High tumor mutation burden (TMB-H) has been proposed as a predictive biomarker for response to immune checkpoint blockade (ICB), largely due to the potential for tumor mutations to generate ...immunogenic neoantigens. Despite recent pan-cancer approval of ICB treatment for any TMB-H tumor, as assessed by the targeted FoundationOne CDx assay in nine tumor types, the utility of this biomarker has not been fully demonstrated across all cancers.
Data from over 10 000 patient tumors included in The Cancer Genome Atlas were used to compare approaches to determine TMB and identify the correlation between predicted neoantigen load and CD8 T cells. Association of TMB with ICB treatment outcomes was analyzed by both objective response rates (ORRs, N = 1551) and overall survival (OS, N = 1936).
In cancer types where CD8 T-cell levels positively correlated with neoantigen load, such as melanoma, lung, and bladder cancers, TMB-H tumors exhibited a 39.8% ORR to ICB 95% confidence interval (CI) 34.9-44.8, which was significantly higher than that observed in low TMB (TMB-L) tumors odds ratio (OR) = 4.1, 95% CI 2.9-5.8, P < 2 × 10−16. In cancer types that showed no relationship between CD8 T-cell levels and neoantigen load, such as breast cancer, prostate cancer, and glioma, TMB-H tumors failed to achieve a 20% ORR (ORR = 15.3%, 95% CI 9.2-23.4, P = 0.95), and exhibited a significantly lower ORR relative to TMB-L tumors (OR = 0.46, 95% CI 0.24-0.88, P = 0.02). Bulk ORRs were not significantly different between the two categories of tumors (P = 0.10) for patient cohorts assessed. Equivalent results were obtained by analyzing OS and by treating TMB as a continuous variable.
Our analysis failed to support application of TMB-H as a biomarker for treatment with ICB in all solid cancer types. Further tumor type-specific studies are warranted.
•TMB-H failed to predict improved or clinically relevant response to ICB in all cancer types.•Cancer types where TMB-H does not predict response generally show no relationship between tumor neoantigen load and CD8 T-cell infiltration.•Further studies should be carried out before application of TMB-H as a biomarker for ICB in all cancer types.
Antiangiogenic therapy resistance occurs frequently in patients with metastatic renal cell carcinoma (RCC). The purpose of this study was to understand the mechanism of resistance to sunitinib, an ...antiangiogenic small molecule, and to exploit this mechanism therapeutically. We hypothesized that sunitinib-induced upregulation of the prometastatic MET and AXL receptors is associated with resistance to sunitinib and with more aggressive tumor behavior. In the present study, tissue microarrays containing sunitinib-treated and untreated RCC tissues were stained with MET and AXL antibodies. The low malignant RCC cell line 786-O was chronically treated with sunitinib and assayed for AXL, MET, epithelial-mesenchymal transition (EMT) protein expression and activation. Co-culture experiments were used to examine the effect of sunitinib pretreatment on endothelial cell growth. The effects of AXL and MET were evaluated in various cell-based models by short hairpin RNA or inhibition by cabozantinib, the multi-tyrosine kinases inhibitor that targets vascular endothelial growth factor receptor, MET and AXL. Xenograft mouse models tested the ability of cabozantinib to rescue sunitinib resistance. We demonstrated that increased AXL and MET expression was associated with inferior clinical outcome in patients. Chronic sunitinib treatment of RCC cell lines activated both AXL and MET, induced EMT-associated gene expression changes, including upregulation of Snail and β-catenin, and increased cell migration and invasion. Pretreatment with sunitinib enhanced angiogenesis in 786-0/human umbilical vein endothelial cell co-culture models. The suppression of AXL or MET expression and the inhibition of AXL and MET activation using cabozantinib both impaired chronic sunitinib treatment-induced prometastatic behavior in cell culture and rescued acquired resistance to sunitinib in xenograft models. In summary, chronic sunitinib treatment induces the activation of AXL and MET signaling and promotes prometastatic behavior and angiogenesis. The inhibition of AXL and MET activity may overcome resistance induced by prolonged sunitinib therapy in metastatic RCC.
Sunitinib malate is an oral multitargeted tyrosine kinase inhibitor exhibiting antiangiogenic activity. Sunitinib demonstrated improved outcomes in comparison to interferon-α in a large phase III ...study of treatment naïve patients with metastatic renal cell carcinoma. Maintaining patients on sunitinib treatment is essential for a sustained disease control as higher exposure to sunitinib has been associated with an improved overall response rate, progression-free survival and overall survival. Various studies have compared the outcomes of patients undergoing sunitinib therapy based on modifications from their standard dose and schedule. Several studies have shown that switching to an alternate schedule with more frequent dose interruptions without affecting dose density over a 6-week cycle is associated with improved outcomes and increased tolerability.
