A systematic review of immunotherapy in high-grade glioma: learning from the past to shape future perspectives

High-grade gliomas (HGGs) constitute the most common malignant primary brain tumor with a poor prognosis despite the standard multimodal therapy. In recent years, immunotherapy has changed the prognosis of many cancers, increasing the hope for HGG therapy. We conducted a comprehensive search on PubMed, Scopus, Embase, and Web of Science databases to include relevant studies. This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Fifty-two papers were finally included (44 phase II and eight phase III clinical trials) and further divided into four different subgroups: 14 peptide vaccine trials, 15 dendritic cell vaccination (DCV) trials, six immune checkpoint inhibitor (ICI) trials, and 17 miscellaneous group trials that included both "active" and "passive" immunotherapies. In the last decade, immunotherapy created great hope to increase the survival of patients affected by HGGs; however, it has yielded mostly dismal results in the setting of phase III clinical trials. An in-depth analysis of these clinical results provides clues about common patterns that have led to failures at the clinical level and helps shape the perspective for the next generation of immunotherapies in neuro-oncology.

Baseline immunity predicts prognosis of pancreatic cancer patients treated with WT1 and/or MUC1 peptide-loaded dendritic cell vaccination and a standard chemotherapy

The prognosis of patients with advanced pancreatic cancer is poor despite the recent introduction of immune checkpoint inhibitors. Therefore, the development of new therapeutic approaches is urgently required. In the present phase I/II study, we have evaluated the safety, the efficacy and the prognostic factors of Wilms' tumor 1 (WT1) and/or mucin 1 (MUC1) peptide-loaded dendritic cell (DC) vaccination in combination with a chemotherapy employing gemcitabine plus nab-paclitaxel or a combination chemotherapy regimen consisting of oxaliplatin, irinotecan, fluorouracil and leucovorin (FOLFIRINOX) in patients with advanced or relapsed pancreatic ductal adenocarcinoma (PDAC). Forty-eight eligible patients were enrolled and received the vaccinations approximately every 2-4 weeks at least seven times. No severe adverse events related to the vaccinations were observed. Median progression free survival and overall survival were 8.1 months and 15.1 months, respectively. DC vaccinations augmented tumor specific immunity which might be related to clinical outcome. The multivariate analyses demonstrated that WT1 or MUC1-specific interferonɤ enzyme-linked immunospot number prior to DC vaccination was an independent prognostic factor related to overall survival. These results indicate that DC-based immunotherapy combined with a conventional chemotherapy is safe and has clinical benefits for patients in advanced stage of PDAC. The precise evaluation of the baseline antitumor specific immunity is critical to predict clinical outcome.

Cellular immunotherapy: a clinical state-of-the-art of a new paradigm for cancer treatment

Cancer immunotherapy has opened a new chapter in Medical Oncology. Many novel therapies are under clinical testing and some have already been approved and implemented in cancer treatment protocols. In particular, cellular immunotherapies take advantage of the antitumor capabilities of the immune system. From dendritic cell-based vaccines to treatments centered on genetically engineered T cells, this form of personalized cancer therapy has taken the field by storm. They commonly share the ex vivo genetic modification of the patient's immune cells to generate or induce tumor antigen-specific immune responses. The latest clinical trials and translational research have shed light on its clinical effectiveness as well as on the mechanisms behind targeting specific antigens or unique tumor alterations. This review gives an overview of the clinical developments in immune cell-based technologies predominantly for solid tumors and on how the latest discoveries are being incorporated within the standard of care.

Blood-derived dendritic cell vaccinations induce immune responses that correlate with clinical outcome in patients with chemo-naive castration-resistant prostate cancer

BACKGROUND

Clinical benefit of cellular immunotherapy has been shown in patients with castration-resistant prostate cancer (CRPC). We investigated the immunological response and clinical outcome of vaccination with blood-derived CD1c⁺ myeloid dendritic cells (mDCs; cDC2) and plasmacytoid DCs (pDCs).

