Nivolumab vs investigator's choice in recurrent or metastatic squamous cell carcinoma of the head and neck: 2-year long-term survival update of CheckMate 141 with analyses by tumor PD-L1 expression

Cost-Effectiveness Analysis Of Pembrolizumab In The Treatment Of Advanced Recurrent Metastatic Head And Neck Squamous Cell Carcinoma In China And The United States

BACKGROUND

Pembrolizumab, a programmed cell death-1 (PD-1) inhibitor, has recently gained prominence as a second-line treatment for recurrent and/or metastatic head and neck squamous cell cancer (R/M HNSCC). This study compares the acceptance and different influencing factors of pembrolizumab in the treatment of R/M HNSCC in developed (i.e., the United States) and developing (i.e., China) countries through cost-effectiveness analysis and provides valuable suggestions for clinical decision making.

METHODS

A Markov model was constructed using TreeAge Pro 2015 software to evaluate the economic value of four treatment strategies. Quality-adjusted life years (QALY) and incremental cost-effectiveness ratio (ICER) were used as economic indicators for incremental cost-effectiveness analysis. The stability of the model was evaluated by one-way sensitivity and probability sensitivity analyses.

RESULTS

The ICERs for the pembrolizumab group versus PD-L1 CPS treatment in China and the US were $7892/QALY and $11,900/QALY, respectively. All ICERs were less than the threshold of $29,306 in China and $50,000 in the US; thus, pembrolizumab is cost effective. Sensitivity analysis confirmed a stable economic advantage in the single-drug regimen of pembrolizumab in China and the US.

CONCLUSION

Pembrolizumab monotherapy as a second-line treatment for R/M HNSCC presents more health benefits in comparison with the standard, PD-L1 TPS and PD-L1 CPS groups in China and the US.

Immunotherapy in head and neck cancer: The great challenge of patient selection

The development of immune checkpoint inhibitors (ICIs) revolutionized the therapeutic landscape in head and neck cancer. However, the majority of patients present primary resistance to ICIs and do not benefit from use of these agents, highlighting the need of developing predictive biomarkers to better determine who will benefit from treatment with ICIs. Patient's related clinical characteristics, disease related features, pathological and molecular factors, as well as emerging immune predictive biomarkers can be considered for the selection of those patients who would be the best candidate for immunotherapy. We examined these factors, emerging from the results of currently available studies in head and neck squamous cell carcinoma (HNSCC), in order to provide a useful tool which could assist the oncologist in their clinical practice.

The changing therapeutic landscape of head and neck cancer

Head and neck cancers are a heterogeneous collection of malignancies of the upper aerodigestive tract, salivary glands and thyroid. In this Review, we primarily focus on the changing therapeutic landscape of head and neck squamous cell carcinomas (HNSCCs) that can arise in the oral cavity, oropharynx, hypopharynx and larynx. We highlight developments in surgical and non-surgical therapies (mainly involving the combination of radiotherapy and chemotherapy), outlining how these treatments are being used in the current era of widespread testing for the presence of human papillomavirus infection in patients with HNSCC. Finally, we describe the clinical trials that led to the approval of the first immunotherapeutic agents for HNSCC, and discuss the development of strategies to decrease the toxicity of different treatment modalities.

Targeting the EGFR and Immune Pathways in Squamous Cell Carcinoma of the Head and Neck (SCCHN): Forging a New Alliance

Despite the recent approval of immune-modulatory agents, EGFR inhibition continues to be a cornerstone in the management of squamous cell carcinoma of the head and neck (SCCHN) namely in combination with radiotherapy in the treatment of locoregionally advanced disease as well as in platinum-sensitive recurrent or metastatic disease in the first-line setting. Importantly, recent evidence has emerged supporting also an immune-modulatory effect of EGFR inhibition, and interest has now focused on utilizing these effects in the current treatment approaches for SCCHN. In this report, we review the rationale and evidence supporting the forging of this new alliance in optimizing the treatment of SCCHN.

Prognostic Value of Tumor-Infiltrating Lymphocytes in Head and Neck Squamous Cell Carcinoma

Importance

Biomarkers that reflect prognosis and cellular immunity in patients with head and neck squamous cell carcinoma (HNSCC) are a prerequisite for improving individualized treatment that limits the intensity and morbidity of conventional treatment and may be useful in the introduction of new immunotherapy regimens.

Objective

To determine if specific classes of tumor-infiltrating lymphocytes (TILs) in pretreatment biopsy specimens have prognostic value for outcomes in a large training and validation cohort of patients with HNSCC.

Design, Setting, and Participants

In this prospective, epidemiologic study with a median follow-up of 47.5 months, in 464 previously untreated patients with available tissue for construction of tissue microarray, HNSCC disease sites included oral cavity (228), oropharynx (147), larynx (74), and hypopharynx (15). The training cohort consisted of 241 patients and the validation cohort consisted of 223 patients. Overall tumor stage was I (55), II (69), III (71), or IV (269). Patients were enrolled between November 2008 to October 2014. Data were analyzed between October 2018 to April 2019.

Main Outcomes and Measures

Semiquantitative levels of CD4, CD8, and FoxP3 lymphocytes were assessed by immunohistologic analysis and correlations with clinical prognostic factors, initial treatment modality, and overall survival (OS) and disease-specific (DSS) survival were determined. A principal component analysis was performed to generate a combined TIL-weighted sum score (TILws).

Results

Of the 464 participants, 135 (29%) were women; mean (SD) age was 61.1 (11.8) years. Higher CD8 counts were associated with improved OS in both training and validation sets (HR, 0.94; 95% CI, 0.90-0.98; and HR, 0.97; 95% CI, 0.95-0.99, respectively). Higher TILws levels were associated with improved OS and DSS in both the training set (HR, 0.91; 95% CI, 0.86-0.96; and HR, 0.93; 95% CI, 0.87-0.99, respectively) and validation set (HR, 0.96; 95% CI, 0.93-0.99; and HR, 0.94; 95% CI, 0.89-0.99, respectively). A multivariable Cox model controlling for batch, age, clinical stage, disease site, comorbidities, HPV status, and smoking, showed that higher TILws levels were associated with improved OS and DSS (HR, 0.94; 95% CI, 0.92-0.97; and HR, 0.94; 95% CI, 0.90-0.98, respectively). When grouped by treatment (surgery vs chemoradiation) and tested for interaction, treatment was found to be an effect modifier for CD4 levels and OS. Low CD4 levels were showed greater association with decreased survival in the chemoradiation cohort than the surgery cohort.

Conclusions and Relevance

The findings from this large cohort study suggest that levels of TILs are an independent prognostic factor in patients with HNSCC. Subsets of TILs and combined TIL scores may be clinically useful predictive and prognostic factors.

Immunotherapies and Future Combination Strategies for Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is often diagnosed at an advanced stage and has a dismal prognosis. Nearly 10 years after the approval of cetuximab, anti-PD1/PD-L1 checkpoint inhibitors are the first drugs that have shown any survival benefit for the treatment on platinum-refractory recurrent/metastatic (R/M) HNSCC. Furthermore, checkpoint inhibitors are better tolerated than chemotherapy. The state of the art in the treatment of R/M HNSCC is changing, thanks to improved results for checkpoint inhibitors. Results for these treatments are also awaited in curative settings and for locally advanced HNSCC. Unfortunately, the response rate of immunotherapy is low. Therefore, the identification of predictive biomarkers of response and resistance to anti-PD1/PD-L1 is a key point for better selecting patients that would benefit the most from immunotherapy. Furthermore, the combination of checkpoint inhibitors with various agents is being currently evaluated to improve the response rate, prolong response duration, and even increase the chances for a cure. In this review, we summarize the most important results regarding immune targeting agents for HNSCC, predictive biomarkers for resistance to immune therapies, and future perspectives.

Immune checkpoint inhibitors: For how long do we need to release the brakes to achieve the optimum acceleration of immune-mediated anti-tumor response?

