A platform for high-resolution immune liquid biopsy analysis to predict response in patients with renal cell carcinoma treated with nivolumab or cabozantinib: Preliminary data from I-RENE trial (Meet-URO 8 study)

Background: Nivolumab, an immune checkpoint inhibitor of PD-1, demonstrated a significant OS benefit in patients with metastatic renal cell carcinoma (mRCC), in progression after a previous line of therapy with anti-VEGFR agents. However, the features of effective immune response and predictive biomarkers of clinical benefit to PD-1 blockade have not yet been recognized. Methods: I-RENE is a prospective translational multicenter Italian study of a real-life mRCC patients treated with nivolumab or cabozantinib after failure of therapy with anti-VEGFR agents. 82 patients were enrolled from December 2018 to August 2022 (nivo 60, cabo 22), with blood samples obtained at baseline and at different time points in both treatment groups. An extended concept of "immune liquid biopsy" is being applied to the study, consisting in the phenotypic and transcriptional profile of lymphoid and myeloid subsets, immune-related miRNA quantification, cyto/chemo-kinome and RNAseq of extracellular vesicle. Results: Multiparametric flow cytometry, performed to monitor the blood frequency and different myeloid and lymphoid cells, show that monocyte subsets (classical, intermediate and non-classical CD14+ cells), monocytic myeloid derived suppressor cells (MDSC, such as CD14+HLA-DRneg and CD14+PD-L1+) and polymorphonucleate (PMN)-MDSC, remain either stable or increase during treatment; concomitantly, CD8+PD-1+ T cells (detected by anti-nivolumab IgG4) increment frequency, acquire the effector CD45RA-CCR7+ phenotype and express the proliferating marker Ki67. Patients receiving cabozantinib display instead a remarkable decrease of all myeloid cell subsets, paired by the boost of cytotoxic CD3-CD16+CD56dim NK cells and more marginally of CD8+PD1+ cells, Preliminary correlations indicate that clinical benefit of nivolumab seems to cluster with the lack of CD14+ cells and M-MDSC increase and blood frequency of total, and the boost in CD8+CD45RA-CCR7+Ki67+ effector T cells. In contrast, the cabozantinib-induced immune modulation occurring in patients treated with does not associate with clinical response Conclusions: This first set of data indicate blood as promising source of dynamic biomarkers for the development of algorithms predicting response to PD-1 blockade. Furthermore, the results so far collected suggest that the potent immunomodulation induced by cabozantinib on the immunosuppressive myeloid compartment may not lead to any tumor control in the absence of specific immune stimulation by checkpoint inhibitors. This study was supported by the Italian Ministry of health (RF-2016_02363001). Clinical trials.gov: NCT04891055