Assays for predicting and monitoring responses to lung cancer immunotherapy

Mass Spectrometry Imaging Reveals Neutrophil Defensins as Additional Biomarkers for Anti-PD-(L)1 Immunotherapy Response in NSCLC Patients

(1) Background: Therapeutic blocking of the interaction between programmed death-1 (PD-1) with its ligand PD-L1, an immune checkpoint, is a promising approach to restore the antitumor immune response. Improved clinical outcomes have been shown in different human cancers, including non-small cell lung cancer (NSCLC). Unfortunately, still a high number of NSCLC patients are treated with immunotherapy without obtaining any clinical benefit, due to the limitations of PD-L1 protein expression as the currently sole predictive biomarker for clinical use; (2) Methods: In this study, we applied mass spectrometry imaging (MSI) to discover new protein biomarkers, and to assess the possible correlation between candidate biomarkers and a positive immunotherapy response by matrix-assisted laser desorption/ionization (MALDI) MSI in 25 formalin-fixed paraffin-embedded (FFPE) pretreatment tumor biopsies (Biobank@UZA); (3) Results: Using MALDI MSI, we revealed that the addition of neutrophil defensin 1, 2 and 3 as pretreatment biomarkers may more accurately predict the outcome of immunotherapy treatment in NSCLC. These results were verified and confirmed with immunohistochemical analyses. In addition, we provide in-vitro evidence of the immune stimulatory effect of neutrophil defensins towards cancer cells; and (4) Conclusions: With proteomic approaches, we have discovered neutrophil defensins as additional prospective biomarkers for an anti-PD-(L)1 immunotherapy response. Thereby, we also demonstrated that the neutrophil defensins contribute in the activation of the immune response towards cancer cells, which could provide a new lead towards an anticancer therapy.

Ectonucleotidase CD39 and Checkpoint Signalling Receptor Programmed Death 1 are Highly Elevated in Intratumoral Immune Cells in Non-small-cell Lung Cancer

Lung cancer is the leading cause of cancer death in both sexes worldwide and has a predicted 5-year survival rate of <20%. Immunotherapy targeting immune checkpoints such as the programmed death 1 (PD-1) signaling pathway has led to a shift of paradigm in the treatment of advanced non–small-cell lung cancer (NSCLC) but remains without effect in ∼80% of patients. Accumulating evidence suggests that several immunosuppressive mechanisms may work together in NSCLC. The contribution and cooperation between different immunosuppressive mechanisms in NSCLC remain unknown. Recently, the CD39-adenosine pathway has gained increasing attention as a crucial immunosuppressive mechanism and possible target for immunotherapy. Immune cells were extracted from lung and tumor tissue after lung resection in 12 patients by combined enzymatic and mechanical tissue disaggregation. A multiparameter flow cytometry panel was established to investigate the expression and coexpression of CD39 and PD-1 on key lymphocyte subtypes. Frequencies of CD39⁺, PD-1⁺, and CD39⁺/PD-1⁺cells were higher among both CD4⁺ and CD8⁺ T cells isolated from NSCLC tumor tissue than in T cells from normal lung tissue. Similarly, the frequency of FoxP3⁺ CD4⁺ T cells (Tregs) was highly significantly elevated in tumor tissue compared to adjacent lung tissue. The consistent upregulation of CD39 on immune cells in tumor microenvironment indicates that the CD39 signaling pathway may, in addition to the PD-1 pathway, represent another important mechanism for tumor-induced immunosuppression in NSCLC. In addition, the present study indicates that a comprehensive immune response profiling with flow cytometry may be both feasible and clinically relevant.

Circulating biomarkers predictive of tumor response to cancer immunotherapy

Introduction: The advent of checkpoint blockade immunotherapy has revolutionized cancer treatment, but clinical response to immunotherapies is highly heterogeneous among individual patients and between cancer types. This represents a challenge to oncologists when choosing specific immunotherapies for personalized medicine. Thus, biomarkers that can predict tumor responsiveness to immunotherapies before and during treatment are invaluable. Areas covered: We review the latest advances in 'liquid biopsy' biomarkers for noninvasive prediction and in-treatment monitoring of tumor response to immunotherapy, focusing primarily on melanoma and non-small cell lung cancer. We concentrate on high-quality studies published within the last five years on checkpoint blockade immunotherapies, and highlight significant breakthroughs, identify key areas for improvement, and provide recommendations for how these diagnostic tools can be translated into clinical practice. Expert opinion: The first biomarkers proposed to predict tumor response to immunotherapy were based on PD1/PDL1 expression, but their predictive value is limited to specific cancers or patient populations. Recent advances in single-cell molecular profiling of circulating tumor cells and host cells using next-generation sequencing has dramatically expanded the pool of potentially useful predictive biomarkers. As immunotherapy moves toward personalized medicine, a composite panel of both genomic and proteomic biomarkers will have enormous utility in therapeutic decision-making.

