9 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

Background

Eribulin was FDA approved in 2010 for the treatment of metastatic breast cancer (mBC) in the United States. Recently, several immunotherapy (IO) regimens and an antibody-drug conjugate (ADC) have been FDA approved for patients with triple-negative breast cancer (TNBC). This study aimed to assess the treatment patterns and clinical outcomes in patients with mBC treated with eribulin following either IO or ADC therapy in US clinical practice.

Methods

A retrospective, noninterventional patient medical chart review study was conducted. Consenting oncologists provided deidentified patient data via an electronic case report form. Adult female patients diagnosed with mBC and who began treatment with eribulin between March 1, 2019, and September 30, 2020, following prior therapy with an IO (atezolizumab [Tecentriq]) or ADC (sacituzumab govitecan [Trodelvy]) were included. Eribulin treatment characteristics were recorded. Overall survival (OS) since eribulin initiation was assessed using Kaplan-Meier methods.

Results

This analysis included 91 eligible patients, of whom 53 received prior atezolizumab, and 38 had prior sacituzumab govitecan. Patients’ median age was 63 years at eribulin treatment initiation, and 57% were Caucasian. The majority of eribulin-treated patients had TNBC (74.7%); 13.2% had hormone receptor–positive/HER2-negative disease. In the study cohort, eribulin was classified as second-line, third-line, and fourth- or later-line in 76%, 13%, and 11% of patients, respectively, in regard to line of therapy in the metastatic setting. At last follow-up, eribulin treatment was ongoing for 36.3% of patients. The median treatment duration was 5.1 months (q1, q3: 3.5-7.3) among those who had discontinued eribulin, and 12.2 months (q1, q3, 11-14) among those who were still on treatment. At last follow-up, 63.7% of patients were alive. Median was not reached for OS subsequent to initiation of eribulin. The estimated OS rates at 12 and 24 months were 77.8% (95% CI, 67.3%-85.3%) and 53.6% (95% CI, 35.1%-68.9%), respectively.

Conclusion

Among patients with mBC who initiated eribulin following an IO or ADC, more than 50% were estimated to be alive after 2 years. Eribulin may be a promising treatment option for patients for whom IO or ADC failed.

Author Affiliations:

Ravi K. Goyal,¹ Jingchuan Zhang,² Samina Dhuliawala,¹ Martina Sluga-O’Callaghan,¹ Peter A. Kaufman³

¹RTI Health Solutions, Research Triangle Park, NC

²Eisai Inc, Nutley, NJ

³Larner College of Medicine, Division of Hematology/ Oncology, University of Vermont Cancer Center, Burlington, VT