Differential Activity of Nivolumab, Pembrolizumab and MPDL3280A according to the Tumor Expression of Programmed Death-Ligand-1 (PD-L1): Sensitivity Analysis of Trials in Melanoma, Lung and Genitourinary Cancers

Anti-PD-1/PD-L1 antibodies in non-small cell lung cancer: the era of immunotherapy

INTRODUCTION

Advanced non-small cell lung cancer (NSCLC) has been conventionally treated with cytotoxic chemotherapy with short-lived responses and significant toxicities. Monoclonal antibodies to programmed death-1 receptor (PD-1) and programmed death ligand 1 (PD-L1) have shown tremendous promise in the treatment of advanced NSCLC in various clinical trials. Areas covered: In this article, we will review the outcomes of various trials of anti-PD-1/anti-PD-L1 antibodies in the treatment of NSCLC. We will also discuss their mechanism of action and toxicities. Expert commentary: Anti-PD-1/PD-L1 antibodies offer several advantages including significant antitumor activity, induction of long lasting responses, and favorable safety profile. Several trials are now being conducted to evaluate their efficacy as first line agents as well as in combination with other agents. More research is also needed to identify other biomarkers, in addition to PD-L1 expression, that could more reliably predict response to these drugs, and aid in better patient selection.

PD-L1 Status in Refractory Lymphomas

Targeted immunotherapy based on PD-1/PD-L1 suppression has revolutionized the treatment of various solid tumors. A remarkable improvement has also been observed in the treatment of patients with refractory/relapsing classical Hodgkin lymphoma (cHL). We investigated PD-L1 status in a variety of treatment resistant lymphomas. Tumor samples from 78 patients with therapy resistant lymphomas were immunohistochemically (IHC) investigated for the expression of PD-L1 using two antibody clones (SP142 and SP263, Ventana). Thirteen PD-L1+ cases were further analyzed for gene copy number variations (CNV) by NGS and for PD-L1/JAK2/PD-L2 co-amplification using fluorescent in-situ hybridization assay (FISH). PD-L1 positivity (≥5% positive cancer cells, IHC) was present in 32/77 (42%) and 33/71 cases (46%) using SP142 and SP263 antibodies, respectively. Concordance between the two anti-PD-L1 clones was high with only three (4%) discrepant cases. The strongest and consistent (10/11 cases) expression was observed in cHL and primary mediastinal B-cell lymphomas (3/3). Diffuse large B-cell lymphomas (DLBCL) were frequently positive (13/26) irrespective of subtype. Follicular (1/8), peripheral T-cell (3/11) and mantle cell (1/8) lymphomas were rarely positive, while small lymphocytic lymphoma/CLL and marginal zone lymphomas were consistently negative (3/3). Co-amplification/CNVs of PD-L1/JAK2/PD-L2 were observed in 3 cases of DLBCL and cHL, respectively. Of note, all three cHL-amplified cases were positive by FISH, but not by NGS. Since only a fraction of the IHC positive lymphoma cases were positive by FISH and NGS assays, other mechanisms are involved in PD-L1 upregulation, especially in DLBCL. FISH assay may be more suitable than NGS assay for determination of PD-L1 alterations in cHL.

Clinical outcomes in metastatic uveal melanoma treated with PD-1 and PD-L1 antibodies

BACKGROUND

Antibodies inhibiting the programmed death receptor 1 (PD-1) have demonstrated significant activity in the treatment of advanced cutaneous melanoma. The efficacy and safety of PD-1 blockade in patients with uveal melanoma has not been well characterized.

METHODS

Fifty-eight patients with stage IV uveal melanoma received PD-1 or PD-1 ligand (PD-L1) antibodies between 2009 and 2015 at 9 academic centers. Patients who were evaluable for response were eligible for the analysis. Imaging was performed every 12 weeks and at the investigators' discretion. Safety and clinical efficacy outcomes, including the best overall response, progression-free survival (PFS), and overall survival (OS), were retrospectively determined.

RESULTS

Of 56 eligible patients, 48 (86%) had received prior therapy, and 35 (63%) had received treatment with ipilimumab. Three patients had an objective response to ipilimumab, and 8 had stable disease as their best response. Thirty-eight patients (68%) received pembrolizumab, 16 (29%) received nivolumab, and 2 (4%) received atezolizumab. Objective tumor responses were observed in 2 patients for an overall response rate of 3.6% (95% confidence interval [CI], 1.8%-22.5%). Stable disease (≥6 months) was observed in 5 patients (9%). The median PFS was 2.6 months (95% CI, 2.4-2.8 months), and the median OS was 7.6 months (95% CI, 0.7-14.6 months). There was no association between prior treatment with ipilimumab or liver-directed therapy and PFS or OS. Treatment was well tolerated, and only 1 patient discontinued treatment because of toxicity.

CONCLUSIONS

PD-1 and PD-L1 antibodies rarely confer durable remissions in patients with metastatic uveal melanoma. Clinical trial enrollment should be prioritized in this population. Cancer 2016;122:3344-3353. © 2016 American Cancer Society.

Gene-expression profiling to predict responsiveness to immunotherapy

Recent clinical successes with immunotherapy have resulted in expanding indications for cancer therapy. To enhance anti-tumor immune responses, and to better choose specific strategies matched to patient and tumor characteristics, genomic-driven precision immunotherapy will be necessary. Herein, we explore the role that tumor gene expression profiling (GEP) and transcriptome expression may play in the prediction of an immunotherapeutic response. Genetic markers associated with response to immunotherapy are addressed as they pertain to the tumor genomic landscape, the extent of DNA damage, tumor mutational load, and tumor-specific neoantigens. Furthermore, genetic markers associated with resistance to checkpoint blockade and relapse are reviewed. Finally, the utility of GEP to identify new tumor types for immunotherapy and implications for combinatorial strategies are summarized.

Checkpoint Proteins in Pediatric Brain and Extracranial Solid Tumors: Opportunities for Immunotherapy

Pediatric brain and extracranial solid tumors are a diverse group of malignancies that represent almost half of all pediatric cancers. Standard therapy includes various combinations of surgery, cytotoxic chemotherapy, and radiation, which can be very harmful to a developing child, and survivors carry a substantial burden of long-term morbidities. Although these therapies have improved survival rates for children with solid tumors, outcomes still remain extremely poor for subsets of patients. Recently, immunosuppressive checkpoint molecules that negatively regulate immune cell function have been described. When found on malignant cells or in the tumor microenvironment, they contribute to immune evasion and tumor escape. Agents designed to inhibit these proteins have demonstrated significant efficacy in human adult solid tumor studies. However, there is limited research focusing on immune checkpoint molecules and inhibitors in pediatric solid tumors. In this review, we examine the current knowledge on immune checkpoint proteins with an emphasis on cytotoxic T lymphocyte antigen-4 (CTLA-4); programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PD-L1); OX-2 membrane glycoprotein (CD200); and indoleamine 2,3-dioxygenase (IDO). We review T-cell signaling, the mechanisms of action of these checkpoint molecules, pediatric preclinical studies on checkpoint proteins and checkpoint blockade, pediatric checkpoint inhibitor clinical trials conducted to date, and future immunotherapy opportunities for childhood cancers. Clin Cancer Res; 23(2); 342-50. ©2016 AACR.

