Immunotherapy In Head And Neck Squamous Cell Carcinoma Research Articles

Immune checkpoint inhibitors in head and neck squamous cell carcinoma: A systematic review of phase-3 clinical trials.

BACKGROUNDThe outcomes of patients diagnosed with head and neck squamous cell carcinoma (HNSCC) who are not candidates for local salvage therapy and of those diagnosed with recurrent or metastatic disease are dismal. A relatively new systemic therapy option that emerged in recent years in the treatment of advanced HNSCC is immunotherapy using immune checkpoint inhibitors (ICIs). The safety profile and anti-tumor activity of these agents demonstrated in early phase clinical trials paved the way to the initiation of several promising phase-3 trials in the field.AIMTo evaluate the evidence on the effectiveness of ICIs in HNSCC, based on published phase-3 clinical trials.METHODSWe searched PubMed, Cochrane Library, Embase, and Scopus to identify published literature evaluating immunotherapy using ICIs in recurrent or metastatic HNSCC (R/M HNSCC) and locally advanced head and neck squamous cell carcinoma (LAHNSCC). We used a combination of standardized search terms and keywords including head and neck squamous cell carcinoma, recurrent, metastatic, locally advanced, immunotherapy, immune checkpoint inhibitors, monoclonal antibodies, programmed cell death protein-1 (PD-1), programmed death-ligand 1 (PD-L1), cytotoxic T- lymphocyte associated protein-4 (CTLA-4), and phase-3 clinical trial. A sensitive search filter was used to limit our results to randomized controlled trials.RESULTSFive phase-3 clinical trials have reported the data on the effectiveness of immunotherapy in HNSCC so far: Four in R/M HNSCC and one in LAHNSCC. In patients with R/M HNSCC, anti-PD-1 agents nivolumab and pembrolizumab demonstrated improved survival benefits in the second-line treatment setting compared to the standard of care (standard single-agent systemic therapy). While the net gain in overall survival (OS) with nivolumab was 2.4 mo [hazard ratio (HR) = 0.69, P = 0.01], that with pembrolizumab was 1.5 mo (HR = 0.80 nominal P = 0.0161). The anti-PD-L1 agent durvalumab with or without the anti-cytotoxic T- lymphocyte associated protein-4 agent tremelimumab did not result in any beneficial outcomes. In the first-line setting, in R/M HNSCC, pembrolizumab plus platinum-based chemotherapy resulted in significant improvement in survival with a net gain in OS of 2.3 mo (HR = 0.77, P = 0.0034) in the overall population and a net gain in OS of 4.2 mo in the PD-L1 positive (combined positive score > 20) population compared to standard of care (EXTREME regime). In patients with PD-L1 positive R/M HNSCC, monotherapy with pembrolizumab also demonstrated statistically significant improvement in survival compared to EXTREME. In LAHNSCC, immunotherapy using avelumab (an anti-PD-L1 agent) along with standard chemoradiation therapy did not result in improved outcomes compared to placebo plus chemoradiation therapy.CONCLUSIONAnti-PD-1 agents provide survival benefits in R/M HNSCC in the first and second-line settings, with acceptable toxicity profiles compared to standard therapy. There is no proven efficacy in the curative setting to date.

Outcomes Following Immunotherapy in Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma: A Single-Institution Experience

