Head and neck mucosal melanoma: The United Kingdom national guidelines

The United Kingdom head and neck mucosal melanoma guideline development group used an evidence-based systematic approach to make recommendations in key areas of uncertainty in the field, including accurate diagnosis and staging; the appropriate treatment pathway including surgery, adjuvant radiation and new systemic treatments, such as targeted agents and immunotherapy; and the surveillance of patients after treatment. The guidelines were sent for international peer review and have been accredited by the National Institute for Health and Care Excellence. A summary of key recommendations is presented. The full documents are available on the Melanoma Focus website (https://melanomafocus.com/activities/mucosal-guidelines/mucosal-melanoma-resources/).

Combining BRAF inhibition with oncolytic herpes simplex virus enhances the immune-mediated antitumor therapy of BRAF-mutant thyroid cancer

BACKGROUND

The aggressive clinical behavior of poorly differentiated and anaplastic thyroid cancers (PDTC and ATC) has proven challenging to treat, and survival beyond a few months from diagnosis is rare. Although 30%-60% of these tumors contain mutations in the BRAF gene, inhibitors designed specifically to target oncogenic BRAF have shown limited and only short-lasting therapeutic benefits as single agents, thus highlighting the need for improved treatment strategies, including novel combinations.

METHODS

Using a BRAFV600E-driven mouse model of ATC, we investigated the therapeutic efficacy of the combination of BRAF inhibition and oncolytic herpes simplex virus (oHSV). Analyses of samples from tumor-bearing mice were performed to immunologically characterize the effects of different treatments. These immune data were used to inform the incorporation of immune checkpoint inhibitors into triple combination therapies.

RESULTS

We characterized the immune landscape in vivo following BRAF inhibitor treatment and detected only modest immune changes. We, therefore, hypothesized that the addition of oncolytic virotherapy to BRAF inhibition in thyroid cancer would create a more favorable tumor immune microenvironment, boost the inflammatory status of tumors and improve BRAF inhibitor therapy. First, we showed that thyroid cancer cells were susceptible to infection with oHSV and that this process was associated with activation of the immune tumor microenvironment in vivo. Next, we showed improved therapeutic responses when combining oHSV and BRAF inhibition in vivo, although no synergistic effects were seen in vitro, further confirming that the dominant effect of oHSV in this context was likely immune-mediated. Importantly, both gene and protein expression data revealed an increase in activation of T cells and natural killer (NK) cells in the tumor in combination-treated samples. The benefit of combination oHSV and BRAF inhibitor therapy was abrogated when T cells or NK cells were depleted in vivo. In addition, we showed upregulation of PD-L1 and CTLA-4 following combined treatment and demonstrated that blockade of the PD-1/PD-L1 axis or CTLA-4 further improved combination therapy.

CONCLUSIONS

The combination of oHSV and BRAF inhibition significantly improved survival in a mouse model of ATC by enhancing immune-mediated antitumor effects, and triple combination therapies, including either PD-1 or CTLA-4 blockade, further improved therapy.

Talimogene Laherparepvec and Pembrolizumab in Recurrent or Metastatic Squamous Cell Carcinoma of the Head and Neck (MASTERKEY-232): A Multicenter, Phase 1b Study

PURPOSE

The prognosis for patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) is poor, and only a minority of patients benefit from checkpoint immunotherapy. Talimogene laherparepvec (T-VEC), an oncolytic immunotherapy approved for advanced melanoma, in combination with pembrolizumab may yield enhanced antitumor activity over either agent alone.

PATIENTS AND METHODS

This was a phase Ib/III, multicenter trial testing intratumoral T-VEC combined with intravenous pembrolizumab in R/M HNSCC refractory to platinum-based chemotherapy. For phase Ib, primary endpoint was incidence of dose-limiting toxicity (DLT). Key secondary endpoints included objective response rate and progression-free survival per irRECIST, overall survival, and safety.

RESULTS

Thirty-six patients were enrolled into the phase Ib study. The data cut-off date was August 28, 2018. Median follow-up was 5.8 months (range, 0.3-24.2). One DLT of T-VEC-related fatal arterial hemorrhage was reported. Twenty (55.6%) and 21 (58.3%) patients experienced adverse events (AE) related to T-VEC and pembrolizumab, respectively. Besides the DLT, there were no treatment-related fatal AEs. A confirmed partial response was observed in 5 (13.9%) patients. Ten (27.8%) patients were unevaluable for response due to early death. Median PFS and OS were 3.0 months [95% confidence interval (Cl), 2.0-5.8] and 5.8 months (95% Cl, 2.9-11.4), respectively.

