Emerging biomarkers as predictors to anti-PD1/PD-L1 therapies in advanced melanoma

Adjuvant anti-PD1 immunotherapy of resected skin melanoma: an example of non-personalized medicine with no overall survival benefit

Randomized clinical trials demonstrated a recurrence-free survival benefit with adjuvant anti-programmed death-1 (anti-PD1) inhibitors of resected stage IIB-IV melanoma. However, no improvement in overall survival has been observed thus far. Furthermore, there are no predictive markers for immunotherapy response in melanoma, therefore adjuvant treatment is offered to all comers based exclusively on the pathological and clinical stages. Additionally, one year of treatment duration and the risk of chronic immune-related adverse effects may negatively impact patients´ quality of life. In this review, we will try to answer whether the currently available data on adjuvant anti-PD1 therapy of stage IIB-IV resected melanoma is sufficient to make this strategy available to all patients. We will also discuss the economic impact of this therapy on healthcare system budgets. Recent studies suggest that the high cost of cancer drugs may affect access to these agents globally by raising questions of sustainability for patients and society.

Correlation between PD-L1 expression of the tumour cells and lymphocytes infiltration in the invasive front of urothelial carcinoma

PURPOSE

Programmed cell death-ligand 1 (PD-L1) as a cell surface glycoprotein can inhibit T cell function when binding to its receptor, PD-1. The newly developed therapy of targeting PD-1/PD-L1 signal pathway has shown great promise for the treatment of non-small cell lung cancer as well as melanoma. Approved by Food and Drug Administration, atezolizumab has become the first new drug to treat advanced bladder cancer. The aim of this study is to evaluate whether PD-L1 is associated with the lymphocytes infiltration in the tumour microenvironment and to assess the prognostic value of PD-L1 expression.

MATERIALS AND METHODS

Among 96 invasive bladder urothelial carcinomas, some were used to construct tissue-microarrays, and some cases with shallow infiltration or large heterogeneity were performed, respectively, for the following work. By means of immunohistochemistry and HE, PD-L1 expression and immune cell infiltration in the invasive front of urothelial carcinoma were analysed.

RESULTS

We find that PD-L1 expression in tumour cells and lymphocytes are significantly associated with more tumour infiltrating lymphocytes (TILs) and more T cells. The integrated TILs, T-PD-L1 and I-PD-L1 are not significantly correlated with the overall survival (OS) of patients. However, the combination of T-PD-L1 and TILs, T-PD-L1 and I-PD-L1 is significantly correlated with the OS of patients. The T-PD-L1 (-)/TIL (-) group show the best prognosis and the T-PD-L1 (+)/I-PD-L1 (-) group show the worst prognosis. Furthermore, a multivariate analysis reveal that PD-L1 expression of lymphocytes is an independent prognostic factor for OS of patients.

CONCLUSIONS

Our study reveal that PD-L1 of tumour cells are associated with the corresponding T cells infiltration and that the combination of T-PD-L1 and I-PD-L1, T-PD-L1 and TILs could be a relevant marker for the determination of the prognostic role of patients with the urothelial carcinoma.

Dual blockage of PD-L/PD-1 and IL33/ST2 axes slows tumor growth and improves antitumor immunity by boosting NK cells

AIMS

Although separate blockage of either IL33/ST2 or PD-L/PD-1 axes has been shown to be beneficial in many tumors, co-blockage of IL33/ST2 and PD-L/PD-1 hasn't been studied yet.

MAIN METHODS

4T1 breast cancer and CT26 colon cancer were inducted in BALB/C wild type (WT) and BALB/C ST2 knockout mice, after which mice underwent anti PD-1 and anti IL-33 treatment.

KEY FINDINGS

Co-blockage of IL33/ST2 and PD-L/PD-1 delayed tumor appearance and slowed tumor growth. Enhanced NK cell cytotoxicity against 4T1 tumor cells in ST2 knockout anti-PD-1 treated mice was associated with overexpression of miRNA-150 and miRNA-155, upregulation of NFκB and STAT3, increased expression of activation markers and decreased expression of immunosuppressive markers in splenic and primary tumor derived NK cells. NK cells from ST2 knockout anti-PD-1 treated mice tend to proliferate more and are less prone to apoptosis. Accumulation of immunosuppressive myeloid derived suppressor cells and regulatory T cells was significantly impaired in spleen and primary tumor of ST2 knockout anti-PD-1 treated mice.

