Meeting Abstract

JL525. Real-World Systemic Therapy Sequences Following a CDK 4/6 Inhibitor Regimen Among Post-Menopausal Women

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ABSTRACT

Abstracts From 
JADPRO Live at APSHO 2017
Marriott Marquis, Houston, Texas • November 2–5, 2017

The posters for the abstracts below can be found at:
eventscribe.com/2017/posters/JADPROLIVE/home.asp

JL525. Real-World Systemic Therapy Sequences Following a CDK 4/6 Inhibitor Regimen Among Post-Menopausal Women With Hormone Receptor–Positive Human Epidermal Growth Factor Receptor 2 Negative (HR+/HER2-) Metastatic Breast Cancer (mBC)

Background: While approval of CDK 4/6 inhibitors (CDK 4/6i), palbociclib and ribociclib, has changed the landscape of metastatic HR+/HER2– breast cancer, limited population-based data are available regarding therapy utilization for mBC patients after progression on CDK 4/6i. The aim of the current analysis is to describe real-world use of systemic therapies following a CDK 4/6i-based line (e.g., second line [2L], third line [3L], and fourth line [4L]) in the United States using a contemporary population-level data set.

Methods: Postmenopausal women with HR+/HER2– mBC were identified from MarketScan administrative claims databases between 1/1/2012 to 4/30/2017. The date of the first claim depicting metastatic disease was index. Patients had 12 months of continuous enrollment in their health plans prior to index and were followed until disenrollment, inpatient death, or study end (4/30/2017). Eligible mBC patients who received standard CDK 4/6i-based treatment were selected. A line of therapy regimen included all BC treatments during the first 45 days following initiation and ended at discontinuation (gap > 60 days and restart on new regimen), switch to new treatment, or censoring.

Results: 1,164 CDK 4/6i-based 1L, 2L, and 3L regimens followed by 375 subsequent post CDK 4/6i lines were included. Of these 42.4% were 2L (N = 159) and 57.6% (N = 216) were 3L/4L lines. Mean age at the start of first line was 62.7 years (SD = 10.5 years), 65.1% were commercially insured, and 65.1% of lines were completed during the study period (ended due to discontinuation or switching). Approximately one-third (37.7%) of 2L regimens (post-CDK 4/6i 1L) were endocrine only, 35.2% were chemotherapy-based, 15.1% were everolimus-based, 8.8% moved to a different CDK 4/6i-based regimen, and 3.1% were others. Across all post-CDK 4/6i lines (2L, 3L, 4L), most chemotherapy-based regimens were capecitabine- (48.1%) or paclitaxel-based regimens (24.4%); among the endocrine-only monotherapy regimens, the most prevalent sequence from the prior CDK 4/6i-based line of therapy was fulvestrant (39.7%) followed by letrozole (26.7%), and exemestane (14.5%).

Conclusions: After CDK 4/6i, patients transition to various regimens, including endocrine monotherapy, endocrine combination with everolimus, or chemotherapy-based regimens. Further research is needed to evaluate the relative efficacy and comparative effectiveness of these different regimens to identify optimal sequencing strategy in the 2nd-4thL setting for patients with mBC.

Recommendations: These data allow health-care providers and payers to understand real-world treatment sequencing following a CDK 4/6-based line of therapy and serve as a first step towards understanding the optimal sequencing tailored to patient’s clinical circumstances.

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