Cancer immunotherapy is a validated and critically important approach for treating patients with cancer. Given the vast research and clinical investigation efforts dedicated to advancing both ...endogenous and synthetic immunotherapy approaches, there is a need to focus on crucial questions and define roadblocks to the basic understanding and clinical progress. Here, we define ten key challenges facing cancer immunotherapy, which range from lack of confidence in translating pre-clinical findings to identifying optimal combinations of immune-based therapies for any given patient. Addressing these challenges will require the combined efforts of basic researchers and clinicians, and the focusing of resources to accelerate understanding of the complex interactions between cancer and the immune system and the development of improved treatment options for patients with cancer.
In recent years, cancer immunotherapy has become a pillar in the treatment of cancer. Hegde and Chen discuss the top ten challenges facing this field, including the opportunity to optimize both synthetic and endogenous immune approaches and to target different immune suppressive mechanisms specific for each patient with cancer.
The critical role of angiogenesis in promoting tumor growth and metastasis has been well established scientifically, and consequently blocking this pathway as a therapeutic strategy has demonstrated ...great clinical success for the treatment of cancer. The holy grail however, has been the identification of patients who derive significant survival benefit from this class of agents. Here we attempt to delineate the diverse mechanisms related to anti-VEGF including its role as an anti-vascular, anti-angiogenic or an anti-permeability factor and review the most promising predictive biomarkers interrogated in large clinical trials, that identify patients who may derive significant survival advantage with VEGF inhibition. Lastly, we describe the function of VEGF as an immunomodulator and illustrate the evidence for anti-VEGF in reprogramming the tumor milieu from an immunosuppressive to an immune permissive microenvironment in human cancers, thus elucidating the role of anti-VEGF as an optimal combination partner for immune checkpoint inhibitors.
Integrated multi-omics evaluation of 823 tumors from advanced renal cell carcinoma (RCC) patients identifies molecular subsets associated with differential clinical outcomes to angiogenesis blockade ...alone or with a checkpoint inhibitor. Unsupervised transcriptomic analysis reveals seven molecular subsets with distinct angiogenesis, immune, cell-cycle, metabolism, and stromal programs. While sunitinib and atezolizumab + bevacizumab are effective in subsets with high angiogenesis, atezolizumab + bevacizumab improves clinical benefit in tumors with high T-effector and/or cell-cycle transcription. Somatic mutations in PBRM1 and KDM5C associate with high angiogenesis and AMPK/fatty acid oxidation gene expression, while CDKN2A/B and TP53 alterations associate with increased cell-cycle and anabolic metabolism. Sarcomatoid tumors exhibit lower prevalence of PBRM1 mutations and angiogenesis markers, frequent CDKN2A/B alterations, and increased PD-L1 expression. These findings can be applied to molecularly stratify patients, explain improved outcomes of sarcomatoid tumors to checkpoint blockade versus antiangiogenics alone, and develop personalized therapies in RCC and other indications.
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•Genomics of 823 RCC tumors, including 134 sarcomatoid tumors, reveals 7 subtypes•Subtype specific angiogenesis, immune, metabolic, stromal, and cell-cycle profiles•Differential prevalence of PBRM1, KDM5C, CDKN2A/2B, and TP53 alterations in subsets•Differential outcomes to VEGF blockade alone or in combination with anti-PD-L1
Motzer et al. perform integrative multi-omics analyses of 823 renal cancer tumors from a randomized clinical trial. A robust molecular classification scheme, based on transcriptional and gene alteration profiles and differential clinical outcomes to VEGF blockade alone or in combination with anti-PD-L1, informs personalized treatment strategies and future therapeutic development in RCC.
The development of human cancer is a multistep process characterized by the accumulation of genetic and epigenetic alterations that drive or reflect tumour progression. These changes distinguish ...cancer cells from their normal counterparts, allowing tumours to be recognized as foreign by the immune system. However, tumours are rarely rejected spontaneously, reflecting their ability to maintain an immunosuppressive microenvironment. Programmed death-ligand 1 (PD-L1; also called B7-H1 or CD274), which is expressed on many cancer and immune cells, plays an important part in blocking the 'cancer immunity cycle' by binding programmed death-1 (PD-1) and B7.1 (CD80), both of which are negative regulators of T-lymphocyte activation. Binding of PD-L1 to its receptors suppresses T-cell migration, proliferation and secretion of cytotoxic mediators, and restricts tumour cell killing. The PD-L1-PD-1 axis protects the host from overactive T-effector cells not only in cancer but also during microbial infections. Blocking PD-L1 should therefore enhance anticancer immunity, but little is known about predictive factors of efficacy. This study was designed to evaluate the safety, activity and biomarkers of PD-L1 inhibition using the engineered humanized antibody MPDL3280A. Here we show that across multiple cancer types, responses (as evaluated by Response Evaluation Criteria in Solid Tumours, version 1.1) were observed in patients with tumours expressing high levels of PD-L1, especially when PD-L1 was expressed by tumour-infiltrating immune cells. Furthermore, responses were associated with T-helper type 1 (TH1) gene expression, CTLA4 expression and the absence of fractalkine (CX3CL1) in baseline tumour specimens. Together, these data suggest that MPDL3280A is most effective in patients in which pre-existing immunity is suppressed by PD-L1, and is re-invigorated on antibody treatment.
