Immunotherapy response assessment in neuro-oncology: a report of the RANO working group

The ratio of HLA-DR and VNN2+ expression on CD14+ myeloid derived suppressor cells can distinguish glioblastoma from radiation necrosis patients

Glioblastoma (GBM) is the most aggressive and lethal type of brain cancer with a median survival of less than two years even following aggressive treatment (Stupp et al., N Engl J Med 352:987-996, 2005). Among the many challenges in treating patients with this devastating disease is the ability to differentiate Magnetic Resonance Imaging (MRI) images that appear following radiation therapy, often termed "radiation necrosis" from true GBM recurrence. Radiation necrosis (RN) and GBM are very difficult to distinguish and currently only a brain biopsy can conclusively differentiate these pathologies. In the present study, we introduce a differential diagnostic approach using a newly identified Myeloid-Derived Suppressor Cell (MDSC) biomarker, vascular non-inflammatory molecule 2 (VNN2⁺), in combination with expression of traditional HLA-DR on peripheral blood CD14⁺ monocytes isolated from GBM and/or RN patients. We performed proof-of-principle experiments confirming the sensitivity and specificity of this approach based upon the combined expression levels of HLA-DR and VNN2 among CD14⁺ Mo-MDSC, which we called the DR-Vanin Index or DVI. The DVI was able to distinguish GBM from RN patients with a high degree of certainty (n = 18 and n = 6 respectively; p = 0.0004). This novel, quick and inexpensive blood-based liquid biopsy could potentially replace invasive brain biopsies in differentiating GBM from RN patients using a minimally-invasive technique.

A phase II trial of autologous dendritic cell vaccination and radiochemotherapy following fluorescence-guided surgery in newly diagnosed glioblastoma patients

Background

Prognosis of patients with glioblastoma multiforme (GBM) remains dismal, with median overall survival (OS) of about 15 months. It is therefore crucial to search alternative strategies that improve these results obtained with conventional treatments. In this context, immunotherapy seems to be a promising therapeutic option. We hypothesized that the addition of tumor lysate-pulsed autologous dendritic cells (DCs) vaccination to maximal safe resection followed by radiotherapy and concomitant and adjuvant temozolomide could improve patients’ survival.

Methods

We conducted a phase-II clinical trial of autologous DCs vaccination in patients with newly diagnosed patients GBM who were candidates to complete or near complete resection. Candidates were finally included if residual tumor volume was lower than 1 cc on postoperative radiological examination. Autologous DCs were generated from peripheral blood monocytes and pulsed with autologous whole tumor lysate. The vaccination calendar started before radiotherapy and was continued during adjuvant chemotherapy. Progression free survival (PFS) and OS were analyzed with the Kaplan–Meier method. Immune response were assessed in blood samples obtained before each vaccines.

Results

Thirty-two consecutive patients were screened, one of which was a screening failure due to insufficient resection. Median age was 61 years (range 42–70). Karnofsky performance score (KPS) was 90–100 in 29%, 80 in 35.5% and 60–70 in 35.5% of cases. MGMT (O⁶-methylguanine-DNA-methyltransferase) promoter was methylated in 45.2% of patients. No severe adverse effects related to immunotherapy were registered. Median PFS was 12.7 months (CI 95% 7–16) and median OS was 23.4 months (95% CI 16–33.1). Increase in post-vaccination tumor specific immune response after vaccines (proliferation or cytokine production) was detected in 11/27 evaluated patients. No correlation between immune response and survival was found.

Conclusions

Our results suggest that the addition of tumor lysate-pulsed autologous DCs vaccination to tumor resection and combined radio-chemotherapy is feasible and safe. A multicenter randomized clinical trial is warranted to evaluate the potential survival benefit of this therapeutic approach.

Trial registration This phase-II trial was registered as EudraCT: 2009-009879-35 and ClinicalTrials.gov Identifier: NCT01006044 retrospectively registered

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1202-z) contains supplementary material, which is available to authorized users.

Novel Opportunities to Use Radiation Therapy with Immune Checkpoint Inhibitors for Melanoma Management

Immunotherapy has revolutionized the systemic management of numerous malignancies. Nowhere has the proven benefit of these agents in clinical practice been more evident than in the management of advanced melanoma. Numerous preclinical studies have revealed the potential benefit of immune-priming radiotherapy in stimulating tumor-specific immune responses. This signal for immune activation may lead to clinically relevant synergy with immune checkpoint inhibitors against malignant cells. In this review, the authors summarize the current data outlining the role radiation therapy may play in the management of advanced melanoma alongside immune checkpoint inhibitors.

