Highlights
- •Real-world treatment patterns and outcomes of first-line palbociclib were evaluated (n = 813).
- •Palbociclib was initiated at the recommended dose of 125 mg in 87% of patients.
- •Of 813 patients, 43% discontinued palbociclib; 11% because of toxicity.
- •Median rwPFS and time to chemotherapy were 20.0 and 36.6 months, respectively.
- •Palbociclib initiation at 125 mg was more effective than lower doses.
Abstract
Introduction
To describe real-world treatment patterns and effectiveness of first-line palbociclib
plus an aromatase inhibitor (PAL+AI) and examine the association between PAL initial
dose and effectiveness among patients with hormone receptor–positive/human epidermal
growth factor receptor 2–negative metastatic/advanced breast cancer (HR+/HER2– MBC)
in routine clinical practice.
Patients and Methods
This retrospective analysis used Flatiron Health's database of electronic health records
from >280 cancer clinics representing >2.4 million actively treated cancer patients
in the United States. Women with HR+/HER2− MBC who received first-line PAL+AI were
included. Real-world progression-free survival (rwPFS) was defined as the time from
starting PAL+AI to death or disease progression. Real-world best tumor response (rwBTR)
was assessed based on the treating clinician's assessment of radiologic evidence for
change in disease burden.
Results
Of 813 eligible patients, median age was 65.0 years, and median follow-up was 21.0
months. PAL was initiated at 125 mg/d and 75/100 mg/d in 86.5% and 13.5% of patients,
respectively. Median duration of PAL+AI was 16.3 months. 43.0% of patients discontinued
PAL+ AI; 11.0% discontinued because of toxicity. Median time to subsequent therapy
and chemotherapy was 24.6 and 36.6 months, respectively. Median rwPFS was 20.0 months,
and best rwBTR rate was 51.9%. Patients starting PAL at 125 versus 75/100 mg/d had
longer median rwPFS (27.8 vs. 18.6 months) and higher rwBTR rate (54.0% vs. 40.4%).
Conclusion
These data demonstrate the benefit of PAL+AI in routine clinical practice and may
support the initiation of palbociclib at the recommended dose of 125 mg/d for HR+/HER2−
MBC.
Trial Registration Number and Date of Registration
NCT04176354, November 25, 2019
Keywords
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Article info
Publication history
Published online: May 04, 2022
Accepted:
May 1,
2022
Received in revised form:
March 11,
2022
Received:
December 21,
2021
Identification
Copyright
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