Nivolumab in melanoma

INTRODUCTION

The treatment of melanoma is evolving rapidly over the past few years. Areas covered: We conducted a comprehensive review of the literature on the role of nivolumab in melanoma Expert commentary: Nivolumab is approved by FDA and EMA for the treatment of patients with metastatic melanoma. Nivolumab is superior to chemotherapy and to ipilimumab in previously untreated patients and to chemotherapy in ipilimumab pre-treated patients. The addition ipilimumab to nivolumab is associated with a higher response rate and a better PFS, particularly in patients with PD-L1 negative tumors, albeit at the cost of an increase in grade 3-4 adverse event rate. Definitive survival data on this combination are pending and the selection of patients most likely to benefit from this combination and its pharmacoeconomics are to be elucidated. Prospectively validated predictive markers are lacking. Of particular interest are immune-related adverse events which should be managed according to published guidelines.

Intra-tumor AvidinOX allows efficacy of low dose systemic biotinylated Cetuximab in a model of head and neck cancer

For locally advanced and metastatic head and neck squamous cell carcinoma (HNSCC), the current clinical use of Cetuximab in chemo/radiotherapy protocols is often associated to severe systemic toxicity. Here we report in vitro data in human FaDu pharynx SCC cells, showing that inactive concentrations of biotinylated Cetuximab (bCet) become active upon anchorage to AvidinOX on the surface of tumor cells. AvidinOX-anchored bCet induces apoptosis and DNA damage as well as specific inhibition of signaling, degradation and abrogation of nuclear translocation of EGFR. In the mouse model of FaDu cancer, we show that intra-tumor injection of AvidinOX allows anti-tumor activity of an otherwise inactive, intraperitoneally delivered, low dose bCet. Consistently with in vitro data, in vivo tumor inhibition is associated to induction of apoptosis, DNA damage and reduced angiogenesis. AvidinOX is under clinical investigation for delivering radioactive biotin to inoperable tumors (ClinicalTrials.gov NCT02053324) and present data support its use for the local treatment of HNSCC in combination with systemic administration of low dose bCet.

Lenvatinib and other tyrosine kinase inhibitors for the treatment of radioiodine refractory, advanced, and progressive thyroid cancer

Lenvatinib is a small oral molecule able to inhibit three of the extracellular and intracellular molecules involved in the modulation of angiogenesis and lymphangiogenesis: vascular endothelial growth factor receptor 1–3, fibroblast growth factor receptor 1–4, and platelet-derived growth factor receptor alpha. Since it is also able to inhibit the REarranged during Transfection oncogene and the protooncogene c-KIT, this drug can also be used to control tumor cell proliferation. The maximum tolerated dose, as demonstrated in Phase I studies, is 25 mg daily. The drug is rapidly absorbed with maximum concentrations achieved within 3 and 5 hours after administration in fasting and nonfasting treated patients, respectively. The most common adverse events, reported in Phase I study and confirmed in the subsequent Phase II and III studies, are hypertension, proteinuria, and gastrointestinal symptoms such as nausea, diarrhea, and stomatitis. In Phase I studies, efficacy of lenvatinib in solid tumors was demonstrated, and these encouraging results have led to the development of a Phase II study using lenvatinib in advance radioiodine-refractory differentiated thyroid cancer (DTCs) patients. Since an overall response rate of 50% was reported, this study also confirmed the efficacy of lenvatinib in DTCs patients with an acceptable toxicity profile. Recently, a Phase III study in patients with DTCs (SELECT study) demonstrated the lenvatinib efficacy in prolonging progression-free survival with respect to the placebo (18.3 vs 3.6 months; P<0.001). Although there was no statistically significant difference in the overall survival of the entire group, this result was observed when the analysis was restricted to both the follicular histotype and the group of senior patients (>65 years). The study confirmed that the most common side effects of this drug are hypertension, diarrhea, decreased appetite, weight loss, nausea, and proteinuria. In this review, we report the results of the main studies on lenvatinib efficacy in patients with advanced and progressive thyroid cancer, mainly in DTCs but also in medullary and anaplastic thyroid cancer. We also compared the efficacy of lenvatinib with that of other tyrosine kinase inhibitors, mainly sorafenib, already tested in the same type of patient population.

Anti-PD-1 increases the clonality and activity of tumor infiltrating antigen specific T cells induced by a potent immune therapy consisting of vaccine and metronomic cyclophosphamide

BACKGROUND

Future cancer immunotherapies will combine multiple treatments to generate functional immune responses to cancer antigens through synergistic, multi-modal mechanisms. In this study we explored the combination of three distinct immunotherapies: a class I restricted peptide-based cancer vaccine, metronomic cyclophosphamide (mCPA) and anti-PD-1 treatment in a murine tumor model expressing HPV16 E7 (C3).

METHODS

Mice were implanted with C3 tumors subcutaneously. Tumor bearing mice were treated with mCPA (20 mg/kg/day PO) for seven continuous days on alternating weeks, vaccinated with HPV16 E749-57 peptide antigen formulated in the DepoVax (DPX) adjuvanting platform every second week, and administered anti-PD-1 (200 μg/dose IP) after each vaccination. Efficacy was measured by following tumor growth and survival. Immunogenicity was measured by IFN-γ ELISpot of spleen, vaccine draining lymph nodes and tumor draining lymph nodes. Tumor infiltration was measured by flow cytometry for CD8α+ peptide-specific T cells and RT-qPCR for cytotoxic proteins. The clonality of tumor infiltrating T cells was measured by TCRβ sequencing using genomic DNA.

RESULTS

Untreated C3 tumors had low expression of PD-L1 in vivo and anti-PD-1 therapy alone provided no protection from tumor growth. Treatment with DPX/mCPA could delay tumor growth, and tri-therapy with DPX/mCPA/anti-PD-1 provided long-term control of tumors. We found that treatment with DPX/mCPA/anti-PD-1 enhanced systemic antigen-specific immune responses detected in the spleen as determined by IFN-γ ELISpot compared to those in the DPX/mCPA group, but immune responses in tumor-draining lymph nodes were not increased. Although no increases in antigen-specific CD8α+ TILs could be detected, there was a trend for increased expression of cytotoxic genes within the tumor microenvironment as well as an increase in clonality in mice treated with DPX/mCPA/anti-PD-1 compared to those with anti-PD-1 alone or DPX/mCPA. Using a library of antigen-specific CD8α+ T cell clones, we found that antigen-specific clones were more frequently expanded in the DPX/mCPA/anti-PD-1 treated group.

CONCLUSIONS

These results demonstrate how the efficacy of anti-PD-1 may be improved by combination with a potent and targeted T cell activating immune therapy.