MRI in Glioma Immunotherapy: Evidence, Pitfalls, and Perspectives

Pseudophenomena, that is, imaging alterations due to therapy rather than tumor evolution, have an important impact on the management of glioma patients and the results of clinical trials. RANO (response assessment in neurooncology) criteria, including conventional MRI (cMRI), addressed the issues of pseudoprogression after radiotherapy and concomitant chemotherapy and pseudoresponse during antiangiogenic therapy of glioblastomas (GBM) and other gliomas. The development of cancer immunotherapy forced the identification of further relevant response criteria, summarized by the iRANO working group in 2015. In spite of this, the unequivocal definition of glioma progression by cMRI remains difficult particularly in the setting of immunotherapy approaches provided by checkpoint inhibitors and dendritic cells. Advanced MRI (aMRI) may in principle address this unmet clinical need. Here, we discuss the potential contribution of different aMRI techniques and their indications and pitfalls in relation to biological and imaging features of glioma and immune system interactions.

Pseudoprogression, radionecrosis, inflammation or true tumor progression? challenges associated with glioblastoma response assessment in an evolving therapeutic landscape

The wide variety of treatment options that exist for glioblastoma, including surgery, ionizing radiation, anti-neoplastic chemotherapies, anti-angiogenic therapies, and active or passive immunotherapies, all may alter aspects of vascular permeability within the tumor and/or normal parenchyma. These alterations manifest as changes in the degree of contrast enhancement or T2-weighted signal hyperintensity on standard anatomic MRI scans, posing a potential challenge for accurate radiographic response assessment for identifying anti-tumor effects. The current review highlights the challenges that remain in differentiating true disease progression from changes due to radiation therapy, including pseudoprogression and radionecrosis, as well as immune or inflammatory changes that may occur as either an undesired result of cytotoxic therapy or as a desired consequence of immunotherapies.

Advanced MRI Techniques in the Monitoring of Treatment of Gliomas

OPINION STATEMENT

With advances in treatments and survival of patients with glioblastoma (GBM), it has become apparent that conventional imaging sequences have significant limitations both in terms of assessing response to treatment and monitoring disease progression. Both 'pseudoprogression' after chemoradiation for newly diagnosed GBM and 'pseudoresponse' after anti-angiogenesis treatment for relapsed GBM are well-recognised radiological entities. This in turn has led to revision of response criteria away from the standard MacDonald criteria, which depend on the two-dimensional measurement of contrast-enhancing tumour, and which have been the primary measure of radiological response for over three decades. A working party of experts published RANO (Response Assessment in Neuro-oncology Working Group) criteria in 2010 which take into account signal change on T2/FLAIR sequences as well as the contrast-enhancing component of the tumour. These have recently been modified for immune therapies, which are associated with specific issues related to the timing of radiological response. There has been increasing interest in quantification and validation of physiological and metabolic parameters in GBM over the last 10 years utilising the wide range of advanced imaging techniques available on standard MRI platforms. Previously, MRI would provide structural information only on the anatomical location of the tumour and the presence or absence of a disrupted blood-brain barrier. Advanced MRI sequences include proton magnetic resonance spectroscopy (MRS), vascular imaging (perfusion/permeability) and diffusion imaging (diffusion weighted imaging/diffusion tensor imaging) and are now routinely available. They provide biologically relevant functional, haemodynamic, cellular, metabolic and cytoarchitectural information and are being evaluated in clinical trials to determine whether they offer superior biomarkers of early treatment response than conventional imaging, when correlated with hard survival endpoints. Multiparametric imaging, incorporating different combinations of these modalities, improves accuracy over single imaging modalities but has not been widely adopted due to the amount of post-processing analysis required, lack of clinical trial data, lack of radiology training and wide variations in threshold values. New techniques including diffusion kurtosis and radiomics will offer a higher level of quantification but will require validation in clinical trial settings. Given all these considerations, it is clear that there is an urgent need to incorporate advanced techniques into clinical trial design to avoid the problems of under or over assessment of treatment response.

Neuroimaging of Peptide-based Vaccine Therapy in Pediatric Brain Tumors: Initial Experience

The potential benefits of peptide-based immunotherapy for pediatric brain tumors are under investigation. Treatment-related heterogeneity has resulted in radiographic challenges, including pseudoprogression. Conventional MR imaging has limitations in assessment of different forms of treatment-related heterogeneity, particularly regarding distinguishing true tumor progression from efficacious treatment responses. Advanced neuroimaging techniques, including diffusion magnetic resonance (MR), perfusion MR, and MR spectroscopy, may add value in the assessment of treatment-related heterogeneity. Observations suggest that recent delineation of specific response criteria for immunotherapy of adult brain tumors is likely relevant to the pediatric population and further validation in multicenter pediatric brain tumor peptide-based vaccine studies is warranted.