The objective was to determine the safety and clinical activity of atezolizumab (MPDL3280A), a humanized programmed death-ligand 1 (PD-L1) antibody, in renal cell carcinoma (RCC). Exploratory ...biomarkers were analyzed and associated with outcomes.
Seventy patients with metastatic RCC, including clear cell (ccRCC; n = 63) and non-clear cell (ncc; n = 7) histologies, received atezolizumab intravenously every 3 weeks. PD-L1 expression was scored at four diagnostic levels (0/1/2/3) that were based on PD-L1 staining on tumor cells and tumor-infiltrating immune cells (IC) with the SP142 assay. Primary end points were safety and toxicity; secondary end points assessed clinical activity per Response Evaluation Criteria in Solid Tumors version 1.1 and immune-related response criteria. Plasma and tissue were analyzed for potential biomarkers of atezolizumab response.
Grade 3 treatment-related and immune-mediated adverse events occurred in 17% and 4% of patients, respectively, and there were no grade 4 or 5 events. Sixty-three patients with ccRCC were evaluable for overall survival (median, 28.9 months; 95% CI, 20.0 months to not reached) and progression-free survival (median, 5.6 months; 95% CI, 3.9 to 8.2 months), and 62 patients were evaluable for objective response rate (ORR; 15%; 95% CI, 7% to 26%). ORR was evaluated on the basis of PD-L1 IC expression (IC1/2/3: n = 33; 18%; 95% CI, 7% to 35%; and IC0: n = 22; 9%; 95% CI, 1% to 29%). The ORR for patients with Fuhrman grade 4 and/or sarcomatoid histology was 22% (n = 18; 95% CI, 6% to 48%). Decreases in circulating plasma markers and acute-phase proteins and an increased baseline effector T-cell-to-regulatory T-cell gene expression ratio correlated with response to atezolizumab.
Atezolizumab demonstrated a manageable safety profile and promising antitumor activity in patients with metastatic RCC. Correlative studies identified potential predictive and pharmacodynamic biomarkers. These results have guided ongoing studies and combinations with atezolizumab in RCC.
Anti-tumour immune activation by checkpoint inhibitors leads to durable responses in a variety of cancers, but combination approaches are required to extend this benefit beyond a subset of patients. ...In preclinical models tumour-derived VEGF limits immune cell activity while anti-VEGF augments intra-tumoral T-cell infiltration, potentially through vascular normalization and endothelial cell activation. This study investigates how VEGF blockade with bevacizumab could potentiate PD-L1 checkpoint inhibition with atezolizumab in mRCC. Tissue collections are before treatment, after bevacizumab and after the addition of atezolizumab. We discover that intra-tumoral CD8(+) T cells increase following combination treatment. A related increase is found in intra-tumoral MHC-I, Th1 and T-effector markers, and chemokines, most notably CX3CL1 (fractalkine). We also discover that the fractalkine receptor increases on peripheral CD8(+) T cells with treatment. Furthermore, trafficking lymphocyte increases are observed in tumors following bevacizumab and combination treatment. These data suggest that the anti-VEGF and anti-PD-L1 combination improves antigen-specific T-cell migration.
