Rodents as an animal model for studying tooth extraction-related medication-related osteonecrosis of the jaw: assessment of outcomes

OBJECTIVE

To assess the outcomes of several rodent animal models for studying tooth extraction-related medication-related osteonecrosis of the jaw (MRONJ).

DESIGN

After a search of the databases, 2004 articles were located, and 118 corroborated the inclusion factors (in vivo studies in rodents evaluating tooth extraction as a risk factor for the development of MRONJ).

RESULTS

Numerous studies attempting to establish an optimal protocol to induce MRONJ were found. Zoledronic acid (ZA) was the most used drug, followed by alendronate (ALN). Even when ZA did not lead to the development of MRONJ, its effect compromised the homeostasis of the bone and soft tissue. The association of other risk factors (dexamethasone, diabetes, and tooth-related inflammatory dental disease) besides tooth extraction also played a role in the development of MRONJ. In addition, studies demonstrated a relationship between cumulative dose and MRONJ.

CONCLUSIONS

Both ZA and ALN can lead to MRONJ in rodents when equivalent human doses (in osteoporosis or cancer treatment) are used. Local oral risk factors and tooth-related inflammatory dental disease increase the incidence of MRONJ in a tooth extraction-related rodent model.

Assessing PD-L1 Expression in Head and Neck Squamous Cell Carcinoma: Trials and Tribulations

Immune checkpoint inhibitors have improved the outcome of patients diagnosed with inoperable recurrent or metastatic head and neck squamous cell carcinoma. However, as only a subset of head and neck cancer patients benefit from this treatment, biomarkers predicting treatment response help guide physicians in their clinical decision-making. PD-L1 expression assessed by immunohistochemistry is the single most clinically relevant biomarker predicting response to PD-1-blocking antibodies. Here, we discuss in which clinical context assessment of PD-L1 expression is instrumental for the choice of therapy, how pathologists score it, and how it affects the approval of anti-PD-1 antibodies. Furthermore, we discuss the heterogeneity of PD-L1 expression and review technical aspects of determining this prominent biomarker-knowledge that might influence clinical decision-making.

CXCL9:SPP1 macrophage polarity identifies a network of cellular programs that control human cancers

Tumor microenvironments (TMEs) influence cancer progression but are complex and often differ between patients. Considering that microenvironment variations may reveal rules governing intratumoral cellular programs and disease outcome, we focused on tumor-to-tumor variation to examine 52 head and neck squamous cell carcinomas. We found that macrophage polarity-defined by CXCL9 and SPP1 (CS) expression but not by conventional M1 and M2 markers-had a noticeably strong prognostic association. CS macrophage polarity also identified a highly coordinated network of either pro- or antitumor variables, which involved each tumor-associated cell type and was spatially organized. We extended these findings to other cancer indications. Overall, these results suggest that, despite their complexity, TMEs coordinate coherent responses that control human cancers and for which CS macrophage polarity is a relevant yet simple variable.

Developing a definition of immune exclusion in cancer: results of a modified Delphi workshop

Checkpoint inhibitors represent an effective treatment approach for a variety of cancers through their inhibition of immune regulatory pathways within the tumor microenvironment (TME). Unfortunately only a minority of patients with cancer achieve clinical benefit from immunotherapy, with the TME emerging as an important predictor of outcomes and sensitivity to therapy. The extent and pattern of T-cell infiltration can vary prominently within/across tumors and represents a biological continuum. Three immune profiles have been identified along this continuum: 'immune-desert' or 'T-cell cold' phenotype, 'immune-active', 'inflamed', or 'T-cell hot' phenotype, and 'immune excluded' phenotype. Of the three profiles, immune excluded remains the most ill-defined with no clear, universally accepted definition even though it is commonly associated with lack of response to immune checkpoint inhibitors and poor clinical outcomes. To address this, 16 multidisciplinary cancer experts from around the world were invited to participate in a symposium using a three-round modified Delphi approach. The first round was an open-ended questionnaire distributed via email and the second was an in-person discussion of the first round results that allowed for statements to be revised as necessary to achieve a maximum consensus (75% agreement) among the rating committee (RC). The final round questionnaire was distributed to the RC via email and had a 100% completion rate. The Delphi process resulted in moving us closer to a consensus definition for immune exclusion that is practical, clinically pertinent, and applicable across a wide range of cancer histologies. A general consensus of the role of immune exclusion in resistance to checkpoint therapy and five research priorities emerged from this process. Together, these tools could help efforts designed to address the underlying mechanisms of immune exclusion that span cancer types and, ultimately, aid in the development of treatments to target these mechanisms to improve patient outcomes.

Effects of periodontitis on cancer outcomes in the era of immunotherapy

Periodontitis results from dysbiosis of the oral microbiome and affects up to 70% of US adults aged 65 years and older. More than 50 systemic inflammatory disorders and comorbidities are associated with periodontitis, many of which overlap with immunotherapy-associated toxicities. Despite the increasing use of immunotherapy for the treatment of cancer, uncertainty remains as to whether the microbial shift associated with periodontal disease can influence response rates and tolerance to cancer immunotherapy. We herein review the pathophysiology of periodontitis and the local and systemic inflammatory conditions related to oral dysbiosis, and discuss the overlapping adverse profiles of periodontitis and immunotherapy. The effects of the presence of Porphyromonas gingivalis, a key pathogen in periodontitis, highlight how the oral microbiome can affect the hosts' systemic immune responses, and further research into the local and systemic influence of other microorganisms causing periodontal disease is necessary. Addressing periodontitis in an ageing population of people with cancer could have potential implications for the clinical response to (and tolerability of) immunotherapy and warrants further investigation.

Targeting TBK1 to overcome resistance to cancer immunotherapy

Despite the success of PD-1 blockade in melanoma and other cancers, effective treatment strategies to overcome resistance to cancer immunotherapy are lacking1,2. Here we identify the innate immune kinase TANK-binding kinase 1 (TBK1)3 as a candidate immune-evasion gene in a pooled genetic screen4. Using a suite of genetic and pharmacological tools across multiple experimental model systems, we confirm a role for TBK1 as an immune-evasion gene. Targeting TBK1 enhances responses to PD-1 blockade by decreasing the cytotoxicity threshold to effector cytokines (TNF and IFNγ). TBK1 inhibition in combination with PD-1 blockade also demonstrated efficacy using patient-derived tumour models, with concordant findings in matched patient-derived organotypic tumour spheroids and matched patient-derived organoids. Tumour cells lacking TBK1 are primed to undergo RIPK- and caspase-dependent cell death in response to TNF and IFNγ in a JAK-STAT-dependent manner. Taken together, our results demonstrate that targeting TBK1 is an effective strategy to overcome resistance to cancer immunotherapy.

Chemoradiation therapy alters the PD-L1 score in locoregional recurrent squamous cell carcinomas of the head and neck

PD-L1 testing guides therapeutic decision-making for head and neck squamous cell carcinoma (HNSCC). We sought to understand whether chemoradiation therapy (CRT) influences the PD-L1 combined positive score (CPS) and other biomarkers of response to immunotherapy. PD-L1 expression was assessed using immunohistochemistry, and bulk RNA sequencing was performed on 146 HNSCC patients (65 primary sites, 50 paired local recurrences, and 31 paired regional recurrences). PD-L1 was scored using the CPS of ≥1, ≥20, and ≥50. Overall, 98 %, 54 %, and 17 % of HNSCCs had a CPS ≥1, ≥20, and ≥50, respectively. When using a cut-off of ≥1, CRT did not significantly change CPS at the locoregional recurrent site. However, there were significant changes when using CPS ≥20 or ≥50. The CPS changed for 32 % of patients when using a CPS ≥20 (p < 0.001). When using a CPS ≥50, there was a 20-23 % (p = 0.0058-0.00067) discordance rate at the site of locoregional recurrence. Oral cavity cancers had a significantly higher discordant rate than other primary sites for CPS ≥50, 44 % (8/18, p = 0.0058) and 58 % (7/12, p = 0.00067) discordance at the site of local and regional recurrence, respectively. When evaluating the 18 gene IFN-ɣ signature predictive of response to anti-PD-1 blockade, there was a statistically significant increase in the IFN-ɣ signature in recurrent larynx cancer (p = 0.02). Our study demonstrates that when using a higher cut-off of CPS ≥20 and ≥50, a repeat biopsy may be warranted after CRT for local and regional recurrent HNSCCs.