SIGNIFICANCE

Co-blockage of IL3/ST2 and PD-L/PD-1 axes impedes tumor progression more efficiently than single blockage of either axes, thus offering potential new approach to immunotherapy of tumors.

Epithelial-mesenchymal transition interaction with CD8+ T cell, dendritic cell and immune checkpoints in the development of melanoma

BACKGROUND

Melanoma is fatal cancer originating from melanocytes, whose high metastatic potential leads to an extremely poor prognosis.

OBJECTIVE

This study aimed to reveal the relationship among EMT, TIICs, and immune checkpoints in melanoma.

METHODS

Gene expression data and clinical data of melanoma were downloaded from TCGA, UCSC Xena and GEO databases. EMT-related DEGs were detected for risk score calculation. "ESTIMATE" and "xCell" were used for estimating TIICs and obtaining 64 immune cell subtypes, respectively. Moreover, we evaluated the relationship between the risk score and immune cell subtypes and immune checkpoints.

RESULTS

Seven EMT-related genes were selected to establish a risk scoring system because of their integrated prognostic relevance. The results of GSEA revealed that most of the gene sets focused on immune-related pathways in the low-risk score group. The risk score was significantly correlated with the xCell score of some TIICs, which significantly affected the prognosis of melanoma. Patients with a low-risk score may be associated with a better response to ICI therapy.

CONCLUSION

The individualized risk score could effectively conduct risk stratification, overall survival prediction, ICI therapy prediction, and TME judgment for patients with melanoma, which would be conducive to patients' precise treatment.

Clinical Significance of Composition Changes in T-cell Subpopulations After Chemotherapy in Patients With Gastric Cancer

BACKGROUND/AIM

New therapeutic agents and prognostic biomarkers for gastric cancer are needed. We analyzed the composition of peripheral blood T-cell subpopulations in response to chemotherapy in patients with gastric cancer.

PATIENTS AND METHODS

Peripheral blood samples were collected from patients diagnosed with gastric cancer before and after chemotherapy (FOLFOX; oxaliplatin, 5-fluorouracil, and leucovorin). Peripheral blood mononuclear cells were isolated. Patients were divided into responder (n=5) and non-responder groups (n=2) based on their chemotherapy outcomes.

RESULTS

Non-responders showed lower numbers of CD4+/total cells and CD8+/total cells after chemotherapy compared to the responder group, but the difference was not significant (p=0.905, p=0.095). Naïve T, central memory T, effector memory T and effector T-cell counts differed in both groups after chemotherapy.

CONCLUSION

Changes in peripheral T-cell subpopulations after chemotherapy were confirmed in patients with gastric cancer, which may be a prognostic predictor and development of therapeutic agents.

Bispecific anti-PD-1/LAG-3 antibodies for treatment of advanced or metastatic solid tumors: a patent evaluation of US2018326054

INTRODUCTION

Due to the primary role of PD-1 and LAG-3 in regulating the immune response in tumors, there is a need to develop therapies focused on the inhibition of PD-1 and LAG-3 in order to improve the immune response in patients with cancer. The authors of US2018326054 patent propose a method to eradicate cancer by using bispecific anti-PD-1/LAG-3 antibodies.

AREAS COVERED

The US2018326054 patent describes anti-PD-1/LAG3 antibodies, pharmaceutical composition that contains it, and their application for cancer treatment, particularly pancreatic carcinoma. Proof concept and preclinical results show anti-PD-1/LAG-3 bispecific antibodies bind and are internalized by CD4 + T cells thereby increasing their effector functions (release of Granzyme B and INF-γ) in the presence of tumor cells, and completely suppress tumors in a murine model.