CONCLUSIONS

The combination of T-VEC and pembrolizumab demonstrated a tolerable safety profile in R/M HNSCC. The efficacy with the combination was similar to that with pembrolizumab monotherapy in historical HNSCC studies. Phase III part of this study was not further pursued (ClinicalTrials.gov Identifier: NCT02626000).

STING and IRF3 in stromal fibroblasts enable sensing of genomic stress in cancer cells to undermine oncolytic viral therapy

Cancer-associated fibroblasts (CAFs) perform diverse roles and can modulate therapy responses1. The inflammatory environment within tumours also influences responses to many therapies, including the efficacy of oncolytic viruses2; however, the role of CAFs in this context remains unclear. Furthermore, little is known about the cell signalling triggered by heterotypic cancer cell-fibroblast contacts and about what activates fibroblasts to express inflammatory mediators1,3. Here, we show that direct contact between cancer cells and CAFs triggers the expression of a wide range of inflammatory modulators by fibroblasts. This is initiated following transcytosis of cytoplasm from cancer cells into fibroblasts, leading to the activation of STING and IRF3-mediated expression of interferon-β1 and other cytokines. Interferon-β1 then drives interferon-stimulated transcriptional programs in both cancer cells and stromal fibroblasts and ultimately undermines the efficacy of oncolytic viruses, both in vitro and in vivo. Further, targeting IRF3 solely in stromal fibroblasts restores oncolytic herpes simplex virus function.

Author Correction: STING and IRF3 in stromal fibroblasts enable sensing of genomic stress in cancer cells to undermine oncolytic viral therapy

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

RIPK1-mediated immunogenic cell death promotes anti-tumour immunity against soft-tissue sarcoma

Drugs that mobilise the immune system against cancer are dramatically improving care for many people. Dying cancer cells play an active role in inducing anti-tumour immunity but not every form of death can elicit an immune response. Moreover, resistance to apoptosis is a major problem in cancer treatment and disease control. While the term "immunogenic cell death" is not fully defined, activation of receptor-interacting serine/threonine-protein kinase 1 (RIPK1) can induce a type of death that mobilises the immune system against cancer. However, no clinical treatment protocols have yet been established that would harness the immunogenic potential of RIPK1. Here, we report the first pre-clinical application of an in vivo treatment protocol for soft-tissue sarcoma that directly engages RIPK1-mediated immunogenic cell death. We find that RIPK1-mediated cell death significantly improves local disease control, increases activation of CD8+ T cells as well as NK cells, and enhances the survival benefit of immune checkpoint blockade. Our findings warrant a clinical trial to assess the survival benefit of RIPK1-induced cell death in patients with advanced disease at limb extremities.

Cost-effectiveness analysis of nivolumab for the treatment of squamous cell carcinoma of the head and neck in the United States

Aim: To assess the cost-effectiveness of nivolumab monotherapy for recurrent/metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) in the US.Methods: We constructed a cohort-based partitioned survival model for three health states (progression-free, progressed disease, and death). Using overall survival and progression-free survival data from the nivolumab and investigator's choice (IC) arms of the CheckMate 141 study, the proportion of patients in each health state was estimated by parametric modeling over a 25-year period. Cost, utility, adverse event, and disease management data inputs were obtained from relevant literature and applied to patients in each health state. A scenario analysis was conducted assuming increased uptake of subsequent immunotherapies. A one-way deterministic sensitivity analysis assessed the impact of variation in multiple parameters. A probabilistic sensitivity analysis in which probabilistic distributions were applied to each input during 1,000 model iterations was also conducted.Results: Total costs incurred were higher with nivolumab ($101,552) than with IC ($38,067). Nivolumab was associated with a higher number of life-years (LY; 1.21) and quality-adjusted life-years (QALYs; 0.89), compared with IC (0.68 and 0.42, respectively). The incremental cost-effectiveness ratio for nivolumab compared with IC was $134,438 per QALY, and this remained qualitatively similar when increased uptake of subsequent immunotherapies was assumed ($129,603 per QALY). Sensitivity analyses supported these findings.Conclusions: These results suggest that, at a willingness-to-pay threshold of $150,000 per QALY, nivolumab is a cost-effective option for therapy of SCCHN in the US.

Impact of antibiotic use during curative treatment of locally advanced head and neck cancers with chemotherapy and radiotherapy

BACKGROUND

Pre-clinical evidence suggests reduced efficacy of anticancer treatment in patients exposed to broad-spectrum antibiotics. It is hypothesised that this phenomenon may be explained by the effects of antibiotics on the composition of the microbiota. To assess this in a clinical setting, we analysed the impact of antibiotics in patients with locally advanced head and neck cancer (LAHNC) treated with curative intent with chemotherapy and radiotherapy (RT).