Autophagy is a conserved process involved in lysosomal degradation of protein aggregates and damaged organelles. The role of autophagy in cancer is a topic of intense debate, and the underlying ...mechanism is still not clear. The hypoxia-inducible factor 2α (HIF2α), an oncogenic transcription factor implicated in renal tumorigenesis, is known to be degraded by the ubiquitin-proteasome system (UPS). Here, we report that HIF2α is in part constitutively degraded by autophagy. HIF2α interacts with autophagy-lysosome system components. Inhibition of autophagy increases HIF2α, whereas induction of autophagy decreases HIF2α. The E3 ligase von Hippel-Lindau and autophagy receptor protein p62 are required for autophagic degradation of HIF2α. There is a compensatory interaction between the UPS and autophagy in HIF2α degradation. Autophagy inactivation redirects HIF2α to proteasomal degradation, whereas proteasome inhibition induces autophagy and increases the HIF2α-p62 interaction. Importantly, clear-cell renal cell carcinoma (ccRCC) is frequently associated with monoallelic loss and/or mutation of autophagy-related gene ATG7, and the low expression level of autophagy genes correlates with ccRCC progression. The protein levels of ATG7 and beclin 1 are also reduced in ccRCC tumors. This study indicates that autophagy has an anticancer role in ccRCC tumorigenesis, and suggests that constitutive autophagic degradation of HIF2α is a novel tumor suppression mechanism.
Immune checkpoint inhibitors (ICIs) are being increasingly utilised in the front-line (1L) setting of metastatic clear-cell renal cell carcinoma (mccRCC). Limited data exist on responses and survival ...on second-line (2L) vascular endothelial growth factor–receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy after 1L ICI therapy.
This is a retrospective study of mccRCC patients treated with 2L VEGFR-TKI after progressive disease (PD) with 1L ICI. Patients were treated at MD Anderson Cancer Center or Memorial Sloan Kettering Cancer Center between December 2015 and February 2018. Objective response was assessed by blinded radiologists' review using Response Evaluation Criteria in Solid Tumours v1.1. Descriptive statistics and Kaplan–Meier method were used.
Seventy patients were included in the analysis. Median age at mccRCC diagnosis was 59 years; 8 patients (11%) had international metastatic database consortium favourable-risk disease, 48 (69%) had intermediate-risk disease and 14 (20%) had poor-risk disease. As 1L therapy, 12 patients (17%) received anti–programmed death ligand-1 (PD-(L)1) monotherapy with nivolumab or atezolizumab, 33 (47%) received nivolumab plus ipilimumab and 25 (36%) received combination anti–PD-(L)1 plus bevacizumab. 2L TKI therapies included pazopanib, sunitinib, axitinib and cabozantinib. On 2L TKI therapy, one patient (1.5%) achieved a complete response, 27 patients (39.7%) a partial response and 36 patients (52.9%) stable disease. Median progression-free survival (mPFS) was 13.2 months (95% confidence interval: 10.1, NA). Forty-five percent of subjects required a dose reduction, and twenty-seven percent of patients discontinued treatment because of toxicity.
In this retrospective study of patients with mccRCC receiving 2L TKI monotherapy after 1L ICI, we observed 2L antitumour activity and tolerance comparable to historical data for 1L TKI.
•Immunotherapy (ICI) is moving to front-line treatment in metastatic RCC for intermediate- and poor-risk patients.•Little data exists on responses to second-line (2L) TKI after front-line (1L) ICI.•Our data showed that 2L VEGFR-TKI have ORR 41% and DCR 94% after 1L ICI–containing regimen.•Median PFS on 2L VEGFR-TKI after 1L ICI in metastatic clear-cell RCC was 13.2 mo.•Safety and tolerability of 2L VEGFR-TKI after 1L ICI is typical of class effects.
Mutations in SETD2, a histone H3 lysine trimethyltransferase, have been identified in clear cell renal cell carcinoma (ccRCC); however it is unclear if loss of SETD2 function alters the genomic ...distribution of histone 3 lysine 36 trimethylation (H3K36me3) in ccRCC. Furthermore, published epigenomic profiles are not specific to H3K36me3 or metastatic tumors. To determine if progressive SETD2 and H3K36me3 dysregulation occurs in metastatic tumors, H3K36me3, SETD2 copy number (CN) or SETD2 mRNA abundance was assessed in two independent cohorts: metastatic ccRCC (n=71) and the Cancer Genome Atlas Kidney Renal Clear Cell Carcinoma data set (n=413). Although SETD2 CN loss occurs with high frequency (>90%), H3K36me3 is not significantly impacted by monoallelic loss of SETD2. H3K36me3-positive nuclei were reduced an average of ~20% in primary ccRCC (90% positive nuclei in uninvolved vs 70% positive nuclei in ccRCC) and reduced by ~60% in metastases (90% positive in uninvolved kidney vs 30% positive in metastases) (P<0.001). To define a kidney-specific H3K36me3 profile, we generated genome-wide H3K36me3 profiles from four cytoreductive nephrectomies and SETD2 isogenic renal cell carcinoma (RCC) cell lines using chromatin immunoprecipitation coupled with high-throughput DNA sequencing and RNA sequencing. SETD2 loss of methyltransferase activity leads to regional alterations of H3K36me3 associated with aberrant RNA splicing in a SETD2 mutant RCC and SETD2 knockout cell line. These data suggest that during progression of ccRCC, a decline in H3K36me3 is observed in distant metastases, and regional H3K36me3 alterations influence alternative splicing in ccRCC.