EXPERT OPINION

Anti-PD-1/LAG-3 bispecific antibodies of the US2018326054 patent are new in a general concept, but treatment data is only shown for pancreatic carcinoma. The results to be obtained in future clinical trials of safety and efficacy could conclude whether these bispecific anti-PD-1/LAG-3 antibodies will be useful in a cancer treatment scheme.

Immuno-PET Imaging of the Programmed Cell Death-1 Ligand (PD-L1) Using a Zirconium-89 Labeled Therapeutic Antibody, Avelumab

OBJECTIVE

The goal is to evaluate avelumab, an anti-PD-L1 monoclonal immunoglobulin G antibody labeled with zirconium-89 in human PD-L1-expressing cancer cells and mouse xenografts for clinical translation.

METHODS

[⁸⁹Zr]Zr-DFO-PD-L1 monoclonal antibody (mAb) was synthesized using avelumab conjugated to desferrioxamine. In vitro binding studies and biodistribution studies were performed with PD-L1+MDA-MB231 cells and MDA-MB231 xenograft mouse models, respectively. Biodistributions were determined at 1, 2, 3, 5, and 7 days post coinjection of [⁸⁹Zr]Zr-DFO-PD-L1 mAb without or with unlabeled avelumab (10, 20, 40, and 400 µg).

RESULTS

[⁸⁹Zr]Zr-DFO-PD-L1 mAb exhibited high affinity (K_d ∼ 0.3 nM) and detected moderate PD-L1 expression levels in MDA-MB231 cells. The spleen and lymph nodes exhibited the highest [⁸⁹Zr]Zr-DFO-PD-L1 mAb uptakes in all time points, while MDA-MB231 tumor uptakes were lower but highly retained. In the unlabeled avelumab dose escalation studies, spleen tissue-muscle ratios decreased in a dose-dependent manner indicating specific [⁸⁹Zr]Zr-DFO-PD-L1 mAb binding to PD-L1. In contrast, lymph node and tumor tissue-muscle ratios increased 4- to 5-fold at 20 and 40 µg avelumab doses.

CONCLUSIONS

[⁸⁹Zr]Zr-DFO-PD-L1 mAb exhibited specific and high affinity for PD-L1 in vitro and had target tissue uptakes correlating with PD-L1 expression levels in vivo. [⁸⁹Zr]Zr-DFO-PD-L1 mAb uptake in PD-L1+tumors increased with escalating doses of avelumab.

Predictive biomarkers for PD-1 and PD-L1 immune checkpoint blockade therapy

The immune system is very important for monitoring and eradicating cancer cells. However, there may be multiple immunosuppressive mechanisms to prevent effective antitumor immunity in the tumor environment, such as the negative immunologic regulators known as checkpoints. Antibodies that block the checkpoints programmed cell death protein 1 (PD-1) pathway have made great success. Nevertheless, the response rates are likely to vary widely. Therefore, several researches are currently underway to determine which biomarkers are able to identify the group of patients who can obtain benefits from PD-1 and programmed cell death-ligand 1 (PD-L1) immune checkpoint blockade therapy. This review focuses on potential predictive biomarkers for PD-1/PD-L1 checkpoint blockade immunotherapy in order to provide advice and guidance for clinical treatment.

Immune checkpoint blockade and its combination therapy with small-molecule inhibitors for cancer treatment

Initially understood for its physiological maintenance of self-tolerance, the immune checkpoint molecule has recently been recognized as a promising anti-cancer target. There has been considerable interest in the biology and the action mechanism of the immune checkpoint therapy, and their incorporation with other therapeutic regimens. Recently the small-molecule inhibitor (SMI) has been identified as an attractive combination partner for immune checkpoint inhibitors (ICIs) and is becoming a novel direction for the field of combination drug design. In this review, we provide a systematic discussion of the biology and function of major immune checkpoint molecules, and their interactions with corresponding targeting agents. With both preclinical studies and clinical trials, we especially highlight the ICI + SMI combination, with its recent advances as well as its application challenges.