MALDI Mass Spectrometry Imaging Linked with Top-Down Proteomics as a Tool to Study the Non-Small-Cell Lung Cancer Tumor Microenvironment

Advanced non-small-cell lung cancer (NSCLC) is generally linked with a poor prognosis and is one of the leading causes of cancer-related deaths worldwide. Since only a minority of the patients respond well to chemotherapy and/or targeted therapies, immunotherapy might be a valid alternative in the lung cancer treatment field, as immunotherapy attempts to strengthen the body’s own immune response to recognize and eliminate malignant tumor cells. However, positive response patterns to immunotherapy remain unclear. In this study, we demonstrate how immune-related factors could be visualized from single NSCLC tissue sections (Biobank@UZA) while retaining their spatial information by using matrix assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI), in order to unravel the molecular profile of NSCLC patients. In this way, different regions in lung cancerous tissues could be discriminated based on the molecular composition. In addition, we linked visualization (MALDI MSI) and identification (based on liquid chromatography higher resolution mass spectrometry) of the molecules of interest for the correct biological interpretation of the observed molecular differences within the area in which these molecules are detected. This is of major importance to fully understand the underlying molecular profile of the NSCLC tumor microenvironment.

Atezolizumab: feasible second-line therapy for patients with non-small cell lung cancer? A review of efficacy, safety and place in therapy

Advanced non-small cell lung cancer (NSCLC) prognosis is still poor and has recently been reformed by the development of immune checkpoint inhibitors and the approval of anti-PD-1 (programmed cell-death 1) treatments such as nivolumab and pembrolizumab in second line. More recently, atezolizumab (MDPL 3280A), a programmed cell-death-ligand 1 (PD-L1) inhibitor, was also studied in this setting. Here, we report a review of the literature assessing the efficacy, safety, and place of atezolizumab in the second-line treatment of advanced NSCLC. We performed a literature search of PubMed, American Society of Clinical Oncology, European Society of Medical Oncology and World Conference on Lung Cancer meetings. Atezolizumab showed a good tolerance profile and efficacy in comparison with docetaxel for second-line treatment of advanced NSCLC. Potential predictive biomarkers also have to be assessed.

Challenges and future of biomarker tests in the era of precision oncology: Can we rely on immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) to select the optimal patients for matched therapy?

Molecular techniques have improved our understanding of the pathogenesis of cancer development. These techniques have also fueled the rational development of targeted drugs for patient populations stratified by their genetic characteristics. These novel methods have changed the classic paradigm of diagnostic pathology; among them are IHC, FISH, polymerase chain reaction (PCR) and microarray technology. IHC and FISH detection methods for human epidermal growth factor receptor-2 (HER2), epidermal growth factor receptor (EGFR) and programmed death ligand-1 (PD-L1) were recently approved by the Food and Drug Administration (FDA) as routine clinical practice for cancer patients. Here, we discuss general challenges related to the predictive power of these molecular biomarkers for targeted therapy in cancer medicine. We will also discuss the prospects of utilizing new biomarkers for fibroblast growth factor receptor (FGFR) and hepatocyte growth factor receptor (cMET/MET) targeted therapies for developing new and robust predictive biomarkers in oncology.

Expression of programmed death ligand-1 predicts poor outcome in nasopharyngeal carcinoma

Programmed death ligand-1 (PD-L1) is a potentially important tumor immunotherapy target. However, whether PD-L1 expression is associated with survival in nasopharyngeal carcinoma (NPC) remains controversial. The aim of the present study was to investigate the association between PD-L1 expression and prognosis in NPC. The expression of PD-L1 was assessed in tumor specimens from 120 patients with NPC using immunohistochemistry. Staining was evaluated using the H-score method. The associations between PD-L1 expression and clinical characteristics and prognosis were analyzed. Overall, 78% of the patients had stage I–III and 22% had stage IV disease. The estimated 5-year overall survival (OS) and disease-free survival (DFS) rates for the entire cohort were 87.5 and 70.1%, respectively. PD-L1 expression was detected in 85 (71%) patients and was localized to the tumor cells. High tumor expression of PD-L1 (median H-score ≥5) was associated with significantly poorer OS (P=0.023) and DFS (P=0.002). Univariate analysis indicated that low PD-L1 expression was associated with better DFS compared with high PD-L1 expression (HR=0.163, 95% CI: 0.044–0.600, P=0.006 for DFS). Multivariate analysis revealed that T stage (HR=8.190, 95% CI: 1.355–18.152; P=0.023) and PD-L1 expression level (HR=0.124, 95% CI: 0.031–0.509; P=0.001) served as independent prognostic factors for DFS. In conclusion, tumor PD-L1 expression was found to be a significant prognostic factor in NPC, and high PD-L1 expression may be of prognostic value for recurrence and metastasis following conventional treatments.