Development of a programmed cell death ligand-1 immunohistochemical assay validated for analysis of non-small cell lung cancer and head and neck squamous cell carcinoma

Background

A high-quality programmed cell-death ligand 1 (PD-L1) diagnostic assay may help predict which patients are more likely to respond to anti-programmed cell death-1 (PD-1)/PD-L1 antibody-based cancer therapy. Here we describe a PD-L1 immunohistochemical (IHC) staining protocol developed by Ventana Medical Systems Inc. and key analytical parameters of its use in formalin-fixed, paraffin-embedded (FFPE) samples of non-small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC).

Methods

An anti-human PD-L1 rabbit monoclonal antibody (SP263) was optimized for use with the VENTANA OptiView DAB IHC Detection Kit on the automated VENTANA BenchMark ULTRA platform. The VENTANA PD-L1 (SP263) Assay was validated for use with FFPE NSCLC and HNSCC tissue samples in a series of studies addressing sensitivity, specificity, robustness, and precision. Samples from a subset of 181 patients from a Phase 1/2 study of durvalumab (NCT01693562) were analyzed to determine the optimal PD-L1 staining cut-off for enriching the probability of responses to treatment. The scoring algorithm was defined using statistical analysis of clinical response data from this clinical trial and PD-L1 staining parameters in HNSCC and NSCLC tissue. Inter-reader agreement was established by three pathologists who evaluated 81 NSCLC and 100 HNSCC samples across the range of PD-L1 expression levels.

Results

The VENTANA PD-L1 (SP263) Assay met all pre-defined acceptance criteria. For both cancer types, a cut-off of 25 % of tumor cells with PD-L1 membrane staining of any intensity best discriminated responders from nonresponders. Samples with staining above this value were deemed to have high PD-L1 expression, and those with staining below it were deemed to have low or no PD-L1 expression. Inter-reader agreement on PD-L1 status was 97 and 92 % for NSCLC and HNSCC, respectively.

Conclusions

These results highlight the robustness and reproducibility of the VENTANA PD-L1 (SP263) Assay and support its suitability for use in the evaluation of NSCLC and HNSCC FFPE tumor samples using the devised ≥25 % tumor cell staining cut-off in a clinical setting. The clinical utility of the PD-L1 diagnostic assay as a predictive biomarker will be further validated in ongoing durvalumab studies.

Trial registration

ClinicalTrials.gov: NCT01693562

Molecular Imaging and Precision Medicine: PET/Computed Tomography and Therapy Response Assessment in Oncology

A variety of methods have been developed to assess tumor response to therapy. Standardized qualitative criteria based on 18F-fluoro-deoxyglucose PET/computed tomography have been proposed to evaluate the treatment effectiveness in specific cancers and these allow more accurate therapy response assessment and survival prognostication. Multiple studies have addressed the utility of the volumetric PET biomarkers as prognostic indicators but there is no consensus about the preferred segmentation methodology for these metrics. Heterogeneous intratumoral uptake was proposed as a novel PET metric for therapy response assessment. PET imaging techniques will be used to study the biological behavior of cancers during therapy.

Pembrolizumab for the treatment of non-small cell lung cancer

INTRODUCTION

Immune checkpoint inhibitors targeting programmed death protein 1 (PD-1) receptor and its ligand, PD-L1, have recently led to significant and durable improvements in the clinical outcomes of some types of cancers including lung cancer.

AREAS COVERED

Pembrolizumab was approved by the US FDA for the treatment of advanced or metastatic NSCLC whose disease has progressed after other treatments and with tumors that express PD-L1. In the phase I KEYNOTE-001 trial, the overall response rate (ORR) was 19.4%, the median progression-free survival (PFS) and overall survival (OS) were 3.7 months and 12.0 months for 495 unselected NSCLC patients. Strong PD-L1 expression (≥ 50%) was associated with higher ORR, longer PFS, and longer OS. The phase II/III randomized KEYNOTE-010 trial demonstrated that pembrolizumab improved OS versus docetaxel in patients with previously treated NSCLC.

EXPERT OPINION

Pembrolizumab, demonstrated durable response and prolonged OS especially in NSCLC patients with high expression of PD-1, thereby suggests a new treatment paradigm. However, many issues remain to be explored, including the identification of other robust biomarkers that can accurately predict the immune-responsiveness of tumors. Along with the identification of predictive biomarkers, further understanding of the tumor microenvironment is necessary to improve treatment outcomes through combinations of immunotherapy or combined with other targeted therapies.

Efficacy of short-term nivolumab treatment in a Chinese patient with relapsed advanced-stage lung squamous cell carcinoma: A case report

INTRODUCTION

Currently, the options are limited for the treatment of patients who have failed 2 lines of chemotherapy for advanced lung squamous cell carcinoma (SCC). Recently, nivolumab, a fully human IgG4 programmed death 1 immune checkpoint inhibitor antibody, was approved to treat patients with advanced stage, relapsed/refractory lung SCC. Although nivolumab has demonstrated antitumor activity with survival benefit in Caucasian patients, its efficacy in Asian patients is unknown.

CASE REPORT

In this report, we describe a Chinese patient with relapsed advanced stage lung SCC who had an excellent response to nivolumab after only 2 doses without any adverse effects. Immunohistochemical analysis indicated the tumor was stained positive for programmed death-ligand 1.

CONCLUSION

To our knowledge, this is the first report of satisfactory efficacy of short-term nivolumab treatment in a Chinese patient with relapsed advanced-stage lung SCC. Further clinical trials in Asian countries are needed to test whether nivolumab immunotherapy is a safe and effective treatment for Asian patients with lung SCC.

Expression of Programmed Death Ligand 1 in Penile Cancer is of Prognostic Value and Associated with HPV Status

PURPOSE

PD-L1 (programmed death ligand 1) inhibits T-cell function and prevents tumor eradication. This is facilitated by PD-L1 positive tumor cells and PD-L1 positive immune cells, and can be prevented by anti-PD-1 (programmed death 1)/PD-L1 immunotherapy. In advanced penile cancer there is a need for new therapeutic strategies. We investigated PD-L1 expression in penile cancers and compared PD-L1 expression with disease specific survival, lymph node metastases at diagnosis and high risk HPV status in a large patient cohort.

MATERIALS AND METHODS

A total of 213 primary tumors were immunohistochemically stained for PD-L1 and scored for tumor (percentage), stroma (binary) and PD-L1 positive tumor infiltrating macrophages. Additionally, PD-L1 positive tumors were scored for expression pattern, that is diffuse or predominantly present at the tumor-stroma margin.

RESULTS

Staining was successful in 200 tumors, of which 75% were high risk HPV negative. Median followup was 62 months. Of 200 tumors 96 (48%) were PD-L1 positive (scored 1% or greater), of which 59 (62%) had a marginal expression pattern and 79 (82%) were high risk HPV negative (p = 0.03). Compared to PD-L1 negative tumors, the PD-L1 expression patterns had different prognostic values in the whole cohort as well as in the high risk HPV negative subgroup. On multivariable analyses a marginal expression pattern was associated with absent lymph node metastases (OR 0.4) while diffuse expression was associated with poor survival (HR 2.58). These results were more prominent in the high risk HPV negative subgroup (OR 0.25, HR 3.92).