Pulmonary manifestations of chronic HPV infection in patients with recurrent respiratory papillomatosis

Human papillomavirus (HPV) types 6 and 11 can infect the squamous epithelium of the respiratory tract. Up to 8·9% of patients with HPV-associated recurrent respiratory papillomatosis (RRP) have pulmonary involvement. Pulmonary manifestations of HPV infection are associated with considerable morbidity, in part because treatment options and management guidelines are lacking. Patients with pulmonary RRP have a 32-times increased lifetime risk of malignant transformation compared with the overall RRP population. We review the clinical and radiographic presentation, pathological features, and genetics of pulmonary RRP, and we provide management algorithms based on our clinical experience with this complex patient population. In patients with suspected pulmonary involvement, tissue-sparing procedures to address growing lesions might be warranted given the chronicity and multifocality of the disease over a patient's lifetime. However, malignant transformation of pulmonary lesion(s) warrants standard-of-care treatment for primary lung squamous cell carcinoma. Large cohort studies are needed to understand the clinical course of pulmonary RRP and to identify molecular markers of increased risk of malignant transformation in order to develop guidelines for optimal and standardised surveillance and treatment.

Multiplexed single-cell analysis of FNA allows accurate diagnosis of salivary gland tumors

Diagnosing salivary gland tumors (SGTs) through fine-needle aspiration (FNA) biopsies is challenging due to the overlapping cytomorphologic features between benign and malignant tumors. The authors developed an innovative, multiplexed cycling technology for the rapid analyses of single cells obtained from FNA that can facilitate the molecular analyses and diagnosis of SGTs. Antibodies against 29 protein markers associated with 7 SGT subtypes were validated and chemically modified via custom linker-bio-orthogonal probes (FAST). Single-cell homogenates and FNA samples were profiled by FAST cyclic imaging and computational analysis. A prediction model was generated using a training set of 151,926 cells from primary SGTs (N = 26) and validated on a separate cohort (N = 30). Companion biomarker testing, such as neurotrophic tyrosine receptor kinase (NTRK), was also assessed with the FAST technology. The FAST molecular diagnostic assay was able to distinguish between benign and malignant SGTs with an accuracy of 0.86 for single-cell homogenate samples and 0.88 for FNA samples. Profiling of multiple markers as compared to a single marker increased the diagnostic accuracy (0.82 as compared to 0.65-0.74, respectively), independent of the cell number sampled. NTRK expression was also assessed by the FAST assay, highlighting the potential therapeutic application of this technology. Application of the novel multiplexed single-cell technology facilitates rapid biomarker testing from FNA samples at low cost. The customizable and modular FAST-FNA approach has relevance to multiple pathologies and organ systems where cytologic samples are often scarce and/or indeterminate resulting in improved diagnostic workflows and timely therapeutic clinical decision-making.

FAST-FNA molecular diagnostic assay facilitates rapid diagnosis and ntrk biomarker testing of salivary gland tumors

e18089

Background: Primary epithelial salivary gland tumors (SGTs)are classified into 31 tumor types. Diagnosing SGTs through fine needle aspiration (FNA) biopsies is challenging due to the overlapping cytomorphologic features between benign and malignant tumors. In this study, we developed an innovative, multiplexed cycling technology which allows for the rapid cellular analyses of single cells obtained from FNA which can facilitate the rapid molecular analyses and diagnosis of SGTs. Methods: Antibodies against 29 cell surface markers associated with 7 SGT subtypes were validated and chemically modified via custom linker–bio-orthogonal quencher probes (FAST). Single cell homogenates and a FNA sample set representing 7 SGT subtypes were profiled by FAST cyclic staining, imaging, and automated computational analysis. A prediction model was generated utilizing a training set of 151,926 single cells obtained from primary SGTs (N = 26) and validated on a separate cohort of SGTs (N = 30). Companion biomarker testing, such as NTRK, was also assessed with the FAST technology. Results: The customized FAST-FNA SGT molecular diagnostic and biomarker panel was validated on human cell lines and specificity confirmed by both flow cytometry and clinical immunohistochemical staining on primary SGTs. The FAST molecular diagnostic assay was able to distinguish between benign and malignant SGTs with an accuracy of 0.86 for single-cell suspension samples and 0.88 for FNA samples. Profiling of multiple markers as compared to a single tumor marker increased the diagnostic accuracy of the SGTs, 0.82 as compared to 0.65-0.74, respectively. The results of the assay were highly reproducible and independent of the cell number sampled. NTRK expression in SGTs was also assessed by the FAST assay within hours, highlighting the potential therapeutic application of this technology. Conclusions: High dimensional single-cell profiling and molecular diagnostic testing on FNA samples are feasible at relatively low cost and as a rapid test. Application of the novel multiplexed single cell technology improves the diagnostic accuracy of SGT biopsy and facilitates multiplex biomarker testing from FNA samples. The customizable and modular FAST-FNA approach has relevance to multiple pathologies and organ systems where cytologic samples are often scarce and/or indeterminate resulting in improved diagnostic workflows and timely therapeutic clinical decision making.

A phase II study of pembrolizumab for HPV-associated papilloma patients with laryngeal, tracheal, and/or pulmonary involvement

2590

Background: Recurrent respiratory papillomatosis (RRP) is caused by human papillomavirus (HPV) types 6 & 11. RRP proliferates in the squamous epithelium lining the respiratory tract impacting breathing, swallowing, and voice and carries a 3-5% risk of malignant transformation. Given the multi-focality of the disease and tolerized host immune response against HPV, in part through upregulation of the PD1:PDL1 axis, the safety and efficacy of systemic pembrolizumab (pembro) as a novel treatment for this benign tumor patient (pt) population was evaluated in a phase II clinical trial. Methods: RRP pts > 12 years of age were treated with pembro 200mg every 3 weeks. Primary endpoints were best overall response (ORR) (measured by endoscopic lesional burden) and safety. Greater than 5 pts with disease response out of 21 (assuming > 1 of first n = 11 with disease in response) provided 86% power to distinguish between a 15% and a 38% ORR (one-sided 8% binomial test). HPV-specific CD8+ T cell frequency and functional states and biomarkers of response and immune resistance are being evaluated in serial tissue and liquid biopsies (up to 8 biopsies/patient over the 24 months of treatment). Results: The Simon two-stage, stage 1 criteria was met. A total of 21 patients were enrolled and all are now off treatment. Median age (range) was 45 (19-68), 57% (12/21) were male and 67% (14/21) were white. 48% (10/21) had Juvenile-onset (Jo)-RRP, 57% (12/21) had pulmonary RRP involvement, and 19% (4/21) had SCC derived from their RRP. 62% (13/21) completed 24 months of treatment. Reasons for discontinuation included disease progression (14%, 3/21), treatment related adverse event (TRAEs) (14%, 3/21), and study withdrawal (10%, 2/21). A partial response (≥25% reduction in endoscopic tumor burden score) was observed in 57% (12/21) (95% CI: 34%-78.2%) of pts (7 of 10 with Jo-RRP and 5 of 11 with Adult-onset (Ao)-RRP disease responded). Stable disease was observed in 33% (7/21). No complete responses were observed. Fatigue was the most frequent TRAEs; Grade 3 TRAEs included uveitis and hypophysitis, both of which were reversible upon pembro discontinuation and steroid use. At a median follow-up: 25.6 (6.2-38.1 months), the mean number of surgical interventions was reduced by 7 surgeries/year (p = 0.004) in pts treated on the trial for > 12 months, and, upon treatment completion, durable clinical benefit was observed with no additional treatment needed for the duration of the clinical trial follow-up for some pts. Conclusions: Pembro reduces the need for routine surgical interventions based on the durable response rates being achieved. Further study of pembro +/- other agents is warranted to achieve and sustain complete responses in this population. Clinical trial information: NCT02632344.

Abstract P056: Rapid serial immunoprofiling of the tumor immune microenvironment by fine needle sampling

As the field of cancer immunotherapy brings forth novel and combinatorial agents, there is increasing effort to discover and integrate predictive and/or prognostic biomarkers into treatment algorithms in order to optimize cancer care. While tissue-based methods can elucidate tumor-immune cell compositions at a single time point, serial assessment of the tumor immune microenvironment (TME) can provide unique insight into how various therapies may modulate target tumor and/or immune cell populations over time. We propose that single-cell sampling via fine needle aspirates (FNA) can facilitate such analyses with a favorable risk-benefit profile. Thus, we developed and optimized a multiplexed bioorthogonal approach (FAST-FNA) which has been coupled with a deep learning algorithm that allows for comprehensive cellular analyses of FNA samples. We demonstrate that the FAST-FNA assay reproducibly captures the TME profile as compared to standard labor-intensive flow cytometry and immunohistochemical assays, and, furthermore, allows for time course analysis of the evolving TME in mouse and human cancers in vivo. The translational significance of the FNA-based technology is highlighted in the ability to rapidly assess PD-L1 expression within the TME and is further extended through the serial quantitation of both tumor and immune cell markers in cancer patients treated with immunotherapy. Collectively, these data indicate that FAST-FNA can serve as a robust and versatile clinical tool to monitor the evolving TME and has the potential to provide early insight into treatment response.

