Therapeutic antibodies that block the programmed death-ligand 1 (PD-L1)/programmed death-1 (PD-1) pathway can induce robust and durable responses in patients with various cancers, including metastatic urothelial cancer (mUC)1–5. However, these responses only occur in a subset of patients. Elucidating the determinants of response and resistance is key to improving outcomes and developing new treatment strategies. Here, we examined tumours from a large cohort of mUC patients treated with an anti–PD-L1 agent (atezolizumab) and identified major determinants of clinical outcome. Response was associated with CD8+ T-effector cell phenotype and, to an even greater extent, high neoantigen or tumour mutation burden (TMB). Lack of response was associated with a signature of transforming growth factor β (TGF-β) signalling in fibroblasts, particularly in patients with CD8+ T cells that were excluded from the tumour parenchyma and instead found in the fibroblast- and collagen-rich peritumoural stroma—a common phenotype among patients with mUC. Using a mouse model that recapitulates this immune excluded phenotype, we found that therapeutic administration of a TGF-β blocking antibody together with anti–PD-L1 reduced TGF-β signalling in stromal cells, facilitated T cell penetration into the centre of the tumour, and provoked vigorous anti-tumour immunity and tumour regression. Integration of these three independent biological features provides the best basis for understanding outcome in this setting and suggests that TGF-β shapes the tumour microenvironment to restrain anti-tumour immunity by restricting T cell infiltration.

Summary Background Patients with metastatic urothelial carcinoma have limited treatment options after failure of platinum-based chemotherapy. This multicenter, single-arm phase 2 trial evaluated atezolizumab, an engineered humanized IgG1 monoclonal antibody that binds selectively to programmed death–ligand 1 (PD-L1), in this population. Methods Three hundred and ten patients received atezolizumab (1200 mg, every 3 weeks). PD-L1 expression on tumor-infiltrating immune cells (IC) was prospectively assessed by immunohistochemistry. The co-primary endpoints were the objective response rate by RECIST v1.1 and immune modified RECIST. A hierarchical testing procedure was used to test whether the objective response rate was significantly higher than the historical control of 10% at alpha level of 0·05. Exploratory analyses included assessing the association between The Cancer Genome Atlas (TCGA) molecular subtypes, CD8+ T cell infiltration, mutation load, and clinical outcomes. Findings By independent review, objective response rates were 26% (95% CI 18 to 36) in the IC2/3 group, 18% (95% CI 13 to 24) in the IC1/2/3 group and 15% (95% CI 11 to 19) in all patients. With a median follow-up of 11·7 months, ongoing responses were observed in 84% of responders. The median duration of response was not reached (range 2·0*, 13·7* months, *censored). The median overall survival was 11·4 months (95% CI 9·0 to not estimable) in the IC2/3 group, 8·8 months (95% CI 7·1 to 10·6) in the IC1/2/3, and 7·9 months (95% CI 6·6 to 9·3) in all patients. Grade 3–4 related treatment-related adverse events occurred in 16% and grade 3–4 immune-mediated adverse events occurred in 5% of treated patients. Exploratory analyses showed TCGA subtypes and mutation load to be independently predictive for response to atezolizumab. Interpretation Atezolizumab demonstrated durable activity and good tolerability in this population. PD-L1 expression on immune cells was associated with response. This is the first report to show the association of TCGA subtypes with response to immune checkpoint inhibition and demonstrate the importance of mutation load as a biomarker of response to this class of agents in advanced urothelial carcinoma. Funding F. Hoffmann-La Roche Ltd.

