received funding under a research contract with Eisai Inc. to conduct this study and provide publication support in the form of manuscript writing, styling, and submission.