<h3>Purpose/Objective(s)</h3> Pembrolizumab and nivolumab are approved in the treatment of recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). However, real-world effectiveness may vary from clinical trial efficacy, partly due to strict exclusion criteria. We reviewed the effectiveness of immunotherapy (IO) in recurrent/metastatic HNSCC at a single tertiary referral center. <h3>Materials/Methods</h3> All HNSCC patients who received single-agent palliative IO for recurrent/metastatic disease were identified from the electronic medical record via ICD codes under an IRB approved protocol. Wilcoxon rank sums test and chi squared test of independence were used to compare characteristics between IO responders (any response) and non-responders (stable or progressive disease) respectively. Kaplan-Meier method was used to estimate overall (OS) and progression free survival (PFS). Multivariable cox proportional hazards method was used to identify predictors of OS. <h3>Results</h3> A total of 138 patients were identified with the following primary tumor sites: p16+ oropharynx (n=45), p16- oropharynx (21), oral cavity (29), larynx (21), hypopharynx (7), nasal/sinus (7), or unknown primary (8). Concurrent chemoradiation was given to 68.8% (95) of patients and palliative chemotherapy was given prior to IO in 26.1% (36). IO was given for unresectable recurrent or metastatic disease in 23.2% (32) and 76.8% (106) of patients respectively, with 95.7% (132) receiving pembrolizumab and 4.3% (6) receiving nivolumab. Median age was 64 years (IQR 58-71), with ECOG status of 0, 1, and 2 in 23.9% (33), 60.9% (84), and 15.2% (21) of patients respectively. Combined positive scores (CPS) were available in 45.7% (63) of patients, with 33.3% (46) having CPS≥1 and 23.9% (33) having CPS≥20. The median number of IO cycles received was 4 (IQR 2-7). Of the 96 patients who survived to undergo imaging after ≥3 cycles, 43.8% (42) of patients had progression, 15.6% (15) had stable disease, 36.5% (35) had partial responses, and 4.2% (4) had complete responses. There were no significant differences in age, time from definitive radiation to IO, or absolute lymphocyte count (ALC) at IO initiation between responders and non-responders. Median PFS from IO initiation was 3.2 months (95%CI 2.8-4.4) months while median OS from IO initiation was 6.6 months (4.7-10.3). In a multivariable model, ECOG status of 1 (HR=2.00, 1.16-3.45) or 2 (HR=3.03, 1.51-6.09) vs ECOG 0 and decreased ALC at IO initiation (100 cells/µL, HR=1.06, 1.01-1.12) were significant predictors of worse OS. <h3>Conclusion</h3> In this real-world cohort, survival with palliative IO in HNSCC was similar to that in randomized control trials. Though ECOG status and ALC were significant predictors of OS, further work into predictors of OS mediated through evidence of tumor response is needed.

M1 macrophage-derived exosomes and their key molecule lncRNA HOTTIP suppress head and neck squamous cell carcinoma progression by upregulating the TLR5/NF-\u03baB pathway

Exosomes serve as a crucial mode of communication between tumor-associated macrophages (TAMs) and cancer cells. This study attempted to explore the function of M1-derived exosomes and clarify their specific mechanism in head and neck squamous cell carcinoma (HNSCC). Moreover, the functional roles of M1-derived exosomes and their key molecule long noncoding RNA (lncRNA) HOXA transcript at the distal tip (HOTTIP) in HNSCC were investigated by conducting a series of in vitro and in vivo experiments. The dual-luciferase test was utilized to clarify the binding capacities between HOTTIP/mRNA and miRNAs. Accordingly, HOTTIP was found to be upregulated in M1-derived exosomes. Meanwhile, the in vitro experiments indicated that M1 exosomes suppressed proliferation, migration and invasion but induced apoptosis of cancer cells. This function was noted to be enhanced by HOTTIP-overexpressed M1 exosomes but was weakened by HOTTIP-knockdown ones, indicating that HOTTIP serves as a key molecule in M1 exosomes. Therefore, the function of HOTTIP in cancer cells was explored, for which overexpression of HOTTIP was found to inhibit proliferation, migration and invasion but induced apoptosis of cancer cells in vitro. A mechanism study further showed that M1 exosomes and HOTTIP activated the TLR5/NF-κB signaling pathway by competitively sponging miR-19a-3p and miR-19b-3p. Furthermore, cancer cells expressing HOTTIP were noted to induce the polarization of both local M1 and M2 macrophages; however, M1 exosomes were observed to reprogram local TAMs into M1 macrophages. More importantly, both cancer cells expressing HOTTIP and M1 exosomes reeducated circulating monocytes to express the M1 phenotype. The corresponding data demonstrated that the M1 exosomal lncRNA HOTTIP suppresses HNSCC progression by upregulating the TLR5/NF-κB signaling pathway through competitively sponging miR-19a-3p and miR-19b-3p. In particular, M1 exosomes and HOTTIP induce the polarization of M1 in circulating monocytes, thus providing novel insight into HNSCC immunotherapy.

Statin in combination with cisplatin makes favorable tumor-immune microenvironment for immunotherapy of head and neck squamous cell carcinoma

The purpose of this study was to determine whether statins can enhance anticancer effects in head and neck squamous cell carcinoma (HNSCC) when used with cisplatin and act as immunogenic cell death (ICD) inducers that can be used in cancer immunotherapy. Statins alone showed both in vitro and in vivo inhibitory effects against HNSCC, and synergistic antitumor effects were observed when combined with cisplatin in a syngeneic murine HNSCC model. Statins increased calreticulin exposure and endoplasmic reticulum stress-related signals in HNSCC cells. In addition, it was confirmed that statins could activate antigen-presenting cells and tumor-specific CD8+ T cells with an increase in their numbers in the tumor tissues and draining lymph nodes, with this effect showing significant improvement following the combination therapy with cisplatin. Moreover, in triple combination with both cisplatin and anti-programmed cell death 1 receptor (anti-PD-1) antibody, statins dramatically induced further tumor eradication and improved the survival of tumor-bearing mice. Taken together, these results demonstrate that statins, administered in combination with anti-PD-1 antibody, could enhance the anticancer effect of cisplatin and potentiate the efficacy of immunotherapy for HNSCC and present a rationale for repurposing statins as an adjuvant immunotherapeutic option for HNSCC.

