Cerebrospinal fluid soluble programmed death-ligand 1 is a useful prognostic biomarker in primary central nervous system lymphoma.

The increased expression of programmed death-ligands 1 and 2 (PD-L1 and PD-L2, respectively) on tumour cells contributes to immune evasion, suggesting that these proteins are attractive therapeutic targets. This study aimed to evaluate the validity of cerebrospinal fluid (CSF) soluble PD-L1 (sPD-L1) and soluble PD-L2 (sPD-L2) as biomarkers for primary central nervous system lymphoma (PCNSL). We determined the CSF concentrations of sPD-L1 and sPD-L2 in 46 patients with PCNSL using enzyme-linked immunosorbent assays (ELISAs). A control group comprised 153 patients with other brain tumours, inflammatory/infectious status, or neurodegenerative diseases. Only CSF sPD-L1 levels were significantly higher in patients with PCNSL relative to the controls. CSF sPD-L1 also exhibited superior overall discrimination performance compared to CSF sPD-L2 in diagnosing PCNSL. Compared with patients with PCNSL with low CSF sPD-L1 levels, more patients with high levels had high serum lactate dehydrogenase levels, leptomeningeal involvement, and deep-brain involvement. Furthermore, CSF sPD-L1 could predict poor survival in PCNSL but CSF sPD-L2 could not. Intriguingly, CSF sPD-L1 levels were correlated with disease status and their dynamic changes post treatment could predict time to relapse. In conclusion, this study identified CSF sPD-L1 as a promising prognostic biomarker, indicating a therapeutic potential of PD-L1 blockade in PCNSL.

The influence of plasma sPD-L1 concentration on the effectiveness of immunotherapy in advanced NSCLC patients.

INTRODUCTION: PD-L1 (Programmed Cell Death Ligand 1) is currently the only recognised marker of response to immunotherapy with anti-PD-1 or anti-PD-L1 antibodies in patients with advanced non-small cell lung cancer (NSCLC). However, this marker is not perfect. Soluble PD-L1 (sPD-L1) may be a novel predictor of immunotherapy efficacy in NSCLC patients. MATERIAL AND METHODS: We enrolled 120 patients (median age 68 ± 6.81 years, 70 males and 50 females) with locally advanced (stage IIIB; 10 patients) or advanced (stage IV; 110 patients) NSCLC. PD-L1 expression in tumour cells was assessed by immunohistochemistry (IHC) in 117 (97.5%) patients. The soluble PD-L1 concentration in plasma samples was measured using enzyme-linked immunosorbent assay (ELISA). The response to immunotherapy, progression-free survival (PFS), and overall survival (OS), calculated from the start of immunotherapy, were assessed in 119 patients. RESULTS: Patients with disease control had significantly lower (p = 0.0006) concentrations of sPD-L1 in blood plasma than patients with progression during the first months of immunotherapy or chemoimmunotherapy Patients with ≥ 6 month progression-free survival had a significantly higher (p = 0.013) percentage of tumor cells with PD-L1 expression than patients with shorter PFS. Patients with ≥ 6 months OS had significantly lower (p = 0.0142) plasma sPD-L1 concentrations than those with shorter overall survival. The median PFS was significantly higher in patients with low sPD-L1 concentrations than in those with high concentrations of this protein (5.8 vs. 2.5 months, HR = 0.6021, p = 0.0156). Similarly, patients with low sPD-L1 levels had a significantly higher median overall survival than those with sPD-L1 levels above the median (16.5 vs. 7 months, HR = 0.5354, p = 0.0071). There was no significant correlation between the percentage of tumour cells expressing PD-L1 and the concentration of sPD-L1 in the blood plasma. CONCLUSION: High sPD-L1 concentration is a negative predictor of immunotherapy efficacy in patients with NSCLC. It is worthwhile to determine sPD-L1 concentration to predict the risk of resistance to anti-PD-1 or anti-PD-L1 antibodies with greater certainty.

Prognostic impact of soluble PD-L1 derived from tumor-associated macrophages in non-small-cell lung cancer.