METHODS

In this randomized phase IIa trial, 21 chemo-naive CRPC patients received maximally 9 vaccinations with mature mDCs, pDCs or a combination of mDCs plus pDCs. DCs were stimulated with protamine/mRNA and loaded with tumor-associated antigens NY-ESO-1, MAGE-C2 and MUC1. Primary endpoint was the immunological response after DC vaccination, which was monitored in peripheral blood and in T cell cultures of biopsies of post-treatment delayed-type hypersensitivity-skin tests. Main secondary endpoints were safety, feasibility, radiological PFS (rPFS) and overall survival. Radiological responses were assessed by MRIs and contrast-enhanced ⁶⁸Ga-prostate-specific membrane antigen PET/CT, according to RECIST 1.1, PCWG2 criteria and immune-related response criteria.

RESULTS

Both tetramer/dextramer-positive (dm⁺) and IFN-γ-producing (IFN-γ⁺) antigen specific T cells were detected more frequently in skin biopsies of patients with radiological non-progressive disease (5/13 patients; 38%) compared to patients with progressive disease (0/8 patients; 0%). In these patients with vaccination enhanced dm⁺ and IFN-γ⁺ antigen-specific T cells median rPFS was 18.8 months (n = 5) vs. 5.1 months (n = 16) in patients without IFN-γ-producing antigen-specific T cells (p = 0.02). The overall median rPFS was 9.5 months. All DC vaccines were well tolerated with grade 1-2 toxicity.

CONCLUSIONS

Immunotherapy with blood-derived DC subsets was feasible and safe and induced functional antigen-specific T cells. The presence of functional antigen-specific T cells correlated with an improved clinical outcome.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02692976, registered 26 February 2016, retrospectively registered.

Phase I/II Pilot Study of Wilms' Tumor 1 Peptide-Pulsed Dendritic Cell Vaccination Combined With Conventional Chemotherapy in Patients With Head and Neck Cancer

The prognosis of metastatic or relapsed head and neck squamous cell carcinoma (HNSCC) remains poor despite the introduction of immune checkpoint blockade agents. We aimed to investigate the safety and the feasibility of a vaccination with Wilms' tumor 1 peptide-loaded dendritic cells (DCs) and OK-432 adjuvant combined with conventional chemotherapy. Eleven eligible patients with metastatic or relapsed HNSCC were enrolled. No severe adverse events related to a vaccination were observed. Five patients had durable stable disease and six other patients had disease progression after DC vaccination. Median progression-free survival and overall survival was 6.4 months and 12.1 months, respectively. DC vaccination augmented Wilms' tumor 1-specific immunity which might be related to clinical outcome. These results indicate that DC-based immunotherapy combined with a conventional chemotherapy is safe and feasible for patients in advanced stage of HNSCC.

Health-related quality of life analysis in stage III melanoma patients treated with adjuvant dendritic cell therapy

BACKGROUND

Health-related quality of life (HRQoL) is an important issue in the rapidly evolving field of adjuvant treatment for stage III melanoma. Dendritic cell vaccination is one of the adjuvant forms of therapy currently investigated.

METHODS

We enrolled adults with stage III melanoma to receive adjuvant dendritic cell vaccination after a complete radical lymph node dissection. HRQoL assessment was one of the secondary endpoints of this trial and investigated with the EORTC-QLQ-C30 questionnaire at baseline and week 26.

RESULTS

Fifteen patients with a median age of 50 years were included in the study, with twelve evaluable patients on study at time of the second questionnaire. Global health status and role functioning improved clinically relevant with a mean difference of 15 (p = 0.010) and 26 points (p = 0.005), respectively.

DISCUSSION

Despite the small number of patients, we found a clinically relevant improved global health status. Besides, compared to the other investigated therapies, toxicity of dendritic cell vaccination is low, which supports our finding.

CONCLUSION

This is the first description of HRQoL in melanoma patients receiving dendritic cell vaccination. We show the expected improvement in global health status after surgical treatment of stage III melanoma. Thus, adjuvant dendritic cell vaccination does not seem to hamper this improvement, as shown in our small explorative study.