MATERIAL AND METHODS

Retrospective data for LAHNC patients treated with curative intent (245 induction chemotherapy followed by chemoradiation [CRT], 17 surgery followed by post-operative CRT, six CRT, three RT alone and one RT with concurrent cetuximab) were analysed. We evaluated the impact of antibiotics prescribed during primary anti-cancer treatment on progression-free survival (PFS), overall survival (OS) and disease-specific survival (DSS) rates by multivariate Kaplan-Meier and Cox proportional hazards regression analysis.

RESULTS

Among 272 patients, those receiving antibiotics between within 1 week before and 2 weeks after treatment (N = 124) progressed significantly earlier and had lower OS and DSS rates. In the multivariate analysis, administration of antibiotics was independently associated with reduced PFS (hazards ratio [HR] 1.98, P = 0.001), OS (HR 1.85, P = 0.001) and DSS (HR 1.95, P = 0.004). This effect was maintained with independence of reason for prescription, type and time of antibiotic prescription. The negative impact was greater for patients who received two or more courses of antibiotics. Antibiotic treatment was correlated with increased risk of locoregional relapse.

CONCLUSIONS

Our data suggest a negative impact of antibiotic therapy on treatment outcomes following CRT with curative intent in patients with LAHNC. This potential harm should be considered when prescribing broad-spectrum and prophylactic antibiotics for such patients.

Inflammatory microenvironment remodelling by tumour cells after radiotherapy

The development of immune checkpoint inhibitors (ICIs) is revolutionizing the way we think about cancer treatment. Even so, for most types of cancer, only a minority of patients currently benefit from ICI therapies. Intrinsic and acquired resistance to ICIs has focused research towards new combination therapy approaches that seek to increase response rates, the depth of remission and the durability of benefit. In this Review, we describe how radiotherapy, through its immunomodulating effects, represents a promising combination partner with ICIs. We describe how recent research on DNA damage response (DDR) inhibitors in combination with radiotherapy may be used to augment this approach. Radiotherapy can kill cancer cells while simultaneously triggering the release of pro-inflammatory mediators and increasing tumour-infiltrating immune cells - phenomena often described colloquially as turning immunologically 'cold' tumours 'hot'. Here, we focus on new developments illustrating the key role of tumour cell-autonomous signalling after radiotherapy. Radiotherapy-induced tumour cell micronuclei activate cytosolic nucleic acid sensor pathways, such as cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING), and propagation of the resulting inflammatory signals remodels the immune contexture of the tumour microenvironment. In parallel, radiation can impact immunosurveillance by modulating neoantigen expression. Finally, we highlight how tumour cell-autonomous mechanisms might be exploited by combining DDR inhibitors, ICIs and radiotherapy.

The PERK Inhibitor GSK2606414 Enhances Reovirus Infection in Head and Neck Squamous Cell Carcinoma via an ATF4-Dependent Mechanism

Reovirus type 3 Dearing (reovirus) is a tumor-selective oncolytic virus currently under evaluation in clinical trials. Here, we report that the therapeutic efficacy of reovirus in head and neck squamous cell cancer can be enhanced by targeting the unfolded protein response (UPR) kinase, protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK). PERK inhibition by GSK2606414 increased reovirus efficacy in both 2D and 3D models in vitro, while perturbing the normal host cell response to reovirus-induced endoplasmic reticulum (ER) stress. UPR reporter constructs were used for live-cell 3D spheroid imaging. Profiling of eIF2a-ATF4, IRE1a-XBP1, and ATF6 pathway activity revealed a context-dependent increase in eIF2a-ATF4 signaling due to GSK2606414. GSK2606414 blocked eIF2a-ATF4 signaling because of the canonical ER stress agent thapsigargin. In the context of reovirus infection, GSK2606414 induced eIF2a-ATF4 signaling. Knockdown of eIF2a kinases PERK, GCN2, and PKR revealed eIF2a-ATF4 reporter activity was dependent on either PERK or GCN2. Knockdown of ATF4 abrogated the GSK2606414-induced increase in reovirus protein levels, confirming eIF2a-ATF signaling as key to the observed phenotype. Our work identifies a novel approach to enhance the efficacy and replication of reovirus in a therapeutic setting.

Consensus guidelines for the definition, detection and interpretation of immunogenic cell death

Cells succumbing to stress via regulated cell death (RCD) can initiate an adaptive immune response associated with immunological memory, provided they display sufficient antigenicity and adjuvanticity. Moreover, multiple intracellular and microenvironmental features determine the propensity of RCD to drive adaptive immunity. Here, we provide an updated operational definition of immunogenic cell death (ICD), discuss the key factors that dictate the ability of dying cells to drive an adaptive immune response, summarize experimental assays that are currently available for the assessment of ICD in vitro and in vivo, and formulate guidelines for their interpretation.