Spatial Mapping of Myeloid Cells and Macrophages by Multiplexed Tissue Staining

An array of phenotypically diverse myeloid cells and macrophages (MC&M) resides in the tumor microenvironment, requiring multiplexed detection systems for visualization. Here we report an automated, multiplexed staining approach, named PLEXODY, that consists of five MC&M-related fluorescently-tagged antibodies (anti - CD68, - CD163, - CD206, - CD11b, and - CD11c), and three chromogenic antibodies, reactive with high- and low-molecular weight cytokeratins and CD3, highlighting tumor regions, benign glands and T cells. The staining prototype and image analysis methods which include a pixel/area-based quantification were developed using tissues from inflamed colon and tonsil and revealed a unique tissue-specific composition of 14 MC&M-associated pixel classes. As a proof-of-principle, PLEXODY was applied to three cases of pancreatic, prostate and renal cancers. Across digital images from these cancer types we observed 10 MC&M-associated pixel classes at frequencies greater than 3%. Cases revealed higher frequencies of single positive compared to multi-color pixels and a high abundance of CD68+/CD163+ and CD68+/CD163+/CD206+ pixels. Significantly more CD68+ and CD163+ vs. CD11b+ and CD11c+ pixels were in direct contact with tumor cells and T cells. While the greatest percentage (~70%) of CD68+ and CD163+ pixels was 0–20 microns away from tumor and T cell borders, CD11b+ and CD11c+ pixels were detected up to 240 microns away from tumor/T cell masks. Together, these data demonstrate significant differences in densities and spatial organization of MC&M-associated pixel classes, but surprising similarities between the three cancer types.

A Novel 3D in Vitro Tumor Model Based on Silk Fibroin/Chitosan Scaffolds To Mimic the Tumor Microenvironment

Drug development involves various evaluation processes to ascertain drug effects and rigorous analysis of biological indicators during in vitro preclinical studies. Two-dimensional (2D) cell cultures are commonly used in numerous in vitro studies, which are poor facsimiles of the in vivo conditions. Recently, three-dimensional (3D) tumor models mimicking the tumor microenvironment and reducing the use of experimental animals have been developed generating great interest to appraise tumor response to treatment strategies in cancer therapy. In this study, silk fibroin (SF) protein and chitosan (CS), two natural biomaterials, were chosen to construct the scaffolds of 3D cell models. Human non-small cell lung cancer A549 cells in the SF/CS scaffolds were found to have a great tendency to gather and form tumor spheres. A549 cell spheres in the 3D scaffolds showed biological and morphological characteristics much closer to the in vivo tumors. Besides, the cells in 3D models displayed better invasion ability and drug resistance than 2D models. Additionally, differences in drug-resistant and immune-related protein levels were found, which indicated that 3D models might resemble the real-life situation. These findings suggested that these 3D tumor models composed of SF/CS are promising to provide a valuable biomaterial platform in the evaluation of anticancer drugs.

Correlation of Neutrophil to Lymphocyte Ratio and Absolute Neutrophil Count With Outcomes With PD-1 Axis Inhibitors in Patients With Advanced Non-Small-Cell Lung Cancer

INTRODUCTION

Programmed death-1 (PD-1) axis inhibitors have become standard therapy in advanced non-small-cell lung cancer (NSCLC). Response might be delayed and pseudo-progression occasionally occurs in patients who eventually benefit from treatment. Additional markers beyond programmed death ligand 1 (PD-L1) expression are needed to assist in patient selection, response evaluation, and treatment decisions.

MATERIALS AND METHODS

The relationship between prospectively collected clinical outcomes (response, disease control rate [DCR], treatment duration, overall survival) and hematologic parameters (neutrophil to lymphocyte ratio [NLR], absolute neutrophil count [ANC], and platelet to lymphocyte ratio [PLR]) was explored retrospectively in advanced NSCLC patients treated with PD-1 axis inhibitors at a major cancer center from May 2013 to August 2016. Hematologic parameters at baseline and during treatment (week 2 or 3 and week 8) were included.

