In the PALOMA-3 trial, palbociclib plus fulvestrant demonstrated a clinically meaningful improvement in overall survival compared with fulvestrant plus placebo in patients (pts) with hormone receptor-positive (HR+), HER2-negative (HER2-) metastatic breast cancer who had relapsed or progressed on prior endocrine therapy (Turner NC et al., NEJM 2018). Detailed analyses for first-line (1L) and later-line (2L+) therapy are still limited.
The prospective, multicenter phase 2 INGE-B trial was designed to generate efficacy and safety data on the combination of palbociclib with letrozole (1L) or fulvestrant (1L, 2L+) in accordance with the PALOMA trials and to generate so far lacking trial data on the combination of palbociclib with anastrozole (1L), exemestane (1L) or letrozole (2L+). This pre-planned interim analysis was conducted to evaluate data on pts receiving palbociclib plus fulvestrant as 1L or 2L+ therapy. The primary objective was the clinical benefit rate (CBR) in pts with measurable disease according to RECIST v1.1. Key secondary endpoints included the overall response rate (ORR), the CBR for all pts, and safety. Data were analyzed with descriptive statistics.
At the cut-off date of the interim analysis (Dec 17, 2018), 124 pts have been recruited from 03/2017 through 06/2018 at 47 sites across Germany to receive palbociclib plus fulvestrant (1L: 57 pts; 2L+: 67 pts). Of those, 54 pts treated in 1L were evaluable. Median age was 69.5 years, 96.3% of pts had an ECOG performance score of 0 or 1. 31.5% of pts had bone-only disease. The CBR was 58% (n = 21) for the 36 pts with measurable disease (RECIST v1.1) and 65% (n = 35) for all pts (investigator assessment). The ORRs were 36% and 30%, respectively. Grade 3/4 adverse events experienced by at least 10% of pts were neutropenia (n = 17, 31.5%) and leukopenia (n = 8, 14.9%).
This INGE-B interim analysis showed for the first time a remarkable clinical benefit for palbociclib plus fulvestrant as first-line therapy for pts with HR+/HER2- advanced breast cancer. No new safety signals emerged.
EudraCT-Nr. 2015-001603-32 29-JAN-2016.
Iomedico AG.
Pfizer Pharma GmbH.
A. Welt: Advisory boards: AstraZeneca, Novartis, Roche, Eisai, Pfizer, Amgen, Lilly; Fees: COCS GmbH, Iomedico AG, Interplan AG; Funding of scientific programs: Novartis; Stock ownership: None. D. Lüftner: Stock ownership: None; Membership on an advisory board or board of directors: Amgen, Novartis, Eli Lilly, Pfizer, Celgene, AstraZeneca; Corporate-sponsored research: Novartis. All other authors have declared no conflicts of interest.