The Association between a Decrease in On-Treatment Neutrophil-to-Eosinophil Ratio (NER) at Week 6 after Ipilimumab Plus Nivolumab Initiation and Improved Clinical Outcomes in Metastatic Renal Cell Carcinoma.

Abstract

Simple SummaryImmune checkpoint inhibitors (ICIs) have significantly changed the treatment paradigm in metastatic renal cell carcinoma (mRCC) and brought an unprecedented durable response. However, there is still a significant proportion of patients who do not response to ICIs, and there are no biomarkers to select responders. In this study, we investigated the change in neutrophil-to-eosinophil ratio (NER) during ipilimumab/nivolumab treatment and clinical response in mRCC. We found that mRCC patients who responded to immunotherapy had lower on-treatment NER during ipilimumab/nivolumab induction. In addition, after accounting for baseline tumor biological characteristics and patient sociodemographic factors, we found that the decrease in NER at week 6 was independently associated with improved outcomes in ipilimumab/nivolumab-treated mRCC. Given that the NER can be easily obtained through routine laboratory work-ups, our results provide initial evidence that the decrease in on-treatment NER during immunotherapy, as a biomarker to predict ICI treatment response, warrants further investigation in prospective studies.A lower baseline neutrophil-to-eosinophil ratio (NER) has been associated with improved responses to immune checkpoint inhibitors (ICI)-treated metastatic renal cell carcinoma (mRCC). This study investigated the decrease in NER at week 6 after ipilimumab/nivolumab (ipi/nivo) initiation and treatment responses in mRCC. A retrospective study of ipi/nivo-treated mRCC at two US academic cancer centers was conducted. A landmark analysis at week 6 was performed to assess the association between the change in NER and clinical responses (progression-free survival (PFS)/overall survival (OS)). Week 6 NER was modeled as a continuous variable, after log transformation (Ln NER), and a categorical variable by percent change. There were 150 mRCC patients included: 78% had clear cell histology, and 78% were IMDC intermediate/poor risk. In multivariable regression analysis, every decrease of 1 unit of Ln NER at week 6 was associated with improved PFS (adjusted hazard ratio (AHR): 0.78, p-value:0.005) and OS (AHR: 0.67, p-value: 0.002). When NER was modeled by percent change, decreased NER > 50% was associated with improved PFS (AHR: 0.55, p-value: 0.03) and OS (AHR: 0.37, p-value: 0.02). The decrease in week 6 NER was associated with improved PFS/OS in ipi/nivo-treated mRCC. Prospective studies are warranted to validate NER change as a biomarker to predict ICI responses.