CONCLUSIONS

PD-L1 was expressed in 48% of penile carcinomas and mainly in high risk HPV negative tumors. The pattern of expression was a prognostic factor as marginal expression was associated with absent lymph node metastases and diffuse expression was associated with poor survival.

Predicting PD-L1 expression on human cancer cells using next-generation sequencing information in computational simulation models

PURPOSE

Interaction of the programmed death-1 (PD-1) co-receptor on T cells with the programmed death-ligand 1 (PD-L1) on tumor cells can lead to immunosuppression, a key event in the pathogenesis of many tumors. Thus, determining the amount of PD-L1 in tumors by immunohistochemistry (IHC) is important as both a diagnostic aid and a clinical predictor of immunotherapy treatment success. Because IHC reactivity can vary, we developed computational simulation models to accurately predict PD-L1 expression as a complementary assay to affirm IHC reactivity.

METHODS

Multiple myeloma (MM) and oral squamous cell carcinoma (SCC) cell lines were modeled as examples of our approach. Non-transformed cell models were first simulated to establish non-tumorigenic control baselines. Cell line genomic aberration profiles, from next-generation sequencing (NGS) information for MM.1S, U266B1, SCC4, SCC15, and SCC25 cell lines, were introduced into the workflow to create cancer cell line-specific simulation models. Percentage changes of PD-L1 expression with respect to control baselines were determined and verified against observed PD-L1 expression by ELISA, IHC, and flow cytometry on the same cells grown in culture.

RESULT

The observed PD-L1 expression matched the predicted PD-L1 expression for MM.1S, U266B1, SCC4, SCC15, and SCC25 cell lines and clearly demonstrated that cell genomics play an integral role by influencing cell signaling and downstream effects on PD-L1 expression.

CONCLUSION

This concept can easily be extended to cancer patient cells where an accurate method to predict PD-L1 expression would affirm IHC results and improve its potential as a biomarker and a clinical predictor of treatment success.

[Update on molecular classifications and new histological classification of bladder cancer]

OBJECTIVE

Comment the new WHO histological classification of tumors of the urinary system and male genital organs 2016 and expose the state of art about urothelial carcinogenesis and molecular modifications of bladder cancer, with the consequences on the treatments.

MATERIAL AND METHOD

A systematic review of the literature search was performed from the data base PubMed, focused on the following keywords: "bladder cancer", "molecular", "subtypes".

RESULTS

The new WHO histological classification of tumors of the urinary system 2016 confirm the importance of pathology in determining the care of patients, especially the grade, the histological type and the infiltration, while taking into account the difficulties. In 2014, the Cancer Genome Atlas reported genetic modifications of bladder cancer. Recently, several studies explored molecular anomalies of bladder cancer and elaborated molecular classifications, analyzing their predictive value. According to the groups, different molecular subtype had been defined: Urobasal A, Urobasal B, genomically unstable, infiltrated, squamous cell carcinoma-like and p53-like luminal bladder cancers. This latter subgroup seems to be chemoresistant.

CONCLUSIONS

The molecular biology and classifications allow a better understanding of bladder cancer and could complete in near future histological data to improve patient management.

Reinstating endogenous antitumor immunity: The concept of therapeutic management of cancer

Strong evidence points to the role of cancer immunoediting and tumor immune infiltrates in regulating cancer progression. By understanding the immune tumor microenvironment, we can now target key pathways that suppress endogenous antitumor responses, thereby re-instating such immune responses and identifying novel targets for immune therapies. Therapies targeting oncogenic pathways and checkpoint blockades turn on a new paradigm shift in immune-therapy for cancer with remarkable clinical efficacy seen in various malignancies. However, a lot of cancer patients will fail to respond and therefore, it becomes crucial to identify biomarkers to predict who of the patients will most likely benefit from these therapies.

Pembrolizumab for the treatment of PD-L1 positive advanced or metastatic non-small cell lung cancer

The emergence of immune checkpoint inhibitors marked an important advancement in the development of cancer therapeutics. Pembrolizumab is a selective humanized IgG4 kappa monoclonal antibody that inhibits the programmed death-1 (PD-1) receptor, an integral component of immune checkpoint regulation in the tumor microenvironment. The drug is currently approved by the Food and Drug Administration for the treatment of advanced melanoma and metastatic squamous and nonsquamous non-small cell lung cancer (NSCLC). Several published studies demonstrate that single-agent pembrolizumab is safe and has efficacy in patients with NSCLC. Many ongoing protocols are investigating the role of pembrolizumab in combination with other agents in lung cancer and various other cancer types. We review the available data on pembrolizumab in NSCLC and examine the role of potential predictive biomarkers of response to therapy.

Nivolumab, anti-programmed death-1 (PD-1) monoclonal antibody immunotherapy: Role in advanced cancers

The development of immune checkpoint inhibitors has altered the landscape of treatment of advanced cancers. These drugs are well tolerated and have shown clinical activity against a wide variety of solid tumors and hematological malignancies. The durability of response is particularly impressive when compared to other forms of systemic therapy. Nivolumab (Opdivo) is an IgG4 antibody that causes immune checkpoint blockade by diminishing inhibitory signaling through the programmed death receptor-1 pathway. It is approved for treatment of recurrent non-small cell lung cancer, melanoma, and renal cell carcinoma. Efforts to identify biomarkers of response to nivolumab are ongoing. Clinical trials are also being conducted to determine the benefits of combining nivolumab with other forms of treatment including chemotherapy, molecular-targeted therapy, radiation therapy, and other forms of immune therapy. This review outlines the clinical trials that have led to the emergence of nivolumab as a treatment option for patients with advanced cancers.

Clinical Neuropathology mini-review 6-2015: PD-L1: emerging biomarker in glioblastoma?

Programmed death 1 (PD-1, CD279) and programmed death ligand 1 (PD-L1, CD274) are involved in generating tumor-associated immunosuppression by suppression of T-cell proliferation and interleukin 2 (IL-2) production and immune checkpoint inhibitors targeting these molecules are showing compelling activity against a variety of human cancers. PD-L1 expression has shown a positive association with response to PD-1 inhibition in non-central nervous system (CNS) tumors, e.g., melanoma or non-small cell lung cancer, and is discussed as a potential predictive biomarker for patient selection in these tumor types. This review summarizes current knowledge and potential clinical implications of PD-L1 expression in glioblastoma. At present, the following conclusions are drawn: (a) functional data support a role for PD-1/PD-L1 in tumor-associated immunosuppression in glioblastoma; (b) the incidence of PD-L1-expressing glioblastomas seems to be relatively high in comparison to other tumor types, however, the reported rates of glioblastomas with PD-L1 protein expression vary and range from 61 to 88%; (c) there is considerable variability in the methodology of PD-L1 assessment in glioblastoma across studies with heterogeneity in utilized antibodies, tissue sampling strategies, immunohistochemical staining protocols, cut-off definitions, and evaluated staining patterns; (d) there are conflicting data on the prognostic role and so far no data on the predictive role of PD-L1 gene and protein expression in glioblastoma. In summary, the ongoing clinical studies evaluating the activity of PD-1/PD-L1 inhibitors in glioblastoma need to be complemented with well designed and stringently executed studies to understand the influence of PD-1/PD-L1 expression on therapy response or failure and to develop robust means of PD-L1 assessment for meaningful biomarker development.