Bayesian Networks to Support Decision-Making for Immune-Checkpoint Blockade in Recurrent/Metastatic (R/M) Head and Neck Squamous Cell Carcinoma (HNSCC).

Simple SummaryTumor therapy in many human malignancies, including head and neck cancer, is increasingly demanding due to advances in diagnostics and individualized treatments. Multidisciplinary tumor boards, especially molecular tumor boards, consider a great amount of information to find the optimal treatment decision. Clinical decision support systems can help in optimizing this complex decision-making process. We designed a digital patient model based on conditional probability algorithms as Bayesian networks to support the decision-making process regarding treatment with approved immunotherapeutic agents (Nivolumab and Pembrolizumab). The model is able to process relevant clinical information to recommend a certain immunotherapeutic agent based on literature, approval, and guidelines.New diagnostic methods and novel therapeutic agents spawn additional and heterogeneous information, leading to an increasingly complex decision-making process for optimal treatment of cancer. A great amount of information is collected in organ-specific multidisciplinary tumor boards (MDTBs). By considering the patient’s tumor properties, molecular pathological test results, and comorbidities, the MDTB has to consent an evidence-based treatment decision. Immunotherapies are increasingly important in today’s cancer treatment, resulting in detailed information that influences the decision-making process. Clinical decision support systems can facilitate a better understanding via processing of multiple datasets of oncological cases and molecular genetic information, potentially fostering transparency and comprehensibility of available information, eventually leading to an optimum treatment decision for the individual patient. We constructed a digital patient model based on Bayesian networks to combine the relevant patient-specific and molecular data with depended probabilities derived from pertinent studies and clinical guidelines to calculate treatment decisions in head and neck squamous cell carcinoma (HNSCC). In a validation analysis, the model can provide guidance within the growing subject of immunotherapy in HNSCC and, based on its ability to calculate reliable probabilities, facilitates estimation of suitable therapy options. We compared actual treatment decisions of 25 patients with the calculated recommendations of our model and found significant concordance (Cohen’s κ = 0.505, p = 0.009) and 84% accuracy.

Multi-Omics Data Analyses Identify B7-H3 as a Novel Prognostic Biomarker and Predict Response to Immune Checkpoint Blockade in Head and Neck Squamous Cell Carcinoma.

B7 homolog 3 (B7-H3) is a recently found superfamily B7 molecule and therefore has significant involvement in immunological regulation. However, the relationships of B7-H3 expression with the tumor microenvironment (TME), response to immunotherapy, and prognosis in head and neck squamous cell carcinoma (HNSCC) are still unknown. In the present analysis, we determined B7-H3 as a novel biomarker that predicts the prognosis and response to immunotherapy in HNSCC. B7-H3 expression is enhanced in HNSCC compared to normal sample and is stably expressed in HNSCC cell line. Besides, high B7-H3 expression is correlated with a dismal prognosis and resistance to immunotherapy and contributes to an immunosuppressive microenvironment. Moreover, single-cell RNA sequencing (scRNA-seq) analysis shows that B7-H3 is mainly expressed in the stromal as well as malignant cells. In conclusion, the study provides insight in understanding the prognostic value of B7-H3 in HNSCC and highlights its involvement in promoting the immunosuppressive microenvironment, which presents an attractive strategy for antibody-based immunotherapy.

Immunotherapy for Head and Neck Cancer: A Paradigm Shift From Induction Chemotherapy to Neoadjuvant Immunotherapy.