Programmed cell death-ligand 1 (PD-L1) on tumor cells can be degraded to soluble form (sPD-L1) and enter circulation, however, the clinical significances of sPD-L1 in peripheral blood remains to be elucidated in non-small-cell lung cancer (NSCLC). We monitored plasma sPD-L1 levels during perioperative periods and evaluated PD-L1-positive cells in tumor tissues in patients with operable NSCLC. Then the correlation between preoperative plasma sPD-L1 levels and relapse-free survival (RFS) was analyzed retrospectively. In patients who underwent radical surgery (n = 61), plasma sPD-L1 levels (median; 63.5 pg/mL) significantly increased 1 month after surgery (72.2 pg/mL, P < 0.001). The combined score of PD-L1-positive cells including tumor cells and tumor-associated macrophages (TAMs) was significantly associated with preoperative plasma sPD-L1 levels. In patients with high levels of preoperative plasma sPD-L1, the probability of 5-year RFS was significantly poor for patients with low PD-L1 expression intensity of tumor cells (tcPD-L1) compared with those with high tcPD-L1 (33.3% vs. 87.5%, respectively, P = 0.016; 95% CI, 0.013-0.964). In former group, PD-L1-positive TAMs were markedly infiltrating compared with those from latter group (246.4 vs. 76.6 counts/mm2, respectively, P = 0.003). In NSCLC, plasma sPD-L1 can reflect the accumulation of PD-L1-posotive TAMs, not just PD-L1-positive tumor cells. In patients with high levels of preoperative plasma sPD-L1, the prognoses after surgery depends on which PD-L1-positive cells, tumor cells or TAMs, are the primary source of the sPD-L1. Thus, measuring both plasma sPD-L1 levels and PD-L1 expression status of tumor cells and TAMs is of benefit for assessment of postoperative prognosis in operable NSCLC.

Clinical roles of soluble PD-1 and PD-L1 in plasma of NSCLC patients treated with immune checkpoint inhibitors.

INTRODUCTION: Immune checkpoint inhibitors (ICIs) have significantly improved the prognosis of non-small cell lung cancer (NSCLC). However, only a limited proportion of patients can benefit from this therapy, and clinically useful predictive biomarkers remain to be elucidated. METHODS: Blood was collected from 189 patients with NSCLC before and six weeks after the initiation of ICI treatment (anti-PD-1 or anti-PD-L1 antibody). Soluble PD-1 (sPD-1) and PD-L1 (sPD-L1) in plasma before and after treatment were analyzed to evaluate their clinical significance. RESULTS: Cox regression analysis demonstrated that higher sPD-L1 levels before treatment significantly predicted unfavorable progression-free survival (PFS; HR 15.4, 95% CI 1.10-86.7, P = 0.009) and overall survival (OS; HR 11.4, 95% CI 1.19-52.3, P = 0.007) in NSCLC patients treated with ICI monotherapy (n = 122) but not in those treated with ICIs combined with chemotherapy (n = 67: P = 0.729 and P = 0.155, respectively). In addition, higher sPD-1 levels after treatment were significantly associated with better OS (HR 0.24, 95% CI 0.06-0.91, P = 0.037) in patients treated with anti-PD-1 monotherapy, whereas higher sPD-L1 levels after treatment were significantly associated with worse PFS (HR 6.09, 95% CI 1.42-21.0, P = 0.008) and OS (HR 42.6, 95% CI 6.83-226, P < 0.001). The levels of sPD-L1 at baseline closely correlated with those of other soluble factors, such as sCD30, IL-2Ra, sTNF-R1, and sTNF-R2, which are known to be released from the cell surface by zinc-binding proteases ADAM10/17. CONCLUSIONS: These findings suggest the clinical significance of pretreatment sPD-L1 as well as posttreatment sPD-1 and sPD-L1 in NSCLC patients treated with ICI monotherapy.

Soluble PD-L1 as a diagnostic and prognostic biomarker in resectable gastric cancer patients.

BACKGROUND: In this study, we compared programmed death-ligand 1 (PD-L1) expression in primary tissue samples and its soluble form (sPD-L1) concentration in matched preoperative plasma samples from gastric cancer patients to understand the relationship between tissue and plasma PD-L1 expression and to determine its diagnostic and prognostic value. METHODS: PD-L1 expression in tissue was assessed by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), and sPD-L1 concentration in plasma was quantified by ELISA. The levels of the CD274 gene, which encodes for PD-L1 protein, were examined as part of bulk tissue RNA-sequencing analyses. Additionally, we evaluated the association between sPD-L1 levels and various laboratory parameters, disease characteristics, and patient outcomes. RESULTS: GC patients had significantly higher levels of sPD-L1 in their plasma (71.69 pg/mL) compared to healthy controls (35.34 pg/mL) (p < 0.0001). Moreover, sPD-L1 levels were significantly correlated with tissue PD-L1 protein, CD274 mRNA expression, larger tumor size, advanced tumor stage, and lymph node metastasis. Elevated sPD-L1 levels (> 103.5 ng/mL) were associated with poor overall survival (HR = 2.16, 95%CI 1.15-4.08, p = 0.017). Furthermore, intratumoral neutrophil and dendritic cell levels were directly correlated with plasma sPD-L1 concentration in the GC patients. CONCLUSIONS: sPD-L1 was readily measurable in GC patients, and its level was associated with GC tissue PD-L1 expression, greater inflammatory cell infiltration, disease progression, and survival. Thus, sPD-L1 may be a useful minimally invasive diagnostic and prognostic biomarker in GC patients.