Immunological impact of cell death signaling driven by radiation on the tumor microenvironment

Therapeutic irradiation of the tumor microenvironment causes differential activation of pro-survival and pro-death pathways in malignant, stromal, endothelial and immune cells, hence causing a profound cellular and biological reconfiguration via multiple, non-redundant mechanisms. Such mechanisms include the selective elimination of particularly radiosensitive cell types and consequent loss of specific cellular functions, the local release of cytokines and danger signals by dying radiosensitive cells, and altered cytokine secretion by surviving radioresistant cells. Altogether, these processes create chemotactic and immunomodulatory cues for incoming and resident immune cells. Here we discuss how cytoprotective and cytotoxic signaling modules activated by radiation in specific cell populations reshape the immunological tumor microenvironment.

Pembrolizumab alone or with chemotherapy versus cetuximab with chemotherapy for recurrent or metastatic squamous cell carcinoma of the head and neck (KEYNOTE-048): a randomised, open-label, phase 3 study

BACKGROUND

Pembrolizumab is active in head and neck squamous cell carcinoma (HNSCC), with programmed cell death ligand 1 (PD-L1) expression associated with improved response.

METHODS

KEYNOTE-048 was a randomised, phase 3 study of participants with untreated locally incurable recurrent or metastatic HNSCC done at 200 sites in 37 countries. Participants were stratified by PD-L1 expression, p16 status, and performance status and randomly allocated (1:1:1) to pembrolizumab alone, pembrolizumab plus a platinum and 5-fluorouracil (pembrolizumab with chemotherapy), or cetuximab plus a platinum and 5-fluorouracil (cetuximab with chemotherapy). Investigators and participants were aware of treatment assignment. Investigators, participants, and representatives of the sponsor were masked to the PD-L1 combined positive score (CPS) results; PD-L1 positivity was not required for study entry. The primary endpoints were overall survival (time from randomisation to death from any cause) and progression-free survival (time from randomisation to radiographically confirmed disease progression or death from any cause, whichever came first) in the intention-to-treat population (all participants randomly allocated to a treatment group). There were 14 primary hypotheses: superiority of pembrolizumab alone and of pembrolizumab with chemotherapy versus cetuximab with chemotherapy for overall survival and progression-free survival in the PD-L1 CPS of 20 or more, CPS of 1 or more, and total populations and non-inferiority (non-inferiority margin: 1·2) of pembrolizumab alone and pembrolizumab with chemotherapy versus cetuximab with chemotherapy for overall survival in the total population. The definitive findings for each hypothesis were obtained when statistical testing was completed for that hypothesis; this occurred at the second interim analysis for 11 hypotheses and at final analysis for three hypotheses. Safety was assessed in the as-treated population (all participants who received at least one dose of allocated treatment). This study is registered at ClinicalTrials.gov, number NCT02358031.

FINDINGS

Between April 20, 2015, and Jan 17, 2017, 882 participants were allocated to receive pembrolizumab alone (n=301), pembrolizumab with chemotherapy (n=281), or cetuximab with chemotherapy (n=300); of these, 754 (85%) had CPS of 1 or more and 381 (43%) had CPS of 20 or more. At the second interim analysis, pembrolizumab alone improved overall survival versus cetuximab with chemotherapy in the CPS of 20 or more population (median 14·9 months vs 10·7 months, hazard ratio [HR] 0·61 [95% CI 0·45-0·83], p=0·0007) and CPS of 1 or more population (12·3 vs 10·3, 0·78 [0·64-0·96], p=0·0086) and was non-inferior in the total population (11·6 vs 10·7, 0·85 [0·71-1·03]). Pembrolizumab with chemotherapy improved overall survival versus cetuximab with chemotherapy in the total population (13·0 months vs 10·7 months, HR 0·77 [95% CI 0·63-0·93], p=0·0034) at the second interim analysis and in the CPS of 20 or more population (14·7 vs 11·0, 0·60 [0·45-0·82], p=0·0004) and CPS of 1 or more population (13·6 vs 10·4, 0·65 [0·53-0·80], p<0·0001) at final analysis. Neither pembrolizumab alone nor pembrolizumab with chemotherapy improved progression-free survival at the second interim analysis. At final analysis, grade 3 or worse all-cause adverse events occurred in 164 (55%) of 300 treated participants in the pembrolizumab alone group, 235 (85%) of 276 in the pembrolizumab with chemotherapy group, and 239 (83%) of 287 in the cetuximab with chemotherapy group. Adverse events led to death in 25 (8%) participants in the pembrolizumab alone group, 32 (12%) in the pembrolizumab with chemotherapy group, and 28 (10%) in the cetuximab with chemotherapy group.