[Brain tumor immunotherapy: Illusion or hope?]

Immunotherapy has proven efficient for many tumors and is now part of standard of care in many indications. What is the picture for brain tumors? The recent development of anti-CTLA-4 and PD1 immune checkpoint inhibitors, which have the ability to restore T lymphocytes activity, has gathered enthusiasm and is now paving the way towards more complex models of immune system manipulation. These models include, among others, vaccination and adoptive T cell transfer technologies. Complementary to those strategies, molecules capable of reshaping the immune tumor microenvironment are currently being investigated in early phase trials. Indeed, the tumor bed is hostile to anti-tumor immune responses due to many escape mechanisms, and this is particularly true in the context of brain tumors, a master in eliciting immunosuppressive cells and molecules. The goal of this review is to describe the hopes and challenges of brain tumors immunotherapy and to propose an inventory of the current clinical research with specific focus on the therapies targeting the tumor microenvironment.

Immune checkpoint inhibition and its relationship with hypermutation phenoytype as a potential treatment for Glioblastoma

Glioblastoma (GBM) is the most common malignant brain tumour in adults. Current prognosis with standard treatment is poor. Immunotherapy is a new paradigm in tumour management. Specifically, recent advances in the field of immune checkpoint molecules have led to dramatic results in many cancers. Inhibition of one particular, programmed cell death-1 (PD-1) has recently been shown to be highly effective in melanoma and non-small cell lung cancer. There has also been recent data to suggest potential benefit in GBM. There also appears to be a relationship between immune checkpoint inhibition and hypermutation, in particular with the mismatch repair process. In this review we look at the current knowledge of immune checkpoint inhibitors with a focus on the PD-1 pathway. We will also review the evidence of PD-1 inhibition in GBM and the role of hypermutation in PD-1 inhibition.

Comparing available criteria for measuring brain metastasis response to immunotherapy

The response assessment in neuro-oncology (RANO) working group recently proposed standardized response criteria for brain metastases (RANO-BM). We sought to compare RANO-BM to other criteria in an ongoing brain metastasis trial. The first 36 patients enrolled on NCT02085070, an ongoing trial of pembrolizumab for patients with untreated brain metastases, were included in this analysis. As RANO-BM had not been proposed when the protocol was written, response on trial was assessed using an institutional modification of RECIST 1.1 (mRECIST), wherein minimum target brain lesion size was 5 mm in longest diameter and up to five target brain lesions were followed. We here additionally assessed response using standard RECIST 1.1, RANO high-grade glioma (RANO-HGG), and RANO-BM. Comparison between the four criteria sets using cases eligible across the board revealed excellent concordance (kappa statistic > 0.8), with only one discordant case. However, compared to RECIST 1.1 or RANO-BM, using a 5 mm threshold for target brain lesions in mRECIST allowed enrollment of 13 additional patients, five of whom had durable responses. Compared to RANO-HGG, 19 additional patients were enrolled using mRECIST, eight of whom had durable responses. Consequently, this resulted in response rates ranging from 12% with RANO-HGG to 28% with mRECIST. This study supports using a 5 mm threshold for target brain lesions when using high resolution MRI with ≤2 mm slices to facilitate accrual to similar clinical trials and provide earlier access to novel therapies for brain metastasis patients. Concordance among the four criteria studied was otherwise very high.

Current State of Immune-Based Therapies for Glioblastoma

Glioblastoma is one of the most aggressive solid tumors, and, despite treatment options such as surgery, radiation, and chemotherapy, its prognosis remains grim. Novel approaches are needed to improve survival. Immunotherapy has proven efficacy for melanoma, lung cancer, and kidney cancer and is now a focus for glioblastoma. In this article, glioblastoma-mediated immunosuppression will be discussed and two exciting immune approaches, checkpoint inhibitors and viral-based therapies, will be reviewed.

Advanced MRI assessment to predict benefit of anti-programmed cell death 1 protein immunotherapy response in patients with recurrent glioblastoma

INTRODUCTION

We describe the imaging findings encountered in GBM patients receiving immune checkpoint blockade and assess the potential of quantitative MRI biomarkers to differentiate patients who derive therapeutic benefit from those who do not.

METHODS

A retrospective analysis was performed on longitudinal MRIs obtained on recurrent GBM patients enrolled on clinical trials. Among 10 patients with analyzable data, bidirectional diameters were measured on contrast enhanced T1 (pGd-T1WI) and volumes of interest (VOI) representing measurable abnormality suggestive of tumor were selected on pGdT1WI (pGdT1 VOI), FLAIR-T2WI (FLAIR VOI), and ADC maps. Intermediate ADC (IADC) VOI represented voxels within the FLAIR VOI having ADC in the range of highly cellular tumor (0.7-1.1 × 10^-3 mm²/s) (IADC VOI). Therapeutic benefit was determined by tissue pathology and survival on trial. IADC VOI, pGdT1 VOI, FLAIR VOI, and RANO assessment results were correlated with patient benefit.

