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Supplementary Figure Legend from The Chemokine Receptor CXCR7 Is Highly Expressed in Human Glioma Cells and Mediates Antiapoptotic Effects

Supplementary Figure 1 from The Chemokine Receptor CXCR7 Is Highly Expressed in Human Glioma Cells and Mediates Antiapoptotic Effects

Both CXC chemokine receptor 4 (CXCR4) and atypical chemokine receptor 3 (ACKR3) are activated by the chemokine CXCL12 yet evoke distinct cellular responses. CXCR4 is a canonical G protein–coupled receptor (GPCR), whereas ACKR3 is intrinsically biased for arrestin. The molecular basis for this difference is not understood. Here, we describe cryo-EM structures of ACKR3 in complex with CXCL12, a more potent CXCL12 variant, and a small-molecule agonist. The bound chemokines adopt an unexpected pose relative to those established for CXCR4 and observed in other receptor-chemokine complexes. Along with functional studies, these structures provide insight into the ligand-binding promiscuity of ACKR3, why it fails to couple to G proteins, and its bias toward β-arrestin. The results lay the groundwork for understanding the physiological interplay of ACKR3 with other GPCRs.

Objective This study aimed to evaluate the safety of avacopan, an orally administered C5a receptor inhibitor, for the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis in addition to standard-of-care (SOC) treatment with glucocorticoids with cyclophosphamide or rituximab. Methods In this randomized 12-week study, twice daily avacopan (10 mg or 30 mg) plus SOC was assessed versus SOC only in patients with newly diagnosed/relapsing ANCA-associated vasculitis. Efficacy measurements included 50% or greater reduction in Birmingham Vasculitis Activity Score (BVAS) at day 85, rapid reduction (day 29) of BVAS to a score of 0 that was sustained through day 85, change in Vasculitis Damage Index (VDI), renal response (improvement in estimated glomerular filtration rate [eGFR], hematuria, and albuminuria), and health-related quality of life (HRQoL). Results Forty-two patients were randomized (n = 13 SOC, n = 13 avacopan 10 mg, and n = 16 avacopan 30 mg). Serious adverse events occurred in 15% and 17% of patients receiving SOC only and patients receiving avacopan with SOC, respectively. In the intent-to-treat population, BVAS response was high across arms (11 of 13 SOC, 11 of 12 avacopan 10 mg, and 12 of 15 avacopan 30 mg); increases in mean VDI were greater with SOC only than with avacopan plus SOC (0.3 versus 0.1). Avacopan 30 mg was numerically superior to placebo and avacopan 10 mg in early remission (15%, 8%, and 20% for SOC only, avacopan 10 mg, and avacopan 30 mg, respectively), improved eGFR (+2.0 ml/min/1.73m2 , +1.3 ml/min/1.73m2 , and +6.2 ml/min/1.73m2 , respectively), renal response (17%, 40%, and 63%, respectively), and measures of HRQoL. Conclusion Avacopan in addition to SOC for ANCA-associated vasculitis was well tolerated, and at the higher study dose, it appeared to improve time to remission (ClinicalTrials.gov identifier NCT02222155).

Immunotherapy directed at the PD-L1/PD-1 axis has produced treatment advances in various human cancers. Unfortunately, progress has not extended to glioblastoma (GBM), with phase III clinical trials assessing anti-PD-1 monotherapy failing to show efficacy in newly diagnosed and recurrent tumors. Myeloid-derived suppressor cells (MDSCs), a subset of immunosuppressive myeloid derived cells, are known to infiltrate the tumor microenvironment of GBM. Growing evidence suggests the CCL2–CCR2 axis is important for this process. This study evaluated the combination of PD-1 blockade and CCR2 inhibition in anti-PD-1–resistant gliomas. CCR2 deficiency unmasked an anti-PD-1 survival benefit in KR158 glioma-bearing mice. CD11b(+)/Ly6C(hi)/PD-L1(+) MDSCs within established gliomas decreased with a concomitant increase in overall CCR2(+) cells and MDSCs within bone marrow of CCR2-deficient mice. The CCR2 antagonist CCX872 increased median survival as a monotherapy in KR158 glioma-bearing animals and further increased median and overall survival when combined with anti-PD-1. Additionally, combination of CCX872 and anti-PD-1 prolonged median survival time in 005 GSC GBM-bearing mice. In both models, CCX872 decreased tumor associated MDSCs and increased these cells within the bone marrow. Examination of tumor-infiltrating lymphocytes revealed an elevated population, increased IFNγ expression, indicating enhanced cytolytic activity, as well as decreased expression of exhaustion markers in CD4(+) and CD8(+) T cells following combination treatment. These data establish that combining CCR2 and PD-1 blockade extends survival in clinically relevant murine glioma models and provides the basis on which to advance this combinatorial treatment toward early-phase human trials.

Several types of psoriasiform dermatitis are associated with increased IL-36 cytokine activity in the skin. A rare, but severe, psoriasis-like disorder, generalized pustular psoriasis (GPP), is linked to loss-of-function mutations in the gene encoding IL-36RA, an important negative regulator of IL-36 signaling. To understand the effects of IL-36 dysregulation in a mouse model, we studied skin inflammation induced by intradermal injections of preactivated IL-36α. We found the immune cells infiltrating IL-36α–injected mouse skin to be of dramatically different composition than those infiltrating imiquimod-treated skin. The IL-36α–induced leukocyte population comprised nearly equal numbers of CD4+ αβ T cells, neutrophils, and inflammatory dendritic cells, whereas the imiquimod-induced population comprised γδ T cells and neutrophils. Ligands for chemokine receptors CCR6 and CXCR2 are increased in both GPP and IL-36α–treated skin, which led us to test an optimized small-molecule antagonist (CCX624) targeting CCR6 and CXCR2 in the IL-36α model. CCX624 significantly reduced the T cell, neutrophil, and inflammatory dendritic cell infiltrates and was more effective than saturating levels of an anti–IL-17RA mAb at reducing inflammatory symptoms. These findings put CCR6 and CXCR2 forward as novel targets for a mechanistically distinct therapeutic approach for inflammatory skin diseases involving dysregulated IL-36 signaling, such as GPP.