INTERPRETATION

Based on the observed efficacy and safety, pembrolizumab plus platinum and 5-fluorouracil is an appropriate first-line treatment for recurrent or metastatic HNSCC and pembrolizumab monotherapy is an appropriate first-line treatment for PD-L1-positive recurrent or metastatic HNSCC.

FUNDING

Merck Sharp & Dohme.

The transformation of radiation oncology using real-time magnetic resonance guidance: A review

Radiation therapy (RT) is an essential component of effective cancer care and is used across nearly all cancer types. The delivery of RT is becoming more precise through rapid advances in both computing and imaging. The direct integration of magnetic resonance imaging (MRI) with linear accelerators represents an exciting development with the potential to dramatically impact cancer research and treatment. These impacts extend beyond improved imaging and dose deposition. Real-time MRI-guided RT is actively transforming the work flows and capabilities of virtually every aspect of RT. It has the opportunity to change entirely the delivery methods and response assessments of numerous malignancies. This review intends to approach the topic of MRI-based RT guidance from a vendor neutral and international perspective. It also aims to provide an introduction to this topic targeted towards oncologists without a speciality focus in RT. Speciality implications, areas for physician education and research opportunities are identified as they are associated with MRI-guided RT. The uniquely disruptive implications of MRI-guided RT are discussed and placed in context. We further aim to describe and outline important future changes to the speciality of radiation oncology that will occur with MRI-guided RT. The impacts on RT caused by MRI guidance include target identification, RT planning, quality assurance, treatment delivery, training, clinical workflow, tumour response assessment and treatment scheduling. In addition, entirely novel research areas that may be enabled by MRI guidance are identified for future investigation.

International Guideline on Dose Prioritization and Acceptance Criteria in Radiation Therapy Planning for Nasopharyngeal Carcinoma

PURPOSE

The treatment of nasopharyngeal carcinoma requires high radiation doses. The balance of the risks of local recurrence owing to inadequate tumor coverage versus the potential damage to the adjacent organs at risk (OARs) is of critical importance. With advancements in technology, high target conformality is possible. Nonetheless, to achieve the best possible dose distribution, optimal setting of dose targets and dose prioritization for tumor volumes and various OARs is fundamental. Radiation doses should always be guided by the As Low As Reasonably Practicable principle. There are marked variations in practice. This study aimed to develop a guideline to serve as a global practical reference.

METHODS AND MATERIALS

A literature search on dose tolerances and normal-tissue complications after treatment for nasopharyngeal carcinoma was conducted. In addition, published guidelines and protocols on dose prioritization and constraints were reviewed. A text document and preliminary set of variants was circulated to a panel of international experts with publications or extensive experience in the field. An anonymized voting process was conducted to rank the proposed variants. A summary of the initial voting and different opinions expressed by members were then recirculated to the whole panel for review and reconsideration. Based on the comments of the panel, a refined second proposal was recirculated to the same panel. The current guideline was based on majority voting after repeated iteration for final agreement.

RESULTS

Variation in opinion among international experts was repeatedly iterated to develop a guideline describing appropriate dose prioritization and constraints. The percentage of final agreement on the recommended parameters and alternative views is shown. The rationale for the recommendations and the limitations of current evidence are discussed.

CONCLUSIONS

Through this comprehensive review of available evidence and interactive exchange of vast experience by international experts, a guideline was developed to provide a practical reference for setting dose prioritization and acceptance criteria for tumor volumes and OARs. The final decision on the treatment prescription should be based on the individual clinical situation and the patient's acceptance of optimal balance of risk.

Patritumab or placebo, with cetuximab plus platinum therapy in recurrent or metastatic squamous cell carcinoma of the head and neck: A randomised phase II study

BACKGROUND

The fully human monoclonal antibody patritumab blocks HER3 activation, a resistance mechanism to cetuximab, induced by heregulin (HRG). A phase Ib study in recurrent and/or metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN) demonstrated tolerability and tumour response of patritumab + cetuximab + platinum.

METHODS

This was a randomised, double-blind, phase II study of patritumab + cetuximab with platinum-based therapy for first-line treatment of R/M SCCHN (Clinicaltrials.gov identifier: NCT02633800). Patients aged ≥18 years received patritumab or placebo, both combined with cetuximab + cisplatin or carboplatin. Co-primary end-points were progression-free survival (PFS) in the intent-to-treat (ITT) and the high-expression HRG (HRG high) populations.