In recent years, cancer immunotherapy has emerged as the fourth pillar of cancer therapy alongside surgery, chemotherapy and radiotherapy. We here report an unusual scenario of a patient with advanced metastatic non-small cell lung cancer who was lost to follow up after two cycles of chemo-immunotherapy who later returned to clinic with complete response; suggesting that in some, all that was needed may have been just a few doses of therapy to "release the breaks."

Immune Checkpoint Inhibitor Toxicity in Head and Neck Cancer: From Identification to Management

Benefiting from the continuously clarifying underlying biology of immune checkpoints and ligand–receptor interactions, the emergence of new anticancer treatment strategy, immunotherapy has shown substantial benefits on several liquid and solid tumors. Immune checkpoint inhibitors (ICIs) can block the negative regulatory components and enhance the T cell function, thus leading to prominent anticancer activity. On account of their promising effect on various malignancies shown in clinical trials, ICIs have been considered to be the most potent anticancer agents in the near future. Head and neck cancer is the seventh most common neoplasm worldwide, and the gross 5-year survival rate was only 60%. Managing locoregionally advanced, recurrent, or metastatic head and neck tumors is still a challenging problem for both oncologists and surgeons. Recent clinical trials employing the immune-modulating antibodies that target cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death 1 (PD-1) herald a new era of anticancer therapy. However, like all other anticancer drugs, ICIs also have side effects while upregulating the immune system to enhance antitumor response, which were known as immune-related adverse events (irAEs). Generally, most irAEs were transient, but sometimes they can cause serious organ dysfunction, even fatal. In addition, due to the distinct anatomical feature, advanced head and neck tumors often affect the upper aerodigestive tract and cause serious dyspnea or dysphagia. Toxicities of ICIs may be more lethal for such patients. Thus, with the increasing application of anti-checkpoint agents in head and neck cancer, there is urgent need to ascertain the safety of this novel treatment strategy. Here, we compile this review of existing clinical trials on the toxicity of ICIs during cancer treatment. The particular clinical manifestation, characteristics of complication development in fatal cases, and the management strategies were discussed. This may provide vital information for future oncology trials and clinical practice.

A Hidden Epidemic of "Intermediate Risk" Oropharynx Cancer

Objectives

Oropharyngeal squamous cell carcinoma (OPSCC) incidence is rapidly increasing in the United States and around the world, driven in large part by infection with the human papillomavirus (HPV). HPV associated OPSCC (HPV+OPSCC) has been shown to have improved response to treatment relative to tobacco‐associated OPSCC. However, improvement in patient survival has not been uniform. Subsets of OPSCC patients in the US and around the world continue to have poor oncologic outcomes. Although the drivers of this phenomenon remain unclear, there is increasing evidence that tobacco exposure plays an important role in modulating HPV+OPSCC clinical outcomes.

Methods

We conducted a review of the literature.

Results

We discuss the potential biological and epidemiological interplay between tobacco and HPV exposure in the context of OPSCC. Multiple retrospective and prospective cohorts show that HPV+OPSCC patients with a history of tobacco exposure have response to treatment and clinical outcomes distinct from HPV+OPSCC non‐smokers which poses clinical and scientific challenges to be addressed over the next decade.

Conclusions

The interaction between tobacco exposure and HPV infection in the context of OPSCC has significant implications for both standard of care treatment regimens and development of novel therapeutic approaches, in particular those which incorporate immunomodulatory agents.

Level of Evidence

5

DNA methylation of indoleamine 2,3-dioxygenase 1 (IDO1) in head and neck squamous cell carcinomas correlates with IDO1 expression, HPV status, patients' survival, immune cell infiltrates, mutational load, and interferon γ signature

Background

The immune checkpoint, indoleamine 2,3-dioxygenase 1, is under investigation as target of novel immunotherapies for cancers, including head and neck squamous cell carcinomas (HNSCC). The aim of our study was to analyze DNA methylation of the encoding gene (IDO1) in HNSCC.

Methods

Methylation of three CpG sites within the promoter, promoter flank, and gene body was investigated and correlated with mRNA expression, immune cell infiltration, mutational burden, human papillomavirus (HPV)-status, and overall survival in a cohort of N = 528 HNSCC patients obtained from The Cancer Genome Atlas. In addition, IDO1 immunohistochemistry and DNA methylation analysis was performed in an independent cohort of N = 138 HNSCC samples.

Findings

Significant inverse correlations of IDO1 methylation and IDO1 mRNA expression were found in the promoter and promoter flank region (Spearman's ρ = −0.163 and ρ = −0.377, respectively) while a positive correlation was present in the gene body (ρ = 0.502; all P < 0.001). IDO1 DNA methylation significantly correlated with IDO1 protein expressing immune cells as well as tumor cells. IDO1 promoter flank hypermethylation was significantly associated with poor overall survival (P < 0.001). In addition, we discovered significant correlations between IDO1 methylation and expression with RNA signatures of immune cell infiltrates and with HPV-status, mutational load (methylation only), and interferon γ signature.

Interpretation

Our results suggest IDO1 expression levels are epigenetically regulated by DNA methylation. This study provides rationale to test IDO1 methylation as potential biomarker for prediction of response to IDO1 immune checkpoint inhibitors in HNSCC.

PD-L1/PD1 Expression, Composition of Tumor-Associated Immune Infiltrate, and HPV Status in Conjunctival Squamous Cell Carcinoma

Purpose

Conjunctival squamous cell carcinoma (SCC), a type of ocular surface neoplasia, is primarily treated by surgical resection and topical immuno- or chemotherapy. Metastatic disease may be treated with systemic chemo- or immunotherapy, albeit with variable response. The purpose of this study was to determine whether immune checkpoint blockade might be considered in the management of conjunctival SCC.

Methods

In this retrospective study, we evaluated tumor programmed death-ligand 1 (PD-L1) expression, high-risk human papillomavirus (HPV) status, and immunohistochemical expression of cluster of differentiation 3 (CD3), cluster of differentiation 8 (CD8), and programmed death 1 (PD1) in tumor-associated immune infiltrate in a series of 31 conjunctival SCCs.

Results

PD-L1 expression in ≥1% of tumor cells was noted in 14 conjunctival SCCs (47%) and was more prevalent in invasive than in situ SCC and among tumors with higher American Joint Committee on Cancer (AJCC) T category (≥T3 versus ≤T2). The density of CD3-positive T cells was higher in primary than recurrent tumors and higher in invasive than in situ tumors. Density of CD3-positive and CD8-positive T cells was higher in higher AJCC stage tumors. Density of CD8-positive T cells was higher in HPV-positive than HPV-negative tumors. PD-L1 expression correlated with a higher density of CD3-, CD8-, and PD1-positive cells in the tumor-associated immune infiltrate but not with HPV status.

Conclusions

Our findings demonstrate that PD-L1 is expressed in almost half of conjunctival SCCs. The density of tumor-associated immune cells correlated with invasive SCC, stage, and HPV status in conjunctival SCC. Our findings support further studies to establish the potential application of immune checkpoint blockade in the management of conjunctival SCC.

The immune microenvironment and expression of PD-L1, PD-1, PRAME and MHC I in salivary duct carcinoma

AIMS

Salivary duct carcinoma (SDC) is an aggressive salivary malignancy that results in high mortality rates and is often resistant to chemotherapy. Anti-programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) checkpoint inhibitors have led to dramatic improvements in patients with various cancers. Other immunotherapeutic approaches, e.g. cancer vaccines, have shown promising results. Cancer testis antigens, e.g. preferentially expressed antigen in melanoma (PRAME), are regarded as promising vaccine targets because of their tumour-specific expression pattern.