2593 Background: The novel small molecule CCX559 is a highly potent and selective PD-L1 inhibitor that induces the dimerization and internalization of cell-surface PD-L1. CCX559, when orally administered in animal models, demonstrated anti-tumor efficacy, including the ability to induce complete responses (Li C, et al. Cancer Res 2021;81(13_Suppl): Abstract nr 1274). Safety pharmacology and toxicology studies in animals demonstrated an acceptable safety profile for CCX559. Taken together, the preclinical data supports the initiation of human trials in patients with advanced solid tumors. PD-(L)1 therapies have been shown to increase peripheral T cell activation and cytokines such as IFNγ and CXCL9 in patients (Herbst RS, et al. Nature.2014; 515(7528):563–567). Methods: This phase 1, first-in-patient, multicenter, open-label, dose-escalation study evaluates safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary anti-tumor activity of CCX559 in patients with refractory, locally advanced or metastatic solid tumors. CCX559 is dosed orally once daily with a starting dose level of 30 mg. Dose escalation/de-escalation is based on the Bayesian Optimal Interval (BOIN) design. PBMC and plasma samples were collected from patients over the first 2 cycles (6 weeks) of treatment, and PD assays were performed, including measurement of cytokines and T cell proliferation. Results: As of February 1, 2022, one patient per cohort was enrolled at the 30 mg and 60 mg levels, and 9 patients were enrolled in the 120 mg dose cohort. Of the 11 patients enrolled, 5 patients (all 120 mg cohort) remain on treatment. No DLTs, treatment-related SAEs, or severe (Grade 3 or higher) treatment-related AEs have been reported. PD assays have been performed with samples from the 30 mg (n=1), 60 mg (n=1), and 120 mg (n=3) cohorts. Patients in all three cohorts showed increased peripheral CD4 and CD8 T cell proliferation starting in the first cycle (21 days) of treatment, as measured by Ki67 positivity. Increases in plasma IFNγ, CXCL9, CXCL10, and CXCL11 levels were observed, in particular in one patient (120 mg cohort) starting 15 days after treatment initiation. Conclusions: Initial results from the phase 1 dose-escalation study of CCX559 indicate on-target PD effects consistent with PD-L1 inhibition. Updated PD data, together with the safety and PK profile, will be presented. Clinical trial information: ACTRN12621001342808.

Background and Aims Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis is a life- or organ-threatening condition in which patients experience severe inflammation of small arteries. Renal involvement is common in ANCA-associated vasculitis and is correlated with high morbidity and mortality. Current treatment regimens have limited efficacy for renal disease in patients presenting with organ- or life-threatening ANCA-associated vasculitis. Avacopan, a novel orally-administered antagonist of the complement fragment C5a receptor (C5aR), was evaluated through a Phase 3 trial in patients with ANCA vasculitis. Efficacy and safety results have been previously reported; this abstract provides details of the effects on renal function in patients with renal involvement. Method The ADVOCATE trial was a randomized, double-blind, active controlled, double-dummy, 52-week treatment Phase 3 trial of 331 patients with ANCA-associated vasculitis. Patients were randomized 1:1 and received either a standard daily prednisone dosing with taper (i.e., starting at 60 mg / day tapered to 0 mg by Week 21), or daily avacopan. Background therapy included either: a) cyclophosphamide (oral or IV) followed by azathioprine, or, b) rituximab (four IV infusions). Patients with active glomerulonephritis at baseline were included in this analysis. Kidney function was analyzed based on the following parameters, which were assessed at pre-specified time-points: changes in the urine albumin-to-creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and Urinary Monocyte Chemoattractant Protein-1 (MCP-1):Creatinine ratio. Results At the baseline visit, 265 patients had renal disease. eGFR improved more in the avacopan group (n=131) compared to the prednisone group (n=134). At Week 26, eGFR increased 5.8 mL/min/1.73 m2 (from a baseline of 44.6 mL/min/1.73 m2), compared to 2.9 mL/min/1.73 m2 in the prednisone group (from a baseline of 45.6 mL/min/m2), P=0.046. At Week 52, the increases in eGFR were 7.3 mL/min/1.73 m2 and 4.1 mL/min/1.73 m2, respectively, P=0.029. The improvement was most prominent in subjects with Stage 4 kidney disease at baseline (eGFR Conclusion Treatment with avacopan in patients with ANCA-associated vasculitis with renal disease led to greater recovery in eGFR when compared to standard prednisone therapy, especially in patients with Stage 4 kidney disease (eGFR

Background and Aims Primary Focal Segmental Glomerulosclerosis (FSGS) is the most common primary glomerular disease in patients with end stage renal disease in the United States. Current treatment regimens target reduction in proteinuria, but may have limited response or exhibit disease recurrence. CCX140 is an orally-administered selective small molecule inhibitor of the C-C chemokine receptor 2 (CCR2) under investigation for the treatment reduction of proteinuria in patients with FSGS. The primary objectives of this study were to evaluate the safety and efficacy of CCX140 in patients with FSGS and a urine protein to creatinine ratio (UPCR) of ≥1 g/g. Efficacy was assessed by the change in UPCR. Method Forty-six adult patients with primary or genetic FSGS were randomized into a double-blind, placebo-controlled Phase 2 dose-ranging study designed to evaluate the safety and efficacy of CCX140. Changes of urinary protein excretion estimation (UPCR) from baseline to Week 12 were measured in four blinded treatment groups (three active CCX140 doses of 5 mg once daily, 10 mg and 15 mg twice-daily (BID) vs placebo). Starting at Week 12, all subjects including those in the placebo group received the CCX140, 15 mg BID for an additional 12 weeks, and UPCR changes from Week 12 to Week 24 were assessed. There was a 4-week follow-up period from Week 24 to Week 28 where no CCX140 was administered. Results In the intent to treat (ITT) analysis of UPCR changes at Week 12 relative to baseline, the 15 mg BID CCX140 group exhibited the greatest reduction of UPCR (median reduction from baseline 0.9 g/g or approximately 30%, and approximately 25% reduction from baseline for the geometric mean), but that did not differ significantly from the placebo group (median reduction from baseline 0.45 g/g; or approximately 22%, and approximately 23% reduction from baseline for the geometric mean). Also, after crossover of the blinded portion of the trial to 15 mg BID active dosing, the previous placebo group did not appear to exhibit an additional reduction of UPCR. CCX140 at all doses was well-tolerated, with no serious adverse events (SAEs) during the blinded trial and a numerically lower rate of treatment-emergent adverse events in the CCX140 treatment groups. Conclusion In the study, CCX140 did not demonstrate a therapeutically meaningful reduction in proteinuria relative to the control group after 12 weeks of blinded treatment. The study provides insights into the natural disease progression of patients with primary or genetic FSGS as part of a clinical trial setting.

Background and Aims Diabetic nephropathy (DN) is a syndrome characterized by pathological levels of proteinuria, glomerular lesions and reduction in the glomerular filtration rate (GFR) in diabetic patients. Several lines of evidence support a role of CCR2 in the pathogenesis of DN. Recent studies have demonstrated that existing small molecule CCR2 antagonists can be placed in two classes, distinguished by their interaction with one of two distinct binding sites on CCR2: an extracellular site for which antagonists compete directly with native ligands (the orthosteric site), or an intracellular allosteric binding site. To better understand the functional differences between these antagonists we compared an example of each class in a murine model of DN. Our results revealed that the allosteric, but not the orthosteric CCR2 inhibitors ameliorated the proteinuria and improved glomerular histopathology in this model of DN. Method We used db/db mice to model DN. Several structurally distinct CCR2 inhibitors with that bind to either the allosteric (CCR2-RA-[R] and CCX872) or orthosteric (MK-0812 and CCX598) sites were compared. Pharmacokinetic (PK) properties and renal functional parameters were assessed, including trough drug levels and proteinuria (urinary albumin excretion rate UAER; urine albumin creatinine ratio UACR). Histopathology and electron microscopy (EM) were performed to assess any potential tissue-protective effects of the antagonists. Results Both the allosteric inhibitors (CCR2-RA-[R] and CCX872) and the orthosteric inhibitors (MK-0812 and CCX598) were potent CCR2 antagonists with desirable PK in mouse in so far as both classes effectively blocked CCR2-mediated monocyte migration into the peritoneal cavity in the thioglycollate-induced peritonitis model. At comparable drug coverage levels, CCR2-RA-[R] and CCX872 rapidly and significantly reduced UAER/UACR (CCX872: 70 % at day 7 vs vehicle, p Conclusion Allosteric antagonists of CCR2 provide significant and rapid renal protection in the db/db murine model of DN, as evidenced by improvements in renal function and histological parameters, while potent orthosteric CCR2 antagonists were not effective in the model. Our data suggest that targeting the effectiveness of CCR2 antagonists in DN are directly dependent on binding to the allosteric site of CCR2.