The integration of systemic and tumor PD-L1 as a predictive biomarker of clinical outcomes in patients with advanced NSCLC treated with PD-(L)1blockade agents.

BACKGROUND: Tumor PD-L1 expression is a predictive biomarker for patients with NSCLC receiving PD-(L)1 blockade agents. However, although increased tumor PD-L1 expression predicts responsiveness, clinical benefit has been observed regardless of tumor PD-L1 expression, suggesting the existence of other PD-L1 sources. The aim of our study was to analyze whether integrating systemic and tumor PD-L1 is more predictive of efficacy in patients with advanced NSCLC receiving PD-(L)1 blockade agents. MATERIAL AND METHODS: Twenty-nine healthy donors and 119 consecutive patients with advanced NSCLC treated with PD-(L)1 drug were prospectively included. Pretreatment blood samples were collected to evaluate PD-L1 levels on circulating immune cells, platelets (PLTs), platelet microparticles (PMPs), and the plasma soluble PD-L1 concentration (sPD-L1). Tumor PD-L1 status was assessed by immunohistochemistry. The percentages of circulating PD-L1 + leukocytes, sPD-L1 levels, and tumor PD-L1 were correlated with efficacy. RESULTS: No differences in the percentages of circulating PD-L1 + leukocytes were observed according to tumor PD-L1 expression. Significantly longer progression-free survival was observed in patients with higher percentages of PD-L1 + CD14 + , PD-L1 + neutrophils, PD-L1 + PLTs, and PD-L1 + PMPs and significantly longer overall survival was observed in patients with higher percentages of PD-L1 + CD14 + and high tumor PD-L1 expression. Integrating the PD-L1 data of circulating and tumor PD-L1 results significantly stratified patients according to the efficacy of PD-(L1) blockade agents. CONCLUSIONS: Our results suggest that integrating circulating PD-L1 + leukocytes, PLT, PMPs, and sPD-L1 and tumor PD-L1 expression may be helpful to decide on the best treatment strategy in patients with advanced NSCLC who are candidates for PD-(L)1 blockade agents.

Circulating PD-L1 is associated with T cell infiltration and predicts prognosis in patients with CRLM following hepatic resection.

BACKGROUND: Exosomal PD-L1 (exoPD-L1) could induce immunosuppression functionally, thus impairing patients' survival in melanoma, NSCLC, and gastric cancer. However, no evidence demonstrates the feasibility of circulating exoPD-L1 and soluble PD-L1 (sPD-L1) as biomarkers for prognosis and early recurrence in colorectal liver metastasis (CRLM) patients following hepatectomy or their association with T cell infiltration at liver metastases. METHODS: In cohort 1, exoPD-L1 and sPD-L1 were preoperatively tested using ELISA. CD3, CD8, granzyme B (GB) and PD1 expressed at liver metastases were evaluated using immunohistochemistry. In cohort 2, exoPD-L1 and sPD-L1 were detected at baseline, before hepatectomy, after hepatectomy, and after disease progression. RESULTS: In cohort 1, higher preoperative exoPD-L1 or sPD-L1 significantly impaired RFS (exoPD-L1, P = 0.0043; sPD-L1, P = 0.0041) and OS (exoPD-L1, P = 0.0034; sPD-L1, P = 0.0061). Furthermore, preoperative exoPD-L1 was negatively correlated with CD3 + T-lymphocytes infiltrated at tumor center (CT), and GB and PD1 were expressed at tumor invasive margin (IM). Preoperative sPD-L1 was negatively correlated with CD3 + and CD8 + T-lymphocytes' infiltration at IM and CT, GB and PD1 expression at IM. In cohort 2, exoPD-L1 and sPD-L1 levels decreased following hepatectomy but increased when tumor progressed. Moreover, higher postoperative exoPD-L1 and sPD-L1 or a small reduction in exoPD-L1 and sPD-L1 levels after hepatectomy suggested higher early recurrence rate. CONCLUSIONS: Both preoperative exoPD-L1 and sPD-L1 had promising prognostic values and were associated with T cell infiltration at liver metastases in CRLM patients following hepatectomy. Dynamically tracking exoPD-L1 and sPD-L1 levels could monitor disease status and detect early recurrence.

Soluble PD-L1 as a predictive biomarker in lung cancer: a systematic review and meta-analysis.