The Dilemma of Cure and Damage in Oligodendroglioma: Ways to Tip the Balance Away from the Damage

Current treatments for oligodendrogliomas are powerful but have a negative impact on the rest of the body. The bone marrow is damaged by the chemotherapeutics, but other parts of the body are also affected. In this paper, the current treatment method and its collateral damage is described. Therefore, therapies are needed that are more effective against the tumor while having less negative effects on the patient’s quality of life. Some potential therapies include optimal removal of the tumor by fluorescent-guided surgery (FGS), intraoperative desorption electrospray ionization-mass spectrometry (DESI-MS), better monitoring of the effects of therapy by pseudo-coloring shades of gray of MRI pictures, and using recent data from RNA sequencing of single cells and immunotherapy. These are all open new ways of treating this tumor. The RNA sequencing of single tumor cells unravels specific tumor antigens present in the differentiation status of the cancer cell. Stem cell antigens were expressed in dividing cells, while hypoxia inducible factor-α (HIF-1α) is expressed in all tumor cells. Cancer stem cell antigens can be loaded on dendritic cells to induce cytotoxic T-cells directed to cancer stem cells. These recent discoveries suggest a better quality of life with the same overall survival.

Vaccination of Urological Cancer Patients With WT1 Peptide-Pulsed Dendritic Cells in Combination With Molecular Targeted Therapy or Conventional Chemotherapy Induces Immunological and Clinical Responses

The prognosis of metastatic or relapsed renal cell carcinoma (RCC) or bladder cancer (BC) remains poor despite the introduction of immune checkpoint blockade agents. We aimed to investigate the safety and the feasibility of a vaccination with WT1 peptide-loaded dendritic cells (DCs) and OK-432 adjuvant combined with molecular targeted therapy or conventional chemotherapy. Five eligible patients with metastatic or relapsed RCC and five eligible patients with BC were enrolled. No severe adverse events related to a vaccination were observed. Seven patients with RCC or non-muscle invasive BC had durable stable disease and three other patients had disease progression after DC vaccination. DC vaccination augmented WT1 specific immunity and the reduction of regulatory T cells which might be related to clinical outcome. These results indicate that DC-based immunotherapy combined with a molecular targeted therapy or a conventional chemotherapy is safe and feasible for patients in advanced stage of RCC or BC.

Recent developments in immunotherapy of acute myeloid leukemia

The advent of new immunotherapeutic agents in clinical practice has revolutionized cancer treatment in the past decade, both in oncology and hematology. The transfer of the immunotherapeutic concepts to the treatment of acute myeloid leukemia (AML) is hampered by various characteristics of the disease, including non-leukemia-restricted target antigen expression profile, low endogenous immune responses, and intrinsic resistance mechanisms of the leukemic blasts against immune responses. However, considerable progress has been made in this field in the past few years.Within this manuscript, we review the recent developments and the current status of the five currently most prominent immunotherapeutic concepts: (1) antibody-drug conjugates, (2) T cell-recruiting antibody constructs, (3) chimeric antigen receptor (CAR) T cells, (4) checkpoint inhibitors, and (5) dendritic cell vaccination. We focus on the clinical data that has been published so far, both for newly diagnosed and refractory/relapsed AML, but omitting immunotherapeutic concepts in conjunction with hematopoietic stem cell transplantation. Besides, we have included important clinical trials that are currently running or have recently been completed but are still lacking full publication of their results.While each of the concepts has its particular merits and inherent problems, the field of immunotherapy of AML seems to have taken some significant steps forward. Results of currently running trials will reveal the direction of further development including approaches combining two or more of these concepts.

Dendritic cell vaccination in melanoma patients: From promising results to future perspectives

Dendritic cells (DCs) play an important role in the induction of antitumor immunity. Therefore, they are used as anti-cancer vaccines in clinical studies in various types of cancer. DC vaccines are generally well tolerated and able to induce antigen-specific T cell responses in melanoma patients. After DC vaccinations, functional tumor-specific T cells are more frequently detected in stage III melanoma patients, as compared to patients with advanced melanoma, indicating that the tumor load influences immunological responses. Furthermore, long-lasting clinical responses were rarely seen in metastatic melanoma patients after DC vaccination. Since more potent treatment options are available, e.g. immune checkpoint inhibitors and targeted therapy, DC vaccination as monotherapy may not be preferred in the treatment of advanced melanoma. However, encouraging results of DC vaccines combined with ipilimumab have been reported in advanced melanoma patients with an objective response rate of 38%. DC vaccines show promising clinical results in stage III patients, although clinical efficacy still needs to be proven in a phase 3 trial. The clinical and immunological results of DC vaccination in stage III melanoma patients might be further improved by using naturally circulating DCs (myeloid DCs and plasmacytoid DCs) and neoantigens to load DCs.