Background and Aims Complement fragment C5a is strongly linked to the pathogenesis of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The C5a receptor (C5aR), is a G protein-coupled receptor present on neutrophils. Avacopan (previously CCX168) is an orally-administered selective antagonist of C5aR which blocks C5a-induced cell activation. Two previous Phase 2 clinical trials provided evidence of effectiveness of avacopan in AAV. This Phase 3 study evaluated the efficacy and safety of avacopan for the treatment of AAV as well as the potential of avacopan to eliminate extensive use of glucocorticoids (GC) and GC-related toxicities. Method Eligible subjects were randomized 1:1 to receive either prednisone or avacopan in combination with either a) cyclophosphamide (oral or IV) followed by azathioprine or b) rituximab (four IV infusions). Randomization was stratified by the treatment regimen (rituximab, IV cyclophosphamide, or oral cyclophosphamide), ANCA serotype, and newly-diagnosed or relapsing disease. Treatment period was 52 weeks; primary efficacy endpoints were the proportion of subjects achieving disease remission at Week 26, and sustained disease remission at Week 52. Remission was defined as a Birmingham Vasculitis Activity Score (BVAS) of zero and not taking glucocorticoids for AAV within 4 weeks prior to Week 26. Sustained remission was defined as being in remission at Week 26 and sustained through Week 52 without relapse. Change in estimated glomerular filtration rate (eGFR) from baseline to week 52 was a pre-specified secondary endpoint. Results 330 subjects were randomized and dosed: 166 in the avacopan and 164 in the prednisone groups. At Week 26, 72.3% subjects achieved remission in the avacopan compared to 70.1% in the prednisone group (p The avacopan arm had a significant reduction in glucocorticoid-related toxicity compared to the prednisone arm as measured by the Glucocorticoid Toxicity Index of Cumulative Worsening Score (p=0.0002) and Aggregate Improvement Score (p=0.0082). In subjects with renal disease at baseline, the avacopan group (n=134) showed a mean increase in eGFR of 7.3 mL/min/1.73 m2 from baseline to week 52 as compared to 4.1 mL/min/1.73 m2 increase in the prednisone group (n=132) (p=0.029). A pre-specified sub-group analysis showed a greater difference in the avacopan sub-group with a baseline eGFR Conclusion Treatment with avacopan resulted in remission in patients with AAV receiving rituximab or cyclophosphamide/azathioprine at a rate that was non-inferior to the active comparator prednisone at Week 26 and superior to prednisone in sustained remission at Week 52. A significant reduction in glucocorticoid-related toxicity was observed in the avacopan vs. prednisone arms. The increase in eGFR seen with avacopan was marked among subjects with more severe renal disease. The safety profile of avacopan was acceptable for use in patients with AAV. The ADVOCATE trial demonstrated avacopan is an effective treatment for patients with AAV.

Background and Aims We have recently demonstrated that small molecule inhibitors of CCR2 rapidly reduced proteinuria and preserved renal structure in animal models of diabetic nephropathy (DN) and focal segmental glomerular sclerosis (FSGS). Similar beneficial effects of CCR2 inhibition were also observed in DN patients in a large diabetic nephropathy Phase 2 clinical trial. Despite its rapid and robust effects in these kidney diseases, the mechanism by which CCR2 inhibition affords such renal protection remains unclear. CCR2 is well-known to be expressed on cells of the immune system, where it mediates inflammation and immunological functions by controlling the trafficking of monocytes and T cells. However, immune cell expression of CCR2 may not adequately explain the rapid pharmacologic benefits of CCR2 inhibitors in DN and FSGS because these diseases do not exhibit appreciable kidney inflammation. To better understand the protective mechanism(s) of CCR2 inhibition in renal diseases, we have used a variety of in vivo nephropathy models to determine if CCR2 is expressed on kidney parenchymal cells. Our results suggest that a subset of CD45 negative, renal parietal epithelial cells express CCR2. Method To characterize CCR2 expression in the kidney we used CCR2 RFP heterozygous mice (CCR2RFP/+) in which one copy of CCR2 was replaced by red fluorescent protein (RFP), whose expression is under the control of the endogenous CCR2 promoter. This approach provided a highly sensitive method for CCR2 detection by both flow cytometry and immunofluorescence, and compensated for the lack of validated, commercially available anti-CCR2 antibodies. Enriched glomerular cells were obtained by a non-enzymatic disruption of kidneys, followed by centrifugation at low speed (80gs), and sieving through 300µm and 150µm meshes. The Adriamycin (ADR)-nephropathy model with CCR2 RFP heterozygous mice was used to determine CCR2 expression on renal cells. 5/6 nephrectomy models of FSGS, as well as the db/db diabetic nephropathy model were used to access the change of activated parietal epithelial cells and proteinuria, both in the presence and absence of a CCR2 inhibitor in the setting of kidney injury. Results We observed dramatic increases in the number of activated parietal epithelial cells (PECs, identified as CD133+CD24+CD44hi cells by flow cytometry) in all three renal disease models. In the ADR nephropathy model, we found that in 30-40% of activated PEC cells within an enriched population of glomerular cells expressed CCR2/RFP. CD44hi RFP+ increased much more dramatically than CD44hi RFP- cells in response to ADR, and this was highly correlated with proteinuria, suggesting that CCR2 plays an important role in PEC cell activation and kidney pathology in ADR induced kidney injury. Furthermore, we found that blocking CCR2 with the CCR2-specific antagonist CCX872 significantly reduced both proteinuria and the number of activated PECs in the 5/6 nephropathy and db/db diabetic nephropathy models. Conclusion This is the first report that CCR2 is present on a subset of activated renal PECs. This population is markedly upregulated during kidney injury in a variety of murine models of nephropathy. Changes in the abundance CCR2+ activated PECs in the glomerular enriched preparations in response to CCR2 inhibition suggests that CCR2 antagonism may represent a novel approach for the treatment of chronic kidney disease.