Background: We performed a meta-analysis to evaluate the association between soluble PD-L1 (sPD-L1) and survival outcomes and treatment response in lung cancer. Methods & methods: Eligible studies were obtained by searching PubMed, EMBASE and Web of Science. Pooled effect estimates were calculated for overall survival (OS), progression-free survival (PFS) and objective response rate (ORR). Results: Twelve eligible studies with 1188 lung cancer patients were included. High sPD-L1 was significantly associated with worse OS (hazard ratio [HR] = 2.20; 95% CI: 1.59-3.05; p < 0.001) and PFS (HR = 2.42; 95% CI: 1.72-3.42; p < 0.001) in patients treated with immune checkpoint inhibitors (ICIs). Meanwhile, high sPD-L1 predicted worse OS (HR = 1.60; 95% CI: 1.31-1.96; p < 0.001) and lower ORR (odds ratio = 0.52; 95% CI: 0.35-0.80; p = 0.002) in patients treated with non-ICI therapies. Conclusion: sPD-L1 is a potential predictive biomarker of lung cancer.

Lay abstract PD-L1 is a molecule that may suppress immune response to tumor by binding to its receptor PD-1. Agents blocking PD-L1/PD-1 pathway have greatly improved survival in many cancer patients. However, biomarkers that help select patients who can respond to these agents versus those who cannot are important. The soluble form of PD-L1 (sPD-L1) in peripheral blood (sPD-L1) can be easily detected. By pooling available evidence via meta-analysis, we find that lung cancer patients with high sPD-L1 level are less likely to response to anti-PD-L1/PD-1 antibodies, may progress earlier and have a shorter survival time than those with lower sPD-L1 level after treatment. Thus, sPD-L1 can be used as a biomarker predicting treatment response and survival in lung cancer. Yet some issues ­ for example, the cutoff and standard detection of sPD-L1 ­ need to be resolved for its clinical utility.

Measurement of soluble PD-1 and soluble PD-L1 as well as PD-L1 and PD-1 from perioperative patients with gastric carcinoma.

BACKGROUND: Till now, no experiment has been performed to detect programmed death ligand 1 (PD-L1)/programmed death 1 (PD-1), soluble PD-L1/soluble PD-1 simultaneously in perioperative patients of gastric carcinoma. Our experiment aims at determining the clinical significance and possible mechanism of soluble PD-L1/soluble PD-1 in gastric carcinoma. METHODS: Thirty patients undergone gastrectomy were selected as the experimental group. Tissue's programmed death ligand 1 and peripheral programmed death 1 were detected using immunofluorescence and flow cytometry. Soluble PD-L1 and soluble PD-1 were detected using enzyme-linked immunosorbent assay. RESULTS: First, preoperative programmed death 1 was higher than control group and decreased to normal post-operatively. Preoperatively ,elevated levels of programmed death 1 on cluster of differentiation (CD)4 T cells indicated less lymphatic metastasis (P < 0.01) and small tumor volume (P < 0.01); elevated programmed death 1 of CD8 T cells indicated big tumor volume (P < 0.01) and well histological differentiation (P < 0.01). Second, preoperative soluble PD-L1 and soluble PD-1 are lower than in control group. Post-operatively, the soluble PD-1 rose to normal, but the soluble PD-L1 showed no change. Third, programmed death ligand 1 can be observed in carcinoma tissue. Fourth, the area under the curve of soluble PD-1 (0.675) for diagnosis was worse than that of soluble PD-L1 (0.885). Kaplan-Meier analysis showed that soluble PD-1 < 245.26 pg/ml in post-operative serum predicted a poor prognosis (overall survival percentage: 60%) at 2 years (P < 0.05). Multivariate analysis revealed that carcinoembryonic antigen (>5 ng/l) and soluble PD-1 after gastrectomy (>245.26 pg/ml) were independent prognostic factors for overall survival (hazard ratio: 20.812, 95% confidence interval: 1.217-355.916, P = 0.036; hazard ratio: 0.028, 95% confidence interval: 0.001-0.786, P = 0.036, respectively). CONCLUSIONS: We propose that soluble PD-1 combined with programmed death ligand 1 are effective not only in protecting T cells from the adhesion by programmed death ligand 1 but also in preventing the occurrence and the development of tumor as well. Through multivariate analysis, we found that soluble PD-1 was an independent protective factor for post-operative prognosis of gastric carcinoma patients, which indirectly verified the vital function of soluble PD-1. Soluble PD-1 might be promising predictive biomarkers for the diagnosis and prognosis of gastric carcinoma patients.

Circulating PD-L1 levels change during bevacizumab-based treatment in recurrent glioma.