Monitoring PD-L1 positive circulating tumor cells in non-small cell lung cancer patients treated with the PD-1 inhibitor Nivolumab

Controversial results on the predictive value of programmed death ligand 1 (PD-L1) status in lung tumor tissue for response to immune checkpoint inhibitors do not allow for any conclusive consideration. Liquid biopsy might allow real-time sampling of patients for PD-L1 through the course of the disease. Twenty-four stage IV NSCLC patients included in the Expanded Access Program with Nivolumab were enrolled. Circulating tumor cells (CTCs) were analyzed by CellSearch with anti-human B7-H1/PD-L1 PE-conjugated antibody. PD-L1 expressing CTCs were assessed at baseline, at 3 and 6 months after starting therapy, and correlated with outcome. At baseline and at 3 months of treatment, the presence of CTCs and the expression of PD-L1 on their surface were found associated to poor patients outcome. Nevertheless, the high frequency of PD-L1 expressing CTCs hampered to discriminate the role of PD-L1 in defining prognosis. Conversely although CTCs were found in all patients 6 months after treatment, at this time patients could be dichotomized into two groups based PD-L1 expression on CTCs. Patients with PD-L1 negative CTCs all obtained a clinical benefit, while patients with PD-L1 (+) CTCs all experienced progressive disease. This suggests that the persistence of PD-L1(+) CTCs might mirror a mechanism of therapy escape.

Development of a Companion Diagnostic for Pembrolizumab in Non-Small Cell Lung Cancer Using Immunohistochemistry for Programmed Death Ligand-1

Context .- Programmed death ligand-1 (PD-L1) expression by tumors may enable them to avoid immunosurveillance. Objective .- To develop a PD-L1 immunohistochemical assay using the 22C3 anti-PD-L1 murine monoclonal antibody on the Dako platform as a possible companion diagnostic for pembrolizumab in patients with non-small cell lung cancer. Design .- Tumor samples from 146 patients with non-small cell lung cancer treated with pembrolizumab in KEYNOTE-001 and for whom response data were available were scored according to their staining intensity by a single pathologist using 4 methods: percentage of tumor cells staining at any intensity (PS1), moderate/strong intensity (PS2), strong intensity (PS3), and H-score (PS1 + PS2 + PS3). The cutoff score for predicting response to pembrolizumab was determined using receiver operating characteristic analysis. Progression-free and overall survival were assessed in patients with measurable disease per Response Evaluation Criteria in Solid Tumors, version 1.1 (n = 146). Results .- The 4 scoring methods assessed performed similarly; PS1 with a 50% cutoff score is the simplest and easiest method to implement in practice. Response to pembrolizumab was observed in 19 of 44 patients (43%) with a PS1 score of 50% or higher and 8 of 102 patients (8%) with PS1 lower than 50% (odds ratio, 8.93). Median progression-free and overall survival was 4.0 months and not yet reached, respectively, for patients with a PS1 of 50% or higher, and 2.1 and 6.1 months, respectively, for those with PS1 lower than 50%. Conclusion .- The PD-L1 immunohistochemical assay shows the potential for enrichment of trial populations and as a companion diagnostic tool in non-small cell lung cancer.

An update on the pharmacodynamics, pharmacokinetics, safety and clinical efficacy of nivolumab in the treatment of solid cancers

INTRODUCTION

Nivolumab is a programmed cell death 1 (PD-1) inhibitor that has been approved for treatment of advanced melanoma, non-small cell lung carcinoma, renal cell carcinoma and classical Hodgkin's lymphoma.

AREAS COVERED

This review summarizes the latest evidence on nivolumab's pharmacodynamics, pharmacokinetics, safety and clinical efficacy in different solid tumors, based on published studies and abstracts from international conferences.

EXPERT OPINION

Multiple high-level evidence has confirmed the efficacy and safety of nivolumab in solid tumors. Further studies should focus on the identification of potential predictive biomarkers and possibility of combining with other immunotherapeutic or cytotoxic agents. The optimal sequence, treatment duration and possibility of re-challenging patients who had prior nivolumab are yet to be defined.

Dramatic response to anti-PD-1 therapy in a patient of squamous cell carcinoma of thymus with multiple lung metastases

Immunotherapy directed at the programmed cell death-1 receptor (PD-1) or its ligand PD-L1 has demonstrated efficacy in some malignancies, such as metastatic melanoma and non-small-cell lung cancer (NSCLC). Compared with cytotoxic chemotherapy, radiotherapy or molecular targeted agent, it is an innovative way to treat malignancies with durable clinical responses and manageable adverse. We present a case of female patient with squamous cell carcinoma of thymus involving multiple lung metastases, who was successfully treated with anti-PD-1 monoclonal antibody, pembrolizumab.

New targeted treatments for non-small-cell lung cancer - role of nivolumab

Non-small-cell lung cancer (NSCLC) is often diagnosed at an advanced stage of disease, where it is no longer amenable to curative treatment. During the last decades, the survival has only improved significantly for lung cancer patients who have tumors harboring a driver mutation. Therefore, there is a clear unmet need for effective therapies for patients with no mutation. Immunotherapy has emerged as an effective treatment for different cancer types. Nivolumab, a monoclonal inhibitory antibody against PD-1 receptor, can prolong survival of NSCLC patients, with a manageable toxicity profile. In two Phase III trials, nivolumab was compared to docetaxel in patients with, respectively, squamous (CheckMate 017) and non-squamous NSCLC (CheckMate 057). In both trials, nivolumab significantly reduced the risk of death compared to docetaxel (41% and 27% lower risk of death for squamous and non-squamous NSCLC, respectively). Therefore, nivolumab has been approved in the US and in Europe as second-line treatment for advanced NSCLC. Unfortunately, accurate predictive factors for patient selection are lacking, making it difficult to decide who will benefit and who will not. Currently, there are many ongoing trials that evaluate the efficacy of nivolumab in different settings and in combination with other agents. This paper reviews the present literature about the role of nivolumab in the treatment of NSCLC. Particular attention has been given to efficacy studies, toxicity profile, and current and emerging predictive factors.