Citation Format: Juhyun Oh, Jonathan C. T. Carlson, Christian Landeros, Hakho Lee, Scott Ferguson, William C. Faquin, John R. Clark, Mikael J. Pittet, Sara I. Pai, Ralph Weissleder. Rapid serial immunoprofiling of the tumor immune microenvironment by fine needle sampling [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P056.

Rapid Serial Immunoprofiling of the Tumor Immune Microenvironment by Fine Needle Sampling

PURPOSE

There is increasing effort to discover and integrate predictive and/or prognostic biomarkers into treatment algorithms. While tissue-based methods can reveal tumor-immune cell compositions at a single time point, we propose that single-cell sampling via fine needle aspiration (FNA) can facilitate serial assessment of the tumor immune microenvironment (TME) with a favorable risk-benefit profile.

EXPERIMENTAL DESIGN

Primary antibodies directed against 20 murine and 25 human markers of interest were chemically modified via a custom linker-bio-orthogonal quencher (FAST) probe. A FAST-FNA cyclic imaging and analysis pipeline were developed to derive quantitative response scores. Single cells were harvested via FNA and characterized phenotypically and functionally both in preclinical and human samples using the newly developed FAST-FNA assay.

RESULTS

FAST-FNA samples analyzed manually versus the newly developed deep learning-assisted pipeline gave highly concordant results. Subsequently, an agreement analysis showed that FAST and flow cytometry of surgically resected tumors were positively correlated with an R2 = 0.97 in preclinical samples and an R2 = 0.86 in human samples with the detection of the relevant tumor and immune biomarkers of interest. Finally, the feasibility of applying this minimally invasive approach to analyze the TME during immunotherapy was assessed in patients with cancer revealing local antitumor immune programs.

CONCLUSIONS

The FAST-FNA is an innovative technology that combines bio-orthogonal chemistry coupled with a computational analysis pipeline for the comprehensive profiling of single cells obtained through FNA. This is the first demonstration that the complex and rapidly evolving TME during treatment can be accurately and serially measured by simple FNA.

Myeloid Cells Are Enriched in Tonsillar Crypts, Providing Insight into the Host Tropism of Human Papillomavirus

Viruses are the second leading cause of cancer worldwide, and human papillomavirus (HPV)-associated head and neck cancers are increasing in incidence in the United States. HPV preferentially infects the crypts of the tonsils rather than the surface epithelium. The present study sought to characterize the unique microenvironment within the crypts to better understand the host tropism of HPV to a lymphoid-rich organ. Laser-capture microdissection of distinct anatomic areas (crypts, surface epithelium, and germinal centers) of the tonsil, coupled with transcriptional analysis and multiparameter immunofluorescence staining, was performed and demonstrated that the tonsillar crypts are enriched with myeloid populations that co-express multiple canonical and noncanonical immune checkpoints, including PD-L1, CTLA-4, HAVCR2 (TIM-3), ADORA2A, IDO1, BTLA, LGALS3, CDH1, CEACAM1, PVR, and C10orf54 (VISTA). The resident monocytes may foster a permissive microenvironment that facilitates HPV infection and persistence. Furthermore, the myeloid populations within HPV-associated tonsil cancers co-express the same immune checkpoints, providing insight into potential novel immunotherapeutic targets for HPV-associated head and neck cancers.

Diagnostic challenges and successful organ-preserving therapy in a case of secretory carcinoma of minor salivary glands

BACKGROUND

Secretory carcinoma is a more recently described subtype of salivary gland carcinoma that may pose diagnostic challenges and frequently harbors NTRK fusions that may successfully be targeted by TRK inhibitors in advanced disease.

CASE

We present the case of a female patient with secretory carcinoma arising in the base of tongue with persistent disease after debulking surgery and definitive chemoradiation. As an alternative to salvage surgery, which would have resulted in significant impairment of swallowing and speech function, a targeted therapy with the TRK-inhibitor larotrectinib against an identified ETV6-NTRK3 fusion product was initiated. Larotrectinib treatment has been well tolerated, resulted in durable complete response and the patient maintains good swallowing and speech function.

CONCLUSION

The presented case underscores the importance of the accurate diagnosis of secretory carcinoma. It further highlights the impact of molecular testing as targeted therapies may play an important role in the management of advanced salivary gland cancers.

Resident Kupffer cells and neutrophils drive liver toxicity in cancer immunotherapy

Immunotherapy is revolutionizing cancer treatment but is often restricted by toxicities. What distinguishes adverse events from concomitant antitumor reactions is poorly understood. Here, using anti-CD40 treatment in mice as a model of T_H1-promoting immunotherapy, we showed that liver macrophages promoted local immune-related adverse events. Mechanistically, tissue-resident Kupffer cells mediated liver toxicity by sensing lymphocyte-derived IFN-γ and subsequently producing IL-12. Conversely, dendritic cells were dispensable for toxicity but drove tumor control. IL-12 and IFN-γ were not toxic themselves but prompted a neutrophil response that determined the severity of tissue damage. We observed activation of similar inflammatory pathways after anti-PD-1 and anti-CTLA-4 immunotherapies in mice and humans. These findings implicated macrophages and neutrophils as mediators and effectors of aberrant inflammation in T_H1-promoting immunotherapy, suggesting distinct mechanisms of toxicity and antitumor immunity.

Patient-reported outcomes (PROs) from a phase II trial of pembrolizumab for HPV-associated papilloma patients with laryngeal, tracheal and/or pulmonary involvement

6080

Background: Recurrent respiratory papillomatosis (RRP) is caused by human papillomavirus (HPV) types 6 & 11. RRP proliferates in the respiratory tract impacting breathing, swallowing, and voice and carries a 1-4% risk of malignant transformation.There is no curative therapy for RRP. Given the tolerized host immune response against HPV, the safety and efficacy of pembrolizumab (pembro) as an alternative treatment for this patient population was evaluated in a phase II clinical trial. Patient reported outcomes (PROs) were assessed during the trial to capture the patient perspective of pembro as an alternative to surgery or in office procedures, both standard of care (SOC). Methods: RRP patients who had previously undergone >3 procedures in any year, or with known tracheal or pulmonary involvement prior to study entry were treated with pembro 200mg every 3 weeks. The primary endpoint of the trial was best ‘overall response rate’ (ORR) measured by an endoscopic-based disease burden score (lower score reflects better ‘response’) and/or RECIST 1.1, secondary endpoint included PROs. Twenty-one patients were required to assess the primary endpoint. Most of the QoL surveys used Likert scale to assess PROs (‘never, sometimes, often, most of the time, always’). The percentage reporting ’never’ having an issue with symptom or activity at baseline, 6 months, and at time of ORR (nadir disease burden score) is reported here. Results: Twenty-one patients were accrued. Median age (range) was 45 (19-68), 57% (12/21) were male and 67% (14/21) were white. Questionnaire completion rates were 100% at baseline, 90% at 6 months, and 85% at ORR. Improvement in: social interactions (less difficulty with: physical intimacy [38%,56%,65% reporting ‘never’ at baseline, 6 months, and at ORR respectively]), discussing disease diagnosis [19%,21%,39%]); personal feelings (less depression [14%,32%,33%], less anxiety [5%,16%,22%], less embarrassment [19%,37%,50%]), and work-related absences (less frequently fabricating reasons for work absence due to disease-related treatment [57%,78%,56%] and less utilization of family vacation or FMLA for disease treatment [29%,53%,56%]) were reported. At ORR, 72% (13/18) patients reported that IV infusion was not emotionally burdensome and 78% (14/18) reported it as the preferred treatment relative to their perceived experience with SOC surgery or in office procedures. Conclusions: PRO results show consistent benefit in key aspects of the patient experience with pembro over procedure based SOC further supporting its overall clinical benefit in patients with HPV-associated RRP. Clinical trial information: NCT02632344.

PD-L1 and PD-L2 Expression Levels Are Low in Primary and Secondary Adenoid Cystic Carcinomas of the Orbit: Therapeutic Implications

PURPOSE

To determine if there is a biologic rationale for using checkpoint inhibitor drugs targeting programmed cell death ligand 1 (PD-L1) and PD-L2 in the treatment of adenoid cystic carcinoma of the orbit.

