Immune checkpoint inhibitors plus debulking surgery for patients with metastatic renal cell carcinoma: clinical outcomes and immunological correlates of a prospective pilot trial

Abstract

Surgical removal of primary tumors reverses tumor-mediated immune suppression in pre-clinical models with metastatic disease. However, how cytoreductive surgery in the metastatic setting modulates the immune responses in patients, especially in the context of immune checkpoint therapy (ICT), is not understood. We report the first prospective, pilot, non-comparative clinical trial (NCT02210117) to evaluate the feasibility, clinical benefits, and immunologic changes of combining three different ICT-containing strategies with cytoreductive surgery or biopsy for patients with metastatic clear cell renal cell carcinoma. Primary safety endpoint of this trial has been met, with 43 patients completing cytoreductive surgery, 36 patients undergoing post-ICT biopsy, and 25 patients without either procedure due to progressive disease or toxicities or withdrawal of consent (total N = 104). Patients receiving ICT with cytoreductive surgery or biopsy, did not experience additional ICT- or procedure-related toxicities. The median overall survival was 54.7 months for patients who received ICT plus cytoreductive surgery. Immune-monitoring studies demonstrated that cytoreductive surgery increased antigen-presenting dendritic cell population and decreased KDM6B-expressing immune-suppressive myeloid cells in the peripheral blood. This study highlighted the feasibility of combining ICT with cytoreductive surgery in a metastatic setting and demonstrated the potential enhancement of immune responses following ICT plus cytoreductive surgery.

Fig. 1. Combination of ICT plus surgery is safe and feasible in the metastatic setting.

a Schema for clinical trial NCT02210117. Patients with mccRCC underwent baseline tumor biopsy and blood sample collection before being randomly assigned to receive nivolumab (n = 30), nivolumab + bevacizumab (n = 45), or nivolumab + ipilimumab (n = 30) for a total of 6 weeks. Four to six weeks after the ICT treatment, based upon evaluation by medical oncologists and urologists specialized on RCC, patients underwent either cytoreductive surgery or tumor biopsy. Two to four weeks after cytoreductive surgery or biopsy, nivolumab was given as maintenance therapy to each patient for up to 2 years or until disease progression or intolerable toxicities or withdrawal from the protocol. Tissue and blood samples were collected at pre-ICT treatment and at the time of surgery or biopsy (4–6 weeks after the initial 6 weeks of ICT treatment) for correlative studies. b Overall survival (OS) in Arm A (nivolumab). c OS in Arm B (nivolumab + bevacizumab). d OS in Arm C (nivolumab + ipilimumab).

Fig. 2. Identification of immuno-genomic biomarkers from tumor tissues of mccRCC patients.

a Oncoplot showing the somatic mutation landscape of the top 5 mutated genes [from TCGA. Kidney Renal Clear Cell Carcinoma (KIRC)]. A total of 58 tumor tissue samples were. analyzed and each column represents a patient. The color bar at the bottom shows response for. each patient (PD=progressive disease, SD=stable disease, PR=partial response). The genes are listed on the left and their respective frequencies are listed on the right of the heatmap. The colored rectangles indicate different types of somatic mutations and the key identifying each mutation type is shown at the bottom of the heatmap. The bar plot on the top shows the somatic mutation count for each patient. The bar plot on the right side shows the counts of mutations for each gene and the colors in the bar plots correspond to the colors showing mutation types in the body of the heatmap. b Stacked bar plot showing a positive association of genomic signature (mutations in PBRM1 or SETD2 genes) with clinical responses. Patients (n = 58) were stratified into Mut (patients with mutations in SETD2 or PBRM1, n = 25) and WT (patients with wild-type SETD2 and PBRM1. genes, n = 33) groups (p = 0.03). c–d Box plots showing association of IFN-γ signature (c) and. TLS signature (d) with clinical responses (n = 83). Box plots represent the median, interquartile. range and the whiskers represent 1.5 x the upper and lower interquartile range values. Welch’s. ANOVA test across the 3 groups for IFN-γ signature (p = 0.025) and TLS signature (p = 0.039). Stacked bar plot showing a positive association of IFN-γ signature (e) and TLS signature (f). with response. Patients (83) were stratified into IFNG^high (n = 41) and IFNG^low (n = 42) groups. (p = 0.02) (e) or into TLS^high (n = 41) and TLS^low (n = 42) (f). Statistical significance was calculated using two-sided Welch’s ANOVA, Welch’s t-test and Fisher’s exact test for comparing z scores in 3 or more unpaired groups, comparing z scores in 2 unpaired groups and comparing group counts, respectively. p < 0.05 was considered statistically significant. The following color scheme is used in all figures showing biological response groups; PD=blue, SD=yellow, and PR=red.

Fig. 3. Spatial distribution of immune cell subsets using CODEX.

a Multiplex IF of immune cell aggregate for a representative partial response (PR) and progressive disease (PD) case showing staining for CD4, CD8, CD20, CD68, Ki-67, Pan CK and CD31 (PR, n = 4; PD, n = 4) (b) Heatmap of the average expression of 25 markers in the different cell clusters is shown. (c) The UMAP plots for PR and PD cases shows a total of 15 cell clusters that were validated by manual inspection of multiplexed immunostains from a 25 markers panel staining using CODEX. Color- code correspond to those for each cluster in the fig. (b). d Pie graph shows percentages of most abundant cell clusters in PR and PD cases. (e, f) Neighborhood (CN) are defined based on the presence of the 15 validated clusters. A total of six CN are identified. The stacked bar graph shows distribution of each cell neighborhood between PR (n = 4) and PD (n = 4) cases. The statistical test used is two-sided pairwise t-tests on the transformed proportions, comparing PR and PD cohorts. The resulting p-values were corrected for multiple testing by the Bonferroni method. g The bar plots show average cell distance to nearest B cells from different cell subsets when comparing 25 regions of interest from a total of eight cases (PR, n = 4; PD, n = 4), each dots represent each region of interest from all PR and PD cases. Box plots represent the median, interquartile range and the whiskers represent 1.5 x the upper and lower interquartile range values. The statistical test used is two-sided Welch Two Sample t-test on the average minimum distance metric between our two patient cohorts.

Fig. 4. Pro-inflammatory changes in innate immune status after cytoreductive surgery.

a UMAP projection of myeloid cell subclusters in peripheral blood. b Dot plot indicating the. average expression of indicated genes as well as the percentage of cells expressing the gene to define myeloid subclusters. c–e Box plots of frequency of cDCs (c), HLA-DR^hi monocytes (d), and KDM6B⁺HIF1A⁺ monocytes (e), from patients who underwent surgery (n = 10) or biopsy (n = 9) comparing post-surgery or post-biopsy samples to baseline (BL). Box plots represent the median, interquartile range and the whiskers represent 1.5 x the upper and lower interquartile range values. P values indicated were analyzed using two-sided Wilcoxon signed-rank test. f, g Identity of differentially expressed genes (DEGs) in cDCs (f) and KDM6B⁺HIF1A⁺ monocytes (g) from PBMCs. P values indicated were analyzed using two-sided Wilcoxon rank-sum test and Bonferroni adjustment was performed for multiple comparisons.