Emerging evidence suggests that cancer cell metabolism can be regulated by cancer-associated fibroblasts (CAFs), but the mechanisms are poorly defined. Here we show that CAFs regulate malignant cell metabolism through pathways under the control of FAK. In breast and pancreatic cancer patients we find that low FAK expression, specifically in the stromal compartment, predicts reduced overall survival. In mice, depletion of FAK in a subpopulation of CAFs regulates paracrine signals that increase malignant cell glycolysis and tumour growth. Proteomic and phosphoproteomic analysis in our mouse model identifies metabolic alterations which are reflected at the transcriptomic level in patients with low stromal FAK. Mechanistically we demonstrate that FAK-depletion in CAFs increases chemokine production, which via CCR1/CCR2 on cancer cells, activate protein kinase A, leading to enhanced malignant cell glycolysis. Our data uncover mechanisms whereby stromal fibroblasts regulate cancer cell metabolism independent of genetic mutations in cancer cells., Cancer associated fibroblasts (CAFs) have been suggested to regulate cancer cell metabolism, but the mechanisms are not completely elucidated. Here, the authors show that low FAK expression in stromal cells correlates with poor prognosis in breast and pancreatic cancer patients and that FAK-silencing in CAFs promotes tumourigenesis by the paracrine regulation of cancer cell metabolism.

Nonalcoholic fatty liver disease (NAFLD) is a common disease, closely associated with obesity and insulin resistance. We investigated the presence of a subset of myeloid cells associated with metabolic disturbance in the liver of patients with NAFLD and a murine model of obesity-induced liver disease. Gene and protein expression in liver and serum was investigated with RT-PCR or ELISA and correlated to clinical disease. Liver-infiltrating immune cells were isolated from normal or diseased human liver for flow cytometric analysis. In animal experiments, mice were fed a high-fat diet (60% of calories from fat) for 16 wk, or high-fat diet with 30% fructose for 32 wk to induce steatohepatitis and fibrosis. A small molecule inhibitor of CC chemokine receptor 2 (CCR2), CCX872, was administered to some mice. A subset of CD11c+CD206+ immune cells was enriched in human liver tissue, and greater infiltration was observed in NAFLD. The presence of CD11c+CD206+ myeloid cells correlated with systemic insulin resistance. CD11c+CD206+ cells expressed high levels of CCR2, and liver CC chemokine ligand 2 (CCL2) expression was increased in nonalcoholic steatohepatitis and correlated with disease activity. In mice, CCR2 inhibition reduced infiltration of liver CD11b+CD11c+F4/80+ monocytes, which are functional homologs of human CD11c+CD206+ cells, and improved liver injury and glycemic control. A role for CCR2/CCL2 in human NAFLD has long been postulated. These data confirm a role for this chemokine/receptor axis, through mediating adipose and hepatic infiltration of myeloid cells. Inhibition of CCR2 improved hepatic inflammation and fibrosis in murine models of NAFLD. These data confirm the rationale for targeting CCR2 to treat NAFLD. NEW & NOTEWORTHY These data show for the first time that CD11c+CD206+ myeloid cells, previously associated with human adipose tissue inflammation, infiltrate into liver tissue in nonalcoholic fatty liver disease. These cells express CCR2. Inhibition of CCR2 in mice inhibits hepatic inflammation caused by a murine homolog of these myeloid cells and improves experimental liver disease.

Previous studies have shown that increased levels of chemokine receptor CXCR7 are associated with the increased invasiveness of prostate cancer cells. We now show that CXCR7 expression is upregulated in VCaP and C4‐2B cells after enzalutamide (ENZ) treatment. ENZ treatment induced apoptosis (sub‐G1) in VCaP and C4‐2B cells, and this effect was further increased after combination treatment with ENZ and CCX771, a specific CXCR7 inhibitor. The levels of p‐EGFR (Y1068), p‐AKT (T308) and VEGFR2 were reduced after ENZ and CCX771 combination treatment compared to single agent treatment. In addition, significantly greater reductions in migration were shown after combination treatment compared to those of single agents or vehicle controls, and importantly, similar reductions in the levels of secreted VEGF were also demonstrated. Orthotopic VCaP xenograft growth and subcutaneous MDA133‐4 patient‐derived xenograft (PDX) tumor growth was reduced by single agent treatment, but significantly greater suppression was observed in the combination treatment group. Although overall microvessel densities in the tumor tissues were not different among the different treatment groups, a significant reduction in large blood vessels (>100 μm2) was observed in tumors following combination treatment. Apoptotic indices in tumor tissues were significantly increased following combination treatment compared with vehicle control‐treated tumor tissues. Our results demonstrate that significant tumor suppression mediated by ENZ and CXCR7 combination treatment may be due, in part, to reductions in proangiogenic signaling and in the formation of large blood vessels in prostate cancer tumors., What's new? Despite promising initial responses to androgen deprivation therapy, advanced prostate cancer eventually progresses to metastatic castration‐resistant disease in the majority of men. This increased aggressiveness in tumor behavior is associated with elevated expression of chemokine receptor CXCR7. Here, in VCaP and C4‐2B prostate cancer cell lines, combined treatment with the androgen receptor signaling inhibitor enzalutamide (ENZ) and the CXCR7 inhibitor CCX771 was found to enhance apoptosis and suppress cell motility, invasion and proangiogenic signaling. Experiments in orthotopic VCaP xenograft and subcutaneous MDA133‐4 patient‐derived xenograft models corroborated observations in cells and demonstrated significant reductions in blood vessel formation.

Introduction: Cancer cells can escape tumor-specific T cell responses via engagement of inhibitory immune checkpoints. PD-L1/PD-1 interaction is one of the major checkpoints that limit effector T cell function against cancer cells, and monoclonal antibodies that block this interaction have been approved as therapies in multiple tumor indications. As a next generation therapy, small molecule inhibitors of PD-L1 potentially have advantageous properties compared to approved monoclonal antibodies, such as better penetration into solid tumors, reduced immunogenicity, lack of Fc-mediated side effects, convenience of oral administration, and lower cost of goods. We therefore embarked on an effort to identify and develop an orally available small molecule capable of targeting PD-L1/PD-1 interactions. Methods: Inhibition of the PD-L1/PD-1 interaction was measured using a binding assay, followed by a cell culture system assessing PD-1 inhibition of T cell receptor (TCR) activation. Human T cell responses were assessed in vitro using the mixed lymphocyte reaction (MLR) assay, and a human peripheral blood mononuclear cell (PBMC)-mediated tumor cell killing assay. For in vivo studies CCX559 was dosed orally in a syngeneic tumor model and in a human tumor cell/PBMC co-implantation model in immune deficient mice. Results: Using structural information and focused medicinal chemistry, we identified CCX559 as a potent inhibitor of PD-L1 interaction with PD-1. CCX559 prevented PD-L1/PD-1 inhibition of TCR signaling in a cell-based reporter assay, increased IFNγ secretion in allogeneic MLR assays, and increased tumor cell killing by human PBMCs. We demonstrated that CCX559 potentially employs multiple mechanisms to inhibit PD-L1, which are distinct from those published for human anti-PD-L1 antibodies. In murine tumor models, orally administered CCX559 reduced tumor growth similarly to a clinically-approved anti-human PD-L1 antibody. Summary: CCX559 is a highly potent, small molecule PD-L1 inhibitor that can be orally administered. CCX559 enhanced primary human T cell activity in vitro and demonstrated anti-tumor efficacy in two murine tumor models. Based on its unique mechanism of PD-L1 inhibition, strong anti-tumor activity, desirable drug properties, and good safety profile, we plan to advance CCX559 into clinical development in the first half of 2021. Citation Format: Chris Li, Marta Vilalta, Linda S. Ertl, Yu Wang, Yibin Zeng, Pingchen Fan, Christopher Lange, Darren McMurtrie, Ju Yang, Rebecca Lui, Ryan Scamp, Vicky Chhina, Alice Kumamoto, Ryan Ong, Ton Dang, Ashton Easterday, Niky Zhao, Shirley Liu, Rajinder Singh, Israel Charo, Kathleen Sullivan, Thomas J. Schall, Penglie Zhang. CCX559 is a potent orally-administered small molecule PD-L1 inhibitor that induces anti-tumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1274.

