Enhanced tumor eradication by combining CTLA-4 or PD-1 blockade with CpG therapy. J Immunother. 2010;33:225-235. [PMID: 20445343 DOI: 10.1097/CJI.0b013e3181c01fcb]

Local controlled release of stabilized monoclonal antibodies

Monoclonal antibody (mAb) therapeutics have become widely successful for treatment of any number of diseases. However, for certain hard-to-reach tissues, e.g., eye, brain, tumors, and joints, local delivery is desired and long-term controlled release is necessary to avoid frequent injections and poor patient compliance. If local and sustained exposure of mAbs (or their Fab or nanobody fragments) could be accomplished by injectable polymer long-acting release (LAR) systems, the incredible potential of mAb therapeutics could be extended to additional diseases, e.g., neovascular age-related macular degeneration (wet AMD) and glioblastoma multiforme (GBM). In prior studies, long-acting delivery of mAbs has been limited by the inability to design a delivery system prepared from a biodegradable polymer used in FDA-approved LARs that achieves long-term continuous release of structurally stable and immunoreactive mAb with a low initial burst release that is easily injectable and avoids material build-up upon repeated injection. Here, we present for the first time a long-acting delivery system capable of delivering several different mAbs for multiple indications by developing a novel process to stabilize mAbs through the combination of formulation, micronization and encapsulation conditions, and to control stabilized mAb exposure in vivo for months by formulation with an appropriate biodegradable polymer (poly(lactic-co-glycolic acid) (PLGA)), utilization of a pH- and pore-modifying agent, and development of a novel PLGA coating layer to control osmotic pressure induced by elevated levels of critical co-encapsulated stabilizers, particularly mAb-stabilizing-trehalose. The resulting implants showed long-term efficacy in animal models for both wet AMD and GBM after single local injections. Although much more work needs to be done before their clinical application to these two diseases, the injectable PLGA platform meets several important benchmarks for controlled mAb delivery and can be developed further for delivery of a wide array of mAbs and other cofactors, offering an improved therapeutic option for treating diseases amenable to local antibody therapy. One Sentence Summary: A generalizable injectable biodegradable PLGA implant platform for site-specific and long-term slow and continuous release of stabilized monoclonal antibody drugs demonstrates improved in vivo efficacy for wet AMD and glioblastoma.

Immunotherapeutic strategies to induce inflection in the immune response: therapy for cancer and COVID-19

Cancer has agonized the human race for millions of years. The present decade witnesses biological therapeutics to combat cancer effectively. Cancer Immunotherapy involves the use of therapeutics for manipulation of the immune system by immune agents like cytokines, vaccines, and transfection agents. Recently, this therapeutic approach has got vast attention due to the current pandemic COVID-19 and has been very effective. Concerning cancer, immunotherapy is based on the activation of the host's antitumor response by enhancing effector cell number and the production of soluble mediators, thereby reducing the host's suppressor mechanisms by induction of a tumour killing environment and by modulating immune checkpoints. In the present era, immunotherapies have gained traction and momentum as a pedestal of cancer treatment, improving the prognosis of many patients with a wide variety of haematological and solid malignancies. Food supplements, natural immunomodulatory drugs, and phytochemicals, with recent developments, have shown positive trends in cancer treatment by improving the immune system. The current review presents the systematic studies on major immunotherapeutics and their development for the effective treatment of cancers as well as in COVID-19. The focus of the review is to highlight comparative analytics of existing and novel immunotherapies in cancers, concerning immunomodulatory drugs and natural immunosuppressants, including immunotherapy in COVID-19 patients.

Plasmacytoid Dendritic Cells Mediate CpG-ODN-induced Increase in Survival in a Mouse Model of Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a devastating disease primarily found in women of reproductive age that leads to cystic destruction of the lungs. Recent work has shown that LAM causes immunosuppression and that checkpoint inhibitors can be used as LAM treatment. Toll-like receptor (TLR) agonists can also reactivate immunity, and the TLR9 agonist CpG oligodeoxynucleotide (CpG-ODN) has been effective in treating lung cancer in animal models. In this study, we investigated the use of TLR9 agonist CpG-ODN as LAM immunotherapy in combination with checkpoint inhibitor anti-PD1 and standard of care rapamycin, and determined the immune mechanisms underlying therapeutic efficacy. We used survival studies, flow cytometry, ELISA, and histology to assess immune response and survival after intranasal treatment with CpG-ODN in combination with rapamycin or anti-PD1 therapy in a mouse model of metastatic LAM. We found that local administration of CpG-ODN enhances survival in a mouse model of LAM. We found that a lower dose led to longer survival, likely because of fewer local side effects, but increased LAM nodule count and size compared with the higher dose. CpG-ODN treatment also reduced regulatory T cells and increased the number of T-helper type 17 cells as well as cytotoxic T cells. These effects appear to be mediated in part by plasmacytoid dendritic cells because depletion of plasmacytoid dendritic cells reduces survival and abrogates T-helper type 17 cell response. Finally, we found that CpG-ODN treatment is effective in early-stage and progressive disease and is additive with anti-PD1 therapy and rapamycin. In summary, we have found that TLR9 agonist CpG-ODN can be used as LAM immunotherapy and effectively synergizes with rapamycin and anti-PD1 therapy in LAM.

Spartalizumab in combination with platinum-doublet chemotherapy with or without canakinumab in patients with PD-L1-unselected, metastatic NSCLC

BACKGROUND

Despite promising outcomes of treatment with anti-programmed cell death (PD)-1/PD-ligand (L)1 agents in combination with platinum-doublet chemotherapy (PDC) in the first-line setting, a significant unmet medical need remains in patients with PD-L1-unselected non-small cell lung cancer (NSCLC).

METHODS

This multicenter, open-label, phase 1b study comprising dose-confirmation and dose-expansion parts investigated the combination of spartalizumab and various PDC regimens, with or without canakinumab, in treatment-naïve patients with PD-L1-unselected, metastatic NSCLC. The primary objectives were to determine maximum tolerated dose (MTD) and/or recommended dose for expansion (RDE) of spartalizumab, with or without canakinumab, in combination with PDC in the dose-confirmation part and antitumor activity of spartalizumab in the dose-expansion part.