METHODS AND RESULTS

We analysed the immunoexpression of PD-L1, PD-1, major histocompatibility complex class I (MHC I) and PRAME in 53 SDCs. The immunoexpression levels of PD-L1 in tumour cells (TCs) and immune cells (ICs), PD-1 in ICs, PRAME in TCs and MHC I in TCs were analysed, and were correlated with outcome. PRAME expression was seen in 83% of SDCs. No PRAME staining was present in normal salivary gland tissue. With the three established diagnostic algorithms proposed for head and neck squamous cell carcinoma, the criteria being a combined positive score of ≥1, TC% ≥1%, and TC% ≥25%, 35 (66%), 17 (32%) and three cases (6%), respectively, were deemed to be positive for PD-L1. PD-1-positive ICs were seen in 35 (66%) cases. MHC I down-regulation was seen in 82% of SDCs. There was a significant correlation among PD-L1 expression in ICs, PD-1 expression in ICs, and PRAME expression in TCs. PD-L1 expression in TCs and lack of PD-1 expression in ICs were associated with decreased disease-specific survival in SDC patients.

CONCLUSIONS

Alterations of the tumour immune microenvironment are common in SDCs, including expression of PD-1/PD-L1 and PRAME, which opens the way to potential novel immune therapies, such as cancer vaccination and PD-1/PD-L1 blockade, in these tumours.

Unexpected Response to Nivolumab in a "Fast Progressor" Head and Neck Cancer Patient

Prior to the advent of immune checkpoint inhibitors targeting PD-1/PD-L1 axis no drug demonstrated to improve survival or quality of life in the second-line treatment of recurrent or metastatic head and neck squamous cell carcinoma (R/M-HNSCC). Nivolumab appear to have a clear clinical benefit for R/M-HNSCC, based on improved survival, good toxicity profile, reduction in symptoms and improvement in overall quality of life. This benefit seems to be greater for PD-L1 positive patients and independent of previous treatment, even being observed among heavily pre-treated patients. However, even in responding tumors acquired resistance to nivolumab usually occurred, limiting the drug's activity. We report a case of unexpected prolonged stable disease in second-line treatment with nivolumab after a rapid progression disease under first-line chemotherapy in biomarker-positive R/M-HNSCC.

Best Practice in Systemic Therapy for Head and Neck Squamous Cell Carcinoma

Treating head and neck cancer patients with systemic therapy is challenging because of tumor related, patient related and treatment related factors. In this review, we aim to summarize the current standard of care in the curative and palliative setting, and to describe best practice with regard to structural requirements, procedures, and monitoring outcome. Treatment advice for individual head and neck cancer patients is best discussed within a multidisciplinary team. Cisplatin is the drug of choice for concomitant chemoradiotherapy in the primary and postoperative setting, and also a main component of induction chemotherapy. However, acute and late toxicity is often significant. Checkpoint inhibitors have recently been proven to be active in the metastatic setting which has resulted in a shift of paradigm. Detailed knowledge, institution of preventive measures, early recognition, and prompt treatment of adverse events during systemic therapy is of paramount importance. Documentation of patient characteristics, tumor characteristics, treatment details, and clinical and patient reported outcome is essential for monitoring the quality of care. Participation in initiatives for accreditation and registries for benchmarking institutional results are powerful incentives for implementation of best practice procedures.

Morphomolecular analysis of the immune tumor microenvironment in human head and neck cancer

Immunotherapy is effective in head and neck squamous cell carcinoma (HNSCC), but only a minority of patients responds to immune checkpoint blockade (ICB). To contribute to a better understanding of the underlying immune biology, we combined histomorphological evaluation and molecular analysis of the HNSCC immune microenvironment in the TCGA cohort. Analyzing digital HE-stained slides, a method for classification of tumor infiltrating lymphocytes (TILs) in the intra-epithelial compartment (ieTILs, present vs. absent) and the stromal compartment (strTILs, high vs. low) was established. We also analyzed the abundance of eight immune cell populations (estimated from RNAseq data) and PD-L1 mRNA expression. Status of ieTILs and status of strTILs were concordant for 61%, but discordant for 39% of tumors. In univariate survival analysis, ieTILs were a positive prognostic marker for DFS in the study cohort (HR = 0.66, p = 0.015) and in the HPV- subcohort (HR = 0.68, p = 0.04), but not in the HPV + subcohort. T cells were a positive prognostic marker for DFS in the study cohort (HR = 0.80, p = 0.03) and in the HPV + subcohort (HR = 0.20, p = 0.001), but not in the HPV- subcohort. In univariate survival analysis, PD-L1 mRNA expression was neither associated with DFS nor with OS. However, in bivariate and multivariate analyses including both PD-L1 mRNA levels and T cells, PD-L1 was a negative prognostic marker of DFS and OS, while T cells remained a positive prognostic marker. In conclusion, ieTILs and strTILs were non-redundant biomarkers in HNSCC and should be evaluated separately. The identified prognostic markers should be evaluated for predictivity in ICB-treated patients.

Management of locally recurrent nasopharyngeal carcinoma

As a consequence of the current excellent loco-regional control rates attained using the generally accepted treatment paradigms involving intensity-modulated radiotherapy for nasopharyngeal carcinoma (NPC), only 10-20% of patients will suffer from local and/or nodal recurrence after primary treatment. Early detection of recurrence is important as localized recurrent disease is still potentially salvageable, but this treatment often incurs a high risk of major toxicities. Due to the possibility of radio-resistance of tumors which persist or recur despite adequate prior irradiation and the limited tolerance of adjacent normal tissues to sustain further additional treatment, the management of local failures remains one of the greatest challenges in this disease. Both surgical approaches for radical resection and specialized re-irradiation modalities have been explored. Unfortunately, available data are based on retrospective studies, and the majority of them are based on a small number of patients or relatively short follow-up. In this article, we will review the different salvage treatment options and associated prognostic factors for each of them. We will also propose a treatment algorithm based on the latest available evidence and discuss the future directions of treatment for locally recurrent NPC.

Association of PD-L1 expression in oral squamous cell carcinoma with smoking, sex, and p53 expression

OBJECTIVES

The aim of this study was to investigate the association between oral cavity squamous cell carcinoma (OSCC) and PD-L1 expression, and smoking, and p53 expression.

STUDY DESIGN

Histologic review of archival slides of patients with OSCC, obtained from the Sydney Head and Neck Cancer Institute database from 1995 to 2015, was undertaken with tissue microarray construction and immunohistochemistry to identify PD-L1 and p53 expression.

RESULTS

Of the 255 patients identified, PD-L1 expression was observed in 70 (27.5%) and more commonly in females (odds ratio [OR] = 2.19; P = .005). PD-L1 expression of 1% or greater was associated with p53 expression (P = .019) and associated with absence of smoking (P = .06). PD-L1 expression, at 1%, was not significantly associated with overall survival (P = .482), disease-specific survival (P = .864), and disease-free survival (P = .731).

CONCLUSIONS

Our data demonstrate that PD-L1 expression of 1% or greater is more frequent in OSCC in females, nonsmokers, and in patients with p53-positive OSCC. These findings have important implications for immune therapy for OSCC.

