Anti PD-L1 DUrvalumab combined with Cetuximab and RadiOtherapy in locally advanced squamous cell carcinoma of the head and neck: A phase I/II study (DUCRO)

Emerging therapeutic frontiers in cancer: insights into posttranslational modifications of PD-1/PD-L1 and regulatory pathways

The interaction between programmed cell death ligand 1 (PD-L1), which is expressed on the surface of tumor cells, and programmed cell death 1 (PD-1), which is expressed on T cells, impedes the effective activation of tumor antigen-specific T cells, resulting in the evasion of tumor cells from immune-mediated killing. Blocking the PD-1/PD-L1 signaling pathway has been shown to be effective in preventing tumor immune evasion. PD-1/PD-L1 blocking antibodies have garnered significant attention in recent years within the field of tumor treatments, given the aforementioned mechanism. Furthermore, clinical research has substantiated the efficacy and safety of this immunotherapy across various tumors, offering renewed optimism for patients. However, challenges persist in anti-PD-1/PD-L1 therapies, marked by limited indications and the emergence of drug resistance. Consequently, identifying additional regulatory pathways and molecules associated with PD-1/PD-L1 and implementing judicious combined treatments are imperative for addressing the intricacies of tumor immune mechanisms. This review briefly outlines the structure of the PD-1/PD-L1 molecule, emphasizing the posttranslational modification regulatory mechanisms and related targets. Additionally, a comprehensive overview on the clinical research landscape concerning PD-1/PD-L1 post-translational modifications combined with PD-1/PD-L1 blocking antibodies to enhance outcomes for a broader spectrum of patients is presented based on foundational research.

Impact of radiation dose on patient-reported acute taste alteration in a prospective observational study cohort in head and neck squamous cell cancer (HNSCC)

PURPOSE

Taste alteration (TA) is a frequent acute side effect of radiation treatment in HNSCC patients. Principal aim of our study was to investigate dosimetric parameters in relation to patient-assessed taste impairment in a prospective cohort treated with intensity-modulated radiotherapy.

METHODS

All patients with locally advanced HNSCC and amenable to radical treatment were included. Chemotherapy-induced taste alteration scale (CITAS), EORTC QLQ-C30 and QLQ-HN43 questionnaires at baseline (T0), 3 weeks (T1) and 3 months (T2) after radiotherapy conclusion were used to assess taste impairment. Base of tongue, submandibular glands (SG), parotid glands (PG) and taste buds, along with anterior and medium third of the tongue, were considered as organs at risk and thus delineated according to consensus guidelines. The mean dose to the above-mentioned structures was correlated with patient-reported outcomes.

RESULTS

Between September 2019 and November 2020, 33 patients were recruited, 31 of which analyzed. 71% had oropharyngeal carcinoma, mostly HPV-related (60%). All were treated with tomotherapy. 77.4% had concurrent cisplatin. Mean scores of general taste alterations, global health status and dry mouth and sticky saliva were assessed. The mean doses to the anterior third, medium third and base of the tongue were 23.85, 35.50 and 47.67 Gy, respectively. Taste buds received 32.72 Gy; right and left parotid 25 and 23 Gy; right and left submandibular glands 47.8 and 39.4 Gy. At univariate analysis, dysgeusia correlated with SG mean dose (95% CI 0-0.02 p = 0.05) and PG mean dose (95% CI 0-0.02 p = 0.05); dry mouth with mean dose to anterior (95% CI 0.03-1.47 p = 0.04) and medium third (95% CI 0.02-0.93 p = 0.04) of the tongue, to taste buds (95% CI 0.06-0.96 p = 0.03) and to SGs (95% CI 0.06-0.63 p = 0.02); pain mouth with mean dose to taste buds (95% CI 0-0.02 p = 0.04), to SGs (95% CI 0-0.03 p = 0.03) and to base tongue (95% CI 0-0.02 p = 0.02).

CONCLUSIONS

Our analysis supports the influence of dose distribution on the development of TA in HNSCC patients. The contribution of dose to taste buds and tongue subvolumes remains unclear and worthy of further investigation.