Quantitative and pathologist-read comparison of the heterogeneity of programmed death-ligand 1 (PD-L1) expression in non-small cell lung cancer

PD-L1 is expressed in a percentage of lung cancer patients and those patients show increased likelihood of response to PD-1 axis therapies. However, the methods and assays for the assessment of PD-L1 using immunohistochemistry are variable and PD-L1 expression appears to be highly heterogeneous. Here, we examine assay heterogeneity parameters toward the goal of determining variability of sampling and the variability due to pathologist-based reading of the immunohistochemistry slide. SP142, a rabbit monoclonal antibody, was used to detect PD-L1 by both chromogenic immunohistochemistry and quantitative immunofluorescence using a laboratory-derived test. Five pathologists scored the percentage of PD-L1 positivity in tumor- and stromal-immune cells of 35 resected non-small cell lung cancer cases, each represented on three separate blocks. An intraclass correlation coefficient of 94% agreement was seen among the pathologists for the assessment of PD-L1 in tumor cells, but only 27% agreement was seen in stromal/immune cell PD-L1 expression. The block-to-block reproducibility of each pathologist's score was 94% for tumor cells and 75% among stromal/immune cells. Lin's concordance correlation coefficient between pathologists' readings and the mean immunofluorescence score among blocks was 94% in tumor and 68% in stroma. Pathologists were highly concordant for PD-L1 tumor scoring, but not for stromal/immune cell scoring. Pathologist scores and immunofluorescence scores were concordant for tumor tissue, but not for stromal/immune cells. PD-L1 expression was similar among all the three blocks from each tumor, indicating that staining of one block is enough to represent the entire tumor and that the spatial distribution of heterogeneity of expression of PD-L1 is within the area represented in a single block. Future studies are needed to determine the minimum representative tumor area for PD-L1 assessment for response to therapy.

Novel active agents in patients with advanced NSCLC without driver mutations who have progressed after first-line chemotherapy

Despite the efficacy of a number of first-line treatments, most patients with advanced-stage non-small cell lung cancer (NSCLC) experience disease progression that warrants further treatment. In this review, we examine the role of novel active agents for patients who progress after first-line therapy and who are not candidates for targeted therapies. More therapeutic options are needed for the management of patients with NSCLC after failure of first-line chemotherapy. A PubMed search was performed for articles from January 2012 to May 2015 using the keywords NSCLC, antiangiogenic, immunotherapy, second-line, novel therapies and English language articles only. Relevant papers were reviewed; papers outside that period were considered on a case-by-case basis. A search of oncology congresses was performed to identify relevant abstracts over this period. In recent years, antiangiogenic agents and immune checkpoint inhibitors have been added to our armamentarium to treat patients with advanced NSCLC who have progressed on first-line chemotherapy. These include nintedanib, a triple angiokinase inhibitor; ramucirumab, a vascular endothelial growth factor receptor-2 antibody; and nivolumab, pembrolizumab and atezolizumab, just three of a growing list of antibodies targeting the programmed death receptor-1 (PD-1)/PD ligand-1 pathway. Predictive and prognostic factors in NSCLC treatment will help to optimise treatment with these novel agents. The approval of new treatments for patients with NSCLC after the failure of first-line chemotherapy has increased options after a decade of few advances, and holds promise for future evolution of the management of NSCLC.