RESULTS

The MTD/RDE of spartalizumab was 300 mg every 3 weeks (Q3W) when administered with either gemcitabine (1250 mg/m2)/cisplatin (75 mg/m2) (group A; no dose-limiting toxicities [DLTs]), pemetrexed (500 mg/m2)/cisplatin (group B; 2 DLTs: grade 2 posterior reversible encephalopathy syndrome and grade 4 hyponatremia), or paclitaxel (200 mg/m2)/carboplatin area under the curve 6 min*mg/mL (group C; 1 DLT: grade 4 neutropenic colitis). The RDE of canakinumab combined with spartalizumab and pemetrexed/cisplatin (group E; no DLTs) was 200 mg Q3W (no dose-expansion part was initiated). No new safety signals were identified. In groups A, B, C, and E, the overall response rates were 57.6%, 55.3%, 51.5%, and 57.1%, respectively. Group B compared with other groups had the longest median progression-free survival (10.4 months vs. 6.2-7.5 months), overall survival (29.7 months vs. 16.1-21.0 months), and duration of response (30.1 months vs. 6.0-8.2 months).

CONCLUSIONS

The combination of spartalizumab and PDC, with or without canakinumab, was well tolerated across treatment groups. The antitumor activity across treatment groups was comparable with that of pembrolizumab and pemetrexed combination. Canakinumab did not appear to improve the antitumor activity when combined with spartalizumab, pemetrexed and cisplatin.

TRIAL REGISTRATION

The trial was registered in Clinicaltrials.gov with identifier no. NCT03064854. Date of Registration: 06 February 2017.

Plasmacytoid dendritic cells mediate CpG-ODN induced increase in survival in a mouse model of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a devastating disease primarily found in women of reproductive age that leads to cystic destruction of the lungs. Recent work has shown that LAM causes immunosuppression and that checkpoint inhibitors can be used as LAM treatment. Toll-like receptor (TLR) agonists can also re-activate immunity and the TLR9 agonist, CpG-ODN, has been effective in treating lung cancer in animal models. Here we investigate the use of TLR9 agonist CpG-ODN as LAM immunotherapy in combination with checkpoint inhibitor, anti-PD1, standard of care rapamycin and determine the immune mechanisms underlying therapeutic efficacy. We used survival studies, flow cytometry, ELISA, and histology to assess immune response and survival after intranasal treatment with CpG-ODN in combination with rapamycin or anti-PD1 therapy in a mouse model of metastatic LAM. We found that local administration of CpG-ODN enhances survival in a mouse model of LAM. We found that a lower dose led to longer survival likely due to fewer local side effects but increased LAM nodule count and size compared to the higher dose. CpG-ODN treatment also reduced regulatory T cells and increased the number of Th17 helper T cells as well as cytotoxic T cells. These effects appear to be mediated in part by plasmacytoid dendritic cells (pDCs), as depletion of pDCs reduces survival and abrogates Th17 T cell response. Finally, we found that CpG-ODN treatment is effective in early stage and progressive disease and is additive with anti-PD1 therapy and rapamycin. In summary, we have found that TLR9 agonist CpG-ODN can be used as LAM immunotherapy and effectively synergizes with rapamycin and anti-PD1 therapy in LAM.

Critical role of the gut microbiota in immune responses and cancer immunotherapy

The gut microbiota plays a critical role in the progression of human diseases, especially cancer. In recent decades, there has been accumulating evidence of the connections between the gut microbiota and cancer immunotherapy. Therefore, understanding the functional role of the gut microbiota in regulating immune responses to cancer immunotherapy is crucial for developing precision medicine. In this review, we extract insights from state-of-the-art research to decipher the complicated crosstalk among the gut microbiota, the systemic immune system, and immunotherapy in the context of cancer. Additionally, as the gut microbiota can account for immune-related adverse events, we discuss potential interventions to minimize these adverse effects and discuss the clinical application of five microbiota-targeted strategies that precisely increase the efficacy of cancer immunotherapy. Finally, as the gut microbiota holds promising potential as a target for precision cancer immunotherapeutics, we summarize current challenges and provide a general outlook on future directions in this field.

MALT1 inhibition suppresses antigen-specific T cell responses

The aim of this study was to assess the potential use of a selective small molecule MALT1 inhibitor in solid tumor treatment as an immunotherapy targeting regulatory T-cells (Tregs). In vitro, MALT1 inhibition suppressed the proteolytic cleavage of the MALT1-substrate HOIL1 and blocked IL-2 secretion in Jurkat cells. It selectively suppressed the proliferation of PBMC-derived Tregs, with no effect on conventional CD4+T-cells. In vivo, however, no evident anti-tumor effect was achieved by MALT1 inhibition monotherapy or in combination with anti-CTLA4 in the MB49 cancer model. Despite decreased Treg-frequencies in lymph nodes of tumor-bearing animals, intratumoral Treg depletion was not observed. We also showed that MALT1-inhibition caused a reduction of antigen-specific CD8+T-cells in an adoptive T-cell transfer model. Thus, selective targeting of Tregs would be required to improve the immunotherapeutic effect of MALT1-inhibition. Also, various dosing schedules and combination therapy strategies should be carefully designed and evaluated further.

Low-dose Paclitaxel with Pembrolizumab Enhances Clinical and Immunologic Responses in Platinum-refractory Urothelial Carcinoma

PURPOSE

Single-agent checkpoint inhibition is effective in a minority of patients with platinum-refractory urothelial carcinoma; therefore, the efficacy of combining low-dose paclitaxel with pembrolizumab was tested.