RESULTS

Five patients were deemed to have received therapeutic benefit and the other five patients did not. The average time on trial for the benefit group was 194 days, as compared to 81 days for the no benefit group. IADC VOI correlated well with the presence or absence of clinical benefit in 10 patients. Furthermore, pGd VOI, FLAIR VOI, and RANO assessment correlated less well with response.

CONCLUSION

MRI reveals an initial increase in volumes of abnormal tissue with contrast enhancement, edema, and intermediate ADC suggesting hypercellularity within the first 0-6 months of immunotherapy. Subsequent stabilization and improvement in IADC VOI appear to better predict ultimate therapeutic benefit from these agents than conventional imaging.

Cancer Imaging in Immunotherapy

Immune therapeutics are revolutionizing cancer treatments. In tandem, new and confounding imaging characteristics have appeared that are distinct from those typically seen with conventional cytotoxic therapies. In fact, only 10% of patients on immunotherapy may show tumor shrinkage, typical of positive responses on conventional therapy. Conversely, those on immune therapies may initially demonstrate a delayed response, transient enlargement followed by tumor shrinkage, stable size, or the appearance of new lesions. New imaging response criteria such as the immune-related Response Evaluation Criteria in Solid Tumors (irRECIST) and immune-related Response Criteria (irRC) are being implemented in many trials. However, FDA approval of emerging therapies including immunotherapies still relies on the current RECIST criteria. In this review, we review the traditional and new imaging response criteria for evaluation of solid tumors and briefly touch on some of the more commonly associated immunotherapy-induced adverse events.

The use of amino acid PET and conventional MRI for monitoring of brain tumor therapy

Routine diagnostics and treatment monitoring of brain tumors is usually based on contrast-enhanced MRI. However, the capacity of conventional MRI to differentiate tumor tissue from posttherapeutic effects following neurosurgical resection, chemoradiation, alkylating chemotherapy, radiosurgery, and/or immunotherapy may be limited. Metabolic imaging using PET can provide relevant additional information on tumor metabolism, which allows for more accurate diagnostics especially in clinically equivocal situations. This review article focuses predominantly on the amino acid PET tracers 11C-methyl-l-methionine (MET), O-(2-[18F]fluoroethyl)-l-tyrosine (FET) and 3,4-dihydroxy-6-[18F]-fluoro-l-phenylalanine (FDOPA) and summarizes investigations regarding monitoring of brain tumor therapy.

Immunotherapy approaches in the treatment of malignant brain tumors

Glioblastoma is the most common malignant primary brain tumor. Despite standard-of-care treatment, consisting of maximal surgical resection followed by chemoradiation, both morbidity and mortality associated with this disease remain very poor. Therefore, there is an urgent need for more efficacious and well tolerated therapies. Advancing knowledge of the intricate interplay between malignant gliomas and the immune system, coupled with the recent launch of immunotherapy research for other cancers, has led to a veritable increase in immunotherapy investigation for glioblastoma and other malignant gliomas. This clinical review highlights the recent breakthroughs in cancer immunotherapy and the complex correlation of the immune system with primary brain tumors, with special attention to multiple immunotherapy modalities currently being investigated for malignant glioma, including peptide vaccines, dendritic cell vaccines, oncolytic viruses, chimeric T-cell receptors, and checkpoint inhibitors. Cancer 2017;123:734-50. © 2016 American Cancer Society.

Clinical PET/MRI in neurooncology: opportunities and challenges from a single-institution perspective

Purpose

Magnetic resonance imaging (MRI) plays a key role in neurooncology, i.e., for diagnosis, treatment evaluation and detection of recurrence. However, standard MRI cannot always separate malignant tissue from other pathologies or treatment-induced changes. Advanced MRI techniques such as diffusion-weighted imaging, perfusion imaging and spectroscopy show promising results in discriminating malignant from benign lesions. Further, supplemental imaging with amino acid positron emission tomography (PET) has been shown to increase accuracy significantly and is used routinely at an increasing number of sites. Several centers are now implementing hybrid PET/MRI systems allowing for multiparametric imaging, combining conventional MRI with advanced MRI and amino acid PET imaging. Neurooncology is an obvious focus area for PET/MR imaging.

Methods

Based on the literature and our experience from more than 300 PET/MRI examinations of brain tumors with ¹⁸F-fluoro-ethyl-tyrosine, the clinical use of PET/MRI in adult and pediatric neurooncology is critically reviewed.