RESULTS

Of 88 patients treated with PD-1 axis inhibitors, 22 (25%) experienced partial response. Baseline NLR ≤4 was associated with superior DCR (74% vs. 50%; P = .025), treatment duration (P = .037), time to progression (P = .053), and overall survival (P = .019), with no differential association according to PD-L1 tumor expression. Lower NLR and ANC during treatment were also associated with response to treatment (P = .025 and P = .017, respectively), and treatment duration (P = .036 and P = .008). No association was found between baseline PLR and DCR, response, treatment duration, nor overall survival.

CONCLUSION

Baseline NLR ≤4 and lower NLR and ANC during treatment might correlate with disease control and treatment response and should be explored further as potential predictors of treatment benefit in larger studies.

Prognosis vs Treatment Interaction

There is a somewhat confused belief that a biomarker must show an interaction effect with a treatment before it can be used to determine the need for such a treatment. This is rarely true for well-established clinical markers such as tumor size or regional lymph node involvement. In many cases, this is also not true for biomarkers, especially when considering nontargeted therapies. Here I argue that for nontargeted treatments prognosis is often more important than interaction with treatment, because it is the absolute and not the relative benefit that matters, and when there is no treatment interaction, the same relative benefit translates into a larger absolute benefit for poor prognosis patients.

Recent development in clinical applications of PD-1 and PD-L1 antibodies for cancer immunotherapy

Antibodies against programmed death (PD) pathway are revolutionizing cancer immunotherapy. Currently five antibodies against PD-1/PD-L1 have been approved. The clinical use of these antibodies is rapidly expanding. Incorporation of PD antibodies into chemotherapy regimens is in active clinical investigations. The combination of pembrolizumab with carboplatin and pemetrexed has been approved for the first line therapy of metastatic non-squamous non-small cell lung cancer. Combination of PD-1/PD-L1 antibodies with small molecule inhibitors such as tyrosine kinase inhibitors and IDO inhibitors are in active clinical trials. This review summarized recent development in clinical trials of PD-1 and PD-L1 antibodies for cancer immunotherapy.

DNA methylation/hydroxymethylation in melanoma

Melanoma is a malignant tumor of melanocytes and is considered to be the most aggressive cancer among all skin diseases. The pathogenesis of melanoma has not been well documented, which may restrict the research and development of biomarkers and therapies. To date, several genetic and epigenetic factors have been identified as contributing to the development and progression of melanoma. Besides the findings on genetic susceptibilities, the recent progress in epigenetic studies has revealed that loss of the DNA hydroxymethylation mark, 5-hydroxymethylcytosine (5-hmC), along with high levels of DNA methylation at promoter regions of several tumor suppressor genes in melanoma, may serve as biomarkers for melanoma. Moreover, 5-Aza-2′-deoxycytidine, an epigenetic modifier causing DNA demethylation, and ten-eleven translocation family dioxygenase (TET), which catalyzes the generation of 5-hmC, demonstrate therapeutic potential in melanoma treatment. In this review, we will summarize the latest progress in research on DNA methylation/hydroxymethylation in melanoma, and we will discuss and provide insight for epigenetic biomarkers and therapies for melanoma. Particularly, we will discuss the role of DNA hydroxymethylation in melanoma infiltrating immune cells, which may also serve as a potential target for melanoma treatment.

Synthetic lethality: emerging targets and opportunities in melanoma

Great progress has been made in the treatment of melanoma through use of targeted therapies and immunotherapy. One approach that has not been fully explored is synthetic lethality, which exploits somatically acquired changes, usually driver mutations, to specifically kill tumour cells. We outline the various approaches that may be applied to identify synthetic lethal interactions and define how these interactions may drive drug discovery efforts.

Immune biomarkers for prognosis and prediction of responses to immune checkpoint blockade in cutaneous melanoma

Existing clinical, anatomopathological and molecular biomarkers fail to reliably predict the prognosis of cutaneous melanoma. Biomarkers for determining which patients receive adjuvant therapies are needed. The emergence of new technologies and the discovery of new immune populations with different prognostic values allow the immune network in the tumor to be better understood. Importantly, new molecules identified and expressed by immune cells have been shown to reduce the antitumor immune efficacy of therapies, prompting researchers to develop antibodies targeting these so-called "immune checkpoints", which have now entered the oncotherapeutic armamentarium.