Acquired resistance to cancer immunotherapy: Role of tumor-mediated immunosuppression

In the tumor microenvironment (TME), tumor cells are constantly evolving to reduce neoantigen generation and the mutational burden to escape the anti-tumor response. This will lower tumor reactivity to the adaptive immune response and give rise to tumor intrinsic factors, such as altered expression of immune regulatory molecules on tumor cells. Tumor-extrinsic factors, such as immunosuppressive cells, soluble suppressive molecules or inhibitory receptors expressed by immune cells will alter the composition and activity of tumor-infiltrating lymphocytes (TILs) (by increasing T regulatory cells:T effector cells ratio and inhibiting T effector cell function) and promote tumor growth and metastasis. Together, these factors limit the response rates and clinical outcomes to a particular cancer therapy. Within the TME, the cross-talks between immune and non-immune cells result in the generation of positive feedback loops, which augment immunosuppression and support tumor growth and survival (termed as tumor-mediated immunosuppression). Cancer immunotherapies, such as immune checkpoint inhibitors (ICIs) and adoptive cell transfer (ACT), have shown therapeutic efficacy in hematologic cancers and different types of solid tumors. However, achieving durable response rates in some cancer patients remains a challenge as a result of acquired resistance and tumor immune evasion. This could be driven by the cellular and molecular suppressive network within the TME or due to the loss of tumor antigens. In this review, we describe the contribution of the immunosuppressive cellular and molecular tumor network to the development of acquired resistance against cancer immunotherapies. We also discuss potential combined therapeutic strategies which could help to overcome such resistance against cancer immunotherapies, and to enhance anti-tumor immune responses and improve clinical outcomes in patients.

pDC depletion induced by CD317 blockade drives the antitumor immune response in head and neck squamous cell carcinoma

OBJECTIVES

Dysregulation of immune cells in the tumor microenvironment is a hallmark of head and neck squamous cell carcinoma (HNSCC). Increased infiltration of pDCs has been reported in the microenvironment of HNSCC. However, the precise immunological role of pDC and the therapeutic effects of pDC depletion in HNSCC need to be further investigated.

MATERIALS AND METHODS

CD317 antibodies were applied for depleting pDCs in an immunocompetent transgenic HNSCC mouse model. Tumor volume was monitored. Flow cytometric analysis was conducted for studying the immune profile changes after pDC depletion. In addition, immunohistochemical staining was carried out in a human HNSCC tissue microarray for detecting the infiltration of pDCs. We also analyzed the survival implication of pDCs and its correlation with other immune related markers in human HNSCC.

RESULTS

pDC depletion in the transgenic HNSCC mouse model significantly delayed tumor growth. After pDCs were depleted, T cells were markedly revitalized, and the proportions of regulatory T cells (Tregs) and monocytic myeloid-derived suppressor cells (MDSCs) were decreased. In human HNSCC microenvironment, pDC infiltration was upregulated and its high infiltration conferred a poor prognosis. Moreover, pDC infiltration was closely correlated with the expression of Foxp-3, PD-1, TIM-3, and LAG-3.

CONCLUSION

Our findings demonstrated that pDCs play a negative immunomodulatory role in HNSCC and may present as a target for effective immunotherapy.

Head and Neck Cancer Immunotherapy beyond the Checkpoint Blockade

The success of immune checkpoint receptor blockade has brought exciting promises for the treatment of head and neck squamous cell carcinoma (HNSCC). While patients who respond to checkpoint inhibitors tend to develop a durable response, <15% of patients with HNSCC respond to immune checkpoint inhibitors, underscoring the critical need to alleviate cancer resistance to immunotherapy. Major advances have been made to elucidate the intrinsic and adaptive resistance mechanisms to immunotherapy. Central genomic events in HNSCC have been found to possess previously unknown roles in suppressing immune sensing. Such inhibitory function affects both the innate and adaptive arms of tumor-specific immunity. While checkpoint blockade effectively reinvigorates adaptive T-cell responses, additional targeting of the oncogenic inhibitors of innate immune sensing likely informs a novel and potent strategy for immune priming. This review discusses the recent advances on the identification of key HNSCC oncogenes that impair antitumor immunity and emerging immune-priming approaches that sensitize poorly immunogenic HNSCCs to checkpoint blockade. These approaches include but are not limited to cancer vaccine systems utilizing novel type I interferon agonists as immune adjuvants, radiation, DNA damage-inducing agents, and metabolic reprogramming. The goal of these multipronged approaches is to expand tumor-specific effector T-cells, break checkpoint receptor-mediated tolerance, and metabolically support sustained T-cell activation. The translation of therapeutics that reverses oncogenic inhibition of immune sensing requires thorough characterization of the HNSCC regulators of innate immune sensors, development of additional immunocompetent HNSCC mouse models, as well as engineering of more robust immune adjuvant delivery systems. Built on the success of checkpoint blockade, validation of novel immune-priming approaches holds key promises to expand the pool of responders to immunotherapy.

The Society for Immunotherapy of Cancer consensus statement on immunotherapy for the treatment of squamous cell carcinoma of the head and neck (HNSCC)

Head and neck cancers, including those of the lip and oral cavity, nasal cavity, paranasal sinuses, oropharynx, larynx and nasopharynx represent nearly 700,000 new cases and 380,000 deaths worldwide per annum, and account for over 10,000 annual deaths in the United States alone. Improvement in outcomes are needed for patients with recurrent and or metastatic squamous cell carcinoma of the head and neck (HNSCC). In 2016, the US Food and Drug Administration (FDA) granted the first immunotherapeutic approvals - the anti-PD-1 immune checkpoint inhibitors nivolumab and pembrolizumab - for the treatment of patients with recurrent squamous cell carcinoma of the head and neck (HNSCC) that is refractory to platinum-based regimens. The European Commission followed in 2017 with approval of nivolumab for treatment of the same patient population, and shortly thereafter with approval of pembrolizumab monotherapy for the treatment of recurrent or metastatic HNSCC in adults whose tumors express PD-L1 with a ≥ 50% tumor proportion score and have progressed on or after platinum-containing chemotherapy. Then in 2019, the FDA granted approval for PD-1 inhibition as first-line treatment for patients with metastatic or unresectable, recurrent HNSCC, approving pembrolizumab in combination with platinum and fluorouracil for all patients with HNSCC and pembrolizumab as a single agent for patients with HNSCC whose tumors express a PD-L1 combined positive score ≥ 1. These approvals marked the first new therapies for these patients since 2006, as well as the first immunotherapeutic approvals in this disease. In light of the introduction of these novel therapies for the treatment of patients with head and neck cancer, The Society for Immunotherapy of Cancer (SITC) formed an expert committee tasked with generating consensus recommendations for emerging immunotherapies, including appropriate patient selection, therapy sequence, response monitoring, adverse event management, and biomarker testing. These consensus guidelines serve as a foundation to assist clinicians' understanding of the role of immunotherapies in this disease setting, and to standardize utilization across the field for patient benefit. Due to country-specific variances in approvals, availability and regulations regarding the discussed agents, this panel focused solely on FDA-approved drugs for the treatment of patients in the U.S.

Different responses to nivolumab therapy between primary and metastatic tumors in a patient with recurrent hypopharyngeal squamous cell carcinoma

We report the case of a 70-year-old man with primary and metastatic tumors, showing clinically progressive disease and complete response to nivolumab therapy, respectively. He underwent total pharyngo-laryngectomy, bilateral neck dissection, and reconstruction with free-jejunum after nivolumab therapy failure, and had no recurrent or newly arising lesions 8 months after the surgery. Immunohistochemistry analysis revealed that metastatic neck tumor with the clinical complete response to nivolumab showed higher PD-L1 expression with higher CD8+ TIL density, while primary lesion with progressive disease showed lower PD-L1 expression with lower CD8+ TIL density. This represents the first case reported on head and neck squamous cell carcinoma treated with salvage surgery after nivolumab therapy failure.

[Recent developments in head and neck immunology : A basis for novel therapeutic strategies?]

Immunological processes play a key role in the pathogenesis of head and neck pathologies. Besides allergies or infections of the tonsils, the paranasal sinuses, and the ear, initiation, progression, and metastasis of malignant tumors are particularly dependent on the immune system. The recruitment of white blood cells to the site of injury or infection is a critical event in the pathogenesis of these diseases. This article will provide a compact overview about recent developments in this rapidly growing field in otorhinolaryngology which might establish the basis for promising therapeutic strategies for previously insufficiently treatable disorders of the head and neck.