METHODS

Twenty-three cases of adenoid cystic carcinoma involving the orbit (13 primary lacrimal gland, 5 secondarily extending into the orbit, and 5 unspecified) were examined histopathologically. Immunohistochemistry for PD-L1, PD-L2, and CD8 was performed. Charts were reviewed for clinical correlations.

RESULTS

Expression of PD-L1 and of PD-L2 was overall low in adenoid cystic carcinoma (mean expression 1.4 ± 0.9 of 5 for PD-L1, mean 0.83 ± 1.1 of 5 for PD-L2), and tumor-infiltrating CD8-positive T-lymphocytes were sparse (mean 1.1 ± 0.51 of 3). Only 13 of the 23 (57%) cases expressed PD-L1 as a combined positive score ≥1 of cells. No associations were found between expression levels of these markers and patient sex, tumor site of origin, Tumor, Node, Metastasis stage, or patient outcome. A significant association was observed between stromal PD-L1 expression and tumor histopathologic subtype (p = 0.05), and between tumor PD-L1 expression and prior exposure to radiation (p = 0.03).

CONCLUSIONS

Checkpoint inhibitor drugs may have limited impact in the treatment and clinical course of orbital adenoid cystic carcinoma based on the low frequency of CD8 infiltrate and low expression of PD-L1 and PD-L2. Pretreatment with radiation, however, may improve tumor response to checkpoint inhibitor drugs.

Defining best practices for tissue procurement in immuno-oncology clinical trials: consensus statement from the Society for Immunotherapy of Cancer Surgery Committee

Immunotherapy is now a cornerstone for cancer treatment, and much attention has been placed on the identification of prognostic and predictive biomarkers. The success of biomarker development is dependent on accurate and timely collection of biospecimens and high-quality processing, storage and shipping. Tumors are also increasingly used as source material for the generation of therapeutic T cells. There have been few guidelines or consensus statements on how to optimally collect and manage biospecimens and source material being used for immunotherapy and related research. The Society for Immunotherapy of Cancer Surgery Committee has brought together surgical experts from multiple subspecialty disciplines to identify best practices and to provide consensus on how best to access and manage specific tissues for immuno-oncology treatments and clinical investigation. In addition, the committee recommends early integration of surgeons and other interventional physicians with expertise in biospecimen collection, especially in clinical trials, to optimize the quality of tissue and the validity of correlative clinical studies in cancer immunotherapy.

New technology on the horizon: Fast analytical screening technique FNA (FAST-FNA) enables rapid, multiplex biomarker analysis in head and neck cancers

PD-L1 profiling was recently approved by the US Food and Drug Administration as a companion diagnostic for anti-PD1 treatment in patients with head and neck cancer, ushering in a new era for precision medicine. However, the routine development and implementation of such testing is still limited by current clinical workflows and the lack of better and more comprehensive alternatives. In this review, the authors discuss the real-world challenges of clinically based biomarker testing and highlight the advantages of developing fine-needle aspiration (FNA)-based biomarker testing that would enable frequent and serial tumor sampling. A conceptual and technological innovation is introduced, fast analytical screening technique (FAST)-FNA (FAST chemistry-enabled FNA), which is being developed to inform immunotherapy treatment options in patients with head and neck cancer and to assist with the development of the next generation of predictive biomarkers.

Antibody-mediated delivery of viral epitopes to tumors harnesses CMV-specific T cells for cancer therapy

Several cancer immunotherapy approaches, such as immune checkpoint blockade and adoptive T-cell therapy, boost T-cell activity against the tumor, but these strategies are not effective in the absence of T cells specific for displayed tumor antigens. Here we outline an immunotherapy in which endogenous T cells specific for a noncancer antigen are retargeted to attack tumors. The approach relies on the use of antibody-peptide epitope conjugates (APECs) to deliver suitable antigens to the tumor surface for presention by HLA-I. To retarget cytomegalovirus (CMV)-specific CD8+ T cells against tumors, we used APECs containing CMV-derived epitopes conjugated to tumor-targeting antibodies via metalloprotease-sensitive linkers. These APECs redirect pre-existing CMV immunity against tumor cells in vitro and in mouse cancer models. In vitro, APECs activated specifically CMV-reactive effector T cells whereas a bispecific T-cell engager activated both effector and regulatory T cells. Our approach may provide an effective alternative in cancers that are not amenable to checkpoint inhibitors or other immunotherapies.

The Paradox of Cancer Immune Exclusion: Immune Oncology Next Frontier

Checkpoint inhibitor therapy (CIT) has revolutionized cancer treatment but it has also reached a standstill when an absent dialog between cancer and immune cells makes it irrelevant. This occurs with high prevalence in the context of "immune silent" and, even perhaps, "immune-excluded" tumors. The latter are characterized by T cells restricted to the periphery of cancer nests. Since in either case T cells do not come in direct contact with most cancer cells, CIT rests immaterial. Adoptive cell therapy (ACT), may also be affected by limited access to antigen-bearing cancer cells. While lack of immunogenicity intuitively explains the immune silent phenotype, immune exclusion is perplexing. The presence of T cells at the periphery suggests that chemo-attraction recruits them and an immunogenic stimulus promotes their persistence. However, what stops the T cells from infiltrating the tumors' nests and reaching the germinal center (GC)? Possibly, a concentric gradient of increased chemo-repulsion or decreased chemo-attraction demarcates an abrupt "do not trespass" warning. Various hypotheses suggest physical or functional barriers but no definitive consensus exists over the weight that each plays in human cancers. On one hand, it could be hypothesized that the intrinsic biology of cancer cells may degenerate from a "cancer stem cell" (CSC)-like phenotype in the GC toward a progressively more immunogenic phenotype prone to immunogenic cell death (ICD) at the periphery. On the other hand, the intrinsic biology of the cancer cells may not change but it is the disorderly architecture of the tumor microenvironment (TME) that alters in a centripetal direction cancer cell metabolism, both directly and indirectly, the function of surrounding stromal cells. In this chapter, we examine whether the paradoxical exclusion of T cells from tumors may serve as a model to understand the requirements for tumor immune infiltration and, correspondingly, we put forth strategies to restore the dialog between immune cells and cancer to enhance the effectiveness of immune oncology (IO) approaches.

SUPREME-HN: a retrospective biomarker study assessing the prognostic value of PD-L1 expression in patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck

Background

Programmed cell death ligand-1 (PD-L1) expression on tumor cells (TCs) is associated with improved survival in patients with head and neck squamous cell carcinoma (HNSCC) treated with immunotherapy, although its role as a prognostic factor is controversial. This study investigates whether tumoral expression of PD-L1 is a prognostic marker in patients with recurrent and/or metastatic (R/M) HNSCC treated with standard chemotherapy.

Methods

This retrospective, multicenter, noninterventional study assessed PD-L1 expression on archival R/M HNSCC tissue samples using the VENTANA PD-L1 (SP263) Assay. PD-L1 high was defined as PD-L1 staining of ≥ 25% TC, with exploratory scoring at TC ≥ 10% and TC ≥ 50%. The primary objective of this study was to estimate the prognostic value of PD-L1 status in terms of overall survival (OS) in patients with R/M HNSCC.

Results

412 patients (median age, 62.0 years; 79.9% male; 88.2% Caucasian) were included from 19 sites in seven countries. 132 patients (32.0%) had TC ≥ 25% PD-L1 expression; 199 patients (48.3%) and 85 patients (20.6%) had TC ≥ 10% and ≥ 50%, respectively. OS did not differ significantly across PD-L1 expression (at TC ≥ 25% cutoff median OS: 8.2 months vs TC < 25%, 10.1 months, P = 0.55) or the ≥ 10% and ≥ 50% cutoffs (at TC ≥ 10%, median OS: 9.6 months vs TC < 10%, 9.4 months, P = 0.32, and at TC ≥ 50%, median OS 7.9 vs TC < 50%, 10.0 months, P = 0.39, respectively).

Conclusions

PD-L1 expression, assessed using the VENTANA PD-L1 (SP263) Assay, was not prognostic of OS in patients with R/M HNSCC treated with standard of care chemotherapies.

Trial registration ClinicalTrials.gov, NCT02543476. Registered September 4, 2015.