Pembrolizumab in the treatment of metastatic non-small-cell lung cancer: patient selection and perspectives

Lung cancer is the leading killer of both men and women in the US, and the 5-year survival remains poor. However, the approval of checkpoint blockade immunotherapy has shifted the treatment paradigm and provides hope for improved survival. The ability of non-small-cell lung cancer (NSCLC) to evade the host immune system can be overcome by agents such as pembrolizumab (MK-3475/lambrolizumab), which is a monoclonal antibody targeting the programmed death 1 (PD-1) receptor. In early studies, treatment with pembrolizumab led to dramatic and durable responses in select patients (PD-L1+ tumors). This remarkable efficacy lead to approval of pembrolizumab in the second-line setting as response rates were almost doubled compared to standard of care (SOC) chemotherapy. Most recently, data in the first-line setting from the KEYNOTE-024 study have redefined the SOC therapy for a selected subset of patients. In patients with ≥50% PD-L1+ tumors, pembrolizumab had a clear progression-free survival and overall survival benefit. Toxicity was mostly immune related and similar to checkpoint blockade toxicities observed in previous studies. The initial approval and subsequent studies of pembrolizumab required and utilized a companion diagnostic test, Dako’s IHC 22C3, to assess PD-L1 status of patients. The evaluation and scoring system of this assay has been used by other companies as a reference to develop their own assays, which may complicate selection of patients. Finally, the impact of pembrolizumab in NSCLC is growing as evidenced by the numerous, ongoing trials open for combinations with chemotherapy, chemoradiation, other immunotherapeutics, immunomodulators, tyrosine kinase inhibitors, PI3K inhibitors, MEK inhibitors, hypomethylating agents, and histone deacetylase inhibitors. Further studies are also evaluating pembrolizumab in small-cell lung cancer and malignant pleural mesothelioma. This explosion of studies truly conveys the lack of therapeutic answers for lung cancer patients and the promise of pembrolizumab.

The promise of PD-1 inhibitors in gastro-esophageal cancers: microsatellite instability vs. PD-L1

Preliminary clinical studies of anti-programmed cell death-1 (anti-PD-1) therapy in gastro-esophageal cancers have suggested promising single-agent activity. In patients who received prior treatment for advanced disease, pembrolizumab has been associated with a response rate of 20% in programmed cell death-1 ligand 1 (PD-L1)-positive tumors, and nivolumab with a response rate of 12% in unselected tumors. Both agents yielded a median duration of response lasting ~6-7 months. PD-L1 expression and microsatellite instability (MSI) have emerged as potential predictive markers for PD-1/PD-L1 blockade. PD-L1 expression in tumor cells and in immune cells within the tumor microenvironment has been detected in 14-24% and ~35% of patients with gastro-esophageal cancer, respectively. PD-L1 tumor cell expression appears to be more common in Epstein-Barr virus (EBV)-positive gastric cancers (GCs) and has been associated with an increased density of tumor-infiltrating lymphocytes (TIL). To date, data are too sparse to determine whether PD-L1 expression predicts efficacy of anti-PD-1 therapy in gastro-esophageal cancer, but data from other tumor types have not been consistent regarding its predictive value. MSI occurs in 10-20% of gastro-esophageal cancers and arises from deficient mismatch repair (MMR). MSI is highly correlated with non-synonymous mutation burden, as well as a dense accumulation of TILs. MSI has been associated with improved response to anti-PD-1 therapy in gastrointestinal cancers. Multiple studies are ongoing which examine therapeutic blockade of the PD-1/PD-L1 axis in unselected patients with gastro-esophageal cancer, as well as patients whose tumors express PD-L1 or exhibit MSI. These studies will clarify their activity in this disease and potentially can determine whether identify a strong predictive biomarker can be identified. Checkpoint inhibition is also being studied in combination with curative-intent chemo (radio) therapy and surgery.

PD-L1 biomarker testing for non-small cell lung cancer: truth or fiction?

Research in cancer immunology is currently accelerating following a series of cancer immunotherapy breakthroughs during the last 5 years. Various monoclonal antibodies which block the interaction between checkpoint molecules PD-1 on immune cells and PD-L1 on cancer cells have been used to successfully treat non-small cell lung cancer (NSCLC), including some durable responses lasting years. Two drugs, nivolumab and pembrolizumab, are now FDA approved for use in certain patients who have failed or progressed on platinum-based or targeted therapies while agents targeting PD-L1, atezolizumab and durvalumab, are approaching the final stages of clinical testing. Despite impressive treatment outcomes in a subset of patients who receive these immune therapies, many patients with NSCLC fail to respond to anti-PD-1/PD-L1 and the identification of a biomarker to select these patients remains highly sought after. In this review, we discuss the recent clinical trial results of pembrolizumab, nivolumab, and atezolizumab for NSCLC, and the significance of companion diagnostic testing for tumor PD-L1 expression.

Programmed cell death ligand-1 (PD-L1) expression by immunohistochemistry: could it be predictive and/or prognostic in non-small cell lung cancer?