Efficacy of chemotherapy after progression with nivolumab in squamous cell carcinoma of the head and neck

Nivolumab, a programmed death-1 (PD-1) inhibitor, has shown promising results against squamous cell carcinoma of the head and neck (SCCHN) in cases of recurrence or in a metastatic setting after platinum-based therapy. However, treatment alternatives for patients with nivolumab-refractory are limited, and a constant opinion is not provided. Recently, accumulating studies have demonstrated that chemotherapy after immune checkpoint inhibitor treatment may induce better objective responses in patients with advanced non-small cell lung cancer. However, there are few reports on the increased effect of chemotherapy after nivolumab treatment in SCCHN. Therefore, cases must be accumulated to identify patients with nivolumab-refractory SCCHN who may benefit from chemotherapy. Here, we present patients with SCCHN who exhibited a significant response to chemotherapy after nivolumab treatment.

Nivolumab treatment beyond RECIST-defined progression in recurrent or metastatic squamous cell carcinoma of the head and neck in CheckMate 141: A subgroup analysis of a randomized phase 3 clinical trial

BACKGROUND

Response patterns with immune checkpoint inhibitors may be different from those with chemotherapy. Therefore, assessment of response to immunotherapy with the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, could result in premature treatment termination. The randomized, open-label, phase 3 CheckMate 141 trial (NCT02105636), which evaluated nivolumab in recurrent/metastatic squamous cell carcinoma of the head and neck after platinum therapy, allowed treatment beyond first RECIST-defined progression (TBP) according to protocol-specified criteria.

METHODS

In CheckMate 141, patients with RECIST-defined progression who had a stable performance status and demonstrated clinical benefit without rapid disease progression were permitted to receive TBP with nivolumab at 3 mg/kg every 2 weeks until further progression, which was defined as an additional ≥10% increase in tumor volume. This post hoc analysis evaluated outcomes for patients who received TBP with nivolumab.

RESULTS

Of 240 patients randomized to nivolumab, 146 experienced RECIST-defined progression. Sixty-two of these patients received TBP, and 84 discontinued treatment (no TBP). Among the 60 TBP patients evaluable for response, 15 (25%) had no change in their tumor burden, and 15 (25%) had reductions in target lesion size; 3 patients (5%) had reductions >30%. The median overall survival among TBP patients was 12.7 months (95% confidence interval, 9.7-14.6 months). No new safety signals were observed with TBP. Exploratory analyses of immune cell biomarkers suggested a potential relationship with initial and TBP responses.

CONCLUSIONS

Tumor burden reduction was noted in a proportion of patients who received TBP with nivolumab in CheckMate 141. Additional research is warranted to identify factors predictive of a TBP benefit in this population.

Approach to the Patient with Recurrent/Metastatic Disease

OPINION STATEMENT

For most of patients with a recurrent/metastatic (R/M) head and neck squamous cell carcinoma (HNSCC), the treatment remains palliative: The main objective is to reduce the symptoms related to the locoregional relapse, prolong life while maintaining quality of life, which is a big challenge. The systemic treatment needs to be adapted to the performance status, comorbidities, and sequelae of patients. For fit patients, the combination of platinum-based chemotherapy and cetuximab (EXTREME) is the standard of care in first-line treatment since 2008, as no other targeted therapy has been approved in this setting until now. The replacement of 5-FU with a taxane (docetaxel) in the EXTREME regimen has been explored in the large randomized international study TPExtreme which results are awaited in a few months. Depending on the study results on survival, response rate, and tolerance, the TPEx regimen may become a treatment option for patients with R/M HNSCC. Unfit patients are usually treated with platinum-free combinations or with the monotherapies which are recommended in second-line setting (methotrexate, taxanes, cetuximab). However, the irruption of new immunotherapies (e.g., checkpoint inhibitors (CPI)) is changing the guidelines. The tolerance of anti-PD-1 CPI is better than that of chemotherapy, and they seem to be a good option for unfit patients. Anti-PD-1 nivolumab and pembrolizumab are now approved for platinum refractory patients, providing prolonged survival in the case of response, and improvement in quality of life. New options arise in first-line setting with pembrolizumab alone or combined with chemotherapy. Patients with a high PD-L1 biomarker level seem to benefit more from immunotherapy. Other situations (e.g., PD-L1-low, PD-L1-negative, high tumor burden) may more likely to benefit from other combinations, such as cetuximab plus chemotherapy, to avoid local failures and life-threatening fast progression. In terms of perspectives, chemo-free and CPI-free approaches, using other immune oncology agents, should be the next steps.

Nivolumab in Patients with Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck: Efficacy and Safety in CheckMate 141 by Prior Cetuximab Use

PURPOSE

Cetuximab, which modulates immune responses, may affect the efficacy of subsequent immunotherapy. Here, we assessed outcomes with nivolumab, by prior cetuximab exposure, in patients with recurrent or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) who had experienced progression within 6 months of platinum-containing chemotherapy.

PATIENTS AND METHODS

In the randomized, open-label, phase III CheckMate 141 trial, patients were randomized 2:1 to nivolumab 3 mg/kg every 2 weeks or investigator's choice (IC) of single-agent chemotherapy, with stratification by prior cetuximab exposure. The primary endpoint was overall survival (OS); additional endpoints were progression-free survival, objective response rate, and safety.

RESULTS

In patients with prior cetuximab exposure, the median OS was 7.1 months with nivolumab versus 5.1 months with IC (HR, 0.84; 95% CI, 0.62-1.15); OS benefit with nivolumab was maintained across most demographic subgroups. In patients without prior cetuximab exposure, the median OS was 8.2 months with nivolumab versus 4.9 months with IC (HR, 0.52; 95% CI, 0.35-0.77); OS benefit with nivolumab was maintained across patient baseline subgroups including tumor programmed death ligand 1 (PD-L1) expression (<1% or ≥1%). Grade 3-4 treatment-related adverse event rates favored nivolumab versus IC in both subgroups.

CONCLUSIONS

Nivolumab appeared to improve efficacy versus IC regardless of prior cetuximab use, supporting its use in patients with R/M SCCHN with or without prior cetuximab exposure. The reduction in risk of death with nivolumab compared with IC was greater in patients without prior cetuximab exposure versus with prior cetuximab exposure.

Immune checkpoint inhibitors in the treatment of virus-associated cancers

Among all malignant tumors that threaten human health, virus-related tumors account for a large proportion. The treatment of these tumors is still an urgent problem to be resolved. The immune system is the "guard" of the human body, resisting the invasion of foreign substances such as viruses. Studies have shown that immunotherapy has clinical significance in the treatment of a variety of tumors. In particular, the emergence of immune checkpoint inhibitors (ICIs) in recent years has opened a new door to cancer therapy. Considering the potential role of ICIs in the treatment of virus-related cancers, we focused on their therapeutic effect in virus-associated cancers and explored whether the therapeutic effect in virus-associated cancers was related to virus infection status. Although there is no clear statistical significance indicates that ICIs are more effective in virus-associated cancers than non-virus infections, the efficacy of checkpoint inhibitors in the treatment of virus-related cancers is promising. We believe that this research provides a good direction for the implementation of individualized precision medicine.

Interference of tumour mutational burden with outcome of patients with head and neck cancer treated with definitive chemoradiation: a multicentre retrospective study of the German Cancer Consortium Radiation Oncology Group

BACKGROUND

Tumour mutational burden (TMB) estimated from whole exome sequencing or comprehensive gene panels has previously been established as predictive factor of response to immune checkpoint inhibitors (ICIs). Its predictive value for the efficacy of concurrent chemoradiation (cCRTX), a potential combination partner of ICI, remains unknown.

METHODS

The accuracy of TMB estimation by an in-house 327-gene panel was established in the Cancer Genome Atlas (TCGA) head and neck squamous cell carcinoma (HNSCC) data set. Interference of TMB with outcome after cCRTX was determined in a multicentre cohort of patients with locally advanced HNSCC uniformly treated with cCRTX. Targeted next-generation sequencing was successfully applied in 101 formalin-fixed, paraffin-embedded pretreatment tumour samples. In a subset of cases (n = 40), tumour RNA was used for immune-related gene expression profiling by the nanoString platform. TMB was correlated with TP53 genotype, human papilloma virus (HPV) status, immune expression signatures and survival parameters. Results were validated in the TCGA HNSCC cohort.