Intratumoral delivery of an HPV vaccine elicits a broad anti-tumor immune response that translates into a potent anti-tumor effect in a preclinical murine HPV model

Therapeutic cancer vaccines have met limited clinical success. In the setting of cancer, the immune system is either tolerized and/or has a limited tumor-specific T cell repertoire. In this study, we explore whether intratumoral (IT) vaccination with an HPV vaccine can elicit quantitative and qualitative differences in immune response as compared to intramuscular (IM) vaccination to overcome immune resistance in established tumors. We report that IT administration of an HPV-16 E7 peptide vaccine formulated with polyinosinic-polycytidylic acid [poly(I:C)] generated an enhanced antitumor effect relative to IM delivery. The elicited anti-tumor effect with IT vaccination was consistent among the vaccinated groups and across various C57BL/6 substrains. IT vaccination resulted in an increased frequency of PD-1^hi TILs, which represented both vaccine-targeted and non-vaccine-targeted tumor-specific CD8⁺ T cells. Overall, the CD8⁺/Treg ratio was increased within the tumor microenvironment using IT vaccination. We also assessed transcriptional changes in several immune-related genes in the tumor microenvironment of the various treated groups, and our data suggest that IT vaccination leads to upregulation of a broad complement of immunomodulatory genes, including upregulation of interferon gamma (IFNγ) and antigen presentation and processing machine (APM) components. IT vaccine delivery is superior to traditional IM vaccination routes with the potential to improve tumor immunogenicity, which has potential clinical application in the setting of accessible lesions such as head and neck squamous cell carcinomas (HNSCCs).

A phase II study of pembrolizumab for HPV-associated papilloma patients with laryngeal, tracheal, and/or pulmonary involvement

2502

Background: Recurrent respiratory papillomatosis (RRP) is caused by human papillomavirus (HPV) types 6 & 11. RRP proliferates in the respiratory tract impacting breathing, swallowing, and voice and carries a 1-4% risk of malignant transformation. There is no curative therapy for RRP. Given the tolerized host immune response against HPV, in part through upregulation of the PD1:PDL1 axis, the safety and efficacy of pembrolizumab (pembro) as a novel treatment for this benign tumor patient (pt) population was evaluated in a phase II clinical trial. Methods: RRP pts > 12 years of age were treated with pembro 200mg every 3 weeks. Adjuvant surgical debridement of RRP was permitted for airway obstruction but not dysphonia. Primary endpoints were best overall response (ORR) (measured by endoscopic lesional burden) and safety. Greater than 5 pts with disease in response out of 21 (assuming > 1 of first n = 11 with disease in response) provided 86% power to distinguish between a 15% and a 38% ORR (one-sided 8% binomial test). Serial biopsies (up to 8 biopsies/patient over the 24 months of treatment) to identify biomarkers of response and mechanisms of immune resistance (PD-L1 expression, mutations in HLA class I antigen presentation machinery, and tumor mutational burden) are underway. Results: Accrual is complete (n = 21 pts accrued between May 2016 and Jan 2019). Median age (range) was 45 (19-68), 57% (12/21) were male and 67% (14/21) were white. As of February 1, 2019, ORR is 43% (9/21) (.95 two-stage CI: 22%-66%) (4 of 11 with juvenile-onset RRP and 5 of 10 with adult-onset RRP disease responded). No complete responses have been observed. Fatigue was the most frequent treatment related adverse event (TRAEs); Grade 3 TRAEs included uveitis and hypophysitis, both were reversible upon pembro discontinuation. The frequency of surgical interventions was reduced in all pts undergoing surgery for airway palliation prior to study entry. Conclusions: Pembro reduces the need for routine surgical interventions based on the response rates being achieved. Further study of pembro +/- other agents is warranted to achieve and sustain complete responses in this population. Clinical trial information: NCT02632344.

A randomized phase II study of pembrolizumab with or without radiation in patients with recurrent or metastatic adenoid cystic carcinoma

6082

Background: Adenoid cystic carcinoma (ACC) is a salivary gland malignancy characterized by a high rate of distant recurrence. Systemic therapy has generally failed to produce durable benefit. Radiation (RT) is used for localized disease and as directed treatment for metastases. Here, we report the safety and efficacy of pembrolizumab (pembro) administered with or without hypofractionated RT in a phase II randomized study. Methods: Eligible patients (pts) had recurrent or metastatic ACC with evidence of progressive disease (PD) within the last 12 mos and >=1 measurable non-CNS lesion, along with 1-5 additional lesions deemed appropriate for RT to 30 Gy in 5 fractions. Pts were randomized to pembro alone (200 mg IV q3 weeks) or in combination with RT given within 7 days of cycle 1, day 1. The primary endpoint was objective response rate (ORR) outside the RT field by RECIST 1.1. Using a parallel two-stage design, if >=1 response out of 10 was observed in either arm, 10 more pts would be enrolled to that arm. If >=3 responded, the null hypothesis (ORR=5%) would be rejected in favor of a 25% ORR. Predefined secondary endpoints included progression free survival (PFS) and toxicity. Analyses of tumor growth rate (TGR) excluding RT lesions and immune biomarkers were exploratory. Results: Ten pts per arm were randomized into the trial’s first stage with median age 65 (45-79). No objective responses were seen. Stable disease (SD) was observed in 13 pts; 6 had PD as best response, 1 was unevaluable. Median PFS was 7 mos 95% CI (3 - 13 mos), with 9 pts without progression at 6 mos. 3 pts remain on study treatment (range 8-11 mos). In pts with SD, TGR decreased by >25% in 7 of 12 pts and by >75% in 4 pts. There was no difference in likelihood of SD or PFS between arms. Treatment related AEs (TRAEs) occurred in 18 pts but there were no G3-5 TRAEs. Among 8 biopsies analyzed, PD-L1+ tumor/immune cells ranged from 12-52%. Conclusions: Pembro alone or with hypofractionated RT was well tolerated. We observed no objective responses, but 65% of pts with PD prior to study entry achieved SD, the majority with decreased TGR, and 15% had prolonged SD. Additional strategies are needed to further delay progression and effect response. Clinical trial information: NCT03087019.

Programmed Cell Death 1 Ligand 1 and Programmed Cell Death 1 Ligand 2 Are Expressed in Conjunctival Invasive Squamous Cell Carcinoma: Therapeutic Implications

PURPOSE

Novel cancer immunotherapies, called immune checkpoint inhibitors, have demonstrated clinical efficacy in the treatment of squamous cell carcinomas of the head and neck. Tissue expression of programmed cell death 1 ligand 1 (PD-L1) and programmed cell death 1 ligand 2 (PD-L2) has been shown to predict tumor response to these drugs. We examine the expression of prognostic immune biomarkers, PD-L1 and PD-L2, in invasive ocular surface squamous neoplasia.

DESIGN

Retrospective case series.

METHODS

Eighteen cases of ocular surface or ocular adnexal invasive squamous cell carcinomas were identified in pathology case files of the Massachusetts General Hospital/Massachusetts Eye and Ear Infirmary and at the Wills Eye Hospital accessioned between January 1, 2014 and January 1, 2017. Immunohistochemical staining for PD-L1, PD-L2, CD8, and p16 was performed and graded in a standardized fashion.

RESULTS

PD-L1 and PD-L2 were expressed on tumor cells to varying degrees, and also on some stromal cells and endothelial cells. Stromal and endothelial cell expression was also seen in control conjunctival specimens. Tumor expression of PD-L1 and PD-L2 was present on the cell membranes. All 18 (100%) of the tumors expressed PD-L1: 7 (39%) expressed a high level, 3 (17%) expressed a medium level, and 8 (44%) expressed a low level. Only 9 (50%) tumors expressed PD-L2 and it was at a low level. The expression of PD-L1 in tumor cells correlated with the presence of CD8-positive cytotoxic T lymphocytes among tumor cells (P < .01) and with the presence of CD8-positive cells in the surrounding stroma (P = .04).

CONCLUSIONS

A subset of ocular invasive conjunctival squamous carcinomas express high levels of PD-L1 and CD8 and therefore may respond therapeutically to immune checkpoint inhibition.

Functional and genomic analyses reveal therapeutic potential of targeting β-catenin/CBP activity in head and neck cancer

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is an aggressive malignancy characterized by tumor heterogeneity, locoregional metastases, and resistance to existing treatments. Although a number of genomic and molecular alterations associated with HNSCC have been identified, they have had limited impact on the clinical management of this disease. To date, few targeted therapies are available for HNSCC, and only a small fraction of patients have benefited from these treatments. A frequent feature of HNSCC is the inappropriate activation of β-catenin that has been implicated in cell survival and in the maintenance and expansion of stem cell-like populations, thought to be the underlying cause of tumor recurrence and resistance to treatment. However, the therapeutic value of targeting β-catenin activity in HNSCC has not been explored.