Blockade of immune checkpoints has recently emerged as a novel therapeutic strategy in various tumors. In particular, monoclonal antibodies targeting programmed cell death 1 (PD-1) or its ligand (PD-L1) have been most studied in lung cancer, and PD-1 inhibitors are now established agents in the management of non-small cell lung cancer (NSCLC). The reports on high-profile clinical trials have shown the association of PD-L1 expression by immunohistochemistry (IHC) with higher overall response rates to the PD-1/PD-L1 axis blockade suggesting that PD-L1 expression may serve as a predictive marker. Unfortunately, however, each PD-1 or PD-L1 inhibitor is coupled with a specific PD-L1 antibody, IHC protocol and scoring system for the biomarker assessment, making the head-to-head comparison of the studies difficult. Similarly, multiple clinical series that correlated PD-L1 expression with clinicopathologic and/or molecular variables and/or survival have reported conflicting results. The discrepancy could be explained by the differences in ethnicity and/or histologic types included in the studies, but it appears to be attributed in part to the differences in PD-L1 IHC methods. Thus, orchestrated efforts to standardize the PD-L1 IHC are warranted to establish the IHC as a predictive and/or prognostic biomarker in NSCLC.

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.

Expression of PD-L1 in triple-negative breast cancer based on different immunohistochemical antibodies

Background

To date, there are no effective therapeutic targeting agents for triple-negative breast cancer (TNBC), and PD-L1 has presented potential as an effective marker of immunotherapeutic agents. The aim of this study was to evaluate the expression of PD-L1 by three different immunohistochemical antibodies in TNBC.

Methods

Interpretation of all three PD-L1 antibodies showed good concordance among three readers (kappa value >0.610) in both cancer cells and immune cells. Using a tissue microarray (TMA) constructed from 218 cases of TNBC, we performed immunohistochemical staining using three of the most popular commercially used PD-L1 monoclonal antibodies (clones 28-8, E1L3N and SP142) in cancer cells and immune cells.

Results

Using various cut-off values of previous studies (1, 5, 10 and 50 %), the expression rates in cancer cells were: PD-L1 (E1L3N) (14.7, 14.7, 11.0, 2.3 %), PD-L1 (28-8) (13.3, 12.4, 10.1, 1.8 %), and PD-L1 (SP142) (11.5, 11.0, 6.9, 0.5 %), respectively. At the 5 % cut-off value, the discordance rate among the three antibodies was 6.0–10.6 % and was highest between PD-L1 (SP142) and the other two antibodies. The expression rates in immune cells were PD-L1 (E1L3N) (37.6 %), PD-L1 (28-8) (36.7 %), and PD-L1 (SP142) (19.3 %), and the discordance rate among the three antibodies ranged from 13.8 to 24.8 % and was also highest between PD-L1 (SP142) and the other two antibodies. Among stromal histologic types, higher PD-L1 expression in cancer cells and immune cells was measured in inflammatory-type (p < 0.05). The absence of PD-L1 (28-8) staining in immune cells was associated with shorter disease free survival (DFS) and overall survival (OS) (p = 0.043, and p = 0.021) in univariate analyses, and with shorter OS in multivariate Cox analysis (hazard ratio: 5.429, 95 % CI 1.214–24.28, p = 0.027).

Conclusions

PD-L1 detection in cancer cells and immune cells varied by antibody clone. The greatest amount of staining occurred with PD-L1 (E1L3N), followed by PD-L1 (28-8) and PD-L1 (SP142). The concordance rate among monoclonal PD-L1 antibodies was higher between PD-L1 (28-8) and PD-L1 (E1L3N). To determine the gold standard antibody and the most appropriate cut-off value, further study of the clinical trial group treated with PD-L1 inhibitor is necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0925-6) contains supplementary material, which is available to authorized users.

Predictive factors of activity of anti-programmed death-1/programmed death ligand-1 drugs: immunohistochemistry analysis

Anti-programmed death-1 (anti-PD1)/programmed death ligand-1 (PD-L1) therapeutic antibodies targeting regulatory pathways in T cells have recently shown to promising clinical effectiveness in several solid tumors by enhancing antitumor immune response. Immune checkpoint therapy has propelled therapeutic efforts opening a new field in cancer treatment. However, durable clinical response has been educed only in a fraction of patients, underlining the need to predictively select those patients most likely to respond, e.g., by detecting predictive biomarkers. Immunohistochemistry (IHC) detection of PD-L1 in tumor cells has been used in various trials of anti-PD-1/PD-L1 agents to try to select those patients most likely to respond. However, since there are different techniques and scoring systems, results have not been conclusive. Thus efforts are needed to develop standardized IHC assays as well as to explore additional biomarkers to evaluate and predict immune responses elicited by anti-PD-1/PD-L1 therapies.