RESULTS

A high accuracy of TMB estimation by the 327-gene panel was established. High TMB was significantly associated with an increased prevalence of TP53 mutations and immune gene expression patterns unrelated to T cell-inflamed gene expression profiles. Kaplan-Meier analysis revealed significantly reduced overall survival in the patient group with high TMB (hazard ratio for death: 1.79, 95% confidence interval: 1.02-3.14; P = 0.042) which remained significant after correcting for confounding factors in the multivariate model. The prognostic value of TMB was confirmed in the TCGA HNSCC cohort.

CONCLUSION

High TMB identifies HNSCC patients with poor outcome after cCRTX who might preferentially benefit from CRTX-ICI combinations.

Cetuximab-Containing Combinations in Locally Advanced and Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma

Cetuximab remains to date the only targeted therapy approved for the treatment of head and neck squamous cell carcinoma (HNSCC). The EGFR pathway plays a key role in the tumorigenesis and progression of this disease as well as in the resistance to radiotherapy (RT). While several anti-EGFR agents have been tested in HNSCC, cetuximab, an IgG1 subclass monoclonal antibody against EGFR, is the only drug with proven efficacy for the treatment of both locoregionally-advanced (LA) and recurrent/metastatic (R/M) disease. The addition of cetuximab to radiotherapy is a validated treatment option in LA-HNSCC. However, its use has been limited to patients who are considered unfit for standard of care chemoradiotherapy (CRT) with single agent cisplatin given the lack of direct comparison of these two regimens in randomized phase III trials and the inferiority suggested by metanalysis and phase II studies. The current use of cetuximab in HNSCC is about to change given the recent results from randomized prospective clinical trials in both the LA and R/M setting. Two phase III studies evaluating RT-cetuximab vs. CRT in Human Papillomavirus (HPV)-positive LA oropharyngeal squamous cell carcinoma (De-ESCALaTE and RTOG 1016) showed inferior overall survival and progression-free survival for RT-cetuximab combination, and therefore CRT with cisplatin remains the standard of care in this disease. In the R/M HNSCC, the EXTREME regimen has been the standard of care as first-line treatment for the past 10 years. However, the results from the KEYNOTE-048 study will likely position the anti-PD-1 agent pembrolizumab as the new first line treatment either alone or in combination with chemotherapy in this setting based on PD-L1 status. Interestingly, cetuximab-mediated immunogenicity through antibody dependent cell cytotoxicity (ADCC) has encouraged the evaluation of combined approaches with immune-checkpoint inhibitors in both LA and R/M-HNSCC settings. This article reviews the accumulated evidence on the role of cetuximab in HNSCC in the past decade, offering an overview of its current impact in the treatment of LA and R/M-HNSCC disease and its potential use in the era of immunotherapy.

Inhibition of EphB4-Ephrin-B2 Signaling Reprograms the Tumor Immune Microenvironment in Head and Neck Cancers

Identifying targets present in the tumor microenvironment that contribute to immune evasion has become an important area of research. In this study, we identified EphB4-ephrin-B2 signaling as a regulator of both innate and adaptive components of the immune system. EphB4 belongs to receptor tyrosine kinase family that interacts with ephrin-B2 ligand at sites of cell-cell contact, resulting in bidirectional signaling. We found that EphB4-ephrin-B2 inhibition alone or in combination with radiation (RT) reduced intratumoral regulatory T cells (Tregs) and increased activation of both CD8⁺ and CD4⁺Foxp3^- T cells compared with the control group in an orthotopic head and neck squamous cell carcinoma (HNSCC) model. We also compared the effect of EphB4-ephrin-B2 inhibition combined with RT with combined anti-PDL1 and RT and observed similar tumor growth suppression, particularly at early time-points. A patient-derived xenograft model showed reduction of tumor-associated M2 macrophages and favored polarization towards an antitumoral M1 phenotype following EphB4-ephrin-B2 inhibition with RT. In vitro, EphB4 signaling inhibition decreased Ki67-expressing Tregs and Treg activation compared with the control group. Overall, our study is the first to implicate the role of EphB4-ephrin-B2 in tumor immune response. Moreover, our findings suggest that EphB4-ephrin-B2 inhibition combined with RT represents a potential alternative for patients with HNSCC and could be particularly beneficial for patients who are ineligible to receive or cannot tolerate anti-PDL1 therapy. SIGNIFICANCE: These findings present EphB4-ephrin-B2 inhibition as an alternative to anti-PDL1 therapeutics that can be used in combination with radiation to induce an effective antitumor immune response in patients with HNSCC.

Tumor-infiltrating lymphocyte quantification stratifies early-stage human papillomavirus oropharynx cancer prognosis

OBJECTIVES/HYPOTHESIS

To evaluate if a simple method for assessing tumor-infiltrating lymphocytes (TIL) in primary tumor specimens improves the prognostic value of the American Joint Committee on Cancer, 8th Edition (AJCC8) cancer staging system in human papillomavirus-positive oropharyngeal squamous cell carcinoma (HPV-OPC).

STUDY DESIGN

Retrospective study.

METHODS

In this study, TIL density was quantified on hematoxylin and eosin (H&E)-stained specimens from patients presenting to Johns Hopkins Hospital between 2009 and 2017 who underwent primary surgical therapy and had primary tumor specimens available for analysis. The prognostic effect of TIL density was evaluated by Kaplan-Meier method and Cox proportional hazards models considering recurrence-free survival (RFS) as the primary outcome.

RESULTS

This study included 132 patients. Ninety-five percent were classified by clinical criteria with AJCC8 early-stage disease (stage I: 82%, stage II: 13%). After 84 months of follow-up, 15 recurrences were observed. Among clinically early-stage disease, TIL_high status was associated with improved RFS compared to TIL_low (P = .002). Adjusted analysis showed TIL_high status was associated with 79% lower risk of recurrence than TIL_low (adjusted hazard ratio [aHR]: 0.210, 95% confidence interval [CI]: 0.061-0.723). In clinical stage I disease, TIL_high status was associated with improved RFS compared to TIL_low in both univariate and multivariate analyses (hazard ratio: 0.235, P = .021; aHR: 0.218; 95% CI: 0.058-0.822). TIL density similarly stratified risk in pathologically staged disease.

CONCLUSIONS

In patients with AJCC8 stage I disease, low TIL density was associated with diminished RFS. Our data suggest that assessing TIL density on H&E-stained primary tumor specimens may enhance the prognostic resolution of the AJCC8 staging criteria for HPV-OPC.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:930-938, 2020.

Treg-mediated acquired resistance to immune checkpoint inhibitors

T Regulatory cells (Tregs) act as a double-edged sword by regulating immune homeostasis (protective role) and inhibiting immune responses in different disease settings (pathological role). They contribute to cancer development and progression by suppressing T effector cell (Teff) functions. Decreased ratios of intratumoral CD8⁺ T cells to Tregs have been associated with poor prognosis in most cancer types. Targeting immune checkpoints (ICs), such as cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death-1 (PD-1), by immune checkpoint inhibitors (ICIs) in cancer patients has been beneficial in inducing anti-tumor immune responses and improving clinical outcomes. However, response rates remain relatively low, ranging from 15 to 40% depending on cancer type. Additionally, a significant proportion of patients who initially demonstrates a clinical response can acquire resistance overtime. This acquired resistance could occur due to the emergence of compensatory mechanisms within the tumor microenvironment (TME) to evade the anti-tumor effects of ICIs. In this review, we describe the immunosuppressive role of Tregs in the TME, the effects of currently approved ICIs on Treg phenotype and function, and the mechanisms of acquired resistance to ICIs mediated by Tregs within the TME, such as the over-expression of ICs, the up-regulation of immunosuppressive molecules, and apoptotic Treg-induced immunosuppression. We also describe potential therapeutic strategies to target Tregs in combination with ICIs aiming to overcome such resistance and improve clinical outcomes. Elucidating the Treg-mediated acquired resistance mechanisms should benefit the designing of well-targeted therapeutic strategies to overcome resistance and maximize the therapeutic efficacy in cancer patients.

