Indices of peripheral leukocytes predict longer overall survival in breast cancer patients on eribulin in Japan

Masato Takahashi,Yasuo Miyoshi,Hirofumi Mukai,Kenzo Muramoto,Toshiyuki Matsuoka,Hiroki Ikezawa,Chiyomi Egawa,Junji Tsurutani,Yukinori Sakata,Takashi Yamanaka,Kenichi Inoue

doi:10.1007/s12282-021-01232-1

Abstract

BackgroundIt was reported that eribulin regulates the tumor microenvironment, including the immune system, by inducing vascular remodeling. Lymphocyte counts are a critical index of immune response in patients. The non-Asian, global EMBRACE study has suggested that baseline absolute lymphocyte count (ALC) may be a predictor of the survival benefit of eribulin in breast cancer patients. We examined whether the baseline ALC is a potential predictor of overall survival (OS) in Japanese patients with HER2-negative advanced breast cancer treated with eribulin.MethodsThis was a post hoc analysis of data from a post-marketing observational study of eribulin in Japan. The OS by baseline ALC was estimated using the Kaplan–Meier method, with the cut-off value of 1500/μL for ALC. The OS by baseline neutrophil-to-lymphocyte ratio (NLR), a general prognostic index in breast cancer patients, was also estimated, with the cut-off value of 3.ResultsThe median OS was longer in patients with an ALC of ≥ 1500/μL than in those with an ALC of < 1500/μL (19.4 vs. 14.3 months; hazard ratio [HR]: 0.628; 95% confidence interval [CI]: 0.492, 0.801). Patients with an NLR of ≥ 3 showed shorter OS than those with an NLR of < 3 (13.2 vs. 18.8 months; HR: 1.552; 95% CI 1.254, 1.921), and NLR also separated OS in patients with an ALC of < 1500/μL.ConclusionsConsistent with the findings of a previous study involving a non-Asian, Western population, our study suggested that baseline ALC may be a predictive factor for the survival benefit of eribulin in Japanese patients.

Highlights

The duration from recurrence to the administration of eribulin and the proportion of patients who underwent pre-operative or post-operative chemotherapy were similar between the subgroups according to the baseline absolute lymphocyte count (ALC) or neutrophil-to-lymphocyte ratio (NLR)
Regardless of the cut-off values, patients with a higher baseline ALC showed longer overall survival (OS). In this post hoc analysis of post-marketing study data, we analyzed the OS according to the baseline ALC or NLR in eribulin-treated patients with breast cancer in Japan using the same cut-off values as those described in the previous EMBRACE study, in which Japanese patients were not included and most patients received later-line treatment [7]
The multivariate Cox regression analysis revealed that both baseline ALC of ≥ 1500/μL and NLR of < 3 were independent factors for prolonged OS

Summary

Introduction

To assess the safety and effectiveness of eribulin in clinical settings in Japan, a post-marketing observational study was conducted in patients with HER2-negative advanced breast cancer, which showed favorable results consistent with the results of clinical trials and real-world studies [4, 5]. The non-Asian, global EMBRACE study has suggested that baseline absolute lymphocyte count (ALC) may be a predictor of the survival benefit of eribulin in breast cancer patients. We examined whether the baseline ALC is a potential predictor of overall survival (OS) in Japanese patients with HER2-negative advanced breast cancer treated with eribulin. Conclusions Consistent with the findings of a previous study involving a non-Asian, Western population, our study suggested that baseline ALC may be a predictive factor for the survival benefit of eribulin in Japanese patients

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