Neoadjuvant immunotherapy has the potential to enhance clinical outcomes by increasing anti-tumor immune responses in the presence of abundant tumor-derived antigen in an immune microenvironment that has not been exposed to previous therapy. The current mainstay of advanced head and neck squamous cell carcinoma (HNSCC) treatment remains surgery and radiotherapy with/without conventional chemotherapy. Despite this multi-modality treatment, advanced human papillomavirus (HPV)-negative HNSCC shows poor prognosis. Treatment intensification with neoadjuvant (induction) chemotherapies with platinum drugs are insufficient to significantly prolong overall survival. Although only 15-20% of patients benefit, immunotherapies have been approved and widely used for recurrent and metastatic HNSCC. These successes have led to checkpoint blockade therapies being testing in earlier treatment settings. Recent clinical trials of neoadjuvant immunotherapy show promising results and this methodology has the potential to change the treatment algorithm of HNSCC. This overview examines the treatment history of neoadjuvant approaches for HNSCC, and especially focuses on the recent topics of neoadjuvant immunotherapy for HNSCC.

Dynamic alterations of circulating T lymphocytes and the clinical response in patients with head and neck squamous cell carcinoma treated with nivolumab.

Cancer immunotherapy using immune checkpoint inhibitors (ICIs) has been recognized as a novel therapeutic option for head and neck squamous cell carcinoma (HNSCC). However, only approximately 20-30% of patients with recurrent/metastatic (R/M) HNSCC benefit. Moreover, the mechanisms underlying the response to ICIs remain unclear. We investigated the proportion, activation status, and expression level of immune checkpoint molecules in circulating T cell subsets in R/M HNSCC patients treated with nivolumab using flow cytometry and mass cytometry, and then determined whether treatment response was associated with these values. We also assessed the changes in the frequency of tumor-associated antigens, MAGE-A4 and p53, -specific T cells prior to and after nivolumab treatment using the IFN-γ ELISPOT assay. The proportion of activated CD4+ and CD8+ TEMRA cells significantly increased in the disease-controlled patients but not in disease-progressed patients. As expected, the expression of PD-1 in T cells markedly decreased regardless of the therapeutic response. Meanwhile, T cell immunoglobulin mucin-3 expression on CD8+ T cells was significantly higher in patients with disease progression than in disease-controlled patients after treatment. The frequency of the tumor-associated antigens, MAGE-A4- and p53-specific T cells, was not correlated with clinical responses; however, in the disease-controlled patients, the frequency of MAGE-A4-specific T cells was significantly augmented. We concluded that in R/M HNSCC patients treated with nivolumab, circulating T cells show dynamic alterations depending on treatment efficacy. An analysis of the immunokinetics of circulating T cells could thus provide new insights into rational therapeutic strategies in cancer immunotherapy for HNSCC.

Expression of placenta-specific 1 and its potential for eliciting anti-tumor helper T-cell responses in head and neck squamous cell carcinoma

ABSTRACT Placenta-specific 1 (PLAC1) is expressed primarily in placental trophoblasts but not in normal tissues and is a targetable candidate for cancer immunotherapy because it is a cancer testis antigen known to be up-regulated in various tumors. Although peptide epitopes capable of stimulating CD8 T cells have been previously described, there have been no reports of PLAC1 CD4 helper T lymphocyte (HTL) epitopes and the expression of this antigen in head and neck squamous cell carcinoma (HNSCC). Here, we show that PLAC1 is highly expressed in 74.5% of oropharyngeal and 51.9% of oral cavity tumors from HNSCC patients and in several HNSCC established cell lines. We also identified an HTL peptide epitope (PLAC131-50) capable of eliciting effective antigen-specific and tumor-reactive T cell responses. Notably, this peptide behaves as a promiscuous epitope capable of stimulating T cells in the context of more than one human leukocyte antigen (HLA)-DR allele and induces PLAC1-specific CD4 T cells that kill PLAC1-positive HNSCC cell lines in an HLA-DR-restricted manner. Furthermore, T-cells reactive to PLAC131-50 peptide were detected in the peripheral blood of HNSCC patients. These findings suggest that PLAC1 represents a potential target antigen for HTL based immunotherapy in HNSCC.

Exploration of Feasible Immune Biomarkers for Immune Checkpoint Inhibitors in Head and Neck Squamous Cell Carcinoma Treatment in Real World Clinical Practice.

