Real-world treatment patterns and outcomes of abemaciclib for the treatment of HR+, HER2− metastatic breast cancer

Abstract

Objective: This retrospective observational study described baseline characteristics, real-world treatment patterns, and outcomes among patients with metastatic breast cancer treated with abemaciclib in the United States. Methods: De-identified electronic health record-derived data were used to describe patients who began abemaciclib treatment on or after 30 June 2016 and !4 months before data cutoff (31 December 2018). Real-world response (rwR) and real-world progression assessments were abstracted from clinical documentation. Descriptive statistics were used to calculate the real-world best response. The Kaplan-Meier method estimated real-world time to first response (rwTTFR) and real-world progression-free survival (rwPFS). Results: The median age of 118 female patients at abemaciclib initiation was 66.5 years (interquartile range, 57.0, 73.0). The breakdown of patients who received abemaciclib in first, second, third, or later lines was 28.8%, 21.2%, 20.3%, and 29.7%, respectively. Patients received abemaciclib as monotherapy (12.7%) or in combination with endocrine therapy: fulvestrant (59.3%); aromatase inhibitor (22.9%); aromatase inhibitor and fulvestrant (5.1%). There were 68 patients (57.6%) with !1 rwR assessment: 41.2% with a real-world complete response or real-world partial response. Median rwTTFR was 3.6 months (95% confidence interval, 3.5, 5.2). Twelve-month rwPFS probability was 61.7%. Conclusions: This study represents utilization and outcomes associated with abemaciclib approximately 1 year following FDA approval. Treatment patterns demonstrated heterogeneity and, as in clinical trials, patients appeared to benefit from abemaciclib treatment in the real world. More research investigating outcomes associated with abemaciclib treatment is needed, with larger samples and longer follow-up to enable closer evaluation by subgroup, regimen, and line of therapy.

Peripheral blood lymphocytes predict clinical outcomes in hormone receptor-positive HER2-negative advanced breast cancer patients treated with CDK4/6 inhibitors

“…Median PFS was 26.1 months (95% CI: 23.4–30.8) in patients receiving CDK4/6i treatment as a first-line therapy, while median PFS was 11.9 months (95% CI: 9.9–13.9) in patients receiving CDK/4/6i as subsequent lines of therapy ( Supplemental Figure 2 ). These data are consistent with results of phase III clinical trials 1 – 3 , 5 – 8 , 12 and with data from previously published real-world cohorts 24 – 27 of patients treated with ET plus CDK4/6i.…”

Treatment patterns of patients with HR+/HER2- metastatic breast cancer receiving CDK4/6 inhibitor-based regimens: a cohort study in the French nationwide healthcare database

“…In the EMERALD trial the 6-month PFS rates were 34.3% for elacestrant monotherapy and 20.4% for standard of care among patients who had progressed on a CDK4/6 inhibitor-based regimen [ 34 ]. These findings along with results from the present study highlight the remaining significant unmet need in HR+/HER2- mBC [ 20 , 35 , 36 ].…”

Real-World Patient Characteristics, Utilization Patterns, and Outcomes of US Patients with HR+, HER2− Metastatic Breast Cancer Treated with Abemaciclib

“…Evidence generated from this study is consistent and complementary to EMR-based analyses of abemaciclib use in the period following initial FDA approval for MBC. In an analysis of data from Flatiron Health from September 2017 to December 2018 [ 21 ], approximately 50% of patients had visceral metastases at abemaciclib initiation. Among patients who received abemaciclib in ≥ 2 L for MBC, 35% and 50% received a prior CDK4 & 6i and prior chemotherapy, respectively, while 16% received both prior CDK4 & 6i and prior chemotherapy in the metastatic setting [ 21 ].…”

“…In an analysis of data from Flatiron Health from September 2017 to December 2018 [ 21 ], approximately 50% of patients had visceral metastases at abemaciclib initiation. Among patients who received abemaciclib in ≥ 2 L for MBC, 35% and 50% received a prior CDK4 & 6i and prior chemotherapy, respectively, while 16% received both prior CDK4 & 6i and prior chemotherapy in the metastatic setting [ 21 ]. During a similar timeframe, data were analyzed from patients treated with abemaciclib, palbociclib, or ribociclib within the US Oncology Network.…”

“…Real-world studies assessing patterns of use and effectiveness outcomes with abemaciclib have recently become available, including studies evaluating outcomes related to abemaciclib following palbociclib in limited numbers of patients with MBC [ 15 – 20 ]. Prior analyses of electronic medical record data in 118 patients with HR+, HER2− MBC treated with abemaciclib indicate that approximately 25% of patients receive either palbociclib or ribociclib as prior treatment for MBC; however, these data are from the first 11 months following initial FDA approval [ 21 ]. Additional analyses with larger numbers of patients and longer follow-up are important to understanding whether these patterns of treatment continue as well as associated outcomes.…”