MATERIALS AND METHODS

This was a prospective, single-arm phase II trial with key inclusion criteria of imaging progression within 12 months of platinum therapy and Eastern Cooperative Oncology Group ≤1. Treatment was pembrolizumab 200 mg day 1 and paclitaxel 80 mg/m2 days 1 and 8 of a 21-day cycle for up to eight cycles unless progression or unacceptable adverse events (AE). The primary endpoint was overall response rate (ORR) with overall survival (OS), 6-month progression-free survival (PFS), and safety as key secondary endpoints. Change in circulating immune cell populations, plasma, and urinary miRs were evaluated.

RESULTS

Twenty-seven patients were treated between April 2016 and June 2020, with median follow-up of 12.4 months. Baseline median age was 68 years, with 81% men and 78% non-Hispanic White. ORR was 33% by intention to treat and 36% in imaging-evaluable patients with three complete responses. Six-month PFS rate was 48.1% [95% confidence interval (CI): 28.7-65.2] and median OS 12.4 months (95% CI: 8.7 months to not reached). Common ≥ grade 2 possibly-related AEs were anemia, lymphopenia, hyperglycemia, and fatigue; grade 3/4 AEs occurred in 56%, including two immune-mediated AEs (pneumonitis and nephritis). Responding patients had a higher percentage of circulating CD4+IFNγ+ T cells. Levels of some miRs, including plasma miR 181 and miR 223, varied in responders compared with nonresponders.

CONCLUSIONS

The addition of low-dose paclitaxel to pembrolizumab is active and safe in platinum-refractory urothelial carcinoma.

SIGNIFICANCE

We found that combining pembrolizumab with low-dose paclitaxel may be effective in patients with urothelial carcinoma progressing on platinum chemotherapy, with favorable safety profiles.

Association of COVID-19 and Lung Cancer: Short-Term and Long-Term Interactions

Background: COVID-19 has been ravaging the globe for more than three years. Due to systemic immunosuppression of anti-tumor therapy, application of chemotherapy and adverse effects of surgery, the short- and long-term prognosis of cancer patients to COVID-19 are of significant concern. Method: This research included three parts of data. The first part of the data came from the public database that covered Veneto residents. The second part of the data included participants in Guangzhou. The third part of the data was used for MR analysis. We assessed the associations by logistic, linear or Cox regression when appropriate. Result: Lung cancer patients with COVID-19 had shorter progression-free survival (PFS) after COVID-19 (Model II: HR: 3.28, 95% CI: 1.6~6.72; Model III: HR: 3.39, 95% CI: 1.45~7.95), compared with lung cancer patients without COVID-19. Targeted therapy patients recovered from SARS-CoV-2 infection more quickly (Model I: β: -0.58, 95% CI: -0.75~-0.41; Model II: β: -0.59, 95% CI: -0.76~-0.41; Model III: β: -0.57; 95% CI: -0.75~-0.40). Conclusions: PFS in lung cancer patients is shortened by COVID-19. The outcome of COVID-19 in lung cancer patients was not significantly different from that of the healthy population. In lung cancer patients, targeted therapy patients had a better outcome of COVID-19, while chemotherapy patients had the worst.

Comparison of the profiles of first-line PD-1/PD-L1 inhibitors for advanced NSCLC lacking driver gene mutations: a systematic review and Bayesian network meta-analysis

Background

Numerous first-line immune checkpoint inhibitors (ICI) were developed for patients with advanced non-small cell lung cancer (NSCLC) lacking driver gene mutations. However, this group consists of a heterogeneous patient population, for whom the optimal therapeutic choice is yet to be confirmed.

Objective

To identify the best first-line immunotherapy regimen for overall advanced NSCLC patients and different subgroups.

Design

Systematic review and Bayesian network meta-analysis (NMA).

Methods

We searched several databases to retrieve relevant literature. We performed Bayesian NMA for the overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and treatment-related adverse events (tr-AEs) with a grade equal or more than 3 (grade ⩾ 3 tr-AEs). Subgroup analysis was conducted according to programed death ligand 1 (PD-L1) levels, histologic type, central nervous system (CNS) metastases and tobacco use history.

Results

For the PD-L1 non-selective patients, sintilimab plus chemotherapy (sinti-chemo) provided the best OS [hazard ratio (HR) = 0.59, 95% confidence interval (CI):0.42-0.83]. Nivolumab plus bevacizumab plus chemotherapy (nivo-bev-chemo) was comparable to atezolizumab plus bevacizumab plus chemotherapy (atezo-bev-chemo) in prolonging PFS (HR = 0.99, 95% CI: 0.51-1.91). Atezo-bev-chemo remarkably elevated the ORR than chemotherapy (OR = 3.13, 95% CI: 1.51-6.59). Subgroup analysis showed pembrolizumab plus chemotherapy (pembro-chemo) ranked first in OS in subgroups of PD-L1 < 1%, non-squamous, no CNS metastases, with or without smoking history, and ranked second in OS in subgroups of PD-L1 ⩾ 1% and PD-L1 1-49%. Cemiplimab and sugemalimab plus chemotherapy ranked first in OS and PFS for squamous subgroup, respectively. For patients with CNS metastases, nivolumab plus ipilimumab plus chemotherapy (nivo-ipili-chemo) and camrelizumab plus chemotherapy provided the best OS and PFS, respectively.

Conclusions

Sinti-chemo and nivo-bev-chemo were two effective first-line regimens ranked first in OS and PFS for overall patients, respectively. Pembro-chemo was favorable for patients in subgroups of PD-L1 < 1%, PD-L1 ⩾ 1%, PD-L1 1-49%, non-squamous, no CNS metastases, with or without smoking history. Addition of bevacizumab consistently provided with favorable PFS results in patients of all PD-L1 levels. Cemiplimab was the best option in squamous subgroup and nivo-ipili-chemo in CNS metastases subgroup due to their advantages in OS.