Combinatorial approach to cancer immunotherapy: strength in numbers

Immune-checkpoint blockade therapy with antibodies targeting CTLA-4 and PD-1 has revolutionized melanoma treatment by eliciting responses that can be remarkably durable and is now advancing to other malignancies. However, not all patients respond to immune-checkpoint inhibitors. Extensive preclinical evidence suggests that combining immune-checkpoint inhibitors with other anti-cancer treatments can greatly improve the therapeutic benefit. The first clinical success of the combinatorial approach to cancer immunotherapy was demonstrated using a dual-checkpoint blockade with CTLA-4 and PD-1 inhibitors, which resulted in accelerated FDA approval of this therapeutic regimen. In this review, we discuss the combinations of current and emerging immunotherapeutic agents in clinical and preclinical development and summarize the insights into potential mechanisms of synergistic anti-tumor activity gained from animal studies. These promising combinatorial partners for the immune-checkpoint blockade include therapeutics targeting additional inhibitory receptors of T cells, such as TIM-3, LAG-3, TIGIT, and BTLA, and agonists of T cell costimulatory receptors 4-1BB, OX40, and GITR, as well as agents that promote cancer cell recognition by the immune system, such as tumor vaccines, IDO inhibitors, and agonists of the CD40 receptor of APCs. We also review the therapeutic potential of regimens combining the immune-checkpoint blockade with therapeutic interventions that have been shown to enhance immunogenicity of cancer cells, including oncolytic viruses, RT, epigenetic therapy, and senescence-inducing therapy.

Pharmacokinetics, pharmacodynamics and clinical efficacy of nivolumab in the treatment of metastatic renal cell carcinoma

INTRODUCTION

Nivolumab is a recombinant, humanized monoclonal antibody that binds PD-1. The binding of PD-1 with PD-L1, expressed on antigen-presenting cells and tumor cells, suppresses the ability of T-lymphocytes to recognize and destroy tumor cells. Nivolumab reverts this inhibitory signal and has led to a significant prolongation of overall survival in patients with metastatic renal cell carcinoma (RCC).

AREAS COVERED

The rationale for immunotherapy in metastatic RCC, key immune checkpoint pathways, nivolumab pharmacodynamics, results from the main clinical trials, and predictors of response are discussed.

EXPERT OPINION

Nivolumab demonstrated a statistically significant advantage over everolimus in overall survival in metastatic RCC patients after first-line antiangiogenic therapy. Nevertheless, a number of issues remain to be resolved regarding the use of this drug in RCC. It is now imperative to identify which patients can benefit most from immunotherapy and studies are ongoing to define its role in other settings and/or in combinations with antiCTLA4 or antiangiogenic drugs.

Biomarkers in melanoma

Malignant melanoma remains the skin cancer with the highest number of mortalities worldwide. While early diagnosis and complete surgical excision remain the best possibility for curing disease, prognosis at the stage of metastasis is still poor. Recent years have brought about considerable advances in terms of understanding the pathogenesis of melanoma and treating advanced disease. The discovery of activating BRAF mutations in around 50% of tumors has led to the introduction of targeted therapies downregulating BRAF signaling output. These have been further refined as combination therapies, which by targeting multiple targets have further improved the clinical outcome. A comparable, potentially even superior therapeutic alternative has been the introduction of immunotherapeutic approaches, including PD-1 and CTLA-4 checkpoint blockade therapies. Despite all genetic knowledge acquired in recent years, a clearly applicable prognostic signature of clinical value has not been established. General prognostic assessment of cutaneous melanoma remains based on clinical and pathological criteria (most importantly tumor thickness). The main challenges lying ahead are to establish a reliable prognostic test effectively determining which tumors will metastasize. Additionally establishing biomarkers which will allow patients to be stratified according to the most promising systemic therapy (immunotherapies and/or BRAF inhibitor therapies) is of utmost importance for patients with metastasized disease. Identifying serum biomarkers enabling disease to be monitored as well as determining tumor properties (i.e. resistance) would also be of great value. While initial results have proven promising, there remains much work to be done.

PD-L1 is upregulated by radiochemotherapy in rectal adenocarcinoma patients and associated with a favourable prognosis

BACKGROUND

The influence of neoadjuvant radiochemotherapy (RCT) on programmed death-ligand 1 (PD-L1) expression, a predictive marker for programmed cell death protein 1 (PD-1) inhibitor therapy, was studied on tumour and inflammatory cells in rectal adenocarcinoma patients along with its prognostic value.

METHODS

PD-L1 immunohistochemistry was performed on tissue microarrays of 103 pre-RCT biopsies and 159 post-RCT surgical specimens (central tumour, invasive front and normal tissue) of 199 patients. In 63 patients, both samples were available. Proportion and maximum intensity of PD-L1-positive (PD-L1+) cells were evaluated.

RESULTS

RCT increased the proportion of PD-L1-expressing cancer cells from 2.1% to 7.8% in the central tumour (p < 0.001) or 9.3% in the invasive front (p < 0.001). Cancer cell PD-L1 on its own could not predict prognosis. High PD-L1 expression on pre-RCT inflammatory cells (maximum intensity: p = 0.048) and post-RCT invasive front inflammatory cells (p = 0.010) correlated with improved no evidence of disease survival. In multivariate analysis, the combination of low PD-L1 in cancer and inflammatory cells was an independent negative prognostic marker for overall survival (OS) pre-RCT (Cox's proportional hazard ratio 0.438, p = 0.045) and in the invasive front post-RCT (Cox's proportional hazard ratio 0.257, p = 0.030).

CONCLUSION

Neoadjuvant RCT is associated with an increased PD-L1 expression in rectal adenocarcinoma patients, which should prompt clinical trials combining radiotherapy and PD-1/PD-L1 pathway blockade. Combined low PD-L1 expression on tumour and inflammatory cells is an independent negative prognostic marker for OS in RCT of rectal adenocarcinoma.

Mechanisms of immune evasion and current status of checkpoint inhibitors in non-small cell lung cancer

In the past several years, immunotherapy has emerged as a viable treatment option for patients with advanced non‐small cell lung cancer (NSCLC) without actionable driver mutations that have progressed on standard chemotherapy. We are also beginning to understand the methods of immune evasion employed by NSCLC which likely contribute to the 20% response rate to immunotherapy. It is also yet unclear what tumor or patient factors predict response to immunotherapy. The objectives of this review are (1) review the immunogenicity of NSCLC (2) describe the mechanisms of immune evasion (3) summarize efforts to target the anti‐program death‐1 (PD‐1) and anti‐program death‐ligand 1(PD‐L1) pathway (4) outline determinants of response to PD‐1/PD‐L1 therapy and (5) discuss potential future areas for research.