Combination therapy with oncolytic viruses and immune checkpoint inhibitors in head and neck squamous cell carcinomas: an approach of complementary advantages

Squamous cell carcinomas are the most common head and neck malignancies. Significant progress has been made in standard therapeutic methods combining surgery, radiation, and chemotherapy. Nevertheless, the 5-year survival rate remains at 40-50%. Immune checkpoint inhibitors (ICIs) are a new strategy for treating head and neck squamous cell carcinomas (HNSCCs). Still, the overall response and effective rates are poor, as HNSCCs are 'cold' tumors with an immunosuppressive tumor microenvironment (TME), limiting ICI's beneficial effects. In this case, transforming the tumor suppression microenvironment before using ICIs could be helpful. Oncolytic viruses (OVs) can transform cold tumors into hot tumors, improving the situation. Talimogene laherparepvec (T-VEC), oncolytic immunotherapy authorized for advanced melanoma, also showed good safety and antitumor activity in treating head and neck cancer and pancreatic cancer. In combination with pembrolizumab, T-Vec may have more anticancer efficacy than either drug alone. Therefore, understanding the mechanisms underpinning OVs and their potential synergism with ICIs could benefit patients with HNSCC.

Therapeutic Potential of Targeting Transforming Growth Factor-beta (TGF-β) and Programmed Death-ligand 1 (PD-L1) in Pancreatic Cancer

Pancreatic cancer (PC) is one the most lethal malignancies worldwide affecting around half a million individuals each year. The treatment of PC is relatively difficult due to the difficulty in making an early diagnosis. Transforming growth factor-beta (TGF-β) is a multifunctional factor acting as both a tumor promoter in early cancer stages and a tumor suppressor in advanced disease. Programmed death-ligand 1 (PD-L1) is a ligand of programmed death-1 (PD-1), an immune checkpoint receptor, allowing tumor cells to avoid elimination by immune cells. Recently, targeting the TGF-β signaling and PD-L1 pathways has emerged as a strategy for cancer therapy. In this review, we have summarized the current knowledge regarding these pathways and their contribution to tumor development with a focus on PC. Moreover, we have reviewed the role of TGF-β and PD-L1 blockade in the treatment of various cancer types, including PC, and discussed the clinical trials evaluating TGF-β and PD-L1 antagonists in PC patients.

Immunotherapy for head and neck cancer: present and future

Immunotherapy has changed the treatment landscape of Head and Neck cancer (HNC). Different immune checkpoint inhibitors targeting PD-1/PD-L1 axis have been approved for different disease settings and many others, alone or in combination, are currently under investigation. Otherwise, as in other cancer types, efficacy, and resistance mechanisms, are not clearly understood. Considering the heterogeneity of the benefit reported in clinical trials, cost-efficacy analysis and the development of an effective patient selection are encouraged. Different pathways involving innate immunity, regulatory T lymphocytes and microbiome are emerging as new potential biomarkers, supported by preclinical and translational data. In this review we report current evidence on immunotherapy in HNC with updates from the main 2021 oncology events as ASCO, AACR and ESMO meetings. We focus on clinical trials results of single agent and combination immunotherapy in different clinical scenario, from (neo)adjuvant to metastatic setting, describing also novel evidence about efficacy and resistance biomarkers.

The Right Partner in Crime: Unlocking the Potential of the Anti-EGFR Antibody Cetuximab via Combination With Natural Killer Cell Chartering Immunotherapeutic Strategies

Cetuximab has an established role in the treatment of patients with recurrent/metastatic colorectal cancer and head and neck squamous cell cancer (HNSCC). However, the long-term effectiveness of cetuximab has been limited by the development of acquired resistance, leading to tumor relapse. By contrast, immunotherapies can elicit long-term tumor regression, but the overall response rates are much more limited. In addition to epidermal growth factor (EGFR) inhibition, cetuximab can activate natural killer (NK) cells to induce antibody-dependent cellular cytotoxicity (ADCC). In view of the above, there is an unmet need for the majority of patients that are treated with both monotherapy cetuximab and immunotherapy. Accumulated evidence from (pre-)clinical studies suggests that targeted therapies can have synergistic antitumor effects through combination with immunotherapy. However, further optimizations, aimed towards illuminating the multifaceted interplay, are required to avoid toxicity and to achieve better therapeutic effectiveness. The current review summarizes existing (pre-)clinical evidence to provide a rationale supporting the use of combined cetuximab and immunotherapy approaches in patients with different types of cancer.