Results

Although the results are increasingly promising, the added value and range of indications for multiparametric imaging with PET/MRI are yet to be established. Robust solutions to overcome the number of issues when using a PET/MRI scanner are being developed, which is promising for a more routine use in the future.

Conclusions

In a clinical setting, a PET/MRI scan may increase accuracy in discriminating recurrence from treatment changes, although sequential same-day imaging on separate systems will often constitute a reliable and cost-effective alternative. Pediatric patients who require general anesthesia will benefit the most from simultaneous PET and MR imaging.

In vivo nanoparticle imaging of innate immune cells can serve as a marker of disease severity in a model of multiple sclerosis

Innate immune cells play a key role in the pathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Current clinical imaging is restricted to visualizing secondary effects of inflammation, such as gliosis and blood-brain barrier disruption. Advanced molecular imaging, such as iron oxide nanoparticle imaging, can allow direct imaging of cellular and molecular activity, but the exact cell types that phagocytose nanoparticles in vivo and how phagocytic activity relates to disease severity is not well understood. In this study we used MRI to map inflammatory infiltrates using high-field MRI and fluorescently labeled cross-linked iron oxide nanoparticles for cell tracking. We confirmed nanoparticle uptake and MR detectability ex vivo. Using in vivo MRI, we identified extensive nanoparticle signal in the cerebellar white matter and circumscribed cortical gray matter lesions that developed during the disease course (4.6-fold increase of nanoparticle accumulation in EAE compared with healthy controls, P < 0.001). Nanoparticles showed good cellular specificity for innate immune cells in vivo, labeling activated microglia, infiltrating macrophages, and neutrophils, whereas there was only sparse uptake by adaptive immune cells. Importantly, nanoparticle signal correlated better with clinical disease than conventional gadolinium (Gd) imaging (r, 0.83 for nanoparticles vs. 0.71 for Gd-imaging, P < 0.001). We validated our approach using the Food and Drug Administration-approved iron oxide nanoparticle ferumoxytol. Our results show that noninvasive molecular imaging of innate immune responses can serve as an imaging biomarker of disease activity in autoimmune-mediated neuroinflammation with potential clinical applications in a wide range of inflammatory diseases.

Melanoma central nervous system metastases: current approaches, challenges, and opportunities

Melanoma central nervous system metastases are increasing, and the challenges presented by this patient population remain complex. In December 2015, the Melanoma Research Foundation and the Wistar Institute hosted the First Summit on Melanoma Central Nervous System (CNS) Metastases in Philadelphia, Pennsylvania. Here, we provide a review of the current status of the field of melanoma brain metastasis research; identify key challenges and opportunities for improving the outcomes in patients with melanoma brain metastases; and set a framework to optimize future research in this critical area.

Advances in immunotherapy for the treatment of glioblastoma

Glioblastoma (GBM) is an aggressive brain tumour, associated with extremely poor prognosis and although there have been therapeutic advances, treatment options remain limited. This review focuses on the use of immunotherapy, harnessing the power of the host's immune system to reject cancer cells. Key challenges in glioma specific immunotherapy as with many other cancers are the limited immunogenicity of the cancer cells and the immunosuppressive environment of the tumour. Although specific antigens have been identified in several cancers; brain tumours, such as GBM, are considered poorly immunogenic. However, as detailed in this review, strategies aimed at circumventing these challenges are showing promise for GBM treatment; including identification of glioma specific antigens and endogenous immune cell activation in an attempt to overcome the immunosuppressive environment which is associated with GBM tumours. An up-to-date summary of current Phase I/II and ongoing Phase III GBM immunotherapy clinical trials is provided in addition to insights into promising preclinical approaches which are focused predominantly on increased induction of Type 1 helper T cell (T_h1) immune responses within patients.

Detecting tumor progression in glioma: current standards and new techniques

INTRODUCTION

The post-treatment monitoring of glioma patients remains an area of active research and development. Conventional imaging with MRI is a highly sensitive modality for detecting and monitoring primary and secondary brain tumors and includes multi-parametric sequences to better characterize the disease. Standardized schemes for measuring response to treatment are in wide clinical use; however, the introduction of new therapeutics have introduced new patterns of response that can confound interpretation of conventional MRI and can cause uncertainty in the proper management following therapy. Areas covered: A summary of current and evolving techniques for assessing glioma response in this era of new therapies that address these challenges are presented in this review. While this review focuses more on clinical and early clinical methodologies for MRI and nuclear medicine techniques some promising pre-clinical techniques are also presented. Expert commentary: While successful single institution results have been widely reported in the literature, any new methodologies must be undertaken in multi-center settings. Additionally, the need for standardization of protocols in quantitative measured are an important area that must be addressed for new and promising techniques to be implemented to a wide array of patients.