Prognostic effect of different PD-L1 expression patterns in squamous cell carcinoma and adenocarcinoma of the cervix

Programmed death-ligand 1 (PD-L1) is expressed in various immune cells and tumor cells, and is able to bind to PD-1 on T lymphocytes, thereby inhibiting their function. At present, the PD-1/PD-L1 axis is a major immunotherapeutic target for checkpoint inhibition in various cancer types, but information on the clinical significance of PD-L1 expression in cervical cancer is largely lacking. Here, we studied PD-L1 expression in paraffin-embedded samples from two cohorts of patients with cervical cancer: primary tumor samples from cohort I (squamous cell carcinoma, n=156 and adenocarcinoma, n=49) and primary and paired metastatic tumor samples from cohort II (squamous cell carcinoma, n=96 and adenocarcinoma, n=31). Squamous cell carcinomas were more frequently positive for PD-L1 and also contained more PD-L1-positive tumor-associated macrophages as compared with adenocarcinomas (both P<0.001). PD-L1-positive tumor-associated macrophages were found to express CD163 and/or CD14 by triple fluorescent immunohistochemistry, demonstrating an M2-like phenotype. Interestingly, disease-free survival (P=0.022) and disease-specific survival (P=0.046) were significantly poorer in squamous cell carcinoma patients with diffuse PD-L1 expression as compared with patients with marginal PD-L1 expression (i.e., on the interface between tumor and stroma) in primary tumors. Disease-specific survival was significantly worse in adenocarcinoma patients with PD-L1-positive tumor-associated macrophages compared with adenocarcinoma patients without PD-L1-positive tumor-associated macrophages (P=0.014). No differences in PD-L1 expression between primary tumors and paired metastatic lymph nodes were detected. However, PD-L1-positive immune cells were found in greater abundance around the metastatic tumors as compared with the paired primary tumors (P=0.001 for squamous cell carcinoma and P=0.041 for adenocarcinoma). These findings point to a key role of PD-L1 in immune escape of cervical cancer, and provide a rationale for therapeutic targeting of the PD-1/PD-L1 pathway.

The anticancer immune response of anti-PD-1/PD-L1 and the genetic determinants of response to anti-PD-1/PD-L1 antibodies in cancer patients

The programmed death-1 (PD-1), a coinhibitory receptor expressed on activated T cells and B cells, is demonstrated to induce an immune-mediated response and play a critical role in tumor initiation and development. The cancer patients harboring PD-1 or PD ligand 1 (PD-L1) protein expression have often a poor prognosis and clinical outcome. Currently, targeting PD-1 pathway as a potential new anticancer strategy is attracting more and more attention in cancer treatment. Several monoclonal antibodies against PD-1 or PD-L1 have been reported to enhance anticancer immune responses and induce tumor cell death. Nonetheless, the precise molecular mechanisms by which PD-1 affects various cancers remain elusive. Moreover, this therapy is not effective for all the cancer patients and only a fraction of patients respond to the antibodies targeting PD-1 or PD-L1, indicating these antibodies may only works in a subset of certain cancers. Thus, understanding the novel function of PD-1 and genetic determinants of response to anti-PD-1 therapy will allow us to develop a more effective and individualized immunotherapeutic strategy for cancer.

A Cost-Effectiveness Analysis of Nivolumab versus Docetaxel for Advanced Nonsquamous NSCLC Including PD-L1 Testing

INTRODUCTION

Nivolumab (NIV) was recently approved in several countries for patients with pretreated advanced NSCLC. NIV is not cost-effective compared with docetaxel (DOC) for the treatment of squamous NSCLC. However, its cost-effectiveness for nonsquamous NSCLC and the consequences of programmed death ligand 1 (PD-L1) testing are unknown.

METHODS

This literature-based health economic study used CheckMate-057 trial data to model the incremental cost-effectiveness ratio (ICER) of NIV versus DOC in the Swiss health care setting. The effect of PD-L1 positivity for patient selection was assessed.

RESULTS

In the base case model, NIV (mean cost CHF66,208; mean effect 0.69 quality-adjusted life-years [QALYs]) compared with DOC (mean cost CHF37,618; mean effect 0.53 QALYs) resulted in an ICER of CHF177,478/QALY gained. Treating only patients with PD-L1-positive tumors (threshold ≥10%) with NIV compared with treating all patients with DOC produced a base case ICER of CHF124,891/QALY gained. Reduced drug price, dose, or treatment duration decreased the ICER partly below a willingness-to-pay threshold of CHF100,000/QALY. Health state utilities strongly influenced cost-effectiveness.

CONCLUSIONS

Compared with DOC, NIV is not cost-effective for the treatment of nonsquamous NSCLC at current prices in the Swiss health care setting. Price reduction or PD-L1 testing and selection of patients for NIV on the basis of test positivity improves cost-effectiveness compared with DOC.

[Molecular and immunohistochemical diagnostics in melanoma]

To provide appropriate therapy and follow-up to patients with malignant melanoma, proper diagnostics are of critical importance. Targeted therapy of advanced melanoma is based on the molecular genetic analyses of tumor tissue. In addition, sequencing of genes and other genetic approaches can provide insight into the origin of melanocytic tumors and can aid in distinguishing benign from malignant lesions. In this regard, spizoid neoplasms remain a challenging entity. Aside from genetic analyses of tumor tissue, immunohistochemistry remains an essential tool in melanoma diagnostics and TNM classification. With new immunotherapies being approved for advanced melanoma, immunohistochemistry to determine PD-L1 expression has gained clinical interest. While PD-L1 expression is associated with response to PD-1 blockade, a substantial number of patients without PD-L1 expression can still experience tumor remission upon treatment. In this review, current and future developments in melanoma diagnostics with regard to molecular genetics and immunohistochemistry are summarized. The utilization of such analyses in clinical decision making is also discussed.

Circulating Biomarkers in Non-Small-Cell Lung Cancer: Current Status and Future Challenges

Despite recent advances, non-small-cell lung cancer remains a devastating disease and carries a grim prognosis. Major contributing factors include difficulties in diagnosing the disease early in its course during the asymptomatic stage and the poor understanding of the biology underlying disease progression. Liquid biopsies, noninvasive blood tests that detect circulating biomarkers such as circulating tumor cells and tumor-derived nucleic acid fragments, are in a rapidly evolving field of research that could provide answers to both of these unmet needs. Herein, we review the relevant data concerning the diagnostic, predictive, and prognostic significance of 3 distinct but potentially complementary circulating biomarkers in non-small-cell lung cancer: circulating tumor cells, cell-free DNA, and microRNAs.

Monitoring immune responses in the tumor microenvironment

Immune monitoring in the tumor microenvironment allows for important insights into immune mechanisms of response and resistance to various cancer treatments; however clinical challenges exist using current strategies. Significant questions remain regarding monitoring of archival versus fresh tissue, assessment of static versus dynamic markers, evaluation of limited tissue samples, and the translation of insights gained from immunologically 'hot' tumors such as melanoma to other 'cold' tumor microenvironments prevalent in other cancer types. Current and emerging immune monitoring strategies will be examined herein, and genomic-based assays complementing these techniques will also be discussed. Finally, host genomic and external environmental factors influencing anti-tumor immune responses will be considered, including the role of the gut microbiome. Though optimal immune monitoring techniques are in evolution, great promise exists in recent advances that will help guide patient selection as far as type, sequence, and combination of therapeutic regimens to enhance anti-tumor immunity and clinical responses.