PURPOSE: In primary brain tumors, the efficacy of immune-modulating therapies is still under investigation as inflammatory responses are restricted by tight immunoregulatory mechanisms in the central nervous system. Here, we measured soluble PD-L1 (sPD-L1) in the plasma of patients with recurrent glioblastoma (GBM) and recurrent WHO grade II-III glioma treated with bevacizumab-based salvage therapy. METHODS: Thirty patients with recurrent GBM and 10 patients with recurrent WHO grade II-III glioma were treated with bevacizumab-based salvage therapy at the Medical University of Vienna. Prior to each treatment cycle, EDTA plasma was drawn and sPD-L1 was measured applying a sandwich ELISA with a lower detection limit of 0.050 ng/ml. Leukocyte counts and C-reactive protein (CRP) levels were measured according to institutional practice. RESULTS: Median number of sPD-L1 measurements was 6 per patient (range: 2-24). At baseline, no significant difference in sPD-L1 concentrations was observed between WHO grade II-III glioma and GBM. Intra-patient variability of sPD-L1 concentrations was significantly higher in WHO grade II-III glioma than in GBM (p = 0.014) and tendentially higher in IDH-mutant than in IDH-wildtype glioma (p = 0.149) In WHO grade II-III glioma, sPD-L1 levels were significantly lower after one administration of bevacizumab than at baseline (median: 0.039 ng/ml vs. 0.4855 ng/ml, p = 0.036). In contrast, no significant change could be observed in patients with GBM. CONCLUSIONS: Changes in systemic inflammation markers including sPD-L1 are observable in patients with recurrent glioma under bevacizumab-based treatment and differ between WHO grade II-III glioma and GBM.

Matrix metalloproteinases cleave membrane-bound PD-L1 on CD90+ (myo-)fibroblasts in Crohn's disease and regulate Th1/Th17 cell responses.

Increased T helper (Th)1/Th17 immune responses are a hallmark of Crohn's disease (CD) immunopathogenesis. CD90+ (myo-)fibroblasts (MFs) are abundant cells in the normal (N) intestinal mucosa contributing to mucosal tolerance via suppression of Th1 cell activity through cell surface membrane-bound PD-L1 (mPD-L1). CD-MFs have a decreased level of mPD-L1. Consequently, mPD-L1-mediated suppression of Th1 cells by CD-MFs is decreased, yet the mechanism responsible for the reduction in mPDL-1 is unknown. Increased expression of matrix metalloproteinases (MMPs) has been reported in CD. Herein we observed that when compared to N- and ulcerative colitis (UC)-MFs, CD-MFs increase in LPS-inducible levels of MMP-7 and -9 with a significant increase in both basal and inducible MMP-10. A similar pattern of MMP expression was observed in the CD-inflamed mucosa. Treatment of N-MFs with a combination of recombinant human MMP-7, -9 and -10 significantly decreased mPD-L1. In contrast, inhibition of MMP activity with MMP inhibitors or anti-MMP-10 neutralizing antibodies restores mPD-L1 on CD-MFs. CD-MFs demonstrated reduced capacity to suppress Th1 and Th17 responses from activated CD4+ T cells. By contrast, supplementation of the CD-MF:T-cell co-cultures with MMP inhibitors or anti-MMP neutralizing antibodies restored the CD-MF-mediated suppression. Our data suggest that (i) increased MMP-10 expression by CD-MFs and concomitant cleavage of PD-L1 from the surface of CD-MFs are likely to be one of the factors contributing to the decrease of mPD-L1-mediated suppression of Th1/Th17 cells in CD; and (ii) MMPs are likely to have a significant role in the intestinal mucosal immune responses.

Non-cytomembrane PD-L1: An atypical target for cancer.

Programmed death ligand 1 (PD-L1) has conventionally been considered as a type I transmembrane protein that can interact with its receptor, programmed cell death 1 (PD-1), thus inducing T cell deactivation and immune escape. However, targeting the PD-1/PD-L1 axis has achieved adequate clinical responses in very few specific malignancies. Recent studies have explored the extracellularly and subcellularly located PD-L1, namely, nuclear PD-L1 (nPD-L1), cytoplasmic PD-L1 (cPD-L1), soluble PD-L1 (sPD-L1), and extracellular vesicle PD-L1 (EV PD-L1), which might shed light on the resistance to anti-PD1/PDL1 therapy. In this review, we summarize the four atypical localizations of PD-L1 with a focus on their novel functions, such as gene transcription regulation, therapeutic efficacy prediction, and resistance to various cancer therapies. Additionally, we highlight that non-cytomembrane PD-L1s are of significant cancer diagnostic value and are promising therapeutic targets to treat cancer.

Serum levels of soluble programmed death-ligand 1 (sPD-L1) in patients with primary central nervous system diffuse large B-cell lymphoma.