Genetic engineering strategies to enhance antitumor reactivity and reduce alloreactivity for allogeneic cell-based cancer therapy

The realm of cell-based immunotherapy holds untapped potential for the development of next-generation cancer treatment through genetic engineering of chimeric antigen receptor (CAR)-engineered T (CAR-T) cell therapies for targeted eradication of cancerous malignancies. Such allogeneic "off-the-shelf" cell products can be advantageously manufactured in large quantities, stored for extended periods, and easily distributed to treat an exponential number of cancer patients. At current, patient risk of graft-versus-host disease (GvHD) and host-versus-graft (HvG) allorejection severely restrict the development of allogeneic CAR-T cell products. To address these limitations, a variety of genetic engineering strategies have been implemented to enhance antitumor efficacy, reduce GvHD and HvG onset, and improve the overall safety profile of T-cell based immunotherapies. In this review, we summarize these genetic engineering strategies and discuss the challenges and prospects these approaches provide to expedite progression of translational and clinical studies for adoption of a universal cell-based cancer immunotherapy.

Tumor response assessment on imaging following immunotherapy

In recent years, various systemic immunotherapies have been developed for cancer treatment, such as monoclonal antibodies (mABs) directed against immune checkpoints (immune checkpoint inhibitors, ICIs), oncolytic viruses, cytokines, cancer vaccines, and adoptive cell transfer. While being estimated to be eligible in 38.5% of patients with metastatic solid or hematological tumors, ICIs, in particular, demonstrate durable disease control across many oncologic diseases (e.g., in melanoma, lung, bladder, renal, head, and neck cancers) and overall survival benefits. Due to their unique mechanisms of action based on T-cell activation, response to immunotherapies is characterized by different patterns, such as progression prior to treatment response (pseudoprogression), hyperprogression, and dissociated responses following treatment. Because these features are not encountered in the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1), which is the standard for response assessment in oncology, new criteria were defined for immunotherapies. The most important changes in these new morphologic criteria are, firstly, the requirement for confirmatory imaging examinations in case of progression, and secondly, the appearance of new lesions is not necessarily considered a progressive disease. Until today, five morphologic (immune-related response criteria (irRC), immune-related RECIST (irRECIST), immune RECIST (iRECIST), immune-modified RECIST (imRECIST), and intra-tumoral RECIST (itRECIST)) criteria have been developed to accurately assess changes in target lesion sizes, taking into account the specific response patterns after immunotherapy. In addition to morphologic response criteria, 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG-PET/CT) is a promising option for metabolic response assessment and four metabolic criteria are used (PET/CT Criteria for Early Prediction of Response to Immune Checkpoint Inhibitor Therapy (PECRIT), PET Response Evaluation Criteria for Immunotherapy (PERCIMT), immunotherapy-modified PET Response Criteria in Solid Tumors (imPERCIST5), and immune PERCIST (iPERCIST)). Besides, there is evidence that parameters on 18F-FDG-PET/CT, such as the standardized uptake value (SUV)max and several radiotracers, e.g., directed against PD-L1, may be potential imaging biomarkers of response. Moreover, the emerge of human intratumoral immunotherapy (HIT-IT), characterized by the direct injection of immunostimulatory agents into a tumor lesion, has given new importance to imaging assessment. This article reviews the specific imaging patterns of tumor response and progression and available imaging response criteria following immunotherapy.

Intratumoral delivery of TransCon™ TLR7/8 Agonist promotes sustained anti-tumor activity and local immune cell activation while minimizing systemic cytokine induction

Background

Intratumoral (IT) delivery of toll-like receptor (TLR) agonists has shown encouraging anti-tumor benefit in preclinical and early clinical studies. However, IT delivery of TLR agonists may lead to rapid effusion from the tumor microenvironment (TME), potentially limiting the duration of local inflammation and increasing the risk of systemic adverse events.

Methods

To address these limitations, TransCon^™ TLR7/8 Agonist—an investigational sustained-release prodrug of resiquimod that uses a TransCon linker and hydrogel technology to achieve sustained and predictable IT release of resiquimod—was developed. TransCon TLR7/8 Agonist was characterized for resiquimod release in vitro and in vivo, in mice and rats, and was assessed for anti-tumor efficacy and pharmacodynamic activity in mice.

Results

Following a single IT dose, TransCon TLR7/8 Agonist mediated potent tumor growth inhibition which was associated with sustained resiquimod release over several weeks with minimal induction of systemic cytokines. TransCon TLR7/8 Agonist monotherapy promoted activation of antigen-presenting cells in the TME and tumor-draining lymph nodes, with evidence of activation and expansion of CD8⁺ T cells in the tumor-draining lymph node and TME. Combination of TransCon TLR7/8 Agonist with systemic immunotherapy further promoted anti-tumor activity in TransCon TLR7/8 Agonist-treated tumors. In a bilateral tumor setting, combination of TransCon TLR7/8 Agonist with systemic IL-2 potentiated tumor growth inhibition in both injected and non-injected tumors and conferred protection against tumor rechallenge following complete regressions.

Conclusions

Our findings show that a single dose of TransCon TLR7/8 Agonist can mediate sustained local release of resiquimod in the TME and promote potent anti-tumor effects as monotherapy and in combination with systemic immunotherapy, supporting TransCon TLR7/8 Agonist as a novel intratumoral TLR agonist for cancer therapy. A clinical trial to evaluate the safety and efficacy of TransCon TLR7/8 Agonist, as monotherapy and in combination with pembrolizumab, in cancer patients is currently ongoing (transcendIT-101; NCT04799054).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02708-6.

Optimization of whole-cell vaccines with CpG/αOX40/cGAMP to strengthen the anti-tumor response of CD4+ T cells in melanomas

Methods

In this study, we developed a strategy for the prevention and therapy of melanoma using a whole-cell vaccine combined with a CpG/αOX40/cGAMP triple adjuvant. The CpG/αOX40/cGAMP triple adjuvant was used to co-culture melanoma cells in vitro to induce immunogenic death of tumor cells. The mixture of inactivated tumor cells and the triple drug was an optimized tumor whole-cell vaccine, which was injected subcutaneously into mice for tumor prevention and therapy. Furthermore, we analyzed the changes of immune cells in spleen and tumor by flow cytometry and immunohistochemistry, and detected the changes of cytokines after vaccine application by cytometric bead array to explore the specific mechanism of vaccine.