RESULTS

Eighty-seven patients (n = 43 in the patritumab group; n = 44 in placebo group) enrolled. A median (range) of 6.5 (1-24) patritumab cycles were completed. Median PFS was similar between the patritumab group and placebo group in the ITT population (5.6 versus 5.5 months; hazard ratio [HR] 0.99 [95% confidence interval [CI], 0.6-1.7]; P = 0.96) and HRG-high subgroup (n = 51; 5.6 versus 5.6 months; HR 0.93 [95% CI, 0.5-1.8]; P = 0.82). Median overall survival in the ITT population was also similar (10.0 versus 12.7 months; HR 1.3 [95% CI, 0.69-2.29]; P = 0.46). All patients experienced ≥1 treatment-emergent adverse event (TEAE). Grade ≥III TEAEs were more frequent in the patritumab than the placebo group (84.1% versus 60.5%). The most common grade ≥III patritumab-related TEAE in the patritumab group (20.5% overall) was rash (6.8%).

CONCLUSION

Patritumab + cetuximab + platinum was tolerable but not superior to cetuximab + platinum.

Phase I Trial of an ICAM-1-Targeted Immunotherapeutic-Coxsackievirus A21 (CVA21) as an Oncolytic Agent Against Non Muscle-Invasive Bladder Cancer

PURPOSE

The CANON [CAVATAK in NON-muscle-invasive bladder cancer (NMIBC)] study evaluated a novel ICAM-1-targeted immunotherapeutic-coxsackievirus A21 as a novel oncolytic agent against bladder cancer.

PATIENTS AND METHODS

Fifteen patients enrolled in this "window of opportunity" phase I study, exposing primary bladder cancers to CAVATAK prior to surgery. The first 9 patients received intravesical administration of monotherapy CAVATAK; in the second stage, 6 patients received CAVATAK with a subtherapeutic dose of mitomycin C, known to enhance expression of ICAM-1 on bladder cancer cells. The primary endpoint was to determine patient safety and maximum tolerated dose (MTD). Secondary endpoints were evidence of viral replication, induction of inflammatory cytokines, antitumor activity, and viral-induced changes in resected tissue.

RESULTS

Clinical activity of CAVATAK was demonstrated by induction of tumor inflammation and hemorrhage following either single or multiple administrations of CAVATAK in multiple patients, and a complete resolution of tumor in 1 patient. Whether used alone or in combination with mitomycin C, CAVATAK caused marked inflammatory changes within NMIBC tissue biopsies by upregulating IFN-inducible genes, including both immune checkpoint inhibitory genes (PD-L1 and LAG3) and Th1-associated chemokines, as well as the induction of the innate activator RIG-I, compared with bladder cancer tissue from untreated patients. No significant toxicities were reported in any patient, from either virus or combination therapy.

CONCLUSIONS

The acceptable safety profile of CAVATAK, proof of viral targeting, replication, and tumor cell death together with the virus-mediated increases in "immunological heat" within the tumor microenvironment all indicate that CAVATAK may be potentially considered as a novel therapeutic for NMIBC.

Development of a new fusion-enhanced oncolytic immunotherapy platform based on herpes simplex virus type 1

BACKGROUND

Oncolytic viruses preferentially replicate in tumors as compared to normal tissue and promote immunogenic cell death and induction of host systemic anti-tumor immunity. HSV-1 was chosen for further development as an oncolytic immunotherapy in this study as it is highly lytic, infects human tumor cells broadly, kills mainly by necrosis and is a potent activator of both innate and adaptive immunity. HSV-1 also has a large capacity for the insertion of additional, potentially therapeutic, exogenous genes. Finally, HSV-1 has a proven safety and efficacy profile in patients with cancer, talimogene laherparepvec (T-VEC), an oncolytic HSV-1 which expresses GM-CSF, being the only oncolytic immunotherapy approach that has received FDA approval. As the clinical efficacy of oncolytic immunotherapy has been shown to be further enhanced by combination with immune checkpoint inhibitors, developing improved oncolytic platforms which can synergize with other existing immunotherapies is a high priority. In this study we sought to further optimize HSV-1 based oncolytic immunotherapy through multiple approaches to maximize: (i) the extent of tumor cell killing, augmenting the release of tumor antigens and danger-associated molecular pattern (DAMP) factors; (ii) the immunogenicity of tumor cell death; and (iii) the resulting systemic anti-tumor immune response.