Recurrent locally advanced or metastatic head and neck squamous cell carcinoma (HNSCC) is associated with dismal prognosis because of its highly invasive behavior and resistance to conventional intensive chemotherapy. The combination of targeted therapy and conventional chemotherapy has significantly improved clinical outcomes. In recent years, the development of immunotherapies, such as immune checkpoint inhibitors (ICIs), has further increased treatment responses and prolonged survival. However, the limited response rate, risk of immunotherapy-related adverse effects and high cost of immunotherapy make the identification of predictive markers to optimize treatment efficacy a critical issue. Biomarkers are biological molecules that have been widely utilized to predict treatment response to certain treatments and clinical outcomes or to detect disease. An ideal biomarker should exhibit good predictive ability, which can guide healthcare professionals to achieve optimal treatment goals and bring clinical benefit to patients. In this review, we summarized the results of recent and important studies focused on HNSCC ICI immunotherapy and discussed potential biomarkers including their strengths and limitations, aiming to gain more insight into HNSCC immunotherapy in real world clinical practice.

Prognostic Value of CD200R1 mRNA Expression in Head and Neck Squamous Cell Carcinoma.

Immune system dysfunction is associated with head and neck squamous cell carcinoma (HNSCC) development and progression and immune checkpoint inhibitors have demonstrated substantial survival benefits in platinum-refractory HNSCC; therefore, we examined the prognostic value of immune-related gene (IRG) expression in HNSCC. We analyzed the expression of 82 IRGs in 71 patients with HNSCC enrolled in a feasibility study for a prospective HNSCC biomarker-driven umbrella trial (Korean Cancer Study Group TRIUMPH study, NCT03292250). CD200R1 was identified as an independent prognostic factor and validated in GEO and TCGA database. CD2000R1 mRNA expression was found to be an independent favorable prognostic factor in patients with HNSCC. Moreover, CD200R1 was found to affect genes and pathways associated with the immune response, while seven differentially expressed genes (CD8A, DOK2, CX3CR1, TYROBP, CXCL9, CD300LF, IFNG) were associated with CD200R1 expression. Samples with higher CD200R1 expression displayed higher tumor-infiltrating immune cell counts both in silico and in histological analysis. These findings will help in the development of more accurate prognostic tools and suggest CD200R1 modulation as a HNSCC immunotherapy.

Abstract IA18: Interrogating anti-PD1 immunotherapy resistance mechanisms

Abstract Background: The response rate of 15-20% with anti-PD1 targeting in head and neck squamous cell carcinoma (HNSCC) highlights the need for strategies to overcome resistance. We have focused on delineating mechanistic aspects of immune checkpoint response and resistance using novel clinical trial approaches coupled with analyses in high-fidelity immunocompetent murine oral carcinoma (MOC) model to study HNSCC immunobiology. Methods: Using the MOC HNSCC model, we generated anti-PD1 resistant models. Whole-exome sequencing and RNA-Seq were used to compare mutational burden and expression signatures. Time of flight mass cytometry (CyTOF) was used to analyze tumor microenvironment (TME) remodeling in response to checkpoint inhibition. 2-D coculture system was used to assess tumor recognition by MHC class I restricted cytotoxic T cells. Tumor cells were loaded with SIINFEKL peptide and OT1 T cells were used as effectors in T-cell cytotoxicity assays. The anti-PD1 resistant MOC model overexpressing CAS9 with high editing efficiency was generated for a genome-scale CRISPR screen. The Broad Institute Genomic Perturbation Platform Brie lentiviral library, including 78,637 gRNAs targeting 19,674 with 1000 controls, was transduced into this line to define modifiers of CD8+ T cell mediated killing. Ezh2 inhibitors and knockout lines were used in characterizing the role of EZH2 in antigen presentation and antitumor immunity. Results: To examine immunotherapy resistance we generated 2 independent anti-PD1 adaptive resistant cell line models, MOC1-esc1 and MOC1-esc2, from their isogenic MOC1 parental line. RNA-Seq showed that MOC1-esc1 upregulated Myc and E2F targets and lost inflammatory signatures whereas -esc2 tumors have upregulated DNA damage and unfolded protein response. When MOC1-esc tumors were retransplanted into naive mice, they exhibited resistance to anti-PD1, while remaining responsive to anti-CTLA4 treatment. To gain comprehensive insights into the tumor microenvironment (TME) as a contributor to adaptive resistance, we analyzed tumor-infiltrating lymphocytes (TIL) in naive MOC1 and MOC1-esc1 tumors using CyTOF with a panel of 38 markers. MOC1-esc1 tumors were highly infiltrated with regulatory T cells (Tregs) and M2-like tumor-associated macrophages (TAMs), while MOC1 tumors have more M1-like TAMs and neutrophils. Furthermore, we observed that both anti-PD1 and anti-CTLA4 treatment dramatically expanded CD8+ T cells and decreased neutrophils in MOC1-esc1 tumors. In responding MOC1-esc1 tumors, anti-CTLA4 treatment resulted in Treg depletion, decreased M2-like TAMs and neutrophils, as well as a striking increase in M1-like TAMs compared with isotype control treated tumors. In contrast, anti-PD1 treated MOC1-esc1 tumors showed decreased M1-like TAMs, while M2-like TAMs were increased compared with control. Depletion of Tregs, neutrophils, or repolarization of TAM using monoclonal antibodies confirmed their contribution in immunotherapy resistance. As the MOC1-esc1 line showed in vitro resistance to T-cell cytotoxicity compared to MOC1 and to define tumor cell intrinsic modulators of T-cell cytotoxicity, we then completed a genome-scale CRISPR screen in MOC1-esc1. This screen identified 355 candidate genes whose loss of function regulated T-cell cytotoxicity. Chromatin modifiers emerged as a major class of genes regulating T-cell recognition of tumor cells. We validated Ezh2 as a therapeutic target and showed that inhibition of this pathway enhanced Class I expression and sensitized MOC1-esc1 cells to T-cell killing in vitro. Analysis of human HNSCC cell line models and TCGA data revealed conservation of Ezh2 impact on Class I expression. Combination therapy with Ezh2 inhibitors and anti-PD1 blockade resulted in enhanced therapeutic efficacy compared to either agent alone in the anti-PD1 resistant MOC1-esc1 model. Conclusions: In summary, this study identified (1) immune modulators within TME involved in adaptive immunotherapy resistance of HNSCC and remodeling with checkpoint therapy and (2) tumor cell intrinsic candidate pathways regulating T-cell recognition. Findings from these studies will advance our understanding of HNSCC immunotherapy resistance and will accelerate the discovery of new combination therapeutic targets and biomarkers in adaptive resistance. Citation Format: Ravindra Uppaluri. Interrogating anti-PD1 immunotherapy resistance mechanisms [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Optimizing Survival and Quality of Life through Basic, Clinical, and Translational Research; 2019 Apr 29-30; Austin, TX. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(12_Suppl_2):Abstract nr IA18.