Alternative C activation is involved in the pathogenesis of ANCA-associated vasculitis. However, glucocorticoids used as treatment contribute to the morbidity and mortality of vasculitis. We determined whether avacopan (CCX168), an orally administered, selective C5a receptor inhibitor, could replace oral glucocorticoids without compromising efficacy. In this randomized, placebo-controlled trial, adults with newly diagnosed or relapsing vasculitis received placebo plus prednisone starting at 60 mg daily (control group), avacopan (30 mg, twice daily) plus reduced-dose prednisone (20 mg daily), or avacopan (30 mg, twice daily) without prednisone. All patients received cyclophosphamide or rituximab. The primary efficacy measure was the proportion of patients achieving a ≥50% reduction in Birmingham Vasculitis Activity Score by week 12 and no worsening in any body system. We enrolled 67 patients, 23 in the control and 22 in each of the avacopan groups. Clinical response at week 12 was achieved in 14 of 20 (70.0%) control patients, 19 of 22 (86.4%) patients in the avacopan plus reduced-dose prednisone group (difference from control 16.4%; two-sided 90% confidence limit, −4.3% to 37.1%; P=0.002 for noninferiority), and 17 of 21 (81.0%) patients in the avacopan without prednisone group (difference from control 11.0%; two-sided 90% confidence limit, −11.0% to 32.9%; P=0.01 for noninferiority). Adverse events occurred in 21 of 23 (91%) control patients, 19 of 22 (86%) patients in the avacopan plus reduced-dose prednisone group, and 21 of 22 (96%) patients in the avacopan without prednisone group. In conclusion, C5a receptor inhibition with avacopan was effective in replacing high-dose glucocorticoids in treating vasculitis.

C-C chemokine receptor 2 (CCR2) is a key driver of monocyte/macrophage trafficking to sites of inflammation and has long been considered a target for intervention in autoimmune disease. However, systemic administration of CCR2 antagonists is associated with marked increases in CCL2, a CCR2 ligand, in the blood. This heretofore unexplained phenomenon complicates interpretation of in vivo responses to CCR2 antagonism. We report that CCL2 elevation after pharmacological CCR2 blockade is due to interruption in a balance between CCL2 secretion by a variety of cells and its uptake by constitutive internalization and recycling of CCR2. We observed this phenomenon in response to structurally diverse CCR2 antagonists in wild-type mice, and also found substantially higher CCL2 plasma levels in mice lacking the CCR2 gene. Our findings suggest that CCL2 is cleared from blood in a CCR2-dependent but G protein (Gαi, Gαs or Gαq/11)–independent manner. This constitutive internalization is rapid: on a given monocyte, the entire cell surface CCR2 population is turned over in

INTRODUCTION Immuno-therapy directed at the PD-1/PD-L1 axis has yielded significant treatment advances in various human cancers. However, these outcomes have not extended to glioblastoma (GBM), wit...

Introduction: Antibody-based therapies targeting the Programmed cell Death-1/ Programmed Death-Ligand 1 (PD-1/PD-L1) immune checkpoint axis have achieved great success in cancer immunotherapy in recent years. As a next generation therapy, small molecule inhibitors of PD-1/PD-L1 offer the potential for increased tumor penetration, shorter half-life (to better manage immune related adverse events), and lower cost. We therefore embarked on an effort to identify and develop orally available small molecules capable of targeting PD-L1. Methods: We designed and optimized a number of small molecule PD-L1 inhibitors which potently disrupted the interaction of PD-1 with PD-L1. Active compounds were first profiled by an ELISA assay measuring inhibition of the PD-1/PD-L1 interaction, followed by a functional cell-based reporter assay, mixed lymphocyte reaction (MLR) assay, and human peripheral blood mononuclear cell (PBMC)-mediated tumor cell killing assay. Targeted medicinal chemistry efforts were employed to improve potency and oral bioavailability, and candidate compounds were then evaluated in murine tumor models. Due to the specific reactivity of these compounds to human PD-L1 (but not murine PD-L1), a syngeneic tumor model with murine MC-38 colon tumor cells expressing human PD-L1 (MC38-hPD-L1 tumor model) was used. Results: The optimized PD-L1 inhibitors were highly potent in cell-based reporter assay, the MLR assay and PBMC-mediated tumor cell killing assays. These compounds also possess high oral bioavailability and desirable safety profiles. In the MC38-hPD-L1 tumor model, Lead compounds potently reduced tumor growth similarly to an anti-human PD-L1 antibody, which was used as a positive control for the experiments. The tumor microenvironment analysis by flow cytometry demonstrated that these compounds almost completely occupied human PD-L1 on the tumor cells in vivo, and thus could potently block the interaction of PD-1/PD-L1 and enhance the immune responses against tumor. Summary: We have identified and advanced unique small molecule inhibitors of human PD-L1 by rational design and optimization. Molecules resulting from these efforts exhibited marked inhibition of the PD-1/PD-L1 interaction and signaling in vitro, and potent anti-tumor effects in an animal model. Citation Format: Shijie "Chris" Li, Marta Vilalta, Linda S. Ertl, Yu Wang, Yibin Zeng, Pingchen Fan, Christopher Lange, Darren McMurtrie, Ju Yang, Rebecca Lui, Ryan Ong, Vicky Chhina, Alice Kumamoto, Simon Yau, Ton Dang, Ashton Easterday, Shirley Liu, Rajinder Singh, Israel Charo, Thomas J. Schall, Penglie Zhang. Anti-tumor effect of orally available small molecule PD-L1 inhibitors in a murine model of colon adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5693.

Enhanced blood vessel (BV) formation is thought to drive tumor growth through elevated nutrient delivery. However, this observation has overlooked potential roles for mural cells in directly affecting tumor growth independent of BV function. Here we provide clinical data correlating high percentages of mural-β3-integrin-negative tumor BVs with increased tumor sizes but no effect on BV numbers. Mural-β3-integrin loss also enhances tumor growth in implanted and autochthonous mouse tumor models with no detectable effects on BV numbers or function. At a molecular level, mural-cell β3-integrin loss enhances signaling via FAK-p-HGFR-p-Akt-p-p65, driving CXCL1, CCL2, and TIMP-1 production. In particular, mural-cell-derived CCL2 stimulates tumor cell MEK1-ERK1/2-ROCK2-dependent signaling and enhances tumor cell survival and tumor growth. Overall, our data indicate that mural cells can control tumor growth via paracrine signals regulated by β3-integrin, providing a previously unrecognized mechanism of cancer growth control.