METHODS

To sample the wide diversity amongst clinical strains of HSV-1, twenty nine new clinical strains isolated from cold sores from otherwise healthy volunteers were screened across a panel of human tumor cell lines to identify the strain with the most potent tumor cell killing ability, which was then used for further development. Following deletion of the genes encoding ICP34.5 and ICP47 to provide tumor selectivity, the extent of cell killing and the immunogenicity of cell death was enhanced through insertion of a gene encoding a truncated, constitutively highly fusogenic form of the envelope glycoprotein of gibbon ape leukemia virus (GALV-GP-R-). A number of further armed derivatives of this virus were then constructed intended to further enhance the anti-tumor immune response which was generated following fusion-enhanced, oncolytic virus replication-mediated cell death. These viruses expressed GMCSF, an anti-CTLA-4 antibody-like molecule, CD40L, OX40L and/or 4-1BB, each of which is expected to act predominantly at the site and time of immune response initiation. Expression of these proteins was confirmed by ELISA and/or western blotting. Immunogenic cell death was assessed by measuring the levels of HMGB1 and ATP from cell free supernatants from treated cells, and by measuring the surface expression of calreticulin. GALV-GP-R- mediated cell to cell fusion and killing was tested in a range of tumor cell lines in vitro. Finally, the in vivo therapeutic potential of these viruses was tested using human A549 (lung cancer) and MDA-MB-231(breast cancer) tumor nude mouse xenograft models and systemic anti-tumor effects tested using dual flank syngeneic 4434 (melanoma), A20 (lymphoma) mouse tumor models alone and in combination with a murine anti-PD1 antibody, and 9 L (gliosarcoma) tumors in rats.

RESULTS

The twenty nine clinical strains of HSV-1 isolated and tested demonstrated a broad range of tumor cell killing abilities allowing the most potent strain to be identified which was then used for further development. Oncolytic ability was demonstrated to be further augmented by the expression of GALV-GP-R- in a range of tumor cell lines in vitro and in mouse xenograft models in nude mice. The expression of GALV-GP-R- was also demonstrated to lead to enhanced immunogenic cell death in vitro as confirmed by the increased release of HMGB1 and ATP and increased levels of calreticulin on the cell surface. Experiments using the rat 9 L syngeneic tumor model demonstrated that GALV-GP-R- expression increased abscopal uninjected (anenestic) tumor responses and data using mouse 4434 tumors demonstrated that virus treatment increased CD8+ T cell levels both in the injected and uninjected tumor, and also led to increased expression of PD-L1. A combination study using varying doses of a virus expressing GALV-GP-R- and mGM-CSF and an anti-murine PD1 antibody showed enhanced anti-tumor effects with the combination which was most evident at low virus doses, and also lead to immunological memory. Finally, treatment of mice with derivatives of this virus which additionally expressed anti-mCTLA-4, mCD40L, m4-1BBL, or mOX40L demonstrated enhanced activity, particularly in uninjected tumors.

CONCLUSION

The new HSV-1 based platform described provides a potent and versatile approach to developing new oncolytic immunotherapies for clinical use. Each of the modifications employed was demonstrated to aid in optimizing the potential of the virus to both directly kill tumors and to lead to systemic therapeutic benefit. For clinical use, these viruses are expected to be most effective in combination with other anti-cancer agents, in particular PD1/L1-targeted immune checkpoint blockade. The first virus from this program (expressing GALV-GP-R- and hGM-CSF) has entered clinical development alone and in combination with anti-PD1 therapy in a number of tumor types (NCT03767348).

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

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

Nivolumab versus investigator's choice in patients with recurrent or metastatic squamous cell carcinoma of the head and neck: Efficacy and safety in CheckMate 141 by age

OBJECTIVES

Many patients with squamous cell carcinoma of the head and neck (SCCHN) are ≥65 years old; comorbidities and other age-related factors may affect their ability to tolerate traditional chemotherapy. Nivolumab is the only immunotherapy to significantly improve overall survival (OS) versus investigator's choice (IC) of single-agent chemotherapy at primary analysis in a phase 3 trial (CheckMate 141) in patients with recurrent/metastatic SCCHN post-platinum therapy. In this post hoc analysis, we report efficacy and safety by age.

PATIENTS AND METHODS

Eligible patients were randomized 2:1 to nivolumab 3 mg/kg every 2 weeks (n = 240) or IC (methotrexate, docetaxel, or cetuximab n = 121). The primary endpoint of the trial was OS. For this analysis, outcomes were analyzed by age < 65 and ≥65 years. The data cut-off date was September 2017 (minimum follow-up 24.2 months).

RESULTS

At baseline, 68 patients (28.3%) receiving nivolumab and 45 patients (37.2%) receiving IC were ≥65 years. Baseline characteristics were generally similar across age groups. OS and tumor response benefits with nivolumab versus IC were maintained regardless of age. The 30-month OS rates of 11.2% (<65 years) and 13.0% (≥65 years) with nivolumab were more than tripled versus corresponding IC rates of 1.4% and 3.3%, respectively. The nivolumab arm had a lower rate of treatment-related adverse events versus IC regardless of age, consistent with the overall patient population.

CONCLUSION

In CheckMate 141, nivolumab resulted in a higher survival versus IC in patients <65 and ≥65 years, with a manageable safety profile in both age groups. ClinicalTrials.gov: NCT02105636.