LncRNA HCG18 suppresses CD8+ T cells to confer resistance to cetuximab in colorectal cancer via miR-20b-5p/PD-L1 axis

Aim: We aimed to explore the effect of long noncoding RNA HCG18 in colorectal cancer (CRC). Materials & methods: Relative gene and protein expression were screened. Colony formation and flow cytometry assays were performed to determine proliferation and apoptosis. Dual luciferase and RNA immunoprecipitation assays were conducted to validate the interaction between indicated molecules. Xenograft in nude mice was applied to verify the conclusion in vivo. Results: HCG18 and PD-L1 were upregulated while miR-20b-5p was downregulated in CRC tissue. Functional analysis revealed that lncRNA HCG18 promoted proliferation, migration and resistance to cetuximab of CRC cells via the miR-20b-5p/PD-L1 axis. Conclusion: HCG18 facilitated progress of the tumor, conferred to cetuximab resistance and suppressed CD8⁺ T cells via the miR-20b-5p/PD-L1 axis.

Cetuximab in locally advanced head and neck squamous cell carcinoma: Biological mechanisms involved in efficacy, toxicity and resistance

Since its introduction, the use of cetuximab in the treatment of head and neck squamous cell carcinoma (HNSCC) has experienced an evolution. Currently, cetuximab associated with radiotherapy is limited to the treatment of patients affected by a locally advanced malignancy and unfit for cisplatin. However, reliable biomarkers of cetuximab efficacy in this cancer setting are still lacking. This review focuses on the mechanisms of action of cetuximab, highlighting, in particular, the consequences of the binding to EGFR, and the pathways involved in the development of adverse events or acquired resistance. Indeed, adverse events, such as skin rash, have been associated with cetuximab efficacy in HNSCC several times. Acquired resistance is associated with microenvironment plasticity, which is, in turn, characterized by an increased immune infiltrate. The better definition of patients eligible for this kind of therapy could improve HNSCC management, possibly proposing a combined treatment with radiotherapy, cetuximab and immune checkpoint inhibitors as recently investigated.

Current landscape of immunotherapy trials in locally advanced and high-risk head and neck cancer

The current standard of therapy for locally advanced (LA) head and neck squamous cell carcinoma (HNSCC) is limited by toxicity and suboptimal control. The role of immunotherapy (IO) is being evaluated in the LA setting. This review aims to summarize the recent advances and the direction of clinical trials in IO in LA or high-risk HNSCC. Despite negative results in some studies, several early phase trials suggest the feasibility and efficacy of IO-based strategies in LA or high-risk HNSCC. Further refining of patient selection and biomarker development is warranted for successful incorporation of IO in this patient population.

Immunotherapy for head and neck cancer: from recurrent/metastatic disease to (neo)adjuvant treatment in surgically resectable tumors

PURPOSE OF REVIEW

We aim to summarize the current evidence on the role of immune checkpoint inhibitors in the (neo)adjuvant treatment of squamous cell carcinoma of the head and neck (HNSCC), with a particular focus on surgically treated patients.

RECENT FINDINGS

Pembrolizumab +/- chemotherapy improves the outcome in patients with previously untreated recurrent/metastatic HNSCC. Nivolumab is superior to chemotherapy after platinum failure. The addition of avelumab to chemoradiation failed to improve the outcome in patients with locally advanced HNSCC. Neoadjuvant presurgical programmed cell death 1 receptor (PD-1) blockade is safe and associated with encouraging overall response rate. KEYNOTE-689 randomizes patients with resectable stage III/IVA HNSCC to surgery and adjuvant standard of care +/- neoadjuvant and adjuvant pembrolizumab. ADHERE assigns surgically treated HNSCC at high risk of recurrence to chemoradiotherapy (CRT) and either durvalumab or placebo. MK-3475-689 evaluates the role of pembrolizumab in patients with resectable HNSCC. NIVOPOSTOP evaluates the addition of nivolumab to CRT in patients with surgically treated pStage III/IV HNSCC or pT3N1/pT4N1 oropharyngeal cancer with at least 20 packs/year at high risk of relapse.