Background:Complement fragment C5a is strongly linked to the pathogenesis of Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated vasculitis (AAV). C5a receptor (C5aR), present on neutrophils, is a G protein-coupled receptor for C5a. Avacopan (previously CCX168) is an orally-administered selective antagonist of C5aR which blocks C5a-induced cell activation. Two previous Phase 2 clinical trials provided evidence of effectiveness of avacopan in AAV and its potential to eliminate extensive use of glucocorticoids (GC) and GC-related toxicities.Objectives:This Phase 3 study evaluated the efficacy and safety of avacopan for the treatment of AAV.Methods:Eligible subjects were randomized 1:1 to receive either prednisone or avacopan in combination with either a) cyclophosphamide (oral or IV) followed by azathioprine or b) rituximab (four IV infusions). Randomization was stratified by the treatment regimen (rituximab, IV cyclophosphamide, or oral cyclophosphamide), ANCA serotype, and newly-diagnosed or relapsing disease. Treatment period was 52 weeks; primary efficacy endpoints were the proportion of subjects achieving disease remission at Week 26, and sustained disease remission at Week 52. Remission was defined as a Birmingham Vasculitis Activity Score (BVAS) of zero and not taking glucocorticoids for AAV within 4 weeks prior to Week 26. Sustained remission was defined as being in remission at Week 26 and also subsequently in remission as defined above at Week 52. Any relapse of AAV between Weeks 26 and 52 was considered not achieving sustained remission.Results:330 subjects were randomized and dosed: 166 in avacopan and 164 in prednisone arms. At Week 26, 72.3% subjects achieved remission in the avacopan arm compared to 70.1% in the prednisone arm (pThe avacopan arm had a significant reduction in glucocorticoid-related toxicity compared to the prednisone arm as measured by the Glucocorticoid Toxicity Index (GTI) of Cumulative Worsening Score (p=0.0002) and Aggregate Improvement Score (p=0.0082).In subjects with renal disease at baseline, the avacopan arm showed a mean increase in estimated glomerular filtration rate (eGFR) of 7.3 mL/min/1.73 m2 from baseline to week 52 as compared to 4.0 mL/min/1.73 m2 increase in the prednisone arm (p=0.0259).Overall subject incidence of serious adverse events (SAEs) was generally consistent with previous AAV trials at 45.1% and 42.2% for prednisone and avacopan groups, respectively. Serious infections were 15.2% and 13.3%, serious hepatic adverse events 3.7% vs 5.4%, and SAEs of white blood cell count decreases were 4.9% vs 2.4% for prednisone and avacopan, respectively. No meningococcal infections were reported.Conclusion:Avacopan treatment resulted in remission in AAV patients receiving rituximab or cyclophosphamide/azathioprine at a rate that was non-inferior to the active comparator prednisone at week 26 and superior to prednisone in sustained remission at Week 52. A significant reduction in glucocorticoid-related toxicity was observed in the avacopan vs. prednisone arms. Significant increase in eGFR in subjects with renal disease was also observed in avacopan vs. prednisone. The safety profile of avacopan appears acceptable for development in AAV. Avacopan treatment for AAV is efficacious and exhibits benefits not seen with chronic prednisone therapy.References:None.Disclosure of Interests:Peter A Merkel Grant/research support from: AstraZeneca, Boeringher-Ingelheim, Bristol-Myers Squibb, Celgene, ChemoCentryx, Forbius, Genentech/Roche, Genzyme/Sanofi, GlaxoSmithKline, InflaRx, Kypha, TerumoBCT, Consultant of: Abbvie, AstraZeneca, Biogen, Boeringher-Ingelheim, Bristol-Myers Squibb, Celgene, ChemoCentryx, CSL Behring, Forbius, Genentech/Roche, Genzyme/Sanofi, GlaxoSmithKline, InflaRx, Insmed, Jannsen, Kiniksa, Pfizer, Sparrow, Talaris, David Jayne Grant/research support from: ChemoCentryx, GSK, Roche/Genentech, Sanofi-Genzyme, Consultant of: Astra-Zeneca, ChemoCentryx, GSK, InflaRx, Takeda, Insmed, Chugai, Boehringer-Ingelheim, Huibin Yue Shareholder of: ChemoCentryx, Employee of: ChemoCentryx, Thomas Schall Shareholder of: ChemoCentryx, Employee of: ChemoCentryx, Catherine Kelleher Shareholder of: Amgen, ChemoCentryx, Inc., Grant/research support from: Not active, Consultant of: Independent Consultant in the past, Employee of: ChemoCentryx, Inc., Pirow Bekker Shareholder of: Stock options ChemoCentryx, Consultant of: ChemoCentryx, Employee of: ChemoCentryx

The development of anti-TNFα immunotherapies has led to great advances in quality of life for Crohn’s and colitis patients, and has allowed a reduction in steroid use for these diseases. However, a significant proportion of IBD patients is resistant to anti-TNFα agents, or becomes resistant over time. Preclinical research and clinical trials suggest that CCR9 antagonism can effectively reduce colon inflammation. CCR9 is expressed on a subset of T cells dedicated to intestinal trafficking. Antagonism of this receptor inhibits the accumulation of T cells within inflamed intestinal epithelium and lamina propria. Since anti-TNFα and CCR9 antagonists act through entirely different mechanisms, we asked whether these two approaches might synergize and expand the effectiveness and scope of each therapy. We used a piroxicam-accelerated version of the MDR1a−/− spontaneous colitis model in mice. We have found that combined dosing of piroxicam-fed MDR1a−/− mice with a CCR9 antagonist and an anti-TNFα MAb significantly reverses loss of body weight, diarrhea score and colon inflammation. The combined dosing was more effective than anti-TNFα or CCR9 antagonist alone, as measured by colon length/weight ratio, neutrophil accumulation in the colonic epithelium and reversal of the loss in body weight characteristic of this model. These data suggest that combining a CCR9 antagonist with existing anti-TNFα treatment regimens may extend the benefits of anti-TNFα immunotherapy to a larger class of patients suffering from IBD, and may prolong the effectiveness of anti-TNFα immunotherapy for those patients already undergoing such treatments.