Plasmacytoid dendritic cells orchestrate innate and adaptive anti-tumor immunity induced by oncolytic coxsackievirus A21

BACKGROUND

The oncolytic virus, coxsackievirus A21 (CVA21), has shown promise as a single agent in several clinical trials and is now being tested in combination with immune checkpoint blockade. Combination therapies offer the best chance of disease control; however, the design of successful combination strategies requires a deeper understanding of the mechanisms underpinning CVA21 efficacy, in particular, the role of CVA21 anti-tumor immunity. Therefore, this study aimed to examine the ability of CVA21 to induce human anti-tumor immunity, and identify the cellular mechanism responsible.

METHODS

This study utilized peripheral blood mononuclear cells from i) healthy donors, ii) Acute Myeloid Leukemia (AML) patients, and iii) patients taking part in the STORM clinical trial, who received intravenous CVA21; patients receiving intravenous CVA21 were consented separately in accordance with local institutional ethics review and approval. Collectively, these blood samples were used to characterize the development of innate and adaptive anti-tumor immune responses following CVA21 treatment.

RESULTS

An Initial characterization of peripheral blood mononuclear cells, collected from cancer patients following intravenous infusion of CVA21, confirmed that CVA21 activated immune effector cells in patients. Next, using hematological disease models which were sensitive (Multiple Myeloma; MM) or resistant (AML) to CVA21-direct oncolysis, we demonstrated that CVA21 stimulated potent anti-tumor immune responses, including: 1) cytokine-mediated bystander killing; 2) enhanced natural killer cell-mediated cellular cytotoxicity; and 3) priming of tumor-specific cytotoxic T lymphocytes, with specificity towards known tumor-associated antigens. Importantly, immune-mediated killing of both MM and AML, despite AML cells being resistant to CVA21-direct oncolysis, was observed. Upon further examination of the cellular mechanisms responsible for CVA21-induced anti-tumor immunity we have identified the importance of type I IFN for NK cell activation, and demonstrated that both ICAM-1 and plasmacytoid dendritic cells were key mediators of this response.

CONCLUSION

This work supports the development of CVA21 as an immunotherapeutic agent for the treatment of both AML and MM. Additionally, the data presented provides an important insight into the mechanisms of CVA21-mediated immunotherapy to aid the development of clinical biomarkers to predict response and rationalize future drug combinations.

Abstract 1470: Development & characterization of a new oncolytic immunotherapy platform based on herpes simplex virus type 1

A number of oncolytic viruses have shown single agent clinical activity and evidence of clinical synergy with immune checkpoint blockade. However, not all patients respond, and as yet most of the promising clinical data have been generated in patients with melanoma. With the objective of maximally activating a patient's immune system against their own cancer which will then provide enhanced synergy with anti-PD1/L1 blockade, we developed a new oncolytic immunotherapy platform based on herpes simplex virus (HSV). This has the dual objectives of killing tumor to provide abundant release of tumor antigens, and potently activating immune responses against these antigens once released. To augment the natural ability of the virus to kill tumors and activate the immune system, these viruses are each armed with multiple therapeutic genes. Initially, we screened 29 new clinical strains of HSV isolated from volunteers who suffer from cold sores across a panel of human tumor cell lines to select a candidate for further development. This strain was then engineered to provide tumor selective replication (deletion of the genes encoding ICP34.5 and ICP47) and to express a potent fusogenic glycoprotein (GALV-GP R-). These modifications greatly enhance both local and systemic antitumor effects, increase immunogenic cell death, potently activate anti-tumor immunity, and are synergistic with PD-1 blockade in pre-clinical models. A virus expressing both GALV-GP R- and human GM-CSF is currently in a Phase 1/2 clinical trial in approximately 150 patients as a single-agent and combined with PD1 blockade in four solid tumor types. Further viruses express additional immune-activating proteins expected to act at the site of immune response initiation in tumors and draining lymph nodes, in particular an anti-CTLA-4 antibody-like molecule and immune co-stimulatory pathway-activating ligands. Each of these demonstrated increased activity in pre-clinical models, particularly an enhanced anenestic effect. The anti-CTLA-4 expressing virus (RP2) is targeted to enter clinical trials in the first half of 2019. Thus, a modular approach to oncolytic immunotherapy development can rapidly generate multiple clinical candidates with multiple mechanisms of action intended to act synergistically with other approaches to cancer therapy. The latest pre-clinical data utilizing this platform will be presented.

Citation Format: Suzanne Thomas, Linta Juncheria, Victoria Roulstone, Joan N. Kyula, Howard L. Kaufman, Kevin J. Harrington, Robert S. Coffin. Development & characterization of a new oncolytic immunotherapy platform based on herpes simplex virus type 1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1470.