METHODS

We utilized a combination of computational and experimental profiling approaches to examine the effects of blocking the interaction between β-catenin and cAMP-responsive element binding (CREB)-binding protein (CBP) using the small molecule inhibitor ICG-001. We generated and annotated in vitro treatment gene expression signatures of HNSCC cells, derived from human oral squamous cell carcinomas (OSCCs), using microarrays. We validated the anti-tumorigenic activity of ICG-001 in vivo using SCC-derived tumor xenografts in murine models, as well as embryonic zebrafish-based screens of sorted stem cell-like subpopulations. Additionally, ICG-001-inhibition signatures were overlaid with RNA-sequencing data from The Cancer Genome Atlas (TCGA) for human OSCCs to evaluate its association with tumor progression and prognosis.

RESULTS

ICG-001 inhibited HNSCC cell proliferation and tumor growth in cellular and murine models, respectively, while promoting intercellular adhesion and loss of invasive phenotypes. Furthermore, ICG-001 preferentially targeted the ability of subpopulations of stem-like cells to establish metastatic tumors in zebrafish. Significantly, interrogation of the ICG-001 inhibition-associated gene expression signature in the TCGA OSCC human cohort indicated that the targeted β-catenin/CBP transcriptional activity tracked with tumor status, advanced tumor grade, and poor overall patient survival.

CONCLUSIONS

Collectively, our results identify β-catenin/CBP interaction as a novel target for anti-HNSCC therapy and provide evidence that derivatives of ICG-001 with enhanced inhibitory activity may serve as an effective strategy to interfere with aggressive features of HNSCC.

PD-L1 and IDO1 Are Expressed in Poorly Differentiated Thyroid Carcinoma

Poorly differentiated thyroid carcinoma (PDTC) is an aggressive form of thyroid cancer that currently has limited effective treatment options. Immune checkpoint inhibitors (ICIs) have shown to be an effective treatment for a variety of carcinomas. In this study, we explore whether immune checkpoint pathways, such as programmed cell death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO1), are activated in a cohort of patients with PDTC to determine whether ICIs may be an effective therapy for these patients. PDTC from 28 patients were stained for IDO1, PD-L1, and CD8 using immunohistochemistry. Staining was scored using an H-score, and PD-L1 and IDO1 expression was correlated with clinicopathologic characteristics. Positivity for PD-L1 and IDO1 was set at an H-score cutoff of five. Twenty-five percent (n = 7/28) of the PDTC were positive for PD-L1 expression. Twenty-nine percent (n = 2/7) of the PD-L1 positive PDTCs also co-expressed IDO1. The expression of PD-L1 in PDTC was significantly associated with tumor size and multifocality, with a non-significant trend towards associations with older age, extrathyroidal extension, presence of metastasis, higher stage, increased number of CD8+ T cells, and decreased disease-free and overall survival. PD-L1 expression occurs in a subset of PDTC, and is associated with a subset of clinical features of aggressive thyroid disease. Given the limited effective treatments for this patient population, consideration for ICIs as monotherapy or in combination with an IDO1 inhibitor should be explored as a novel treatment modality for patients with PDTC.

HLA class I antigen processing machinery (APM) component expression and PD-1:PD-L1 pathway activation in HIV-infected head and neck cancers

Human immunodeficiency virus (HIV)-infected individuals are at increased risk for developing several non-AIDS related malignancies and are often excluded from cancer immunotherapy regimens. To evaluate the immune competence of this cancer patient population, we evaluated HLA class I antigen presenting machinery (APM) component expression and PD-1:PD-L1 pathway upregulation in HIV(+) and HIV(-) head and neck cancers (HNCs). Sixty-two HIV(+) and 44 matched HIV(-) controls diagnosed with HNC between 1991 and 2011 from five tertiary care referral centers in the United States were identified. HLA class I APM component, PD-1, and PD-L1 expression were analyzed by immunohistochemical staining with monoclonal antibodies (mAbs). Clinical data was abstracted from the medical records. There was no significant difference between the cases and controls in LMP2, TAP1, HLA-A and HLA-B/C, as well as PD-1 and PD-L1 expression. Overall, 62% of all subjects had high PD-1 expression and 82% of the subjects expressed PD-L1 within the tumor microenvironment. LMP2, HLA-A and HLA-B/C expression were significantly associated with moderate to high PD-1 expression in the HIV(+) HNC cases (p = .004, p = .026, and p = .006, respectively) but not in the HIV(-) controls. In addition, HLA-A expression was significantly associated with PD-L1 expression in the HIV(+) HNC cases only (p = .029). HIV-infected individuals diagnosed with HNC do not have any detectable defects in HLA class I APM component expression and in PD-1:PD-L1 pathway activation. Given the current successes of HAART therapy in maintaining immune cell counts, HIV(+) patients diagnosed with cancer may benefit from the recently FDA-approved immune checkpoint blockade therapy.

Distinct pattern of TP53 mutations in human immunodeficiency virus-related head and neck squamous cell carcinoma

BACKGROUND

Human immunodeficiency virus-infected individuals (HIVIIs) have a higher incidence of head and neck squamous cell carcinoma (HNSCC), and clinical and histopathological differences have been observed in their tumors in comparison with those of HNSCC patients without a human immunodeficiency virus (HIV) infection. The reasons for these differences are not clear, and molecular differences between HIV-related HNSCC and non-HIV-related HNSCC may exist. This study compared the mutational patterns of HIV-related HNSCC and non-HIV-related HNSCC.

METHODS

The DNA of 20 samples of HIV-related HNSCCs and 32 samples of non-HIV-related HNSCCs was sequenced. DNA libraries covering exons of 18 genes frequently mutated in HNSCC (AJUBA, CASP8, CCND1, CDKN2A, EGFR, FAT1, FBXW7, HLA-A, HRAS, KEAP1, NFE2L2, NOTCH1, NOTCH2, NSD1, PIK3CA, TGFBR2, TP53, and TP63) were prepared and sequenced on an Ion Personal Genome Machine sequencer. DNA sequencing data were analyzed with Ion Reporter software. The human papillomavirus (HPV) status of the tumor samples was assessed with in situ hybridization, the MassARRAY HPV multiplex polymerase chain reaction assay, and p16 immunostaining. Mutation calls were compared among the studied groups.

RESULTS

HIV-related HNSCC revealed a distinct pattern of mutations in comparison with non-HIV-related HNSCC. TP53 mutation frequencies were significantly lower in HIV-related HNSCC. Mutations in HIV+ patients tended to be TpC>T nucleotide changes for all mutated genes but especially for TP53.

CONCLUSIONS

HNSCC in HIVIIs presents a distinct pattern of genetic mutations, particularly in the TP53 gene. HIV-related HNSCC may have a distinct biology, and an effect of the HIV virus on the pathogenesis of these tumors should not be ruled out. Cancer 2018;124:84-94. © 2017 American Cancer Society.

PD-1 Expression in Head and Neck Squamous Cell Carcinomas Derives Primarily from Functionally Anergic CD4+ TILs in the Presence of PD-L1+ TAMs

Oral tongue squamous cell carcinoma (OTSCC) is the most common oral cavity tumor. In this study, we examined the basis for the activity of programmed cell death protein (PD-1)-based immune checkpoint therapy that is being explored widely in head and neck cancers. Using multispectral imaging, we systematically investigated the OTSCC tumor microenvironment (TME) by evaluating the frequency of PD-1 expression in CD8⁺, CD4⁺, and FoxP3⁺ tumor-infiltrating lymphocytes (TIL). We also defined the cellular sources of PD-1 ligand (PD-L1) to evaluate the utility of PD-1:PD-L1 blocking antibody therapy in this patient population. PD-L1 was expressed in 79% of the OTSCC specimens examined within the TME. Expression of PD-L1 was associated with moderate to high levels of CD4⁺ and CD8⁺ TILs. We found that CD4⁺ TILs were present in equal or greater frequencies than CD8⁺ TILs in 94% of OTSCC and that CD4⁺FOXP3neg TILs were colocalized with PD-1/PD-L1/CD68 more frequently than CD8⁺ TILs. Both CD4⁺PD1⁺ and CD8⁺PD1⁺ TILs were anergic in the setting of PD-L1 expression. Overall, our results highlight the importance of CD4⁺ TILs as pivotal regulators of PD-L1 levels and in determining the responsiveness of OTSCC to PD1-based immune checkpoint therapy. Cancer Res; 77(22); 6365-74. ©2017 AACR.