Immunotherapy improves efficacy and safety of patients with HPV positive and negative head and neck cancer: A systematic review and meta-analysis.

Despite multiple modalities used to management of head and neck squamous cell carcinoma (HNSCC), disease control remains unsatisfactory. Immunotherapy is emerging as a novel therapeutic approach. This systematic review assesses clinical data regarding immunotherapy efficacy and safety. Data from 11 clinical trials testing immunotherapy in HNSCC were assessed. We performed the meta-analysis to correlate the overall survival (OS), response rate (RR), adverse effects, HPV status, and PD-L1 expression. Immunotherapy extended OS (hazard ratio = 0.77, p < 0.0001) and RR significantly (risk ratio = 1.41, p = 0.02). Patients with HPV-positive HNSCC exhibited a better RR (risk ratio = 1.29, p = 0.24) and OS (11.5 vs. 6.3 months). PD-L1 positive tumors showed a higher OS (9.9 vs. 6.5 months). Moreover, immunotherapy caused less adverse effects than standard therapy. Our results indicate the benefit of immunotherapy for improving RR and OS of HNSCC patients. The benefit is higher in patients with HPV and PD-L1 positive tumors.

Tumor Membrane Vesicle Vaccine Augments the Efficacy of Anti-PD1 Antibody in Immune Checkpoint Inhibitor-Resistant Squamous Cell Carcinoma Models of Head and Neck Cancer.

Immune checkpoint inhibitor (ICI) immunotherapy improved the survival of head and neck squamous cell carcinoma (HNSCC) patients. However, more than 80% of the patients are still resistant to this therapy. To test whether the efficacy of ICI therapy can be improved by vaccine-induced immunity, we investigated the efficacy of a tumor membrane-based vaccine immunotherapy in murine models of HNSCC. The tumors, grown subcutaneously, are used to prepare tumor membrane vesicles (TMVs). TMVs are then incorporated with glycolipid-anchored immunostimulatory molecules GPI-B7-1 and GPI-IL-12 by protein transfer to generate the TMV vaccine. This TMV vaccine inhibited tumor growth and improved the survival of mice challenged with SCCVII tumor cells. The tumor-free mice survived for several months, remained tumor-free, and were protected following a secondary tumor cell challenge, suggesting that the TMV vaccine induced an anti-tumor immune memory response. However, no synergy with anti-PD1 mAb was observed in this model. In contrast, the TMV vaccine was effective in inhibiting MOC1 and MOC2 murine oral cancer models and synergized with anti-PD1 mAb in extending the survival of tumor-bearing mice. These observations suggest that tumor tissue based TMV vaccines can be harnessed to develop an effective personalized immunotherapy for HNSCC that can enhance the efficacy of immune checkpoint inhibitors.