BACKGROUND: The interaction of programmed death-1 protein (PD-1) and programmed death-1 ligand (PD-L1) produces immunosuppressive activity, protecting tumor cells from anti-tumor immunity and possibly releasing soluble PD-L1 (sPD-L1) from PD-L1 expressing tumor cells. Therefore, we measured serum levels of sPD-L1 in patients with primary central nervous system lymphoma (PCNSL) and explored its clinical implications. METHODS: Sixty-eight patients with newly diagnosed PCNSL had diffuse large B-cell lymphoma and were treated with high-dose methotrexate-containing chemotherapy. The measurement of sPD-L1 and cytokines was performed using serum samples archived at diagnosis, and the tissue expression of PD-L1 was also analyzed from archived paraffin-embedded tissue blocks. Disease relapse, progression-free survival (PFS), and overall survival (OS) were analyzed according to the extent of sPD-L1 in serum and PD-L1 in tissue. RESULTS: The median level of serum sPD-L1 (0.429 ng/mL) was higher than in healthy control patients (0.364 ng/mL). The occurrence of relapse was more frequent in the high sPD-L1 (78%) than the low sPD-L1 group (50%), though the groups did not have different clinical or pathological characteristics at diagnosis. As a result, the OS and PFS for the high sPD-L1 group were significantly lower than those in the low group. PD-L1-positive tumor cells were found in 35 patients (67%), and the extent of PD-L1-postive tumor cells was positively associated with serum sPD-L1 levels (r = 0.299, P = 0.031). Among the 34 cytokines analyzed, only the serum level of IL-7 correlated with the serum level of sPD-L1 (r = 0.521, P < 0.001). CONCLUSIONS: Serum levels of sPD-L1 could reflect the expression of PD-L1 in PCNSL tumor cells and predict patient survival outcomes. Therefore, sPD-L1 in serum could be a feasible biomarker for determining a risk-adapted treatment strategy for PCNSL patients. TRIAL REGISTRATION: The study population was patients who were diagnosed with PCNSL between January 2009 and February 2017 and registered for our prospective cohort studies after providing written informed consent (ClinicalTrials.gov: NCT00822731 [date of registration - January 14, 2009] and NCT01877109 [date of registration - June 13, 2013]).

Lysosomal degradation of PD-L1 is associated with immune-related adverse events during anti-PD-L1 immunotherapy in NSCLC patients.

Background: Immune checkpoint inhibitors (ICIs) can induce immune-related adverse events (irAEs). Liquid biomarkers to predict irAE occurrence are urgently needed. We previously developed an ELISA system to specifically detect soluble PD-L1 (sPD-L1) with PD-1-binding capacity (bsPD-L1). Here, we investigated the relationship between sPD-L1 and bsPD-L1 in gastric cancer (GC) and non-small cell lung cancer (NSCLC) treated with PD-1/PD-L1 blockade and their association with irAEs. Methods: We examined sPD-L1, bsPD-L1, matrix metalloproteinases (MMPs), and proinflammatory cytokine levels by ELISA in plasma samples from 117 GC patients prior to surgery and 72 NSCLC patients prior to and at 2 months after ICI treatment (anti-PD-1, n = 48; anti-PD-L1, n = 24). In mice treated with anti-PD-1/PD-L1 antibodies (Abs), sPD-L1 levels and localization of Abs were examined by ELISA and immunohistochemistry, respectively. Results:sPD-L1 was detected with higher frequency in GC patients than in NSCLC patients, whereas bsPD-L1 was detected with similar frequencies in GC and NSCLC patients. sPD-L1 levels were correlated with IL-1α, IL-1ß, TNF-α, and IL-6 levels, while bsPD-L1 levels were correlated with MMP13, MMP3, and IFN-γ levels. In NSCLC patients, anti-PD-L1, but not anti-PD-1, treatment increased sPD-L1, which was associated with irAE development, but not with clinical outcomes. In mice, trafficking of anti-PD-L1 Abs to lysosomes in F4/80+ macrophages resulted in sPD-L1 production, which was suppressed by treatment with lysosomal degradation inhibitor chloroquine and macrophage depletion. Conclusion: Anti-PD-L1-mediated lysosomal degradation induces sPD-L1 production, which can serve as an indicator to predict irAE development during anti-PD-L1 treatment.

Effects of Apatinib combined with Temozolomide on levels of sPD-1 and sPD-L1 in patients with drug-resistant recurrent glioblastoma.