Prognostic biomarkers in patients with human immunodeficiency virus-positive disease with head and neck squamous cell carcinoma

BACKGROUND

We examined the prognostic value of a panel of biomarkers in patients with squamous cell carcinoma of the head and neck (SCCHN) who were human immunodeficiency virus (HIV) positive (HIV-positive head and neck cancer) and HIV negative (HIV-negative head and neck cancer).

METHODS

Tissue microarrays (TMAs) were constructed using tumors from 41 disease site-matched and age-matched HIV-positive head and neck cancer cases and 44 HIV-negative head and neck cancer controls. Expression of tumor biomarkers was assessed by immunohistochemistry (IHC) and correlations examined with clinical variables.

RESULTS

Expression levels of the studied oncogenic and inflammatory tumor biomarkers were not differentially regulated by HIV status. Among patients with HIV-positive head and neck cancer, laryngeal disease site (P = .003) and Clavien-Dindo classification IV (CD4) counts <200 cells/μL (P = .01) were associated with poor prognosis. Multivariate analysis showed that p16 positivity was associated with improved overall survival (OS; P < .001) whereas increased expression of transforming growth factor-beta (TGF-β) was associated with poor clinical outcome (P = .001).

CONCLUSION

Disease site has significant effect on the expression of biomarkers. Expression of tumor TGF-β could be a valuable addition to the conventional risk stratification equation for improving head and neck cancer disease management strategies.

IDO1 as a mechanism of adaptive immune resistance to anti-PD1 monotherapy in HNSCC

6053

Background: Patients with recurrent/metastatic human papillomavirus-associated head and neck squamous cell carcinoma (HPV-HNSCC) demonstrate improved response rates to anti-PD-1 blockade, which may be attributed to the inherent inflammation associated with the local expression of foreign, highly immunogenic viral antigens. However, these response rates are at best 25%, suggesting there may be immune resistance networks that are limiting clinical responses to anti-PD-1 therapy. To address this question, we investigated other potential immune checkpoint pathways that may be upregulated in PD-L1 expressing HPV-HNSCCs. Methods: Using a custom microarray of 59 immune-related genes, we compared the gene expression profile of laser-captured micro-dissected PD-L1 (+) and (-) immune fronts in HPV-HNSCCs. Gene expression was validated using quantitative PCR (qPCR) and protein expression geographically localized using quantitative multiplex biomarker imaging in a separate cohort of HPV-HNSCCs. Furthermore, we assayed pre- and post-treatment biopsies from anti-PD-1 treated patients and correlated gene expression with clinical responses. Results: Of the immune-related genes, IDO1 was increased 65-fold in 10 PD-L1(+) as compared to 5 PD-L1(-) HPV-HNSCCs (p = 0.004). qPCR confirmed upregulated expression of IDO1 and quantitative immunofluorescence demonstrated that PD-L1 and IDO1 geographically co-localized within the tumor microenvironment in a validation cohort of 25 HPV-HNSCC patients. In anti-PD1 treated patients, IDO1 expression increased up to two-fold and correlated with disease progression in HNSCC patients. Conclusions: IDO1 is an immune checkpoint molecule that modulates T cell activity through the depletion of L-tryptophan. We propose that IDO1 is an adaptive immune resistance pathway to anti-PD-1 monotherapy. The results provide rationale for combinatorial therapies targeting the IDO1 and PD-1:PD-L1 networks in HNSCC patients.

A retrospective cohort study of PD-L1 expression in recurrent and/or metastatic squamous cell carcinoma of the head and neck (SUPREME-HN)

6040

Background: Patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) have a poor prognosis. Targeting the PD-1/PD-L1 axis has resulted in clinically meaningful antitumor activity and improved overall survival (OS) in R/M HNSCC patients. Tumoral PD-L1 expression correlates with response to blocking PD-1/PD-L1 antibodies. We investigated the prognostic value of PD-L1 expression in R/M HNSCC patients. Methods: Archival tumor samples from R/M HNSCC patients diagnosed between March 2011 and June 2015 at 12 institutions in 6 countries were stained for PD-L1 and clinic-demographic data were abstracted from medical records. Tumoral PD-L1 protein expression was assessed with the validated Ventana SP263 assay and scored as high (≥25% of tumor cells [TC]) or low/negative ( < 25% of TC). Extracted data included demographic and tumor characteristics, treatment patterns, and clinical outcomes. Descriptive analyses were conducted and survival estimated by the Kaplan-Meier method. OS was defined from the diagnosis index date of R/M disease to time of death. Results: As ofSeptember 26, 2016 (interim analysis), data were available for 143 patients of whom 138 were eligible for analysis. Median age was 62.0 years (range, 28.0−88.0), 76.8% were male, and 84.0% were white. PD-L1 protein expression was high in 43 patients (31.2%), low/negative in 91 (65.9%), and unknown in 4 (2.9%). Median OS (8.2 vs. 8.8 months; P = 0.94) and progression-free survival (PFS) from the start of first-line (6.0 vs. 5.6 months; P = 0.29) or second-line therapy (7.1 vs. 1.8 months; P = 0.11) did not significantly differ between PD-L1 high and low/negative patients, respectively. There were no significant differences in OS based on PD-L1 status within subgroups defined by age, race, tobacco or alcohol use, primary tumor site, performance status, metastatic disease at diagnosis, or treatment with platinum-based chemotherapy. Conclusions: Interim analyses indicate that PD-L1 status is not associated with OS or PFS in R/M HNSCC patients.

Intact APM and PD-1:PD-L1 pathway upregulation in HIV-infected head and neck cancer patients

6058

Background: HIV-infected individuals have a higher incidence of oral infection with human papillomavirus (HPV) and possibly a higher incidence of head and neck cancer (HNC). Whether this observation reflects defects in the ability of this Òimmune-compromisedÓ patient population to mount sufficient tumor specific immune responses and/or reflects activation of immune escape mechanisms is not known. To address this question, we investigated the expression of HLA class I antigen processing machinery (APM) components and PD-1:PD-L1 pathway activation in HIV(+) HNC patients. Methods: 62 HIV(+) HNC patients diagnosed between 1991-2011 from five tertiary care referral centers in the United States and matched HIV(-) HNC controls were identified. HLA class I APM component, PD-1, and PD-Ll expression were analyzed by immunohistochemical staining. Clinical data was abstracted from the medical records. Results: 44 of 62 (71%) HIV(+) HNC cases were matched based on gender, age ( < 10 years), and anatomic sub-site to HIV(-) HNC patients. There was no significant difference between the cases and controls in HLA-A, HLA-B/C, LMP2, and TAP1, as well as PD-1 and PD-L1 expression. Overall, 62% of all subjects had high PD-1 expression and 82% of the subjects expressed PD-L1. HLA-A, HLA-B/C, and LMP2 expression was significantly correlated with moderate to high PD-1 expression in the HIV(+) HNC cases (p = 0.004, p = 0.026, and p = 0.006, respectively) but not in the HIV(-) controls. Similarly, HLA-A expression was also significantly associated with PD-L1 expression only in the HIV(+) HNC cases (p = 0.029). Conclusions: No defects were detected in the expression of the HLA class I APM components tested. PD-1:PD-L1 pathway was found to be upregulated in both HIV(+) and HIV(-) HNC patients. Our data suggest that recently approved anti-PD-1 immunotherapy should not exclude HIV(+) patients.

Adjuvant radiotherapy is not supported in patients with verrucous carcinoma of the oral cavity

OBJECTIVE

To analyze the impact of adjuvant radiation therapy (RT) on overall survival (OS) and disease-specific survival (DSS) in patients with verrucous carcinoma (VC) as compared to squamous cell carcinoma (SCC) of the oral cavity.

STUDY DESIGN

Cross-sectional population analysis.

METHODS

Cases of nonmetastatic VC/SCC of the oral cavity were extracted from the Surveillance, Epidemiology, and End Results (SEER) database (1988-2013). Kaplan-Meier survivals, stratified according to T stage, were compared between VC and SCC for treatment with or without adjuvant RT.

RESULTS

A total of 18,819 VC/SCC cases were identified. There were 581 (3.1%) VC (mean age 69.6 years, 48.9% female) versus 18,238 (97.0%) SCC (mean age, 65.3, 37.1% female) patients. Verrucous carcinoma patients receiving surgery alone (N = 539) demonstrated a trend toward improved OS versus VC patients receiving surgery and RT (N = 40) (117.0 vs. 71.4 months, respectively, P = 0.119). There was a statistically significant improvement in DSS in VC patients receiving surgery alone (217.2 vs. 110.9 months, P = 0.05). Verrucous carcinoma patients treated with adjuvant RT demonstrated a trend toward a worse OS (71.4 vs. 93.0 months, P = 0.992) and DSS (110.9 vs. 162.3 months, P = 0.275) compared to SCC treated with adjuvant RT, suggesting a different biology and radiosensitivity between VC and SCC.