SUMMARY

Multiple trials are currently evaluating the role of immunotherapy in HNSCC amenable to surgery. Neoadjuvant presurgical PD-1 blockade is feasible and safe and is associated with an encouraging overall response rate.

Comprehending the crosstalk between Notch, Wnt and Hedgehog signaling pathways in oral squamous cell carcinoma - clinical implications

BACKGROUND

Oral squamous cell carcinoma (OSCC) is a malignant oral cavity neoplasm that affects many people, especially in developing countries. Despite several advances that have been made in diagnosis and treatment, the morbidity and mortality rates due to OSCC remain high. Accumulating evidence indicates that aberrant activation of cellular signaling pathways, such as the Notch, Wnt and Hedgehog pathways, occurs during the development and metastasis of OSCC. In this review, we have articulated the roles of the Notch, Wnt and Hedgehog signaling pathways in OSCC and their crosstalk during tumor development and progression. We have also examined possible interactions and associations between these pathways and treatment regimens that could be employed to effectively tackle OSCC and/or prevent its recurrence.

CONCLUSIONS

Activation of the Notch signaling pathway upregulates the expression of several genes, including c-Myc, β-catenin, NF-κB and Shh. Associations between the Notch signaling pathway and other pathways have been shown to enhance OSCC tumor aggressiveness. Crosstalk between these pathways supports the maintenance of cancer stem cells (CSCs) and regulates OSCC cell motility. Thus, application of compounds that block these pathways may be a valid strategy to treat OSCC. Such compounds have already been employed in other types of cancer and could be repurposed for OSCC.

Precision Medicine Approaches to Overcome Resistance to Therapy in Head and Neck Cancers

Head and neck squamous cell carcinoma (HNSCC) is the sixth most incident cancer worldwide. More than half of HNSCC patients experience locoregional or distant relapse to treatment despite aggressive multimodal therapeutic approaches that include surgical resection, radiation therapy, and adjuvant chemotherapy. Before the arrival of immunotherapy, systemic chemotherapy was previously employed as the standard first-line protocol with an association of cisplatin or carboplatin plus 5-fluorouracil plus cetuximab (anti-EFGR antibody). Unfortunately, acquisition of therapy resistance is common in patients with HNSCC and often results in local and distant failure. Despite our better understanding of HNSCC biology, no other molecular-targeted agent has been approved for HNSCC. In this review, we outline the mechanisms of resistance to the therapeutic strategies currently used in HNSCC, discuss combination treatment strategies to overcome them, and summarize the therapeutic regimens that are presently being evaluated in early- and late-phase clinical trials.

Role of HPV status and PD-L1 expression in prognosis of laryngeal squamous cell carcinoma

PURPOSE

Human papillomavirus (HPV) infection has been recognized as a cause of head and neck squamous cell carcinomas (HNSCC). Laryngeal squamous cell carcinoma (LSCC) is one of the most common pathologic types of HNSCC. Clinical trials show that there are differences in response to immunotherapy according to HPV status. It was reported that a high level of programmed cell death-ligand 1 (PD-L1) is correlated with better survival in HPV-positive head and neck cancer. In this study, we investigated the expression of PD-L1 in HPV-positive and HPV-negative LSCC to determine its prevalence and prognostic value.

METHODS

52 cases of LSCC were collected from Tangshan Head and Neck Disease Pathology Research Base. PCR-reverse dot blot hybridization and RNAscope in situ hybridization were used to detect HPV status. PD-L1 expression was evaluated by immunohistochemistry and all cases were followed up for survival. SPSS24.0 was used for data entry and statistical analysis. Kaplan-Meier method and Log-rank time series analysis were used for single factor analysis. Multivariate analysis was performed using Cox proportional hazard regression model, and HR and 95% CI were calculated.