OBJECTIVE: This study aimed to explore the effects of Apatinib combined with Temozolomide (TMZ) on the levels of Soluble PD-1 (sPD-1) and Soluble Programmed Death-1 Ligand (sPD-L1) in patients with drug-resistant recurrent Glioblastoma (GB). STUDY DESIGN: A total of 69 patients with recurrent GB from September 2020 to March 2022 were recruited and assigned to the control group (n = 34) and observation group (n = 35) according to different treatment options after tumor recurrence. The control group was treated with TMZ, and the observation group was treated with Apatinib combined with TMZ. Levels of sPD-1 and spd-l1, clinical efficacy, survival time and adverse reactions were observed and compared between the two groups. RESULTS: General data including gender, age, body mass index, and combined diseases indicated no statistical significance between groups (p > 0.05). Before the intervention, sPD-1 and sPD-L1 levels were not significantly different in the two groups (p > 0.05). After interventions, levels of PD-1 and sPD-L1 levels decreased significantly (p < 0.05). The objective remission rate and clinical benefit rate of the observation group were higher and overall survival and progression-free survival were longer than those of the control group (p < 0.05). No significant difference was observed in major adverse reactions among patients (p > 0.05). CONCLUSIONS: Apatinib combined with TMZ is safe and effective in the treatment of recurrent GB. The combined application of the two can reduce the levels of sPD-1 and sPD-L1, which has important clinical application value.

Prognostic significance of soluble PD-L1 in prostate cancer.

Purpose: The aim of this study was to assess the role of sPD-L1 and sPD-1 as potential biomarkers in prostate cancer (PCa). The association of the values of these soluble proteins were correlated to the clinical data: stage of disease, Gleason score, biochemical recurrence etc. For a comprehensive study, the relationship between sPD-L1 and sPD-1 and circulating immune cells was further investigated. Methods: A total of 88 patients with pT2 and pT3 PCa diagnosis and 41 heathy men were enrolled. Soluble sPD-L1 and sPD-1 levels were measured in plasma by ELISA method. Immunophenotyping was performed by flow cytometry analysis. Results: Our study's findings demonstrate that PCa patients had higher levels of circulating sPD-L1 and sPD-1 comparing to healthy controls (p < 0.001). We found a statistically significant (p < 0.05) relationship between improved progression free survival and lower initial sPD-L1 values. Furthermore, patients with a lower sPD-1/sPD-L1 ratio were associated with a higher probability of disease progression (p < 0.05). Additionally, a significant (p < 0.05) association was discovered between higher Gleason scores and elevated preoperative sPD-L1 levels and between sPD-1 and advanced stage of disease (p < 0.05). A strong correlation (p < 0.05), between immunosuppressive CD4+CD25+FoxP3+ regulatory T cells and baseline sPD-L1 was observed in patients with unfavorable postoperative course of the disease, supporting the idea that these elements influence each other in cancer progression. In addition to the postoperative drop in circulating PD-L1, the inverse relationship (p < 0.05), between the percentage of M-MDSC and sPD-L1 in patients with BCR suggests that M-MDSC is not a source of sPD-L1 in PCa patients. Conclusion: Our findings suggest the potential of sPD-L1 as a promising prognostic marker in prostate cancer.

Preclinical Pharmacokinetics and Pharmacology Study of RC98: A Programmed Cell Death Ligand 1 Monoclonal Antibody in Cynomolgus Monkeys.

INTRODUCTION: RC98 is the monoclonal antibody against Programmed Cell Death Ligand 1 (PD-L1). Relevant reports have confirmed that the influence of PD-L1 expressed by tumor cells on antitumor CD8+ T cell responses is well characterized, but the impact of PD-L1 expressed by immune cells has not been well defined. OBJECTIVE: This study aimed to design a Pharmacokinetics/Pharmacology (PK/PD) study of RC98 in normal cynomolgus monkeys to research the effect on the immune system. METHODS: RC98 and vehicle were administered to cynomolgus monkeys at 15 mg/kg via intravenous infusion once a week for 4 weeks to evaluate the relationship between PK and PD. The pharmacodynamic activity was measured by the PD-L1 receptor occupancy (RO) in CD3+ T cells, A T-cell-dependent antibody response (TDAR), and the concentration of soluble PD-L1. RESULTS: The pharmacokinetic result showed that the exposure from the last administration was lower than that of the first administration, probably due to immunogenicity production. There was a strong correlation between systemic exposure and RO in CD3+ T cells but decreased RO levels after the last dose, which indirectly reflected the activation of T cells. The keyhole limpet hemocyanin (KLH)-induced TDAR in the RC98 group was higher than in the vehicle group. The concentration of soluble PD-L1 had increased feedback with RC98, and the concentration of soluble PD-L1 was maintained at a higher level after multiple doses than before dosing. CONCLUSION: These data indicate that the immune system was clearly activated. In addition, the non-clinical data could provide a basis for its efficacy evaluation in clinical trials.