Role of tumor gene mutations in treatment response to immune checkpoint blockades

Early studies shed light on the immune suppression of immune checkpoint molecules in the cancer microenvironment, with later studies applying immune checkpoint blockade (ICB) in treatment of various malignancies. Despite the encouraging efficacy of ICBs in a substantial subset of cancer patients, the treatment response varies. Gene mutations of both tumor cells and immune cells in the tumor microenvironment have recently been identified as potential predictors of the ICB response. Recent developments in gene expression profiling of tumors have allowed identification of a panel of mutated genes that may affect tumor cell response to ICB treatment. In this review, we discuss the association of the ICB response with gene expression and mutation profiles in tumor cells, which it is hoped will help to optimize the clinical application of ICBs in cancer patients.

From immune checkpoints to vaccines: The past, present and future of cancer immunotherapy

Cancer is a worldwide medical problem with significant repercussions on individual patients and societies as a whole. In order to alter the outcomes of this deadly disease the treatment of cancer over the centuries has undergone a unique evolution. However, utilizing the best treatment modalities and achieving cures or long-term durable responses have been inconsistent and limited, that is until recently. Contemporary research has highlighted a fundamental gap in our understanding of how we approach treating cancer, by revealing the intricate relationship between the immune system and tumors. In this atmosphere, the growth of immunotherapy has not only forever changed our understanding of cancer biology, but the manner by which we treat patients. It's paradigm shifting success has led to the approval of over 10 different immunotherapeutic agents, including checkpoint inhibitors, vaccine-based therapies, oncolytic viruses and T cell directed therapies for nearly 20 different indications across countless tumor types. Despite the breakthroughs that have occurred in the field of immunotherapy, it has not been the panacea for all cancers. With a deeper understanding of the immune system we have been able to peer into tumor immune escape and therapy resistance. Simultaneously this understanding has paved the way for the investigation and development of novel immune system altering agents and combinatorial therapies. In this chapter we review the immune system and its intricate relationship with cancer, the evolution of immunotherapy, its current landscape, and future directions in the context of resistance mechanisms and the challenges faced by immunotherapy against cancer.

Sanctuary site central nervous system relapse-refractory DLBCL responding to nivolumab and lenalidomide

Despite improvement in survival in diffuse large B-cell lymphoma (DLBCL) with the introduction of rituximab, central nervous system (CNS) relapse continues to represent a clinical challenge. In diffuse large B-cell lymphoma (DLBCL), the incidence of CNS relapse is only ∼5% in unselected cohorts. Immunotherapy is the treatment that either boosts the patient's own immune system or uses man-made versions of the normal parts of the immune system to kill lymphoma cells or slow their growth. We are presenting a thirty-eight year old man who, presented with neck nodes, axillary nodes, altered sensorium, abnormal body movements, unconsciousness, weight loss and, fever, with a past history of DLBCL in May 2008, treated with 6 cycles of CHOP and completed in November 2008. After 9 years in April 2018, the patient developed similar symptoms and treated with salvage chemotherapy with R-DHAP which was completed in September 2018. Post-treatment PET-CT showed partial metabolic response and we started external beam radiotherapy to initial bulky disease. After completion of radiotherapy, the patient was very reluctant for any type of therapy and went home. After one month he presented to us with persistent vomiting, abnormal body movements and, altered sensorium. On examination, his Glasgow Coma Scale (GCS) was E2V3M2 and he was admitted in Intensive Care Unit. The patient was managed with mannitol, dexamethasone, antiepileptics, antibiotics and other supportive care medicines. His brain magnetic resonance imaging (MRI) was showing multiple heterogeneously enhancing lesions with surrounding vasogenic oedema and his cerebrospinal fluid analysis was positive for malignant cells. He was managed with triple intrathecal chemotherapy with methotrexate 12 mg, Cytarabine 50 mg, and Hydrocortisone 50 mg along with other supportive care medicines, and after 4-5 days he regained consciousness and he was able to talk and understand verbal commands. In view of improvement in general condition and performance status, we started biweekly triple intra-thecal therapy, and Inj. Nivolumab 3 mg per kg q 2 weekly. From the second cycle, we started Lenalidomide 10 mg once a day for 21 days with 7 days gap along with 2 weekly nivolumab and biweekly triple IT chemotherapy. After one month his CSF analysis was negative for malignant cells. Now he is on regular treatment with weekly IT chemotherapy, 2 weekly nivolumab and 3 weeks on and one week off lenalidomide. After 2 months of treatment, his MRI Brain was showing. At the time of submission of this article, he has completed the fifth cycle of immunotherapy and two cycles of lenalidomide. He was able to manage his daily ADL and able to walk with a stick. The patient tolerated immunotherapy, triple IT therapy and lenalidomide very well without much intolerable side effects. Therefore, we concluded that nivolumab and lenalidomide was well tolerated and exhibited antitumor activity in extensively pretreated patients with relapsed or refractory sanctuary site CNS B- cell lymphomas. Additional studies of Nivolumab and lenalidomide in these diseases are ongoing.

An update of knowledge on PD-L1 in head and neck cancers: Physiologic, prognostic and therapeutic perspectives

Programmed cell death-ligand 1 (PD-L1) is a transmembrane protein that acts as a co-inhibitory factor in the immune response. Its receptor, programmed cell death protein 1 (PD-1), is found on immune cells, where binding to PD-L1 can reduce the proliferation of PD-1-positive cells, inhibit their cytokine secretion and induce apoptosis. PD-L1 in immune-privileged tissue plays a crucial role in peripheral tolerance. PD-L1 can be overexpressed in various malignancies, including oral squamous cell carcinoma, where it can attenuate the host immune response to tumour cells and has been associated with a worse prognosis. Monoclonal antibody therapies targeting the PD-1:PD-L1 axis have shown initial promise, but further research is needed to identify which patients will benefit. We provide an update of knowledge on PD-L1, including its structure, function and regulation. We also review studies on the overexpression of PD-L1 in cancer, specifically oral squamous cell carcinoma, and explore its potential value as a therapeutic target.

Intratumor heterogeneity of PD-L1 expression in head and neck squamous cell carcinoma

Intratumor heterogeneity may contribute to the ambiguous clinical results on PD-L1 status as a predictor for immunotherapy response in patients with HNSCC. This decreases the utility of PD-L1 expression from single tumour biopsies as a predictive biomarker. In this prospective study, intratumor heterogeneity of PD-L1 expression in HNSCC was investigated with both Tumour Proportion Score (TPS) and Combined Positive Score (CPS). Thirty-three whole surgical specimens from 28 patients with HNSCC were included. PD-L1 expression in six random core biopsies from each surgical specimen was used to assess the concordance between multiple biopsies and the negative predictive value of a single negative core biopsy. With 1% cut off, 36% of the specimens were concordant with TPS and 52% with CPS. With a 50% cut-off value the concordance was 70% with TPS and 55% with CPS. Defining a tumour as positive if just a single-one of the biopsies was positive, the negative predictive value (NPV) of a single negative core biopsy was 38.9 and 0% (1% cut off), and 79.9% and 62.8% (50% cut off) for TPS and CPS, respectively. In conclusion, PD-L1 positivity varies markedly within the tumour, both with TPS and CPS, challenging the utility of this biomarker.