RESULTS

Of the 52 LSCC patients, 32.7% (17/52) were HPV-positive by RNAscope in situ hybridization, and 51.9% (27/52) of patients were positive for PD-L1 expression by immunohistochemistry. Regression analysis showed that with a median follow-up period of 69 months, smoking and late stage were associated with poor overall survival (OS), whereas HPV positivity and PD-L1 expression showed a better overall survival outcome.

CONCLUSION

Smoking status, tumor stage, HPV status, and PD-L1 expression in tumor cells may represent useful prognostic biomarkers in patients with LSCC.

Prospective longitudinal study of immune checkpoint molecule (ICM) expression in immune cell subsets during curative conventional therapy of head and neck squamous cell carcinoma (HNSCC)

Programmed-death-1 (PD1) antibodies are approved for recurrent and metastatic head and neck squamous cell carcinoma. Multiple drugs targeting costimulatory and coinhibitory immune checkpoint molecules (ICM) have been discovered. However, it remains unknown how these ICM are affected by curative conventional therapy on different immune cell subsets during the course of treatment. In the prospective noninterventional clinical study titled "Immune Response Evaluation to Curative conventional Therapy" (NCT03053661), 22 patients were prospectively enrolled. Blood samples were drawn at defined time points throughout curative conventional treatment and follow-up. Immune cells (IC) from the different time points were assessed by multicolor flow cytometry. The following ICM were measured by flow cytometry: PD1, CTLA4, BTLA, CD137, CD27, GITR, OX40, LAG3 and TIM3. Dynamics of ICM expression were assessed using nonparametric paired samples tests. Significant changes were noted for PD1, BTLA and CD27 on multiple IC types during or after radiotherapy. Nonsignificant trends for increased expression of OX40 and GITR from baseline until the end of RT were observed on CD4 T cells and CD4⁺ CD39⁺ T cells. In patients with samples at recurrence of disease, a nonsignificant increase of TIM3 and LAG3 positive CD4⁺ CD39⁺ T cells was evident, accompanied by an increase of double positive cells for TIM3/LAG3. Potential future targets to be combined with RT in the conventional treatment and anti-PD1/PD-L could be BTLA agonists, or agonistic antibodies to costimulatory ICM like CD137, OX40 or GITR. The combination of cetuximab with CD27 agonistic antibodies enhancing ADCC or the targeting of TIM3/LAG3 may be another promising strategy.

The Tumor Microenvironment and Immunotherapy of Oropharyngeal Squamous Cell Carcinoma

Oropharyngeal squamous cell carcinoma (OPSCC) develops as a consequence of several mutations in the tumor suppressor pathways or after a progressive infection with high risk human papillomavirus (HPV). The dismal side effects of the current standard of care and the clear involvement of the immune system has led to a surge in clinical trials that aim to reinforce the tumor-specific immune response as a new treatment option. In this review, we have focused on the most recent literature to discuss the new findings and insights on the role of different immune cells in the context of OPSCC and its etiology. We then applied this knowledge to describe potential biomarkers and analyzed the rationale and outcomes of earlier and ongoing immunotherapy trials. Finally, we describe new developments that are still at the preclinical phase and provide an outlook on what the near future may bring, now that several new and exciting techniques to study the immune system at the single cell level are being exploited.

Combining radiotherapy and immunotherapy in definitive treatment of head and neck squamous cell carcinoma: review of current clinical trials