Results

In vaccine prevention and therapy experiments, it was observed that the tumor growth was significantly inhibited in the whole-cell vaccine group, and the survival time of mice was significantly prolonged. Flow cytometry results showed that the proportion of CD4+ T cells and CD8+ T cells in tumor of mice in vaccine group was higher than that in control group, especially the CD4+ T cells.

Conclusion

The optimized vaccine has the unique ability to amplify tumor-specific CD4+ T cells, which improves antitumor sensitivity, and has a significant effect on the prevention and therapy of melanoma mice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-022-04117-8.

Strategies for Manipulating T Cells in Cancer Immunotherapy

T cells are attractive targets for the development of immunotherapy to treat cancer due to their biological features, capacity of cytotoxicity, and antigen-specific binding of receptors. Novel strategies that can modulate T cell functions or receptor reactivity provide effective therapies, including checkpoint inhibitor, bispecific antibody, and adoptive transfer of T cells transduced with tumor antigen-specific receptors. T cell-based therapies have presented successful pre-clinical/clinical outcomes despite their common immune-related adverse effects. Ongoing studies will allow us to advance current T cell therapies and develop innovative personalized T cell therapies. This review summarizes immunotherapeutic approaches with a focus on T cells. Anti-cancer T cell therapies are also discussed regarding their biological perspectives, efficacy, toxicity, challenges, and opportunities.

Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer: Progress, Challenges, and Prospects

Non-small cell lung cancer is one of the most common types of malignances worldwide and the main cause of cancer-related deaths. Current treatment for NSCLC is based on surgical resection, chemotherapy, radiotherapy, and targeted therapy, with poor therapeutic effectiveness. In recent years, immune checkpoint inhibitors have applied in NSCLC treatment. A large number of experimental studies have shown that immune checkpoint inhibitors are safer and more effective than traditional therapeutic modalities and have allowed for the development of better guidance in the clinical treatment of advanced NSCLC patients. In this review, we describe clinical trials using ICI immunotherapies for NSCLC treatment, the available data on clinical efficacy, and the emerging evidence regarding biomarkers.

Gut microbiota: impacts on gastrointestinal cancer immunotherapy

The association of gut microbiota with gastrointestinal carcinogenesis has been heavily investigated since the recent advance in sequencing technology. Accumulating evidence has revealed the critical roles of commensal microbes in cancer progression. Given by its importance, emerging studies have focussed on targeting microbiota to ameliorate therapeutic effectiveness. It is now clear that the microbial community is closely related to the efficacy of chemotherapy, while the correlation of microbiota with immunotherapy is much less studied. Herein, we review the up-to-date findings on the influence of gut microbiota on three common immunotherapies including adoptive cell transfer, immune checkpoint blockade, and CpG-oligodeoxynucleotide therapy. We then explore three microbiota-targeted strategies that may improve treatment efficacy, involving dietary intervention, probiotics supplementation, and fecal microbiota transplantation.

Potentiating Vγ9Vδ2 T cell proliferation and assessing their cytotoxicity towards adherent cancer cells at the single cell level

Vγ9Vδ2 T cells is the dominant γδ T cell subset in human blood. They are cytotoxic and activated by phosphoantigens whose concentrations are increased in cancer cells, making the cancer cells targets for Vγ9Vδ2 T cell immunotherapy. For successful immunotherapy, it is important both to characterise Vγ9Vδ2 T cell proliferation and optimise the assessment of their cytotoxic potential, which is the aim of this study. We found that supplementation with freshly-thawed human serum potentiated Vγ9Vδ2 T cell proliferation from peripheral mononuclear cells (PBMCs) stimulated with (E)-4-Hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) and consistently enabled Vγ9Vδ2 T cell proliferation from cryopreserved PBMCs. In cryopreserved PBMCs the proliferation was higher than in freshly prepared PBMCs. In a panel of short-chain prenyl alcohols, monophosphates and diphosphates, most diphosphates and also dimethylallyl monophosphate stimulated Vγ9Vδ2 T cell proliferation. We developed a method where the cytotoxicity of Vγ9Vδ2 T cells towards adherent cells is assessed at the single cell level using flow cytometry, which gives more clear-cut results than the traditional bulk release assays. Moreover, we found that HMBPP enhances the Vγ9Vδ2 T cell cytotoxicity towards colon cancer cells. In summary we have developed an easily interpretable method to assess the cytotoxicity of Vγ9Vδ2 T cells towards adherent cells, found that Vγ9Vδ2 T cell proliferation can be potentiated media-supplementation and how misclassification of non-responders may be avoided. Our findings will be useful in the further development of Vγ9Vδ2 T cell immunotherapy.

Paliperidone Inhibits Glioblastoma Growth in Mouse Brain Tumor Model and Reduces PD-L1 Expression

Simple Summary

The present study showed that a prescribed psychotropic medicine paliperidone inhibits GBM growth and prolongs survival in mouse brain tumor model and decreased the programmed death ligand 1 expression. Using the 3D co-culture also found that dopamine receptor D2 regulates the interaction of GBM-macrophage-induced PD-L1 expression in GBMs. In addition, the expression of DRD2 and PD-L1 in GBM modulates tumor-associated macrophage polarization. Our results also indicated that there is a contact-independent mechanism of PD-L1 induction in GBM upon interaction between GBM and monocytes. The present study also found that the interaction of GBM-macrophage-enhanced PD-L1 expression in GBM occurred by modulating the ERK and STAT3 signaling pathways. In addition, the inhibition of DRD2 reduces the upregulation of PD-1 expression, and it is regulating signaling in GBM.

