Introduction
Immune checkpoint inhibitor (ICI)-based combinations are standard first-line (1L) treatment for patients with advanced renal cell carcinoma (aRCC), and several combinations have been approved.1 2 Identification of reliable predictive and prognostic biomarkers may enable more individualised treatment for patients with aRCC.3 The most commonly used prognostic model for aRCC is the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) classification, which uses 6 factors (time interval from diagnosis to treatment, Karnofsky performance status, haemoglobin level, platelet count, neutrophil count and serum calcium concentration) to categorise patients into risk groups.4 The predictive and prognostic value of various biomarkers has been explored in aRCC, including programmed death ligand 1 (PD-L1) expression, genomic alterations, gene expression signatures and peripheral blood biomarkers.3 5
Given the link between inflammation and the pathogenesis and progression of cancer, inflammatory biomarkers have been a focus of research for ICI-based treatment regimens.6–8 Various studies in solid tumours have found that levels or ratios of different types of blood cells including platelet-to-lymphocyte, lymphocyte-to-monocyte, neutrophil-to-lymphocyte and neutrophil-to-eosinophil ratios (NERs) are associated with efficacy outcomes in patients receiving ICI-based therapy.9–17 Clinical data from patients with metastatic RCC suggest that an increase in eosinophil levels during treatment may be prognostic for response to ICIs or tyrosine kinase inhibitor (TKIs).18 19 In a recent study, a lower baseline NER was associated with improved clinical outcomes in patients with aRCC treated with 1L nivolumab plus ipilimumab.20 Observations were similar in retrospective studies of patients with metastatic RCC who received various ICI-based regimens or who received nivolumab as second-line or later treatment.21 22 Preclinical studies suggest that eosinophil activation regulates macrophage polarisation and promotes CD8+ T cell recruitment and response to ICIs.23–25 Further analyses of NER as a predictive marker in patients with aRCC receiving 1L ICI plus TKI treatment, including comparisons with other treatment regimens, are required.
In the phase 3 JAVELIN Renal 101 trial (NCT02684006), 1L treatment with avelumab, a fully human anti-PD-L1 monoclonal antibody, plus axitinib, a selective antiangiogenic TKI, significantly improved progression-free survival (PFS) and the objective response rate (ORR) in patients with aRCC compared with sunitinib, an antiangiogenic TKI therapy that was the prior 1L standard of care.26 27 Exploratory analyses have shown that various genomic and transcriptomic biomarker signatures, in addition to C reactive protein levels, can predict efficacy outcomes with avelumab plus axitinib but not sunitinib, whereas neutrophil-to-lymphocyte ratio (NLR) was prognostic and associated with outcomes for both treatment regimens.17 28 29 The potential for NER to serve as a prognostic or predictive biomarker for 1L avelumab plus axitinib treatment in comparison with sunitinib has not been assessed. In the exploratory analyses reported here, we assessed the association between baseline NER and efficacy outcomes in the avelumab plus axitinib and sunitinib arms of the JAVELIN Renal 101 trial.