Ipilimumab administered to metastatic melanoma patients who progressed after dendritic cell vaccination

Background: Ipilimumab has proven to be effective in metastatic melanoma patients. The purpose of this study was to determine the efficacy of ipilimumab in advanced melanoma patients who showed progressive disease upon experimental dendritic cell (DC) vaccination. Methods: Retrospective analysis of 48 stage IV melanoma patients treated with ipilimumab after progression upon DC vaccination earlier in their treatment. DC vaccination was given either as adjuvant treatment for stage III disease (n = 18) or for stage IV disease (n = 30). Ipilimumab (3 mg/kg) was administered every 3 weeks for up to 4 cycles. Results: Median time between progression upon DC vaccination and first gift of ipilimumab was 5.4 mo. Progression-free survival (PFS) rates for patients that received ipilimumab after adjuvant DC vaccination, and patients that received DC vaccination for stage IV melanoma, were 35% and 7% at 1 y and 35% and 3% at 2 y, while the median PFS was 2.9 mo and 3.1 mo, respectively. Median overall survival of patients pre-treated with adjuvant DC vaccination for stage III melanoma was not reached versus 8.0 mo (95% CI, 5.2–10.9) in the group pre-treated with DC vaccination for stage IV disease (HR of death, 0.36; p = 0.017). Grade 3 immune-related adverse events occurred in 19% of patients and one death (2%) was related to ipilimumab. Conclusions: Clinical responses to ipilimumab were found in a considerable number of advanced melanoma patients with progression after adjuvant DC vaccination for stage III disease, while the effect was very limited in patients who showed progression after DC vaccination for stage IV disease.

Medical costs of treatment and survival of patients with acute myeloid leukemia in Belgium

The advent of new cell-based immunotherapies for leukemia offers treatment possibilities for certain leukemia subgroups. The wider acceptability of these new technologies in clinical practice will depend on its impact on survival and costs. Due to the small patient groups who have received it, these aspects have remained understudied. This non-randomized single-center study evaluated medical costs and survival for acute myeloid leukemia between 2005 and 2010 in 50 patients: patients treated with induction and consolidation chemotherapy (ICT) alone; patients treated with ICT plus allogeneic hematopoietic stem cell transplantation (HCT), which is the current preferred post-remission therapy in patients with intermediate- and poor-risk AML with few co-morbidities, and patients treated with ICT plus immunotherapy using autologous dendritic cells (DC) engineered to express the Wilms' tumor protein (WT1). Total costs including post- consolidation costs on medical care at the hematology ward and outpatient clinic, pharmaceutical prescriptions, intensive care ward, laboratory tests and medical imaging were analyzed. Survival was markedly better in HCT and DC. HCT and DC were more costly than ICT. The median total costs for HCT and DC were similar. These results need to be confirmed to enable more thorough cost-effectiveness analyses, based on observations from multicenter, randomized clinical trials and preferably using quality-adjusted life-years as an outcome measure.

Current status and perspectives of immune-based therapies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a frequent cancer with a high mortality. For early stage cancer there are potentially curative treatments including local ablation, resection and liver transplantation. However, for more advanced stage disease, there is no optimal treatment available. Even in the case of a "curative" treatment, recurrence or development of a new cancer in the precancerous liver is common. Thus, there is an urgent need for novel and effective (adjuvant) therapies to treat HCC and to prevent recurrence after local treatment in patients with HCC. The unique immune response in the liver favors tolerance, which remains a genuine challenge for conventional immunotherapy in patients with HCC. However, even in this "immunotolerant" organ, spontaneous immune responses against tumor antigens have been detected, although they are insufficient to achieve significant tumor death. Local ablation therapy leads to immunogenic tumor cell death by inducing the release of massive amounts of antigens, which enhances spontaneous immune response. New immune therapies such as dendritic cell vaccination and immune checkpoint inhibition are under investigation. Immunotherapy for cancer has made huge progress in the last few years and clinical trials examining the use of immunotherapy to treat hepatocellular carcinoma have shown some success. In this review, we discuss the current status of and offer some perspectives on immunotherapy for hepatocellular carcinoma, which could change disease progression in the near future.