There have been no major advances for the treatment of metastatic urothelial bladder cancer (UBC) in the last 30 years. Chemotherapy is still the standard of care. Patient outcomes, especially for ...those in whom chemotherapy is not effective or is poorly tolerated, remain poor. One hallmark of UBC is the presence of high rates of somatic mutations. These alterations may enhance the ability of the host immune system to recognize tumour cells as foreign owing to an increased number of antigens. However, these cancers may also elude immune surveillance and eradication through the expression of programmed death-ligand 1 (PD-L1; also called CD274 or B7-H1) in the tumour microenvironment. Therefore, we examined the anti-PD-L1 antibody MPDL3280A, a systemic cancer immunotherapy, for the treatment of metastatic UBC. MPDL3280A is a high-affinity engineered human anti-PD-L1 monoclonal immunoglobulin-G1 antibody that inhibits the interaction of PD-L1 with PD-1 (PDCD1) and B7.1 (CD80). Because PD-L1 is expressed on activated T cells, MPDL3280A was engineered with a modification in the Fc domain that eliminates antibody-dependent cellular cytotoxicity at clinically relevant doses to prevent the depletion of T cells expressing PD-L1. Here we show that MPDL3280A has noteworthy activity in metastatic UBC. Responses were often rapid, with many occurring at the time of the first response assessment (6 weeks) and nearly all were ongoing at the data cutoff. This phase I expansion study, with an adaptive design that allowed for biomarker-positive enriched cohorts, demonstrated that tumours expressing PD-L1-positive tumour-infiltrating immune cells had particularly high response rates. Moreover, owing to the favourable toxicity profile, including a lack of renal toxicity, patients with UBC, who are often older and have a higher incidence of renal impairment, may be better able to tolerate MPDL3280A versus chemotherapy. These results suggest that MPDL3280A may have an important role in treating UBC-the drug received breakthrough designation status by the US Food and Drug Administration (FDA) in June 2014.
Close proximity between cytotoxic T lymphocytes and tumour cells is required for effective immunotherapy. However, what controls the spatial distribution of T cells in the tumour microenvironment is ...not well understood. Here we couple digital pathology and transcriptome analysis on a large ovarian tumour cohort and develop a machine learning approach to molecularly classify and characterize tumour-immune phenotypes. Our study identifies two important hallmarks characterizing T cell excluded tumours: 1) loss of antigen presentation on tumour cells and 2) upregulation of TGFβ and activated stroma. Furthermore, we identify TGFβ as an important mediator of T cell exclusion. TGFβ reduces MHC-I expression in ovarian cancer cells in vitro. TGFβ also activates fibroblasts and induces extracellular matrix production as a potential physical barrier to hinder T cell infiltration. Our findings indicate that targeting TGFβ might be a promising strategy to overcome T cell exclusion and improve clinical benefits of cancer immunotherapy.
PD-L1/PD-1 blocking antibodies have demonstrated therapeutic efficacy across a range of human cancers. Extending this benefit to a greater number of patients, however, will require a better ...understanding of how these therapies instigate anticancer immunity. Although the PD-L1/PD-1 axis is typically associated with T cell function, we demonstrate here that dendritic cells (DCs) are an important target of PD-L1 blocking antibody. PD-L1 binds two receptors, PD-1 and B7.1 (CD80). PD-L1 is expressed much more abundantly than B7.1 on peripheral and tumor-associated DCs in patients with cancer. Blocking PD-L1 on DCs relieves B7.1 sequestration in cis by PD-L1, which allows the B7.1/CD28 interaction to enhance T cell priming. In line with this, in patients with renal cell carcinoma or non-small cell lung cancer treated with atezolizumab (PD-L1 blockade), a DC gene signature is strongly associated with improved overall survival. These data suggest that PD-L1 blockade reinvigorates DC function to generate potent anticancer T cell immunity.
Abstract
Immune checkpoint inhibitors targeting the PD-1/PD-L1 axis lead to durable clinical responses in subsets of cancer patients across multiple indications, including non-small cell lung cancer ...(NSCLC), urothelial carcinoma (UC) and renal cell carcinoma (RCC). Herein, we complement PD-L1 immunohistochemistry (IHC) and tumor mutation burden (TMB) with RNA-seq in 366 patients to identify unifying and indication-specific molecular profiles that can predict response to checkpoint blockade across these tumor types. Multiple machine learning approaches failed to identify a baseline transcriptional signature highly predictive of response across these indications. Signatures described previously for immune checkpoint inhibitors also failed to validate. At the pathway level, significant heterogeneity is observed between indications, in particular within the PD-L1
+
tumors. mUC and NSCLC are molecularly aligned, with cell cycle and DNA damage repair genes associated with response in PD-L1- tumors. At the gene level, the CDK4/6 inhibitor
CDKN2A
is identified as a significant transcriptional correlate of response, highlighting the association of non-immune pathways to the outcome of checkpoint blockade. This cross-indication analysis reveals molecular heterogeneity between mUC, NSCLC and RCC tumors, suggesting that indication-specific molecular approaches should be prioritized to formulate treatment strategies.
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