The Breast: VOLUME
54, P286-292, DECEMBER 01, 2020
Highlights
• CDK4/6 inhibitors combined with endocrine therapy have
been widely accepted as a new standard therapy for hormone receptor-positive
metastatic breast cancer patients in first or second line.
• Palbociclib alone or in combination with aromatase
inhibitors, fulvestrant, or tamoxifen was effective and safe in heavily
pretreated HR+/HER2- metastatic breast cancer patients.
• Palbociclib could be of higher benefit to patients with
endocrine-sensitive disease that had a long duration of response to previous
endocrine therapy.
• Real-world evidence of effectiveness and safety of use of
palbociclib in heavily pretreated advanced breast cancer patients complements
data from randomized clinical trials.
Abstract
Background
This study evaluated efficacy and safety of palbociclib, a
CDK4/6 inhibitor, in heavily-pretreated hormone receptor-positive and human
epidermal growth factor receptor 2-negative (HR+/HER2-) metastatic breast
cancer (mBC) patients during the compassionate use program in Spain from
February 2015 to November 2017.
Patients and methods
Patient data were collected retrospectively from 35
hospitals in Spain. Patients with HR+/HER2- mBC who had progressed on ≥4
treatments for advanced disease were eligible.
Results
A total of 219 patients received palbociclib in combination
with aromatase inhibitors (110; 50.2%), fulvestrant (87; 39.7%), tamoxifen (8;
3.6%) or as single agent (10; 4.6%). Mean age of the patients was 58 years; 31
patients (16.1%) were premenopausal and 162 (83.9%) were postmenopausal at the beginning
of treatment with palbociclib. Patients had received a median of 3 previous
lines of endocrine therapy (ET) for advanced disease. Real-world tumor response
(rwTR) and clinical benefit rate were 5.9% (n = 13) and 46.2%
(n = 101), respectively. The median real world progression-free
survival (rwPFS) was 6.0 months (95% CI 5.7–7.0) and the median overall
survival was 19.0 months (95% CI 16.4–21.7). Subgroup analysis revealed a
significant difference in median rwPFS in patients treated with palbociclib plus
fulvestrant depending on the duration of prior treatment with fulvestrant
monotherapy (>6 versus ≤6 months; HR 1.93, 95% CI 1.37–2.73,
p < 0.001). The most frequently reported toxicities were
neutropenia, asthenia, thrombopenia and anemia.
Conclusions
Palbociclib can be an effective and safe treatment option in
patients with heavily pretreated endocrine-sensitive mBC, especially in those
with longer PFS to previous ET.