Combination of plasma MMPs and PD-1-binding soluble PD-L1 predicts recurrence in gastric cancer and the efficacy of immune checkpoint inhibitors in non-small cell lung cancer.

Background: The tumor microenvironment (TME) impacts the therapeutic efficacy of immune checkpoint inhibitors (ICIs). No liquid biomarkers are available to evaluate TME heterogeneity. Here, we investigated the clinical significance of PD-1-binding soluble PD-L1 (bsPD-L1) in gastric cancer (GC) patients and non-small cell lung cancer (NSCLC) patients treated with PD-1/PD-L1 blockade. Methods: We examined bsPD-L1, matrix metalloproteinases (MMPs), and IFN-γ levels in plasma samples from GC patients (n = 117) prior to surgery and NSCLC patients (n = 72) prior to and 2 months after ICI treatment. We also examined extracellular matrix (ECM) integrity, PD-L1 expression, and T cell infiltration in tumor tissues from 25 GC patients by Elastica Masson-Goldner staining and immunohistochemical staining for PD-L1 and CD3, respectively. Results: bsPD-L1 was detected in 17/117 GC patients and 16/72 NSCLC patients. bsPD-L1 showed strong or moderate correlations with plasma MMP13 or MMP3 levels, respectively, in both GC and NSCLC patients. bsPD-L1 expression in GC was associated with IFN-γ levels and intra-tumoral T cell infiltration, whereas MMP13 levels were associated with loss of ECM integrity, allowing tumor cells to access blood vessels. Plasma MMP3 and MMP13 levels were altered during ICI treatment. Combined bsPD-L1 and MMP status had higher predictive accuracy to identify two patient groups with favorable and poor prognosis than tumor PD-L1 expression: bsPD-L1+MMP13high in GC and bsPD-L1+(MMP3 and MMP13)increased in NSCLC were associated with poor prognosis, whereas bsPD-L1+MMP13low in GC and bsPD-L1+(MMP3 or MMP13)decreased in NSCLC were associated with favorable prognosis. Conclusion: Plasma bsPD-L1 and MMP13 levels indicate T cell response and loss of ECM integrity, respectively, in the TME. The combination of bsPD-L1 and MMPs may represent a non-invasive tool to predict recurrence in GC and the efficacy of ICIs in NSCLC.

Soluble PD-L1 predicts tumor response and immune-related adverse events in patients with advanced melanoma treated with anti-PD-1 antibodies.

Immune checkpoint inhibitors (ICIs) bring prognostic benefits to patients with malignancies. However, there is a substantial number of patients whose lesions are not improved by ICIs. In addition, ICIs may cause immune-related adverse events (irAEs), which could lead to an unfavorable prognosis with fatal consequences. Therefore, we conducted a retrospective study to evaluate the utility of circulating sPD-L1 (soluble programmed cell death 1 ligand 1) as a biomarker in patients with advanced melanoma treated with anti-PD-1 (programmed cell death 1 protein) antibodies. Sera from 31 consecutive patients were prospectively collected before and after anti-PD-1 antibody treatment and the serum level of sPD-L1 was evaluated. We found that high sPD-L1 levels before treatment were associated with better prognosis, and this association was observed only in patients with a low tumor burden. We also found that sPD-L1 levels were elevated in patients who developed severe irAEs after treatment, and the patients with severe irAEs had significantly higher fluctuations in sPD-L1 (delta sPD-L1) than those without severe irAEs. Our study suggests that serum sPD-L1 level is a useful biomarker to predict tumor response and irAE development in patients with advanced melanoma treated with anti-PD-1 antibodies.

[The circulating PD-L1: An emerging predictive biomarker for immune checkpoint inhibitors response]. / Le taux circulant de PD-L1 : un biomarqueur émergent de réponse aux inhibiteurs de checkpoints immunitaires.

Immune checkpoint inhibitors (ICI) have recently become the standard of care for many metastatic solid tumors, with considerable improvements in patient prognosis. However, a non-negligible proportion of patients does not respond to this type of treatment, making it essential to identify predictive factors of this response in order to better adapt the therapy. Among the biomarkers that have been most extensively studied in recent years, tumor PD-L1 levels come out on top, with controversial results for predicting response to ICI. The determination of circulating PD-L1 (or soluble PD-L1) in peripheral blood seems to be an interesting emerging biomarker. Indeed, several studies have investigated its prognostic value, and/or its potential predictive value of response to immunotherapy, and it would appear that there is a correlation between the level of soluble PD-L1 and the level of tumor aggressiveness and therefore prognosis. Furthermore, the results suggest that higher PD-L1 levels are associated with a poorer response to immunotherapy, although this remains to be confirmed in large-scale studies.