Utilization and outcomes of Eribulin Mesylate POst a cyclin-dependent kinase 4/6 inhibitor (CDK 4/6i): An observational real-World study in UnitEd States community oncology pRactices (EMPOWER)
Authors: S. Mougalian, E. Wang, K. Alexis, B.A. Feinberg, D. Nero, T. Miller, J. Laney, D. Chatterjee, R. Knoth, J. Kish
Journal: Annals of Oncology (2019)

Background: As CDK 4/6i therapy becomes the standard of care in the early-line treatment of hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2−), metastatic breast cancer (mBC), this study evaluated the safety and effectiveness of eribulin mesylate when used post-CDK 4/6i treatment. Methods: This was a retrospective, observational cohort study. Providers from community oncology practices in the United States selected female HR+, HER2− patients with MBC who were treated with any CDK 4/6i from Feb/03/15-Dec/31/17, and who subsequently initiated eribulin post-CDK 4/6i treatment. Patients were assigned to 1 of 3 protocol-defined treatment groups: "on-label" was defined as eribulin post-CDK4/6i treatment, >2 prior chemotherapies in the metastatic setting, and treatment with an anthracycline and taxane prior to eribulin; "third-line" (3L) was eribulin following treatment with a CDK4/6i and any other regimen; "other" was neither on-label nor 3L. Adverse events (AEs), objective response rate (ORR) per RECIST v1.1 guidelines, and time to progression during eribulin treatment were compared to findings from the registrational EMBRACE trial. Results: 395 Patients were selected by 45 providers: on-label n = 135 patients, 3L n = 111, and other n = 149 (n = 121 with second-line eribulin ["other-2L"]) (Table). Based on target lesion measurements, the ORR in the on-label cohort was 26.7%, or twice that observed in EMBRACE (13%). Time to progression was similar to the EMBRACE median progression-free survival (PFS) estimate. Reported grade 3/4 AE rates were lower than in EMBRACE (neutropenia=8.1% vs 45%; peripheral neuropathy=0.5% vs 9%). Conclusions: The results shown here for eribulin post-CDK4/6i were similar to those in the EMBRACE study. Longer follow-up will be needed to fully evaluate its influence on PFS and OS.Table167PParameterAll¶Includes 28 "other non-2L".On-label3LOther-2Ln = 395n = 135n = 111n = 121Stage IV at diagnosis, %63.557.857.776.9Visceral metastases, %87.392.691.086.8Easter Cooperative Oncology Group-performance status ≥ 2, %23.020.718.923.1Mean duration of CDK 4/6i treatment (months)11.010.19.912.9Still receiving eribulin,%77.584.485.667.8Median duration of eribulin (months)3.82.74.26.1AE (grade 3/4)*Per provider report., %Neutropenia8.16.710.87.4Any febrile neutropenia1.30.70.92.5%Peripheral neuropathy0.50.00.90.8Diarrhea0.00.00.00.0Discontinuation due to toxicity, %0.81.50.00.0ORR†Response Evaluation Criteria In Solid Tumors version 1.1., %30.626.726.142.4Median time to progression (months)‡Among patients with progression (55 patients).3.72.74.25.112-Months survival from eribulin start§60 Deaths., %73.354.377.588.4* Per provider report.† Response Evaluation Criteria In Solid Tumors version 1.1.‡ Among patients with progression (55 patients).§ 60 Deaths.¶ Includes 28 "other non-2L". Open table in a new tab Editorial acknowledgement: Tarah Connolly of Oxford PharmaGenesis, Newtown, PA, USA. Legal entity responsible for the study: Eisai, Inc. Funding: Eisai, Inc. Disclosure: K. Alexis, D. Chatterjee R. Knoth: Employee: Eisai, Inc, Woodcliff Lake, NJ. B.A. Feinberg, D. Nero, T. Miller, J. Laney, J. Kish: Employee: Cardinal Health Specialty Solutions, Dallas, TX. All other authors have declared no conflicts of interest.