Ipilimumab and Bevacizumab in Glioblastoma

The median survival in glioblastoma is just over a year, with no standard second-line therapy. Ipilimumab is an immune checkpoint inhibitor that activates the anti-tumour immune response by cytotoxic T-lymphocyte antigen-4 blockade. There is significant evidence supporting its role in the treatment of malignant melanoma, including in patients with brain metastases. The addition of the anti-angiogenesis agent, bevacizumab, seems to offer additional benefit and limit the immune-related side-effects of ipilimumab in melanoma. To date there have been no clinical trials investigating this combination in glioblastoma. In this single practice case series, 20 patients with glioblastoma were consented for and treated with ipilimumab and bevacizumab in combination. Safety, tolerability and the response to treatment were reviewed for all patients. Three patients were treated after palliative first-line radiotherapy, one patient after first-line chemoradiation and 16 patients were treated with recurrent disease. Sixty-five per cent of patients completed four cycles of 3 weekly ipilimumab therapy, administered with 2 weekly bevacizumab. Radiographic responses for patients with recurrent disease were evaluated by Response Assessment in Neuro-oncology (RANO) criteria; 31% of patients showed a partial response, 31% had stable disease and 38% had disease progression. The treatment combination was well tolerated, with treatment terminated before completion due to adverse events in two patients. Autoimmune toxicity was manageable with systemic corticosteroid therapy. Ipilimumab and bevacizumab in combination show promising activity with a predictable and manageable toxicity profile, warranting further clinical studies.

Perspectives for immunotherapy in endocrine cancer

The fight against cancer has seen major breakthroughs in recent years. More than a decade ago, tyrosine kinase inhibitors targeting constitutively activated signaling cascades within the tumor inaugurated a new era of oncological therapy. Recently, immunotherapy with immune checkpoint inhibitors has started to revolutionize the treatment of several malignancies, most notably malignant melanoma, leading to the renaissance and the long-awaited breakthrough of immunooncology. This review provides an overview of the basis of immunotherapy from its initial concepts of anti-tumor immunity and cell-based therapy to the development of immune checkpoint inhibitors and discusses published studies and the perspectives of immunooncology for the treatment of endocrine malignancies.

A Cancer Research UK First Time in Human Phase I Trial of IMA950 (Novel Multipeptide Therapeutic Vaccine) in Patients with Newly Diagnosed Glioblastoma

PURPOSE

To perform a two-cohort, phase I safety and immunogenicity study of IMA950 in addition to standard chemoradiotherapy and adjuvant temozolomide in patients with newly diagnosed glioblastoma. IMA950 is a novel glioblastoma-specific therapeutic vaccine containing 11 tumor-associated peptides (TUMAP), identified on human leukocyte antigen (HLA) surface receptors in primary human glioblastoma tissue.

EXPERIMENTAL DESIGN

Patients were HLA-A*02-positive and had undergone tumor resection. Vaccination comprised 11 intradermal injections with IMA950 plus granulocyte macrophage colony-stimulating factor (GM-CSF) over a 24-week period, beginning 7 to 14 days prior to initiation of chemoradiotherapy (Cohort 1) or 7 days after chemoradiotherapy (Cohort 2). Safety was assessed according to NCI CTCAE Version 4.0 and TUMAP-specific T-cell immune responses determined. Secondary observations included progression-free survival (PFS), pretreatment regulatory T cell (Treg) levels, and the effect of steroids on T-cell responses.

RESULTS

Forty-five patients were recruited. Related adverse events included minor injection site reactions, rash, pruritus, fatigue, neutropenia and single cases of allergic reaction, anemia and anaphylaxis. Two patients experienced grade 3 dose-limiting toxicity of fatigue and anaphylaxis. Of 40 evaluable patients, 36 were TUMAP responders and 20 were multi-TUMAP responders, with no important differences between cohorts. No effect of pretreatment Treg levels on IMA950 immunogenicity was observed, and steroids did not affect TUMAP responses. PFS rates were 74% at 6 months and 31% at 9 months.

CONCLUSIONS

IMA950 plus GM-CSF was well-tolerated with the primary immunogenicity endpoint of observing multi-TUMAP responses in at least 30% of patients exceeded. Further development of IMA950 is encouraged. Clin Cancer Res; 22(19); 4776-85. ©2016 AACRSee related commentary by Lowenstein and Castro, p. 4760.

