Purpose
In the initial PALOMA-2 (NCT01740427) analysis with median follow-up of 23 months, palbociclib plus letrozole significantly prolonged progression-free survival (PFS) in women with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2−) advanced breast cancer (ABC) [hazard ratio (HR) 0.58;
P
< 0.001]. Herein, we report results overall and by subgroups with extended follow-up.
Methods
In this double-blind, phase 3 study, post-menopausal women with ER+/HER2− ABC who had not received prior systemic therapy for their advanced disease were randomized 2:1 to palbociclib-letrozole or placebo-letrozole. Endpoints include investigator-assessed PFS (primary), safety, and patient-reported outcomes (PROs).
Results
After a median follow-up of approximately 38 months, median PFS was 27.6 months for palbociclib–letrozole (
n
= 444) and 14.5 months for placebo-letrozole (
n
= 222) (HR 0.563; 1-sided
P
< 0.0001). All subgroups benefited from palbociclib treatment. The improvement of PFS with palbociclib-letrozole was maintained in the next 2 subsequent lines of therapy and delayed the use of chemotherapy (40.4 vs. 29.9 months for palbociclib–letrozole vs. placebo-letrozole). Safety data were consistent with the known profile. Patients’ quality of life was maintained.
Conclusions
With approximately 15 months of additional follow-up, palbociclib plus letrozole continued to demonstrate improved PFS compared with placebo plus letrozole in the overall population and across all patient subgroups, while the safety profile remained favorable and quality of life was maintained. These data confirm that palbociclib-letrozole should be considered the standard of care for first-line therapy in patients with ER+/HER2− ABC, including those with low disease burden or long disease-free interval. Sponsored by Pfizer; ClinicalTrials.gov: NCT01740427.
Electronic supplementary material
The online version of this article (10.1007/s10549-018-05125-4) contains supplementary material, which is available to authorized users.
In order to examine the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-P) in combination with bevacizumab (B) and gemcitabine (G) for the first-line treatment of patients with HER2-negative metastatic breast cancer (MBC). In this single-center, open-label phase II trial, patients with HER2-negative MBC received gemcitabine 1500 mg/m(2), nab-paclitaxel 150 mg/m(2), and bevacizumab 10 mg/kg (each administered intravenously) on days 1 and 15 of a 28-day cycle. The primary end point was progression free survival (PFS); secondary end points were overall response rate (ORR), complete (CR) and partial (PR) response rates, clinical benefit (ORR + stable disease), overall survival (OS), and safety. Thirty patients were enrolled. One patient was ineligible and was not included in analysis. Median PFS was 10.4 months (95% CI: 5.6-15.2 months). ORR was 75.9%, comprising eight (27.6%) CRs and 14 (48.3%) PRs; five patients had stable disease (SD) and two patients (6.9%) had progressive disease (PD) as their best response. The clinical benefit rate was 93.1% (27/29) in the overall group and 84.6% in the triple-negative cohort (11/13). The 18-month survival rate was 77.2% (95% CI: 51.1-90.5%). Eight (27.6%) patients experienced grade 3 or 4 toxicity: grade 4 neutropenic fever (n = 1) and grade 3 infection (n = 6), leukopenia, thrombocytopenia, peripheral neuropathy, seizure, shortness of breath, hematuria, and cardiac tamponade (one each). First-line therapy with nab-P, B, and G demonstrated a median PFS of 10.4 months and a 75.9% ORR with acceptable toxicity; this novel combination warrants investigation in a randomized study.
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