Management of Immune-Related Dermatitis and Mucositis Associated With Pembrolizumab in Metastatic Human Papillomavirus-Associated Squamous Cell Carcinoma of the Oropharynx.

On June 10, 2019, the US Food and Drug Administration approved pembrolizumab for first-line treatment of metastatic or unresectable human papillomavirus (HPV)-positive and HPV-negative recurrent head and neck squamous cell carcinoma (HNSCC) based on the KEYNOTE-048 phase III study. Pembrolizumab is now the first anti-programmed cell death protein 1 (PD-1) therapy approved in the first-line HNSCC setting. Pembrolizumab is approved as first-line monotherapy for tumors that express programmed death-ligand 1 (PD-L1) or in combination with chemotherapy regardless of PD-L1 expression. As the indications for immunotherapy for HNSCC broaden, practitioners will need to know how to recognize and manage more immunotherapy-related toxicities. The following case study provides insight into the assessment and management of the specific immune-related toxicities of dermatitis and mucositis associated with pembrolizumab-chemotherapy combination therapy using Immuno-Oncology Essentials guidance. Assessment and early management of immunotherapy toxicity is critical, as is a multidisciplinary approach.

Abstract 1509: Identification of immunotherapy resistance mechanisms within tumor microenvironment in a mouse model of oral squamous cell carcinoma

Abstract The response rate of 15-20% with anti-PD1 in head and neck squamous cell carcinoma (HNSCC) highlights the urgent need for strategies to overcome resistance. Our lab has previously developed a carcinogen-induced immunocompetent murine oral carcinoma (MOC) model to study HNSCC immunobiology. Specifically, MOC1 is an immunogenic cell line that, despite sensitivity to anti-PD-1, exhibits occasional development of escape tumors (MOC1esc). MOC1esc escape tumors display a resistance phenotype similar to those observed in HNSCC patients undergoing anti-PD1 therapy. When independent escape tumors are harvested and re-transplanted into naïve mice, they grow progressively and are resistant to anti-PD1 therapy. Intriguingly, whileMOC1esc is resistant to anti-PD1, it is completely rejected in tumor bearing mice treated with anti-CTLA4. Therefore, the anti-PD1 responsive MOC1 and resistant MOC1esc mouse model is an isogenic system that provides an excellent opportunity to study mechanism(s) in adaptive resistance to anti-PD1 therapy of HNSCC. To gain a comprehensive insight into the tumor microenvironment (TME) as a contributor to adaptive resistance, we analyzed tumor infiltrating lymphocytes (TIL) in naïve MOC1 and MOC1esc tumors using mass cytometry time-of-flight (CyTOF) with a 38-cell marker panel.MOC1esc tumors were highly infiltrated by CD103+ effector/memory regulatory T cells (Tregs) and M2-like tumor associated macrophages (TAMs), while MOC1 tumors have more M1-like TAMs and neutrophils. Furthermore, we observed that both anti-PD1 and anti-CTLA4 treatment dramatically expanded CD8+ T cells and decreased neutrophils in MOC1esc tumors. In responding MOC1esc tumors, anti-CTLA4 treatment resulted in depleted Tregs, decreased M2-like TAMs and neutrophils, as well as a striking increase in M1-like TAMs compared with isotype control treated tumors. In contrast, anti-PD1 treated resistant MOC1esc tumors showed decreased M1-like TAMs, while M2-like TAMs were increased compared with controls. Tregs were not affected by anti-PD1 treatment. Therefore, the comparison between the TME of anti-PD1 treated resistant tumors and anti-CTLA4 treated responding tumors suggeststhat Tregs, neutrophils, and TAMs may contribute to the sensitivity (or resistance) to checkpoint blockade therapy. Ongoing studies will test the functional contribution of these distinct TME components in antitumor immunity including cytokine production, proliferative capacity, and their roles in immunotherapy resistance. In summary, this study identified immune modulators within TME involved in adaptive immunotherapy resistance of HNSCC. Findings from this study have advanced our understanding of HNSCC immunotherapy resistance and will accelerate the discovery of new therapeutic targets and biomarkers for adaptive resistance. Citation Format: Liye Zhou, Yasutaka Nakahori, Fei Guo, Joshua Keegan, Rachel Riley, James A. Lederer, Ravindra Uppaluri. Identification of immunotherapy resistance mechanisms within tumor microenvironment in a mouse model of oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1509.

