Abstract 302P
Background
Eosinophil is one of the crucial immune cells in anti-tumor immunity in cancer patients treated with immune checkpoint inhibitors. However, there are lack of evidence regarding the impact of eosinophil on efficacy and safety in patients with metastatic renal cell carcinoma (RCC) treated with ipilimumab plus nivolumab. Therefore, this study investigated association between eosinophil and efficacy and safety in RCC treated with ipilimumab plus nivolumab.
Methods
We retrospectively analyzed 161 patients with RCC received ipilimumab plus nivolumab at eight multicenter. We divided into two groups depending on whether patients had experienced irAEs (irAE group) or not (non-irAE group). Eosinophil was examined before 1- (baseline sample), 2-course of treatment (2-course sample) and two weeks after 1-course of treatment (2-week sample). We defined 3.0% of eosinophil as the optimal cut-off value for irAEs according to previous our study. Multivariate analysis was undertaken to identify predictors of irAEs and progression free survival (PFS).
Results
Patients in the irAE group showed higher eosinophil in 2-week (mean, 6.2% vs. 3.3%) and 2-course sample (mean, 6.7% vs. 5.1%) than those in the non-irAE group (P<0.05). The eosinophil in the baseline samples did not differ (mean, 2.9% vs. 2.5%, P=0.20). In multivariate analyses, eosinophils of ≥3.0% was increased the risk for irAEs (P<0.05, odds ratio 3.44, 95% confidence interval 1.06–11.2). Median PFS was longer in the irAE group than in the non-irAE group (P<0.05, 10.1 months vs. 5.3 months). Consistently, median PFS of eosinophils of ≥3.0% was longer than those of eosinophils of <3.0% (P<0.05, 10.1 months vs. 6.0 months). Multivariate analysis identified that eosinophils of ≥3.0% decreased the risk for disease progression (P<0.05, hazard ratio 0.54, 95% confidence interval 0.32–0.91).
Conclusions
An increased eosinophil associated with improvement of clinical outcome and high incidence of irAEs. Therefore, eosinophil may be predictor for efficacy and safety in RCC treated with ipilimumab plus nivolumab.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Y. Tasaki.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.