Background Head and neck squamous cell carcinoma (HNSCC) presents as locally advanced disease in a majority of patients and is prone to relapse despite aggressive treatment. Since immune checkpoint inhibitors (ICI) have shown clinically significant efficacy in patients with recurrent/metastatic HNSCC (R/M HNSCC), a plethora of trials are investigating their role in earlier stages of disease. At the same time, preclinical data showed the synergistic role of concurrently administered radiotherapy and ICIs (immunoradiotherapy) and explained several mechanisms behind it. Therefore, this approach is prospectively tested in a neoadjuvant, definitive, or adjuvant setting in non-R/M HNSCC patients. Due to the intricate relationship between host, immunotherapy, chemotherapy, and radiotherapy, each of these approaches has its advantages and disadvantages. In this narrative review we present the biological background of immunoradiotherapy, as well as a rationale for, and possible flaws of, each treatment approach, and provide readers with a critical summary of completed and ongoing trials. Conclusions While immunotherapy with ICIs has already become a standard part of treatment in patients with R/M HNSCC, its efficacy in a non-R/M HNSCC setting is still the subject of extensive clinical testing. Irradiation can overcome some of the cancer's immune evasive manoeuvres and can lead to a synergistic effect with ICIs, with possible additional benefits of concurrent platinum-based chemotherapy. However, the efficacy of this combination is not robust and details in trial design and treatment delivery seem to be of unprecedented importance.

Re-irradiation for oligoprogression under Nivolumab in recurrent head and neck squamous cell carcinoma: A case report

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Immunotherapy is a new option for head and neck squamous cell carcinoma.

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Very limited data are available for concurrent radio-immunotherapy in recurrent disease.

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Our case report adds to this very limited series, focusing on oligopression under immunotherapy.

Immune checkpoint inhibitors (ICIs) represent a recently introduced class of agents active in head and neck squamous cell carcinoma (HNSCC). For a subgroup of patients with recurrent or metastatic disease, long-term benefit can be achieved: maintaining a sustained response to immunotherapy is therefore a critical factor for its efficacy at an individual level. In analogy to targeted agents, a limited pattern of progression, or “oligoprogression”, can occur. For locally recurrent HNSCC, the potential biologic interplay between the efficacy of ICIs and the design of radiation fields chosen for primary treatment is currently unknown. Here, we report on a patient who presented two subsequent oligoprogressions successfully treated with re-irradiation without interrupting Nivolumab. Both oligoprogressive lesions developed in previously unirradiated areas. We hypothesize the existence of a synergistic effect with optimal spatial cooperation between ICIs and re-irradiation for oligoprogressive disease under immunotherapy.

Cetuximab and Radiation Therapy Versus Cisplatin and Radiation Therapy for Locally Advanced Head and Neck Cancer: Long-Term Survival and Toxicity Outcomes of a Randomized Phase 2 Trial

PURPOSE

This study describes the long-term survival and toxicity outcomes of a multicenter randomized phase 2 trial comparing radiation therapy (RT) plus cisplatin (CDDP) or cetuximab (CTX) as first line treatment in locally advanced head and neck cancer (LASCCHN).

METHODS AND MATERIALS

Between January 2011 and August 2014, 70 patients were enrolled and randomized to receive RT plus weekly CDDP (40 mg/m²) or CTX (250 mg/m² plus a loading dose of 400 mg/m²). This updated series focuses on late toxicities (graded by using Common Terminology Criteria for Adverse Events version 4.0) and long-term survival outcomes in terms of local control, overall survival, cancer-specific survival, and metastasis-free survival (MFS). A supplementary analysis based on human papilloma virus (HPV) status was also performed.

RESULTS

No statistically significant difference was found in terms of late effects (xerostomia, fibrosis, mucosal atrophy, weight loss). In the CDDP arm and the CTX arm, 5-year local control rates were 67% and 48%; 5-year MFS rates were 83% and 97%; 5-year overall survival rates were 61% and 52%; and 5-year cancer-specific survival rates were 70% and 59%, respectively. None of these differences reached statistical significance. A subgroup analysis by HPV status and anatomic subsites revealed that in HPV+ oropharyngeal carcinoma, better survival was obtained in the CDDP arm (although statistical tests were not performed owing to the small sample size). Conversely, no statistically significant differences were observed in HPV- oropharyngeal carcinoma and other anatomic subsites, except for the confirmed better MFS rates of the CTX arm.

CONCLUSIONS

Long-term results are in line with current literature suggesting that RT + CTX is inferior to RT + CDDP for the definitive treatment of LASCCHN. However, if not as an alternative to CDDP, CTX might still play a role in LASCCHN, particularly in HPV- cases.