Abstract

A previous study from our group reported that monocyte adhesion to glioblastoma (GBM) promoted tumor growth and invasion activity and increased tumor-associated macrophages (TAMs) proliferation and inflammatory mediator secretion as well. The present study showed that prescribed psychotropic medicine paliperidone reduced GBM growth and immune checkpoint protein programmed death ligand (PD-L)1 expression and increased survival in an intracranial xenograft mouse model. An analysis of the database of patients with glioma showed that the levels of PD-L1 and dopamine receptor D (DRD)2 were higher in the GBM group than in the low grade astrocytoma and non-tumor groups. In addition, GFP expressing GBM (GBM-GFP) cells co-cultured with monocytes-differentiated macrophage enhanced PD-L1 expression in GBM cells. The enhancement of PD-L1 in GBM was antagonized by paliperidone and risperidone as well as DRD2 selective inhibitor L741426. The expression of CD206 (M2 phenotype marker) was observed to be markedly increased in bone marrow-derived macrophages (BMDMs) co-cultured with GBM. Importantly, treatment with paliperidone effectively decreased CD206 and also dramatically increased CD80 (M1 phenotype marker) in BMDMs. We have previously established a PD-L1 GBM-GFP cell line that stably expresses PD-L1. Experiments showed that the expressions of CD206 was increased and CD80 was mildly decreased in the BMDMs co-cultured with PD-L1 GBM-GFP cells. On the other hands, knockdown of DRD2 expression in GBM cells dramatically decreased the expression of CD206 but markedly increased CD80 expressions in BMDMs. The present study suggests that DRD2 may be involved in regulating the PD-L1 expression in GBM and the microenvironment of GBM. Our results provide a valuable therapeutic strategy and indicate that treatments combining DRD2 antagonist paliperidone with standard immunotherapy may be beneficial for GBM treatment.

Macrophages Impair TLR9 Agonist Antitumor Activity through Interacting with the Anti-PD-1 Antibody Fc Domain

Simple Summary

We evaluated the contribution of macrophages to the effect of combinatorial immunotherapeutic treatments based on TLR9 stimulation (with CpG-ODNs) and PD-1 blockade in an ovarian cancer preclinical model. We observed a strong reduction in the antitumor efficacy of a TLR9 agonist upon anti-PD-1 antibody administration. Specifically, we found that TLR9-stimulated macrophages, through interacting with the fragment crystallizable (Fc) domain of the anti-PD-1 antibody, acquire an immunoregulatory phenotype leading to dampening of CpG-ODN antitumor effect. Since the stimulation of macrophage TLRs can be achieved not only by synthetic agonists but also by molecules present in the tumor microenvironment, the data we are presenting may represent another possible mechanism of anti-PD-1 antibody therapy resistance. Indeed, it is possible that when delivered as a monotherapy, anti-PD-1 antibody Fc domain may interact with macrophages in which TLR signaling has already been triggered by endogenous ligands, mirroring the biological effects described in the present study.

Abstract

Background. A combination of TLR9 agonists and an anti-PD-1 antibody has been reported to be effective in immunocompetent mice but the role of innate immunity has not yet been completely elucidated. Therefore, we investigated the contribution of the innate immune system to this combinatorial immunotherapeutic regimens using an immunodeficient mouse model in which the effector functions of innate immunity can clearly emerge without any interference from T lymphocytes. Methods. Athymic mice xenografted with IGROV-1 human ovarian cells, reported to be sensitive to TLR9 agonist therapy, were treated with cytosine–guanine (CpG)-oligodeoxynucleotides (ODNs), an anti-PD-1 antibody or their combination. Results. We found that PD-1 blockade dampened CpG-ODN antitumor activity. In vitro studies indicated that the interaction between the anti-PD-1 antibody fragment crystallizable (Fc) domain and macrophage Fc receptors caused these immune cells to acquire an immunoregulatory phenotype, contributing to a decrease in the efficacy of CpG-ODNs. Accordingly, in vivo macrophage depletion abrogated the detrimental effect exerted by the anti-PD-1 antibody. Conclusion. Our data suggest that if TLR signaling is active in macrophages, coadministration of an anti-PD-1 antibody can reprogram these immune cells towards a polarization state able to negatively affect the immune response and eventually promote tumor growth.

Ex vivo dendritic cell-based (DC) vaccine pulsed with a low dose of liposomal antigen and CpG-ODN improved PD-1 blockade immunotherapy

Lack of pre-existing tumor infiltrated T cells resulting in resistance to programmed cell death protein 1 (PD-1) blockade therapies can be solved by combining with anti-cancer vaccines and CpG-ODN in increasing T cell expansion and infiltration. Therefore, we prepared an ex vivo dendritic cell-based (DC) vaccine pulsed with a low dose of either liposomal or non-liposomal gp100 antigen (2.8 µg) plus CpG-ODN (800 ng) formulations and evaluated its anti-tumor activity in combination with anti-PD-1 therapy. Our results showed a combination of liposomal peptide plus CpG-ODN pulsed DC with anti-PD-1 antibody was more efficacious, as evidenced by a significant increase in T_eff/T_reg TILs with a marked fourfold elevation of IFN-γ expression level in the tumor site of treated mice which reversed resistance to PD-1 blockade in a CD8 T cell-dependent manner. Furthermore, this combination also led to a remarkable tumor remission and prolonged survival rate in melanoma-bearing mice compared to non-liposomal peptide plus CpG-ODN or single-treated liposomal peptide formulations. Our results provide essential insights to devise combining regimens to improve the efficacy of immune checkpoint blockers even by a low dose of peptide and CpG-ODN.