Cellular immunotherapy in ovarian cancer: Targeting the stem of recurrence

Ovarian cancer is a devastating disease with a high relapse rate. Due to a mostly asymptomatic early stage and lack of early diagnostic tools, the disease is usually diagnosed in a late stage. Surgery and chemotherapy with taxanes and platinum compounds are very effective in reducing tumor burden. However, relapses occur frequently and there is a lack of credible second-line options. Therefore, new treatment modalities are eagerly awaited. The presence and influx of immune cells in the ovarian cancer tumor microenvironment are correlated with survival. High numbers of infiltrating T cells correlate with improved progression free and overall survival, while the presence of regulatory T cells and expression of T cell inhibitory molecules is correlated with a poor prognosis. These data indicate that immunotherapy, especially cell-based immunotherapy could be a promising novel addition to the treatment of ovarian cancer. Here, we review the available data on the immune contexture surrounding ovarian cancer and discuss novel strategies and targets for immunotherapy in ovarian cancer. In the end the addition of immunotherapy to existing therapeutic options could lead to a great improvement in the outcome of ovarian cancer, especially when targeting cancer stem cells.

Restoring immunosurveillance by dendritic cell vaccines and manipulation of the tumor microenvironment

Cancer cells evolve from normal cells throughout life and are usually recognized by our immune system and destroyed, a process called immunosurveillance. Unfortunately, in some instances cancer cells paralyze our immune system, resulting in outgrowth and spreading of the tumor. Understanding the complexity of immunomodulation by tumors is important for the development of therapeutical strategies. Nowadays, various approaches have been developed to enhance anti-tumor immune responses and abrogate the immune dampening effect of the tumor and its surrounding environment, including dendritic cell-based vaccines, therapies to counteract myeloid derived suppressor cell function within the tumor and antagonists of inhibitory signaling pathways to overcome 'immune checkpoints'. The challenge is now to find the right combination of immune based therapies to fully restore immune function and provide a more efficacious and enduring anti-tumor response.

Dendritic cell-based vaccine for the treatment of malignant glioma: a systematic review

OBJECTIVE

Glioblastoma multiforme (GBM) has a poor prognosis. The purpose of this systematic review and meta-analysis was to analyze the outcomes of clinical trials which compared immunotherapy with conventional therapy for the treatment of malignant gliomas.

METHODS

PubMed, Cochrane and Google Scholar databases were searched for relevant studies. The 2-year survival rate was used to evaluate effectiveness of immunotherapy.

RESULTS

Of 171 studies identified, six comparative trials were included in the systematic review. Immunotherapy was associated with a significantly longer OS and 2-year survival compared to conventional therapy.

CONCLUSION

Immunotherapy may improve the survival of patients with GBM.

Vitamin C treatment of mouse bone marrow-derived dendritic cells enhanced CD8(+) memory T cell production capacity of these cells in vivo

Vitamin C has been found to stimulate dendritic cells (DCs) to secrete more IL-12 and thereby drive naïve CD4(+) T cells to differentiate into Th1 cells. In the present study, we evaluated the effect of these vitamin C-treated DCs on CD8(+) T cell differentiation both in vitro and in vivo. Mouse bone marrow-derived DCs were prepared in the presence of GM-CSF and IL-15. With vitamin C treatment, these DCs, when LPS-stimulated, secreted more IL-12p70 and IL-15 than did untreated DCs. And when co-cultured with T cells, they yielded a higher frequency of IFN-γ(+) CD8(+) T cells. Moreover, we found that administering vitamin C-treated and tumor lysate-loaded DCs into mice yielded a higher frequency of CD44(high) CD62L(low) CD8(+) effector and effector memory T cells, which showed an increased ex vivo killing effect of the tumor cells. These DCs also elicited enhanced protective effects against inoculated tumor cells, most probably by way of the increased cytotoxic T cells, as was revealed by the decreased growth of the inoculated tumor cells in these mice. This ex vivo vitamin C treatment effect on DCs can be considered as a strategy for boosting DC vaccination potency against tumors.