T cell Bim levels reflect responses to anti-PD-1 cancer therapy

Immune checkpoint therapy with PD-1 blockade has emerged as an effective therapy for many advanced cancers; however, only a small fraction of patients achieve durable responses. To date, there is no validated blood-based means of predicting the response to PD-1 blockade. We report that Bim is a downstream signaling molecule of the PD-1 pathway, and its detection in T cells is significantly associated with expression of PD-1 and effector T cell markers. High levels of Bim in circulating tumor-reactive (PD-1⁺CD11a^hiCD8⁺) T cells were prognostic of poor survival in patients with metastatic melanoma who did not receive anti-PD-1 therapy and were also predictive of clinical benefit in patients with metastatic melanoma who were treated with anti-PD-1 therapy. Moreover, this circulating tumor-reactive T cell population significantly decreased after successful anti-PD-1 therapy. Our study supports a crucial role of Bim in both T cell activation and apoptosis as regulated by PD-1 and PD-L1 interactions in effector CD8⁺ T cells. Measurement of Bim levels in circulating T cells of patients with cancer may provide a less invasive strategy to predict and monitor responses to anti-PD-1 therapy, although future prospective analyses are needed to validate its utility.

PD-L1 expression in non-small cell lung cancer: Correlations with genetic alterations

Inhibition of the PD-1/PD-L1 pathway may induce anticancer immune responses in non-small cell lung cancer (NSCLC). Two PD-L1 immunohistochemistry (IHC) assays have been approved as companion diagnostic tests for therapeutic anti-PD-1 antibodies. However, many aspects of PD-L1 prevalence and association with genetically defined subtypes have not been addressed systematically. Here, we analyzed PD-L1 expression in 436 genetically annotated NSCLC specimens enriched for early stages using PD-L1 antibody 5H1. Expression of PD-L1 was detected in the tumor cells (TC) (34% of cases) and in associated immune cells (IC) (49%) across all stages of NSCLC, either alone or in combination. PD-L1 IHC-positive TC, but not IC showed significantly higher PD-L1 RNA expression levels. Expression in TC was associated with TP53, KRAS and STK11 mutational status in adenocarcinomas (AD) and with NFE2L2 mutations in squamous cell carcinomas (SQ). No correlations with histological subtype, clinical characteristics and overall survival were found. The presence of PD-L1-positive IC was significantly associated with patients' smoking status in AD. The findings are in agreement with the emerging concept that tumors with high mutational burden are more likely to benefit from immunotherapy, since TP53 and KRAS mutations are linked to smoking, increased numbers of somatic mutations and expression of neoantigens. Current clinical studies focus on stage IIIB and IV NSCLC; however, PD-L1 expression occurs in earlier stages and might be a predictive biomarker in clinical trials testing (neo-) adjuvant strategies.

Immunotherapy for lung cancer

Treatment of lung cancer remains a challenge, and lung cancer is still the leading cause of cancer-related mortality. Immunotherapy has previously failed in lung cancer but has recently emerged as a very effective new therapy, and there is now growing worldwide enthusiasm in cancer immunotherapy. We summarize why immune checkpoint blockade therapies have generated efficacious and durable responses in clinical trials and why this has reignited interest in this field. Cancer vaccines have also been explored in the past with marginal success. Identification of optimal candidate neoantigens may improve cancer vaccine efficacy and may pave the way to personalized immunotherapy, alone or in combination with other immunotherapy such as immune checkpoint blockade. Understanding the steps in immune recognition and eradication of cancer cells is vital to understanding why previous immunotherapies failed and how current therapies can be used optimally. We hold an optimistic view for the future prospect in lung cancer immunotherapy.

Oncogenic roles and drug target of CXCR4/CXCL12 axis in lung cancer and cancer stem cell

Although the great progress has been made in diagnosis and therapeutic in lung cancer, it induces the most cancer death worldwide in both males and females. Chemokines, which have chemotactic abilities, contain up to 50 family members. By binding to G protein-coupled receptors (GPCR), holding seven-transmembrane domain, they function in immune cell trafficking and regulation of cell proliferation, differentiation, activation, and migration, homing under both physiologic and pathologic conditions. The alpha-chemokine receptor CXCR4 for the alpha-chemokine stromal cell-derived-factor-1 (SDF-1) is most widely expressed by tumors. In addition to human tissues of the bone marrow, liver, adrenal glands, and brain, the CXC chemokine SDF-1 or CXCL12 is also highly expressed in lung cancer tissues and is associated with lung metastasis. Lung cancer cells have the capabilities to utilize and manipulate the CXCL12/CXCR system to benefit growth and distant spread. CXCL12/CXCR4 axis is a major culprit for lung cancer and has a crucial role in lung cancer initiation and progression by activating cancer stem cell. This review provides an evaluation of CXCL12/CXCR4 as the potential therapeutic target for lung cancers; it also focuses on the synergistic effects of inhibition of CXCL12/CXCR4 axis and immunotherapy as well as chemotherapy. Together, CXCL12/CXCR4 axis can be a potential therapeutic target for lung cancers and has additive effects with immunotherapy.

Correlation between PD-L1 expression and outcome of NSCLC patients treated with anti-PD-1/PD-L1 agents: A meta-analysis

BACKGROUND

A meta analysis of the correlation between PD-L1 levels and outcomes of PD-1/PD-L1 inhibitors in advanced non small cell lung cancer (NSCLC) has been performed.

METHODS

Eligible studies included those evaluating PD-1/PD-L1 inhibitors in advanced NSCLC and correlating the outcomes to PD-L1 levels.

RESULTS

The search strategy yielded 250 potentially relevant citations from searched databases. After preclusion of ineligible studies, 12 studies were included. Comparing PD-1/PD-L1 inhibitors to docetaxel in second line treatment, the pooled hazard ratio (HR) for progression free survival (PFS) and overall survival (OS) was 0.75 (95% CI 0.62-0.90; p=0.002) and 0.61 (95% CI 0.50-75; p=0.00001) respectively; while the pooled odds ratio (OR) for objective response rate (ORR) was 1.98 (95% CI 1.28-3.07; p=0.002) in the PD-L1>1% population. Moreover, for PD-L1>1% patients versus PD-L1<1% patients treated with PD-1/PD-L1 targeted agents, the OR of ORR was 2.18 (95% CI 1.45-3.29; p=0.0002); while for PD-L1>5% patients versus PD-L1<5% patients, it was 2.66 (95% CI 1.74-4.07; p<0.00001); and for PD-L1>10% versus PD-L1<10% patients, it was 3.38 (95% CI 2.23-5.13; p<0.00001); and for PD-L1>50% versus PD-L1<50% patients, it was 3.99 (95% CI 2.81-5.66; p<0.00001).

CONCLUSIONS

The current analysis of data indicates that the benefit from PD-1 inhibitors versus docetaxel in second line treatment of NSCLC is limited to the PD-L1>1% subpopulation. Moreover, a possible dose effect relationship between the intensity of PD-L1 staining and the potential benefit from PD-1/PD-L1 targeted agents does exist with higher intensity associated with higher ORR.