Cabozantinib prolongs overall survival (OS) and progression-free survival (PFS) in patients with metastatic clear cell renal cell carcinoma (RCC) that progressed on first-line vascular endothelial ...growth factor receptor–tyrosine kinase inhibitor (VEGFR-TKI). The role of cabozantinib has not been established in non-clear cell renal cell carcinoma (nccRCC).
This is a retrospective study of 30 patients with nccRCC who received cabozantinib from January 2013 to January 2017. Information collected included baseline characteristics, toxicity, dose reductions, PFS and OS. A fellowship trained abdominal radiologist, blinded to patient history and clinical data, assessed radiographic response using RECIST, v1.1.
With a median follow-up of 20.6 months (95% confidence interval CI: 11.4–28.8), median PFS was 8.6 months (95% CI: 6.1–14.7), and median OS was 25.4 months (95% CI: 15.5–35.4). Of the 28 patients with measurable disease, 4 had partial responses (2 papillary, 1 chromophobe and 1 unclassified RCC), 18 had stable disease (64.2%) and 6 had progressive disease (21.4%), resulting in a 14.3% objective response rate and a 78.6% disease control rate. Two patients with papillary RCC who had experienced disease progression on savolitinib achieved durable partial response and stable disease, respectively, following treatment with cabozantinib. Of the 21 patients who started cabozantinib at 60 mg/d, 12 (57.1%) required dose reduction due to toxicity.
In this retrospective study, cabozantinib produced a clinically meaningful benefit in patients with metastatic nccRCC, the majority of whom had disease progression on prior VEGFR-TKIs. Prospective trials of cabozantinib in nccRCC are warranted.
•Non-clear cell histology renal cell carcinoma (nccRCC) represents 30% of all RCC cases.•nccRCC includes papillary, chromophobe, translocation, unclassified and others.•Cabozantinib (cabo) treatment has substantial activity in metastatic nccRCC.•Disease control with cabo was found in multiple subtypes of metastatic nccRCC.
The hypoxia-regulated tumor-suppressor von Hippel-Lindau (VHL) is an E3 ligase that recognizes its substrates as part of an oxygen-dependent prolyl hydroxylase (PHD) reaction, with hypoxia-inducible ...factor α (HIFα) being its most notable substrate. Here we report that VHL has an equally important function distinct from its hypoxia-regulated activity. We find that Aurora kinase A (AURKA) is a novel, hypoxia-independent target for VHL ubiquitination. In contrast to its hypoxia-regulated activity, VHL mono-, rather than poly-ubiquitinates AURKA, in a PHD-independent reaction targeting AURKA for degradation in quiescent cells, where degradation of AURKA is required to maintain the primary cilium. Tumor-associated variants of VHL differentiate between these two functions, as a pathogenic VHL mutant that retains intrinsic ability to ubiquitinate HIFα is unable to ubiquitinate AURKA. Together, these data identify VHL as an E3 ligase with important cellular functions under both normoxic and hypoxic conditions.
Activation of the phosphoinisitide-3 kinase (PI3K) pathway through mutation and constitutive upregulation has been described in renal cell carcinoma (RCC), making it an attractive target for ...therapeutic intervention. We performed a randomized phase II study in vascular endothelial growth factor (VEGF) therapy refractory patients to determine whether MK-2206, an allosteric inhibitor of AKT, was more efficacious than the mammalian target of rapamycin inhibitor everolimus.
A total of 43 patients were randomized in a 2:1 distribution, with 29 patients assigned to the MK-2206 arm and 14 to the everolimus arm. Progression-free survival (PFS) was the primary endpoint.
The trial was closed at the first futility analysis with an observed PFS of 3.68 months in the MK-2206 arm and 5.98 months in the everolimus arm. Dichotomous response rate profiles were seen in the MK-2206 arm with one complete response and three partial responses in the MK-2206 arm versus none in the everolimus arm. On the other hand, progressive disease was best response in 44.8% of MK2206 versus 14.3% of everolimus-treated patients. MK-2206 induced significantly more rash and pruritis than everolimus, and dose reduction occurred in 37.9% of MK-2206 versus 21.4% of everolimus-treated patients. Genomic analysis revealed that 57.1% of the patients in the PD group had either deleterious TP53 mutations or ATM mutations or deletions. In contrast, none of the patients in the non-PD group had TP53 or ATM defects. No predictive marker for response was observed in this small dataset.
Dichotomous outcomes are observed when VEGF therapy refractory patients are treated with MK-2206, and MK-2206 does not demonstrate superiority to everolimus. Additionally, mutations in DNA repair genes are associated with early disease progression, indicating that dysregulation of DNA repair is associated with a more aggressive tumor phenotype in RCC.
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