A state-of-the-art review and guidelines for tumor treating fields treatment planning and patient follow-up in glioblastoma

Tumor treating fields (TTFields) are an integral treatment modality in the management of glioblastoma and extend overall survival when combined with maintenance temozolomide in newly diagnosed patients. Complexities exist regarding correct selection of imaging sequences with which to perform TTFields treatment planning. Guidelines are warranted first, to facilitate treatment planning standardization across medical disciplines and institutions, to ensure optimal TTFields delivery to the tumor and peritumoral brain zone while maximizing patient safety, and also to mitigate the risk of premature cessation of a potentially beneficial treatment. This summary guideline outlines methods for starting patients on TTFields, for monitoring patient response to therapy and provides a framework for evaluating when therapy should be re-planned, based on the extent of sequential imaging changes.

Response Assessment in Neuro-Oncology Criteria and Clinical Endpoints

The Response Assessment in Neuro-Oncology (RANO) Working Group is an international multidisciplinary group whose goal is to improve response criteria and define endpoints for neuro-oncology trials. The RANO criteria for high-grade gliomas attempt to address the issues of pseudoprogression, pseudoresponse, and nonenhancing tumor progression. Incorporation of advanced MR imaging may eventually help improve the ability of these criteria to define enhancing and nonenhancing disease better. The RANO group has also developed criteria for neurologic response and evaluation of patients receiving immunologic therapies. RANO criteria have been developed for brain metastases and are in progress for meningiomas, leptomeningeal disease, spinal tumors, and pediatric tumors.

Immunological effects of chemotherapy and radiotherapy against brain tumors

INTRODUCTION

The mainstays of brain tumor therapy are surgery, radiotherapy and chemotherapy. Cancer immunotherapy is explored as an additional treatment modality. However, emerging evidence indicates that also radio- and chemotherapy have immunological effects in addition to their cytotoxic and cytostatic activities.

AREA COVERED

We summarize the literature on radio- and chemotherapy-mediated immunological effects in primary and secondary brain tumors and outline open questions within the field. To this end, a literature search was performed using the terms 'brain tumor', 'immune system', 'immunogenic cell death', 'vaccination', 'checkpoint inhibition', 'radiotherapy', 'chemotherapy' and derivations thereof. Expert commentary: Immunological effects of chemo- and radiotherapy in brain tumors involve direct immunogenic modulations of tumor cells, changes of the microenvironment and functional alterations of innate and adaptive immune cells. Each treatment modality can exert various effects that comprise both immune-stimulatory and immunosuppressive mechanisms. A detailed knowledge of these mechanisms is indispensable for an optimal combination of conventional anti-tumor treatments and novel immunotherapeutic approaches.

Cellular immunotherapy for malignant gliomas

INTRODUCTION

Cancer immunotherapy has made much progress in recent years. Clinical trials evaluating a variety of immunotherapeutic approaches are underway in patients with malignant gliomas. Thanks to recent advancements in cell engineering technologies, infusion of ex vivo prepared immune cells have emerged as promising strategies of cancer immunotherapy.

AREAS COVERED

Herein, the authors review recent and current studies using cellular immunotherapies for malignant gliomas. Specifically, they cover the following areas: a) cellular vaccine approaches using tumor cell-based or dendritic cell (DC)-based vaccines, and b) adoptive cell transfer (ACT) approaches, including lymphokine-activated killer (LAK) cells, γδ T cells, tumor-infiltrating lymphocytes (TIL), chimeric antigen receptor (CAR)-T cells and T-cell receptor (TCR) transduced T cells.

EXPERT OPINION

While some of the recent studies have shown promising results, the ultimate success of cellular immunotherapy in brain tumor patients would require improvements in the following areas: 1) feasibility in producing cellular therapeutics; 2) identification and characterization of targetable antigens given the paucity and heterogeneity of tumor specific antigens; 3) the development of strategies to promote effector T-cell trafficking; 4) overcoming local and systemic immune suppression, and 5) proper interpretation of imaging data for brain tumor patients receiving immunotherapy.

Investigational new drugs for brain cancer

INTRODUCTION

Despite substantial improvements in standards of care, the most common aggressive pediatric and adult high-grade gliomas (HGG) carry uniformly fatal diagnoses due to unique treatment limitations, high recurrence rates and the absence of effective treatments following recurrence. Recent advancements in our understanding of the pathophysiology, genetics and epigenetics as well as mechanisms of immune surveillance during gliomagenesis have created new knowledge to design more effective and target-directed therapies to improve patient outcomes.

AREAS COVERED

In this review, the authors discuss the critical genetic, epigenetic and immunologic aberrations found in gliomas that appear rational and promising for therapeutic developments in the presence and future. The current state of the latest therapeutic developments including tumor-specific targeted drug therapies, metabolic targeting, epigenetic modulation and immunotherapy are summarized and suggestions for future directions are offered. Furthermore, they highlight contemporary issues related to the clinical development, such as challenges in clinical trials and toxicities.