Heterogeneity of the Head and Neck Squamous Cell Carcinoma Immune Landscape and Its Impact on Immunotherapy

Head and neck squamous cell carcinomas (HNSCCs) are highly aggressive, multi-factorial tumors in the upper aerodigestive tract affecting more than half a million patients worldwide each year. Alcohol, tobacco, and human papillomavirus (HPV) infection are well known causative factors for HNSCCs. Current treatment options for HNSCCs are surgery, radiotherapy, chemotherapy, or combinatorial remedies. Over the past decade, despite the marked improvement in clinical outcome of many tumor types, the overall 5-year survival rate of HNSCCs remained ∼40–50% largely due to poor availability of effective therapeutic options for HNSCC patients with recurrent disease. Therefore, there is an urgent and unmet need for the identification of specific molecular signatures that better predict the clinical outcomes and markers that serve as better therapeutic targets. With recent technological advances in genomic and epigenetic analyses, our knowledge of HNSCC molecular characteristics and classification has been greatly enriched. Clinical and genomic meta-analysis of multicohort HNSCC gene expression profile has clearly demonstrated that HPV⁺ and HPV^- HNSCCs are not only derived from tissues of different anatomical regions, but also present with different mutation profiles, molecular characteristics, immune landscapes, and clinical prognosis. Here, we briefly review our current understanding of the biology, molecular profile, and immunological landscape of the HPV⁺ and HPV^- HNSCCs with an emphasis on the diversity and heterogeneity of HNSCC clinicopathology and therapeutic responses. After a review of recent advances and specific challenges for effective immunotherapy of HNSCCs, we then conclude with a discussion on the need to further enhance our understanding of the unique characteristics of HNSCC heterogeneity and the plasticity of immune landscape. Increased knowledge regarding the immunological characteristics of HPV⁺ and HPV^- HNSCCs would improve therapeutic targeting and immunotherapy strategies for different subtypes of HNSCCs.

Targeted Therapies and Immune-Checkpoint Inhibition in Head and Neck Squamous Cell Carcinoma: Where Do We Stand Today and Where to Go?

With an increased understanding of the tumor biology of squamous cell carcinoma of the head and neck (SCCHN), targeted therapies have found their way into the clinical treatment routines against this entity. Nevertheless, to date platinum-based cytostatic agents remain the first line choice and targeting the epidermal growth factor-receptor (EGFR) with combined cetuximab and radiation therapy remains the only targeted therapy approved in the curative setting. Investigation of immune checkpoint inhibitors (ICI), such as antibodies targeting programmed cell death protein 1 (PD-1) and its ligand PD-L1, resulted in a change of paradigms in oncology and in the first approval of new drugs for treating SCCHN. Nivolumab and pembrolizumab, two anti-PD-1 antibodies, were the first agents shown to improve overall survival for patients with metastatic/recurrent tumors in recent years. Currently, several clinical trials investigate the role of ICI in different therapeutic settings. A robust set of biomarkers will be an inevitable tool for future individualized treatment approaches including radiation dose de-escalation and escalation strategies. This review aims to summarize achieved goals, the current status and future perspectives regarding targeted therapies and ICI in the management of SCCHN.

Phase 1 Study Evaluating the Association of the Cyclin-Dependent Kinase 4/6 Inhibitor Ribociclib and Cetuximab in Recurrent/Metastatic p16-Negative Squamous Cell Carcinoma of the Head and Neck

Background: The majority of human papillomavirus (HPV)-negative squamous cell carcinoma of the head and neck (SCCHN) present upregulation of the epidermal growth factor receptor (EGFR) and frequent alterations in the cyclin D1-cyclin dependent kinase (CDK) 4/6 (CDK 4/6)-retinoblastoma protein (pRb) pathway, resulting in cell cycle progression and tumor proliferation. This study investigated the combination of ribociclib, an orally highly selective inhibitor of CDK 4/6, and cetuximab in recurrent and/or metastatic (R/M) SCCHN. Methods: A phase I trial using a 3 + 3 design was performed to determine the dose limiting toxicity (DLT) and maximum tolerated dose (MTD) of ribociclib with standard dose of weekly cetuximab in HPV-negative patients with R/M SCCHN. Ribociclib was administered orally (3 weeks on/1 week off) at dose level 1 of 400 mg daily and dose level 2 of 600 mg daily. The MTD of ribocilib was then further evaluated in an expansion cohort. Results: 10 patients were enrolled in the escalation trial. No DLTs were observed at dose level 1 (n = 3); at dose level 2, one patient was replaced due to rapid disease progression, and one patient out of six evaluable patients experienced a DLT (grade 4 thrombocytopenia >7 days). Ribociclib 600 mg daily was thus determined to be the MTD. Eleven additional patients were enrolled in the expansion cohort. Diarrhea (52%), rash (52%), fatigue (43%), nausea (33%), and mucositis (28%) were the most frequent grade 1-2 adverse events (AE). Neutropenia was the most frequent grade 3-4 AE (20%). Median progression-free survival (PFS) was 3.5 months (range 0.4-17.3 months) and median overall survival (OS) was 8.3 months (range 0.4-24.1 months). Among the 19 radiologically evaluable patients, two (10.5%) achieved a partial response and 11 (58%) had stable disease. Conclusions: The MTD of ribociclib is 600 mg daily when administered in combination with standard dose cetuximab for 3 weeks on and 1 week off. This combination was safe and showed efficacy. Further clinical trials should be conducted to evaluate the antitumor effects of this combination. Trial Information: ClinicalTrials.gov: NCT02429089; Eudract number 2014-005371-83.

Immunotherapy Approaches Beyond PD-1 Inhibition: the Future of Cellular Therapy for Head and Neck Squamous Cell Carcinoma

OPINION STATEMENT

In a span of a few years, the surprising early successes of programmed cell death 1 (PD-1) inhibitors across a vast range of tumor types have transformed our understanding of cancer immunogenicity and provided proof of principle that T cells, if manipulated, can mediate meaningful tumor regression. In head and neck cancer, only a minority of patients respond to PD-1 therapy, but these small outcomes have fueled the enthusiasm for the next generation of immunotherapy-adoptive cell therapy-which employs recent advances in genetic engineering and cell culturing methods to generate T cells with enhanced anti-tumor efficacy for infusion back into the patient. Head and neck cancer is comprised of biologically distinct cancers, HPV-positive and HPV-negative, and the clinical responses to PD-1 inhibitors in both HPV-positive and HPV-negative head and neck patients have showcased better than any other cancer type that there are distinct pathways to immunogenicity that may lend themselves to different therapeutic approaches. Thus, head and neck cancer is uniquely poised to benefit from the personalized approach of adoptive cell therapy as well as provide a valuable platform to explore contrasting T cell modalities. In this article, we will review the growing portfolio of trials of adoptive cell therapies in head and neck cancer and discuss the future directions of this emerging new field.

Non-murine models to investigate tumor-immune interactions in head and neck cancer

The immune response has important roles in the biology of solid tumors, including oncogenesis, tumor growth, invasion and metastasis, and response to treatment. Improved understanding of tumor-immune system interactions has provided promising therapeutic options that are based on the rescue and enhancement of the anti-tumoral host response. Immune-based treatments have been approved for clinical use in various types of cancer, including head and neck cancer (HNC); other strategies involving combination therapies are currently in development. These novel therapies were developed based on knowledge derived from in vitro, in silico, and in vivo pre-clinical studies. However, clinical trials seldom replicate the efficacy observed in pre-clinical animal studies. This lack of correlation between pre-clinical studies and clinical trials may be related to limitations of the models used; which highlights the relevance of considering immune-related aspects of different pre-clinical models. Murine models are the most frequently used pre-clinical models of HNC and are discussed elsewhere. Non-murine models have characteristics that offer unique opportunities for the study of HNC etiology, therapeutic strategies, and tumor-immune system interactions. The current review focuses on immune-related aspects of non-murine models, including dog, cat, pig, zebrafish, and frog, that could be used to investigate tumor-immune interactions in HNC.