Importance of the immune system in head and neck cancer.

Head and neck squamous cell carcinoma (HNSCC) are a heterogeneous group of tumors, mainly caused by exposure to cigarette smoke and/or alcohol. In recent years, a virally driven subset of cancers driven by human papillomavirus subtype 16 [HPV-16]) has emerged. Our own data and data from other groups have demonstrated the favorable clinical outcome of HPV-driven oropharyngeal tumors and in both HPV+ and HPV- cancers the importance of a high density of tumor-associated lymphocytes for survival. These data underpin manipulation and activation of the patients' immune system by treatment, and as a result immunotherapy is rapidly taking its place in the management of HNSCC. Here we review the role the immune system in relation to HNSCC and consider the implications these have for HNSCC immunotherapy. Studies to quantify survival benefits and treatment-associated toxicities are ongoing.

HNSCC and Immunotherapy: The Beginning of a Long Story

The immunotherapy revolution has not spared Head and neck squamous cell carcinoma (HNSCC). Checkpoint inhibitors (anti-PD-1 / PD-L1) were the first to be validated in second line treatment and soon come to the first line in local or metastatic recurrence. Many studies are currently underway to expand the indications of these new therapies, whether as monotherapy or in combination. In addition, immunotherapy is not limited to checkpoint inhibitors and many other immunotherapy molecules are currently under study. The selection of patients who benefit from immunotherapy and the evaluation of the response to these treatments are problems not completely solved. The aim here is to present the state of art on immunotherapy in HNSCC.

Immunotherapy and its advances in the management of head-and-neck cancer

Head-and-neck squamous cell carcinoma (HNSCC) consists of biologically aggressive tumors of a heterogeneous group. Despite the advances made in the surgical and radiological treatment methods for HNSCC, the limitations in the control of the disease and the treatment-associated toxicity have kept the 5-year overall survival at a dismal rate. The multifactorial methods used for the treatment of HNSCC bring their deleterious effects on patient's quality of life due to lasting xerostomia, sensorineural hearing loss, and diminished swallowing function. The inadequate improvement in the survival rate and associated side effects with the existing treatments have shifted the attention in HNSCC research toward the finding of less toxic and more effective treatments. The outstanding improvements in the survival outcomes of certain advanced cancers treated with immunotherapy have encouraged extensive interest in the field. Cancer surveillance is maintained by a competent immune system, and hence, activation of immune system is included as an overall goal against the cancer. This review explores recent advances in the treatment of HNSCC focusing on immunotherapy describing briefly the developing areas of immunotherapy research, challenges, and future actions for the comprehensive application of immunotherapy in HNSCC.

Stromal interleukin-33 promotes regulatory T cell-mediated immunosuppression in head and neck squamous cell carcinoma and correlates with poor prognosis.

Regulatory T cells (Tregs) mediate immunosuppressive signals that can contribute to the progression of head and neck squamous cell carcinoma (HNSCC). Interleukin-33 (IL-33) is defined as an 'alarmin', an endogenous factor that is expressed during tissue and cell damage, which has been shown to promote Treg proliferation in non-lymphoid organs. However, the interaction between IL-33 and Tregs in the HNSCC tumor microenvironment remains uncertain. In this study, we examined IL-33+ and Foxp3+ cells by immunohistochemistry in 68 laryngeal squamous cell cancer patients, followed by functional analysis of IL-33 in Tregs. In addition, the suppressive function of Tregs was assessed by cell proliferation assays. The level of stromal IL-33 was significantly upregulated in advanced versus early stage HNSCC patients and positively correlated with Foxp3+ Treg infiltration as well as a poor prognosis. ST2 is regarded as the only receptor of IL-33. Infiltrated ST2-expressing Tregs were responsive to IL-33, and the percentage of Tregs was increased upon IL-33 stimulation. Functional investigation demonstrated that IL-33 increased the proportion of Foxp3+GATA3+ Tregs and improved the suppressive functions of Tregs by inducing IL-10 and TGF-β1 as well as decreasing the proliferation of responder T cells. Blockade of ST2 abrogated the immunosuppression caused by IL-33. Our data demonstrate that stromal IL-33 both expands the Treg population and enhances their functions in the tumor microenvironment. Furthermore, stromal IL-33 has prognostic value for tumor progression. Thus, stromal IL-33 is a potential target for future HNSCC immunotherapy.