Introduction: Chemokines and their receptors influence many of the hallmark processes in cancer: they act not only on infiltrating leukocytes, but also on fibroblasts, endothelial cells, and directly on some types of tumor cells. C-C chemokine receptor 4 (CCR4) and its ligands have been found to be highly expressed in multiple types of human tumors and are associated with poor prognosis. CCR4 antagonism has been demonstrated to reduce tumor growth in various mouse tumor models. Here we assess small-molecule inhibition of CCR4 as a therapeutic agent to potentiate the effects of checkpoint inhibitors in the CT26 and KCM tumor models. Methods: The subcutaneous CT26 colon cancer model and the orthotopic KCM pancreatic cancer model were used to assess the effects of a CCR4 inhibitor, CCX6239, in combination with anti-CTLA-4 antibody. CT26 cells were implanted into the flanks of 9wk female Balb/c mice. Mice were randomized into study groups based on the tumor sizes on day 6, and dosing of both CCX6239 and anti-CTLA-4 started on day 7. For the orthotopic pancreatic cancer model, KCM cells were implanted directly into the pancreas, and dosing of CCX6239 and anti-CTLA-4 also began on day 7. CCX6239 was dosed orally twice daily at 30mg/kg, and anti-CTLA-4 was dosed IP on days 7, 11 and 15 at 100μg/mouse. Results: Blockade of CCR4 appreciably enhanced the therapeutic effects of anti-CTLA-4 in both models. Combined anti-CTLA-4/CCR4 inhibitor significantly decreased tumor size and increased the proportion of long-term survivors in the CT26 model. The antitumor response was CT26-specific; long-term survivors were resistant to reinoculation with CT26 cells (without further dosing of either drug), but 4T1 breast tumors grew well upon challenge of CT26 survivors. Mice with tumor regression exhibited a high proportion of CD8 T cells that recognized a CT26-specific neoantigen, as illustrated by AH1 peptide-MHC tetramer staining. Although long-term survival has not yet been examined in the KCM model, CCX6239 alone significantly reduced tumor burden in 3 independent studies. Anti-CTLA-4 alone provided substantial inhibition of tumor growth in this model, which was further enhanced by CCX6239. Summary: A specific CCR4 small-molecule inhibitor enhanced the effectiveness of anti-CTLA-4 in 2 preclinical models, suggesting that targeting CCR4 may be a viable clinical approach for combinatorial treatment with checkpoint blockers. Citation Format: Shijie “Chris” Li, James J. Campbell, Linda S. Ertl, Zhenhua Miao, Vicky Chhina, Alice Kumamoto, Simon Yau, Ton Dang, Penglie Zhang, Thomas J. Schall, Rajinder Singh. C-C chemokine receptor 4 (CCR4) antagonism enhances the effectiveness of checkpoint Inhibition in mouse tumor models [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B08.

mAbs that neutralize IL-17 or its receptor have proven efficacious in treating moderate-to-severe psoriasis, confirming IL-17 as an important driver of this disease. In mice, a rare population of T cells, γδT17 cells, appears to be a dominant source of IL-17 in experimental psoriasis. These cells traffic between lymph nodes and the skin, and are identified by their coexpression of the TCR variable regions γ4 and δ4. These cells are homologous to the Vγ9Vδ2 T cell population identified in human psoriatic plaques. In this study we report that a potent and specific small molecule antagonist of the CCR6 chemokine receptor, CCX2553, was efficacious in reducing multiple aspects of psoriasis in two different murine models of the disease. Administration of CCX2553 ameliorated skin inflammation in both the IL-23–induced ear swelling model and the topical imiquimod model, and significantly reduced the number of γδT17 cells in inflamed skin. γδT17 cells were greatly reduced in imiquimod-treated skin of CCR6−/− mice, but adoptively transferred wild-type (CCR6+/+) γδT17 cells homed normally to the skin of imiquimod-treated CCR6−/− mice. Our data suggest that γδT17 cells are completely dependent on CCR6 for homing to psoriasiform skin. Thus, CCR6 may constitute a novel target for a mechanistically distinct therapeutic approach to treating psoriasis.

Chemokines drive cell migration through their interactions with seven-transmembrane (7TM) chemokine receptors on cell surfaces. The atypical chemokine receptor 3 (ACKR3) binds chemokines CXCL11 and CXCL12 and signals exclusively through β-arrestin-mediated pathways, without activating canonical G-protein signalling. This receptor is upregulated in numerous cancers making it a potential drug target. Here we collected over 100 distinct structural probes from radiolytic footprinting, disulfide trapping, and mutagenesis to map the structures of ACKR3:CXCL12 and ACKR3:small-molecule complexes, including dynamic regions that proved unresolvable by X-ray crystallography in homologous receptors. The data are integrated with molecular modelling to produce complete and cohesive experimentally driven models that confirm and expand on the existing knowledge of the architecture of receptor:chemokine and receptor:small-molecule complexes. Additionally, we detected and characterized ligand-induced conformational changes in the transmembrane and intracellular regions of ACKR3 that elucidate fundamental structural elements of agonism in this atypical receptor., The atypical chemokine receptor 3 (ACKR3) is important for cell migration in development and cancer. Here the authors combine radiolytic footprinting, disulfide trapping, mutagenesis and molecular modelling to characterize the ligand interactions and ligand-induced conformational changes in ACKR3.

Necrotizing and crescentic GN (NCGN) with a paucity of glomerular immunoglobulin deposits is associated with ANCA. The most common ANCA target antigens are myeloperoxidase (MPO) and proteinase 3. In a manner that requires activation of the alternative complement pathway, passive transfer of antibodies to mouse MPO (anti-MPO) induces a mouse model of ANCA NCGN that closely mimics human disease. Here, we confirm the importance of C5aR/CD88 in the mediation of anti-MPO–induced NCGN and report that C6 is not required. We further demonstrate that deficiency of C5a-like receptor (C5L2) has the reverse effect of C5aR/CD88 deficiency and results in more severe disease, indicating that C5aR/CD88 engagement enhances inflammation and C5L2 engagement suppresses inflammation. Oral administration of CCX168, a small molecule antagonist of human C5aR/CD88, ameliorated anti-MPO–induced NCGN in mice expressing human C5aR/CD88. These observations suggest that blockade of C5aR/CD88 might have therapeutic benefit in patients with ANCA-associated vasculitis and GN.

Pancreatic ductal adenocarcinoma (PDAC) cells (PCC) have an exceptional propensity to metastasize early into intratumoral, chemokine-secreting nerves. However, we hypothesized the opposite process, that precancerous pancreatic cells secrete chemokines that chemoattract Schwann cells (SC) of nerves and thus induce ready-to-use routes of dissemination in early carcinogenesis. Here we show a peculiar role for the chemokine CXCL12 secreted in early PDAC and for its receptors CXCR4/CXCR7 on SC in the initiation of neural invasion in the cancer precursor stage and the resulting delay in the onset of PDAC-associated pain. SC exhibited cancer- or hypoxia-induced CXCR4/CXCR7 expression in vivo and in vitro and migrated toward CXCL12-expressing PCC. Glia-specific depletion of CXCR4/CXCR7 in mice abrogated the chemoattraction of SC to PCC. PDAC mice with pancreas-specific CXCL12 depletion exhibited diminished SC chemoattraction to pancreatic intraepithelial neoplasia and increased abdominal hypersensitivity caused by augmented spinal astroglial and microglial activity. In PDAC patients, reduced CXCR4/CXCR7 expression in nerves correlated with increased pain. Mechanistically, upon CXCL12 exposure, SC down-regulated the expression of several pain-associated targets. Therefore, PDAC-derived CXCL12 seems to induce tumor infiltration by SC during early carcinogenesis and to attenuate pain, possibly resulting in delayed diagnosis in PDAC.