HPV16 E5 Mediates Resistance to PD-L1 Blockade and Can Be Targeted with Rimantadine in Head and Neck Cancer

There is a critical need to understand mechanisms of resistance and to develop combinatorial strategies to improve responses to checkpoint blockade immunotherapy (CBI). Here, we uncover a novel mechanism by which the human papillomavirus (HPV) inhibits the activity of CBI in head and neck squamous cell carcinoma (HNSCC). Using orthotopic HNSCC models, we show that radiation combined with anti-PD-L1 immunotherapy significantly enhanced local control, CD8⁺ memory T cells, and induced preferential T-cell homing via modulation of vascular endothelial cells. However, the HPV E5 oncoprotein suppressed immune responses by downregulating expression of major histocompatibility complex and interfering with antigen presentation in murine models and patient tumors. Furthermore, tumors expressing HPV E5 were rendered entirely resistant to anti-PD-L1 immunotherapy, and patients with high expression of HPV16 E5 had worse survival. The antiviral E5 inhibitor rimantadine demonstrated remarkable single-agent antitumor activity. This is the first report that describes HPV E5 as a mediator of resistance to anti-PD-1/PD-L1 immunotherapy and demonstrates the antitumor activity of rimantadine. These results have broad clinical relevance beyond HNSCC to other HPV-associated malignancies and reveal a powerful mechanism of HPV-mediated immunosuppression, which can be exploited to improve response rates to checkpoint blockade. SIGNIFICANCE: This study identifies a novel mechanism of resistance to anti-PD-1/PD-L1 immunotherapy mediated by HPV E5, which can be exploited using the HPV E5 inhibitor rimantadine to improve outcomes for head and neck cancer patients. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/4/732/F1.large.jpg.

Inter- and intraobserver agreement of programmed death ligand 1 scoring in head and neck squamous cell carcinoma, urothelial carcinoma and breast carcinoma

AIMS

Programmed death-ligand 1 (PD-L1) expression by tumour cells (TC) is a mechanism for tumour immune escape through down-regulation of antitumour T cell responses and is a target for immunotherapy. PD-L1 status as a predictor of treatment response has led to the development of multiple biomarkers with different reference cut-offs. We assessed pathologist consistency in evaluating PD-L1 immunopositivity by examining the inter- and intraobserver agreement using various antibody clones and different cancer types.

METHODS AND RESULTS

PD-L1 expression in TC and immune cells (IC) was manually scored in 27 head and neck squamous cell carcinoma (HSCC), 30 urothelial carcinoma (UC) and breast carcinoma (BC) using three commercial clones (SP263, SP142, 22C3) and one platform-independent test (E1L3N). For interobserver agreement, PD-L1 status was evaluated blindly by three pathologists. For intraobserver agreement, PD-L1 expression was re-evaluated following a wash-out period. Intraclass correlation coefficient (ICC), overall percentage agreement (OPA) and κ-values were calculated. Using clinical algorithms, the percentage of PD-L1-positive cases in HSCC, BC and UC were 15-81%, 47-67% and 7-43%, respectively. The percentage of PD-L1 positive cases relied heavily on the algorithm/cut-off values used. Almost perfect interobserver agreement was achieved using SP263 and E1L3N in HSCC, 22C3, SP142 and E1L3N in BC and 22C3 in UC. The SP142 clone in UC and HSCC showed moderate agreement and was associated with lower ICC and decreased intraobserver concordance.

CONCLUSIONS

Excellent inter- and intraobserver agreement can be achieved using SP263, 22C3 and E1L3N, whereas PD-L1 scoring using SP142 clone is associated with a higher level of subjectivity.

Re-introducing the same chemotherapy after exposure to anti-PD-1 therapy

Cytotoxic chemotherapy after exposure to nivolumab (nivo), an anti-programmed death-1 (PD-1) antibody, has been associated with good response compared with historical data in various cancers including head and neck squamous cell carcinoma (HNSCC). In a previous report, different chemotherapy regimens were used before and after treatment with nivo. This HNSCC case is the first report of a good response when the same cytotoxic chemotherapy regimen was used before and after nivo. In addition, the efficacy of anti-epidermal growth factor receptor antibody after nivo treatment may be better than without exposure to nivo.