Single-cell RNAseq and longitudinal proteomic analysis of a novel semi-spontaneous urothelial cancer model reveals tumor cell heterogeneity and pretumoral urine protein alterations

Bladder cancer, one of the most prevalent malignancies worldwide, remains hard to classify due to a staggering molecular complexity. Despite a plethora of diagnostic tools and therapies, it is hard to outline the key steps leading up to the transition from high-risk non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC). Carcinogen-induced murine models can recapitulate urothelial carcinogenesis and natural anti-tumor immunity. Herein, we have developed and profiled a novel model of progressive NMIBC based on 10 weeks of OH-BBN exposure in hepatocyte growth factor/cyclin dependent kinase 4 (R24C) (Hgf-Cdk4R24C) mice. The profiling of the model was performed by histology grading, single cell transcriptomic and proteomic analysis, while the derivation of a tumorigenic cell line was validated and used to assess in vivo anti-tumor effects in response to immunotherapy. Established NMIBC was present in females at 10 weeks post OH-BBN exposure while neoplasia was not as advanced in male mice, however all mice progressed to MIBC. Single cell RNA sequencing analysis revealed an intratumoral heterogeneity also described in the human disease trajectory. Moreover, although immune activation biomarkers were elevated in urine during carcinogen exposure, anti-programmed cell death protein 1 (anti-PD1) monotherapy did not prevent tumor progression. Furthermore, anti-PD1 immunotherapy did not control the growth of subcutaneous tumors formed by the newly derived urothelial cancer cell line. However, treatment with CpG-oligodeoxynucleotides (ODN) significantly decreased tumor volume, but only in females. In conclusion, the molecular map of this novel preclinical model of bladder cancer provides an opportunity to further investigate pharmacological therapies ahead with regards to both targeted drugs and immunotherapies to improve the strategies of how we should tackle the heterogeneous tumor microenvironment in urothelial bladder cancer to improve responses rates in the clinic.

Tumor hypoxia-activated combinatorial nanomedicine triggers systemic antitumor immunity to effectively eradicate advanced breast cancer

Hypoxia is a major obstacle towards successful cancer treatment, due to the hypoxia-mediated resistance to radiotherapy and chemotherapy, as well as immunosuppression. Therefore, engineering hypoxia-sensitive cytotoxic and immunogenic nanomedicines would promote the therapeutic efficacy. In this study, we developed novel tumor-targeted polymeric micelles sensing hypoxia in tumors to activate strong cytotoxicity and immunogenic responses for effectively eradicating advanced breast cancer. The hypoxia-activatable polymeric micelles could efficiently deliver anticancer drugs and photosensitizers into cancer cells, to trigger synergistic cytotoxicity and immunogenic cell death through chemotherapy and photodynamic therapy (PDT)/photothermal therapy (PTT). The long-circulating micelles efficiently delivered drugs to triple negative 4T1 breast tumors for accurate tumor diagnosis by photoacoustic imaging (PA), and effectively eliminating primary tumors without recurrence, including hypoxic 4T1 tumors. In addition, the micelle-based eradication of primary tumors could elicit robust systemic immune responses to inhibit tumor recurrence and significantly suppress distant 4T1 tumors and lung metastasis by combining with CpG and aCTLA4. These results indicate the high performance of our innovative multifunctional micelles for synergistic therapy against tumor malignancy, bringing opportunity for effectively dealing with disseminated and metastatic tumors.

CpG Oligonucleotides as Vaccine Adjuvants

CpG Oligonucleotides (ODN) are immunomodulatory synthetic oligonucleotides specifically designed to stimulate Toll-like receptor 9. TLR9 is expressed on human plasmacytoid dendritic cells and B cells and triggers an innate immune response characterized by the production of Th1 and pro-inflammatory cytokines. This chapter reviews recent progress in understanding the mechanism of action of CpG ODN and provides an overview of human clinical trial results using CpG ODN to improve vaccines for the prevention/treatment of cancer, allergy, and infectious disease.

Improving Anti-PD-1/PD-L1 Therapy for Localized Bladder Cancer

In high-risk non-muscle invasive bladder cancer (HR-NMIBC), patient outcome is negatively affected by lack of response to Bacillus-Calmette Guérin (BCG) treatment. Lack of response to cisplatin-based neoadjuvant chemotherapy and cisplatin ineligibility reduces successful treatment outcomes in muscle-invasive bladder cancer (MIBC) patients. The effectiveness of PD-1/PD-L1 immune checkpoint inhibitors (ICI) in metastatic disease has stimulated its evaluation as a treatment option in HR-NMIBC and MIBC patients. However, the observed responses, immune-related adverse events and high costs associated with ICI have provided impetus for the development of methods to improve patient stratification, enhance anti-tumorigenic effects and reduce toxicity. Here, we review the challenges and opportunities offered by PD-1/PD-L1 inhibition in HR-NMIBC and MIBC. We highlight the gaps in the field that need to be addressed to improve patient outcome including biomarkers for response stratification and potentially synergistic combination therapy regimens with PD-1/PD-L1 blockade.

Efficacy of immune-checkpoint inhibitors in PD-L1 selected or unselected patients vs. control group in patients with advanced or metastatic urothelial carcinoma

Most patients with advanced or metastatic urothelial carcinoma do not benefit significantly from Immune checkpoint inhibitors (ICIs) use. A systematic review and meta-analysis of randomized controlled trials to assess the efficacy and activity of ICIs, in terms of Overall Survival (OS), Progression-free survival (PFS), and Objective Response Rate (ORR). We systematically searched for articles from PubMed, Cochrane Library, Embase, and Web of science from their inception to December 1, 2020 with no language restrictions. The search was performed to identify all clinical trials (phase I, phase II, phase III) of ICIs for treating urothelial carcinoma. The endpoints of the meta-analysis were OS, PFS, and ORR, compared unselected patients and in the subgroup of patients characterized by high expression of PD-L1 (PD-L1 selected patients). Sixteen studies comprising 5559 patients were identified, of which data for OS comparison were available from 4 RCTs (2342 patients), two studies for PFS (649 patients), and four RCTs were eligible for ORR analysis (2921 patients). Both pembrolizumab and atezolizumab have showed to improve OS compared to chemotherapy in unselected patients (HR 0.86, 95% CI 0.80-0.93, P = .0001, I2 = 60%), while the difference was not significant in PD-L1 selected patients (HR 0.91, 95% CI 0.77-1.07, P = .23, I2 = 0%). PFS difference was not observed in neither unselected population nor PD-L1 selected patients, the pooled HR of PFS for immunotherapy compared to control treatment was 1.05 (95% CI 0.74-1.49, P = .79, I2 = 85%) and 0.84 (95% CI 0.68-1.03, P = .09, I2 = 0%, respectively. Similar result was observed in ORR, the pooled HR of ORR for immunotherapy compared to control treatment was 1.45 (95% CI 0.53-3.98, P = .47, I2 = 95%) and 2.19 (95% CI 0.79-6.08, P = .13, I2 = 83%), respectively. Immunotherapy could significantly improve survival advantage in unselected patients but not in PD-L1 selected population, indicating that PD-L1 expression may not be a reliable marker in previously platinum-treated patients.