We describe results from IMmotion150, a randomized phase 2 study of atezolizumab (anti-PD-L1) alone or combined with bevacizumab (anti-VEGF) versus sunitinib in 305 patients with treatment-naive metastatic renal cell carcinoma. Co-primary endpoints were progression-free survival (PFS) in intent-to-treat and PD-L1+ populations. Intent-to-treat PFS hazard ratios for atezolizumab + bevacizumab or atezolizumab monotherapy versus sunitinib were 1.0 (95% confidence interval (CI), 0.69-1.45) and 1.19 (95% CI, 0.82-1.71), respectively; PD-L1+ PFS hazard ratios were 0.64 (95% CI, 0.38-1.08) and 1.03 (95% CI, 0.63-1.67), respectively. Exploratory biomarker analyses indicated that tumor mutation and neoantigen burden were not associated with PFS. Angiogenesis, T-effector/IFN-γ response, and myeloid inflammatory gene expression signatures were strongly and differentially associated with PFS within and across the treatments. These molecular profiles suggest that prediction of outcomes with anti-VEGF and immunotherapy may be possible and offer mechanistic insights into how blocking VEGF may overcome resistance to immune checkpoint blockade.

In multiple sclerosis (MS4) B cell depleting therapy using monoclonal anti-CD20 antibodies, including rituximab (RTX) and ocrelizumab (OCR), effectively reduces disease activity. Based on indirect evidence, it is generally believed that elimination of the antigen presenting capabilities and antigen non-specific immune functions of B cells underlie the therapeutic efficacy. However, a small subset of T lymphocytes (T cells) was shown to also express CD20, but controversy prevails surrounding the true existence of this T cell subpopulation. Using single-cell imaging flow cytometry and expression profiling of sorted lymphocyte subsets, we unequivocally demonstrate the existence of CD3+CD20dim T cells. We show that in MS patients increased levels of CD3+CD20dim T cells are effectively depleted by RTX. The pathological relevance of this T cell subset in MS remains to be determined. However, given their potential pro-inflammatory functionality, depletion of CD20-expressing T cells may also contribute to the therapeutic effect of RTX and other monoclonal antibodies targeting CD20.

© 2019 American Association for Cancer Research T cells T cells aPDL1 MHCI and MHCII ARGI iNOS CD40 CD86 proinflammatory cytokines Phagocytosis pathways Proinflammatory Suppressive MacrophageWithout treatment, tumor macrophages maintain a suppressive phenotype.Following anti-PD-L1 treatment, increased IFN signaling remodels the macrophage compartment towards a more proinflammatory phenotype, which can enhance T-cell responses.Remodeling of the macrophage compartment is driven by IFN following anti-PD-L1 treatment. Macrophage Cancer cells ARGI IFNγIFNγ Checkpoint inhibitors like anti-PD1/PD-L1 have demonstrated significant therapeutic efficacy in a subset of patients partly through reinvigoration of CD8 T cells. However, their impact on myeloid cells remains largely unknown. Here, we report that anti-PD-L1 treatment favorably impacts the phenotype and function of tumor macrophages by polarizing the macrophage compartment toward a more proinflammatory phenotype. This phenotype was characterized by a decrease in Arginase-I (ARG1) expression and an increase in iNOS, MHCII, and CD40 expression. Whole-transcriptome profiling further confirmed extensive polarization of both tumor monocytes and macrophages from a suppressive to a proinflammatory, immunostimulatory phenotype. This polarization was driven mainly through IFNg and was associated with enhanced T-cell activity. Transfer of monocytes into anti-PD-L1treated tumor-bearing mice led to macrophage differentiation into a more proinflammatory phenotype, with an increase in CD8 T cells expressing granzyme-B and an increase in the CD8/Treg ratio compared with control-treated mice. Although in responsive tumor models, anti-PD-L1 treatment remodeled the macrophage compartment with beneficial effects on T cells, both macrophage reprogramming and depletion were needed to maximize anti-PD-L1 responses in a tumor immune contexture with high macrophage burden. Our results demonstrate that anti-PD-L1 treatment can favorably remodel the macrophage compartment in responsive tumor models toward a more proinflammatory phenotype, mainly through increased IFNg levels. They also suggest that directly targeting these cells with reprogramming and depleting agents may further augment the breadth and depth of response to anti-PD-L1 treatment in less responsive or more macrophage-dense tumor microenvironments.