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

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

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

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

Immune Modulation of Head and Neck Squamous Cell Carcinoma and the Tumor Microenvironment by Conventional Therapeutics

Head and neck squamous cell carcinoma (HNSCC) accounts for more than 600,000 cases and 380,000 deaths annually worldwide. Although human papillomavirus (HPV)-associated HNSCCs have better overall survival compared with HPV-negative HNSCC, loco-regional recurrence remains a significant cause of mortality and additional combinatorial strategies are needed to improve outcomes. The primary conventional therapies to treat HNSCC are surgery, radiation, and chemotherapies; however, multiple other targeted systemic options are used and being tested including cetuximab, bevacizumab, mTOR inhibitors, and metformin. In 2016, the first checkpoint blockade immunotherapy was approved for recurrent or metastatic HNSCC refractory to platinum-based chemotherapy. This immunotherapy approval confirmed the critical importance of the immune system and immunomodulation in HNSCC pathogenesis, response to treatment, and disease control. However, although immuno-oncology agents are rapidly expanding, the role that the immune system plays in the mechanism of action and clinical efficacy of standard conventional therapies is likely underappreciated. In this article, we focus on how conventional and targeted therapies may directly modulate the immune system and the tumor microenvironment to better understand the effects and combinatorial potential of these therapies in the context and era of immunotherapy.

Durvalumab: a newly approved checkpoint inhibitor for the treatment of urothelial carcinoma

Until a recent introduction to checkpoint inhibitors, there were limited second-line chemotherapy options for urothelial carcinoma (UC) patients with disease progression after first-line, platinum-based treatment. Outcomes for patients with advanced disease over the past 30 years have highlighted a need for new and better therapy. In response to evolving interest, durvalumab (MEDI4736) was introduced as a potential treatment for advanced stages of UC. Durvalumab is a selective, high-affinity, human IgG1 kappa monoclonal antibody engineered with a triple mutation to reduce toxicity. This checkpoint inhibitor has shown promise in advanced UC and is currently the topic of much discussion in the cancer research community. This review article will explore the details surrounding durvalumab, while also giving a brief overview of additional immunotherapeutic agents utilized for UC.

The impact of margin reduction on outcome and toxicity in head and neck cancer patients treated with image-guided volumetric modulated arc therapy (VMAT)

BACKGROUND AND PURPOSE

In recent decades, outcomes of patients with head and neck cancer (HNC) have improved as a result of implementing several strategies, such as chemoradiation. However, these improvements were achieved at the cost of increased toxicity. One way to reduce radiation-related toxicity is by reducing the margins.

MATERIALS AND METHODS

Between 2013 and 2016, 206 consecutive patients were treated with CTV-PTV margin of 5 mm and subsequently 208 patients with 3 mm margin. This study evaluates the impact of reducing clinical target volume (CTV) to planning target volume (PTV) margin on outcome and toxicity.

RESULTS

All patients were treated with volumetric modulated arc therapy (VMAT) with daily-image guidance using cone-beam CT (CBCT). Overall acute grade 3 toxicity was significantly lower in 3 mm-group, compared to 5 mm-group (53.8% vs. 65%, respectively, p = 0.032). The same was true for acute grade 3 mucositis (30.8% vs. 42.2%, p = 0.008) and for acute grade 3 dysphagia (feeding tube-dependence) (22.1% vs. 33.5%, p = 0.026). The incidence of ongoing feeding tube-dependence after 3 months of radiotherapy was 11.1% and 20.4%, respectively (p = 0.012). The 2-year incidence of late grade ≥2 xerostomia was 15.8% and 19.4% (p = 0.8). The 2-year loco-regional control rates of patients treated in 3 mm and 5 mm-groups were 79.9% and 79.2% (p = 1.0). The figures for disease-free survival were 71.5% and 72.7 (p = 0.6) and for overall survival were 75.2% and 75.1% (p = 0.9).

CONCLUSION

Reducing the CTV-PTV margin from 5 to 3 mm combined with daily CBCT-guided VMAT reduced the severity, frequency, and duration of radiation-related toxicity without jeopardizing outcome.