CONCLUSION

Verrucous carcinoma treated with adjuvant RT had a worse OS and DSS compared to both VC treated with surgery alone and SCC treated with surgery and adjuvant RT. Consideration should be given to surgical re-section rather than adjuvant RT in patients with positive margins or local recurrence.

LEVEL OF EVIDENCE

2C. Laryngoscope, 127:1334-1338, 2017.

High-Risk HPV, Biomarkers, and Outcome in Matched Cohorts of Head and Neck Cancer Patients Positive and Negative for HIV

In this study, high-risk HPV (hrHPV) incidence, prognostic biomarkers, and outcome were assessed in HIV-positive (case) and HIV-negative (control) patients with head and neck squamous cell cancer (HNSCC). HIV-positive cases were matched to controls by tumor site, sex, and age at cancer diagnosis. A tissue microarray (TMA) was constructed and DNA isolated from tumor tissue. MultiPlex-PCR MassArray, L1-PCR, and in situ hybridization were used to assess hrHPV. TMA sections were stained for p16ink4a, TP53, RB, CCND1, EGFR, and scored for intensity and proportion of positive tumor cells. The HNSCC cohort included 41 HIV-positive cases and 41 HIV-negative controls. Tumors from 11 of 40 (28%) cases, and 10 of 41 (24%) controls contained hrHPV. p16 expression, indicative of E7 oncogene activity, was present in 10 of 11 HPV-positive cases and 7 of 10 HPV-positive controls. Low p16 and high TP53 expression in some HPV-positive tumors suggested HPV-independent tumorigenesis. Survival did not differ in cases and controls. RB expression was significantly associated with poor survival (P = 0.01). High TP53 expression exhibited a trend for poorer survival (P = 0.12), but among cases, association with poor survival reached statistical significance (P = 0.04). The proportion of HPV-positive tumors was similar, but the heterogeneity of HPV types was higher in the HIV-positive cases than in HIV-negative controls. High RB expression predicted poor survival, and high TP53 expression was associated with poorer survival in the HIV-positive cases but not HIV-negative controls.

IMPLICATIONS

HIV infection did not increase risk of death from HNSCC, and HPV-positive tumors continued to be associated with a significantly improved survival, independent of HIV status. Mol Cancer Res; 15(2); 179-88. ©2016 AACR.

The role of antagonists of the PD-1:PD-L1/PD-L2 axis in head and neck cancer treatment

We review the current clinical knowledge surrounding one of the most promising immune checkpoint pathways currently investigated in head and neck squamous cell carcinoma patients, programmed cell death-1 (PD-1) and its ligands (PD-L1 and PD-L2). We review ongoing clinical trials and associated clinical responses observed with targeting the receptor, PD-1, and its ligand, PD-L1. A recent phase III clinical trial (Checkmate 141) demonstrated an improved overall survival in head and neck cancer patients treated with anti-PD-1 monotherapy as compared to standard of care for recurrent and/or metastatic disease, which raises questions on how best to incorporate immunotherapy in the context of standard of care. We discuss biomarkers of response to this class of novel drugs, which is an area of active investigation. Lastly, we project future directions in the field wherein understanding how the Fc portions of the various monoclonal antibodies may impact their clinical efficacy as well as discuss areas where our next advances may take place, such as combination strategies.

Eurogin Roadmap 2015: How has HPV knowledge changed our practice: Vaccines

This review is one of two complementary reviews that have been prepared in the framework of the Eurogin Roadmap 2015 to evaluate how knowledge about HPV is changing practices in HPV infection and disease control through vaccination and screening. In this review of HPV vaccine knowledge, we present the most significant findings of the past year which have contributed to our knowledge of the two HPV prophylactic vaccines currently in widespread use and about the recently licensed nonavalent HPV vaccine. Whereas anal cancer is dealt with in the companion mini-review on screening, we also review here the rapidly evolving evidence regarding HPV-associated head and neck cancer and priority research areas.

Sequential cisplatin therapy and vaccination with HPV16 E6E7L2 fusion protein in saponin adjuvant GPI-0100 for the treatment of a model HPV16+ cancer

Clinical studies suggest that responses to HPV16 E6E7L2 fusion protein (TA-CIN) vaccination alone are modest, and GPI-0100 is a well-tolerated, potent adjuvant. Here we sought to optimize both the immunogenicity of TA-CIN via formulation with GPI-0100 and treatment of HPV16+ cancer by vaccination after cisplatin chemotherapy. HPV16 neutralizing serum antibody titers, CD4+ T cell proliferative and E6/E7-specific CD8+ T cell responses were significantly enhanced when mice were vaccinated subcutaneously (s.c.) or intramuscularly (i.m.) with TA-CIN formulated with GPI-0100. Vaccination was tested for therapy of mice bearing syngeneic HPV16 E6/E7+ tumors (TC-1) either in the lung or subcutaneously. Mice treated with TA-CIN/GPI-0100 vaccination exhibited robust E7-specific CD8+ T cell responses, which were associated with reduced tumor burden in the lung, whereas mice receiving either component alone were similar to controls. Since vaccination alone was not sufficient for cure, mice bearing s.c. TC-1 tumor were first treated with two doses of cisplatin and then vaccinated. Vaccination with TA-CIN/GPI-0100 i.m. substantially retarded tumor growth and extended survival after cisplatin therapy. Injection of TA-CIN alone, but not GPI-0100, into the tumor (i.t.) was similarly efficacious after cisplatin therapy, but the mice eventually succumbed. However, tumor regression and extended remission was observed in 80% of the mice treated with cisplatin and then intra-tumoral TA-CIN/GPI-0100 vaccination. These mice also exhibited robust E7-specific CD8+ T cell and HPV16 neutralizing antibody responses. Thus formulation of TA-CIN with GPI-0100 and intra-tumoral delivery after cisplatin treatment elicits potent therapeutic responses in a murine model of HPV16+ cancer.

In-situ tumor vaccination: Bringing the fight to the tumor

After decades of development in the shadow of traditional cancer treatment, immunotherapy has come into the spotlight. Treatment of metastatic tumors with monoclonal antibodies to T cell checkpoints like programed cell death 1 (PD-1) or its ligand, (PD-L1), have resulted in significant clinical responses across multiple tumor types. However, these therapies fail in the majority of patients with solid tumors, in particular those who lack PD1(+)CD8(+) tumor-infiltrating lymphocytes within their tumors. Intratumoral "in situ vaccination" approaches seek to enhance immunogenicity, generate tumor infiltrating lymophcytes (TIL) and drive a systemic anti-tumor immune response, directed against "unvaccinated," disseminated tumors. Given the emerging picture of intratumoral immunotherapy as safe and capable of delivering systemic efficacy, it is anticipated that these approaches will become integrated into future multi-modality therapy.

Adaptive immune resistance in HPV-associated head and neck squamous cell carcinoma

Human papillomavirus (HPV) types associated with head and neck cancer generally induce a robust immune response. Despite the establishment of such an inflammatory microenvironment, HPV is able to persist and promote malignant transformation. The PD-1:PD-L1 immune checkpoint may play a critical role in the creation of an immunoprivileged site for viral persistence and the subsequent development of cancer.

Xenograft model for therapeutic drug testing in recurrent respiratory papillomatosis

OBJECTIVE

Identifying effective treatment for papillomatosis is limited by a lack of animal models, and there is currently no preclinical model for testing potential therapeutic agents. We hypothesized that xenografting of papilloma may facilitate in vivo drug testing to identify novel treatment options.

METHODS

A biopsy of fresh tracheal papilloma was xenografted into a NOD-scid-IL2Rgamma(null) (NSG) mouse.

RESULTS

The xenograft began growing after 5 weeks and was serially passaged over multiple generations. Each generation showed a consistent log-growth pattern, and in all xenografts, the presence of the human papillomavirus (HPV) genome was confirmed by polymerase chain reaction (PCR). Histopathologic analysis demonstrated that the squamous architecture of the original papilloma was maintained in each generation. In vivo drug testing with bevacizumab (5 mg/kg i.p. twice weekly for 3 weeks) showed a dramatic therapeutic response compared to saline control.

CONCLUSION

We report here the first successful case of serial xenografting of a tracheal papilloma in vivo with a therapeutic response observed with drug testing. In severely immunocompromised mice, the HPV genome and squamous differentiation of the papilloma can be maintained for multiple generations. This is a feasible approach to identify therapeutic agents in the treatment of recurrent respiratory papillomatosis.