INTRODUCTION: Immuno-therapy directed at the PD-1/PD-L1 axis has produced significant treatment advances in various human cancers. Unfortunately, this progress has not extended to glioblastoma, with recent clinical trials failing to show efficacy of anti-PD-1 monotherapy in recurrent tumors. Commonly employed murine glioma models exhibit varied responsiveness to anti-PD-1 monotherapy, e.g. GL261 gliomas are sensitive while KR158 tumors are resistant. Previously, we reported that combining PD-1 blockade with either chemokine receptor CCR2 deficiency or a CCR2 antagonist improved survival over anti-PD-1 monotherapy in GL261 gliomas. This was associated with reduced numbers of MDSCs within tumors. The current study evaluated the combination of PD-1 blockade and a novel CCR2 antagonist in anti-PD-1 resistant gliomas. OBJECTIVE: Determine if combination anti-PD-1/CCR2 antagonist therapy is an effective treatment in anti-PD-1 insensitive gliomas. METHODS: Overall survival and immune cell characteristics were determined in KR158 and 005GSC gliomas established in either CCR2 deficient or wild type mice treated with CCR2 antagonist (CCX872) and/or PD-1 blockade. RESULTS: CCR2 deficiency unmasked an anti-PD-1 survival benefit in KR158 glioma-bearing mice. CCX872 increased median survival as a monotherapy in KR158 tumor-bearing animals, and significantly increased median and durable overall survival when combined with anti-PD-1. In 005GSC tumors, the combination of CCX872 and anti-PD-1 prolonged median survival time. Increases in overall CCR2(+) cells and CD11b(+)/Ly6C(hi) myeloid derived suppressor cells (MDSC, known to be CCR2(+)) were evident in the bone marrow of CCR2-deficient mice. Additionally, these mice exhibited decreased MDSCs within established gliomas. The data demonstrate CCX872/anti-PD-1 synergize to increase survival in clinically relevant glioma models via reduced MDSC infiltration, resulting in a tumor microenvironment favorable for anti-PD-1 efficacy. CONCLUSION: The combination of CCX872 and anti-PD-1 is effective in clinically relevant murine glioma models, providing a basis on which to progress this novel combinatorial treatment toward early phase human trials.

Several types of psoriasiform dermatitis are associated with increased IL-36 cytokine activity in the skin. A rare but severe psoriasis-like disorder, generalized pustular psoriasis (GPP), is linked to loss-of-function mutations in the gene encoding IL-36RA, an important negative regulator of IL-36 signaling. To understand the effects of IL-36 dysregulation in a mouse model, we studied skin inflammation induced by intradermal injections of pre-activated IL-36α. This type of inflammation was characterized by markedly increased total skin thickness and epidermal thickness. The inflammation was accompanied by increased concentrations of CCR6 and CXCR2 ligand chemokines in the skin, and large accumulations of CD4 T cells, neutrophils, and inflammatory DC. The accumulated inflammatory subsets in IL-36α-treated skin all expressed either CCR6 or CXCR2 to some extent, prompting the hypothesis that increased CCR6 and CXCR2 ligand concentrations in IL-36α-treated skin might constitute a viable target for relieving inflammation in this model. We found that the orally bioavailable small molecule CCR6/CXCR2 antagonist CCX624 did indeed reverse inflammatory cell accumulation in skin, as well as decrease total skin thickness and epidermal thickness. CCX624 was effective in both prophylactic and therapeutic dosing regimens. CCX624 treatment was more effective than saturating doses of anti-TNFα or anti-IL17RA, which are used in the clinic for treating GPP as first or second line treatments (respectively). These findings put CCR6 and CXCR2 forward as novel targets for a mechanistically distinct therapeutic approach for inflammatory skin diseases involving dysregulated IL-36 signaling, such as GPP.

Recent literature indicates that mice deficient in the chemokine receptor CCR9 (CCR9 −/− mice) are unable to generate oral tolerance. The present report describes how such inability can be overcome by increasing the dose of oral antigen. Pharmacological inhibition of CCR9 did not affect the generation of oral tolerance, regardless of antigen dose. These results highlight the inadequacy of genetic deletion of CCR9 when predicting the effects of pharmacological CCR9 inhibition on intestinal biology.

Chemokines play a key role in orchestrating leukocytic recruitment during inflammatory responses, including those to viral infections. Chemokines are soluble cytokines which mediate their effects through specific G protein-coupled, seven-transmembrane receptors which are expressed on a wide range of cells, including monocytes, T-cells, dendritic cells, and NK cells. Analyses of herpesvirus genomes have revealed that these viral pathogens encode their own versions of both chemokines and chemokine receptors. Viral genes encoding chemokine elements were likely to have been acquired from the host genome and have been remodeled during virus evolution to presumably optimize function or acquire new properties not displayed by their cellular homologues. Virus-encoded chemokines and chemokine receptors are important players in the continuing confrontation between viruses and their mammalian hosts. Detailed characterization of these elements will provide a better understanding of how the immune system responds to viral infection and may suggest new antiviral drug targets and new avenues for the development of antiviral therapies. We will review here the chemokine elements encoded by herpesviruses and how they may aid viral infection and propagation.

To date, the treatment of immune-mediated kidney diseases has only marginally benefited from highly specific biological drugs that have demonstrated remarkable effects in many other diseases. What accounts for this disparity? In April 2016, the International Society of Nephrology held a Nexus meeting on Translational Immunology in Nephrology in Berlin, Germany, to identify and discuss hurdles that block the translational flow of target identification, and preclinical and clinical target validation in the domain of immune-mediated kidney disease. A broad panel of experts including basic scientists, translational researchers, clinical trialists, pharmaceutical industry drug developers, and representatives of the American and European regulatory authorities made recommendations on how to overcome such hurdles at all levels of the translational research process. The results of these discussions are presented here, which may serve as a roadmap for how to optimize the process of developing more innovative and effective drugs for patients with immune-mediated kidney diseases.

The complement 5a receptor has been an attractive therapeutic target for many autoimmune and inflammatory disorders. However, development of a selective and potent C5aR antagonist has been challenging. Here we describe the characterization of CCX168 (avacopan), an orally administered selective and potent C5aR inhibitor. CCX168 blocked the C5a binding, C5a-mediated migration, calcium mobilization, and CD11b upregulation in U937 cells as well as in freshly isolated human neutrophils. CCX168 retains high potency when present in human blood. A transgenic human C5aR knock-in mouse model allowed comparison of the in vitro and in vivo efficacy of the molecule. CCX168 effectively blocked migration in in vitro and ex vivo chemotaxis assays, and it blocked the C5a-mediated neutrophil vascular endothelial margination. CCX168 was effective in migration and neutrophil margination assays in cynomolgus monkeys. This thorough in vitro and preclinical characterization enabled progression of CCX168 into the clinic and testing of its safety, tolerability, pharmacokinetic, and pharmacodynamic profiles in a Phase 1 clinical trial in 48 healthy volunteers. CCX168 was shown to be well tolerated across a broad dose range (1 to 100 mg) and it showed dose-dependent pharmacokinetics. An oral dose of 30 mg CCX168 given twice daily blocked the C5a-induced upregulation of CD11b in circulating neutrophils by 94% or greater throughout the entire day, demonstrating essentially complete target coverage. This dose regimen is being tested in clinical trials in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis. Trial Registration ISRCTN registry with trial ID ISRCTN13564773.