EXPERT OPINION

The commitment to understanding the process of gliomagenesis has created a catalogue of aberrations that depict multiple mechanisms underlying this disease, many of which are suitable to therapeutic inhibition and are currently tested in clinical trials. Thus, future treatment endeavors will employ multiple treatment modalities that target disparate tumor characteristics personalized to the patient's individual tumor.

Cancer Immunotherapy for Gliomas: Overview and Future Directions

Immunotherapy has been highlighted because we have obtained much evidence, which includes theoretical backborn as well as favorable results from clinical trials. As immunotherapy gives an apparently different cytotoxic mechanism and a little adverse event, the promising results are getting a lot of attention. In this article, cancer immunotherapy for gliomas is reviewed thoroughly from the literature, focusing on the clinical trial results.

Immune Checkpoint Inhibition for Hypermutant Glioblastoma Multiforme Resulting From Germline Biallelic Mismatch Repair Deficiency

PURPOSE

Recurrent glioblastoma multiforme (GBM) is incurable with current therapies. Biallelic mismatch repair deficiency (bMMRD) is a highly penetrant childhood cancer syndrome often resulting in GBM characterized by a high mutational burden. Evidence suggests that high mutation and neoantigen loads are associated with response to immune checkpoint inhibition.

PATIENTS AND METHODS

We performed exome sequencing and neoantigen prediction on 37 bMMRD cancers and compared them with childhood and adult brain neoplasms. Neoantigen prediction bMMRD GBM was compared with responsive adult cancers from multiple tissues. Two siblings with recurrent multifocal bMMRD GBM were treated with the immune checkpoint inhibitor nivolumab.

RESULTS

All malignant tumors (n = 32) were hypermutant. Although bMMRD brain tumors had the highest mutational load because of secondary polymerase mutations (mean, 17,740 ± standard deviation, 7,703), all other high-grade tumors were hypermutant (mean, 1,589 ± standard deviation, 1,043), similar to other cancers that responded favorably to immune checkpoint inhibitors. bMMRD GBM had a significantly higher mutational load than sporadic pediatric and adult gliomas and all other brain tumors (P < .001). bMMRD GBM harbored mean neoantigen loads seven to 16 times higher than those in immunoresponsive melanomas, lung cancers, or microsatellite-unstable GI cancers (P < .001). On the basis of these preclinical data, we treated two bMMRD siblings with recurrent multifocal GBM with the anti-programmed death-1 inhibitor nivolumab, which resulted in clinically significant responses and a profound radiologic response.

CONCLUSION

This report of initial and durable responses of recurrent GBM to immune checkpoint inhibition may have implications for GBM in general and other hypermutant cancers arising from primary (genetic predisposition) or secondary MMRD.

Immune responses and outcome after vaccination with glioma-associated antigen peptides and poly-ICLC in a pilot study for pediatric recurrent low-grade gliomas

BACKGROUND

Low-grade gliomas (LGGs) are the most common brain tumors of childhood. Although surgical resection is curative for well-circumscribed superficial lesions, tumors that are infiltrative or arise from deep structures are therapeutically challenging, and new treatment approaches are needed. Having identified a panel of glioma-associated antigens (GAAs) overexpressed in these tumors, we initiated a pilot trial of vaccinations with peptides for GAA epitopes in human leukocyte antigen-A2+ children with recurrent LGG that had progressed after at least 2 prior regimens.

METHODS

Peptide epitopes for 3 GAAs (EphA2, IL-13Rα2, and survivin) were emulsified in Montanide-ISA-51 and administered subcutaneously adjacent to intramuscular injections of polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose every 3 weeks for 8 courses, followed by booster vaccines every 6 weeks. Primary endpoints were safety and T-lymphocyte responses against GAA epitopes. Treatment response was evaluated clinically and by MRI.

RESULTS

Fourteen children were enrolled. Other than grade 3 urticaria in one child, no regimen-limiting toxicity was encountered. Vaccination induced immunoreactivity to at least one vaccine-targeted GAA in all 12 evaluable patients: to IL-13Rα2 in 3, EphA2 in 11, and survivin in 3. One child with a metastatic LGG had asymptomatic pseudoprogression noted 6 weeks after starting vaccination, followed by dramatic disease regression with >75% shrinkage of primary tumor and regression of metastatic disease, persisting >57 months. Three other children had sustained partial responses, lasting >10, >31, and >45 months, and one had a transient response.

CONCLUSIONS

GAA peptide vaccination in children with recurrent LGGs is generally well tolerated, with preliminary evidence of immunological and clinical activity.