Small molecular drugs reshape tumor microenvironment to synergize with immunotherapy

Recently, immune checkpoint blockade (ICB), especially anti-programmed death 1 (anti-PD-1) and anti-programmed death-ligand 1 (anti-PD-L1) therapy, has become an increasingly appealing therapeutic strategy for cancer patients. However, only a small portion of patients responds to anti-PD treatment. Therefore, treatment strategies are urgently needed to reverse the ICB-resistant tumor microenvironment (TME). It has become clear that the TME has diminished innate sensing that is critical to activate adaptive immunity. In addition, tumor cells upregulate various immunosuppressive factors to diminish the immune response and resist immunotherapy. In this review, we briefly update the current small molecular drugs that could synergize with immunotherapy, especially anti-PD therapy. We will discuss the modes of action by those drugs including inducing innate sensing and limiting immunosuppressive factors in the TME.

TLRs as a Promise Target Along With Immune Checkpoint Against Gastric Cancer

Gastric cancer (GC) is one of the most common cancers in the world, and the incidence of gastric cancer in Asia appears to increase in recent years. Although there is a lot of improvement in treatment approaches, the prognosis of GC is poor. So it is urgent to search for a novel and more effective treatment to improve the survival rate of patients. Both innate immunity and adaptive immunity are important in cancer. In the innate immune system, pattern recognition receptors (PRRs) activate immune responses by recognizing pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). Toll-like receptors (TLRs) are a class of pattern recognition receptors (PRRs). Many studies have reported that TLRs are involved in the occurrence, development, and treatment of GC. Therefore, TLRs are potential targets for immunotherapy to gastric cancer. However, gastric cancer is a heterogeneous disorder, and TLRs function in GC is complex. TLRs agonists can be potentially used not only as therapeutic agents to treat gastric cancer but also as adjuvants in conjunction with other immunotherapies. They might provide a promising new target for GC treatment. In the review, we sort out the mechanism of TLRs involved in tumor immunity and summarize the current progress in TLRs-based therapeutic approaches and other immunotherapies in the treatment of GC.

LAG-3, TIM-3 and VISTA Expression on Tumor-Infiltrating Lymphocytes in Oropharyngeal Squamous Cell Carcinoma-Potential Biomarkers for Targeted Therapy Concepts

Tumor growth and survival requires a particularly effective immunosuppressant tumor microenvironment (TME) to escape destruction by the immune system. While immunosuppressive checkpoint markers like programmed cell death 1 ligand (PD-L1) are already being targeted in clinical practice, lymphocyte-activation-protein 3 (LAG-3), T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) and V-domain Ig suppressor of T cell activation (VISTA) inhibitors are currently under investigation in clinical trials. Reliable findings on the expression status of those immune checkpoint inhibitors on tumor-infiltrating lymphocytes (TILs) in the TME of oropharyngeal squamous cell carcinoma (OPSCC) are lacking. This work aims to describe the expression of LAG-3, TIM-3, and VISTA expression in the TME of OPSCC. We created a tissue microarray of paraffin-embedded tumor tissue of 241 OPSCC. Expression of the immune checkpoint protein LAG-3, TIM-3, and VISTA in OPSCC was evaluated using immunohistochemistry and results were correlated with CD8+ T-cell inflammation and human papillomavirus (HPV)-status. 73 OPSCC stained positive for LAG-3 (31%; HPV+:44%; HPV-:26%, p = 0.006), 122 OPSCC stained positive for TIM-3 (51%; HPV+:70%; HPV-:44%, p < 0.001) and 168 OPSCC (70%; HPV+:75%; HPV-:68%, p = 0.313) for VISTA. CD8+ T-cells were significantly associated with LAG-3, TIM-3 and VISTA expression (p < 0.001, p < 0.001, p = 0.007). Immune checkpoint therapy targeting LAG-3, TIM-3, and/or VISTA could be a promising treatment strategy especially in HPV-related OPSCC. Future clinical trials investigating the efficacy of a checkpoint blockade in consideration of LAG-3, TIM-3, and VISTA expression are required.

The Immunostimulative Effect and Mechanisms of a Novel Mouse Anti-Human PD-1 Monoclonal Antibody on Jurkat Lymphocytic Cells Cocultured with Hepatoma Cells

BACKGROUND

Monoclonal antibodies (mAbs) that target the programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint have demonstrated substantial clinical benefit for a variety of solid tumors. However, their applications in patients with hepatocellular carcinoma (HCC) are reported with unclear molecular mechanisms. Here, we report a novel mouse anti-human PD-1 mAb that can reverse the immunosuppressive effect of HePG2 cells on Jurkat cells.

MATERIALS AND METHODS

HepG2 liver cancer cells, which were induced to overexpress PD-L1 by IFN-γ, were co-cultured with PHA-activated Jurkat lymphocytic cells to investigate the immunostimulative effect and mechanisms of the 14 newly generated PD-1 mAbs. Multiple cellular and molecular biology experiments were performed in this study, such as CCK-8, ELISA, flow cytometry, immunofluorescence and Western blot.

RESULTS

We found that mAb B1C4 significantly enhanced the tumor-killing cytokine secretion level by Jurkat cells in the co-culture system and increased the killing ability of Jurkat cells on HepG2 cells. Co-culture with HePG2 cells led to Jurkat cell cycle delay in S phase, and B1C4 promoted cell cycle progression from S to G2/M. Co-culture with HePG2 cells also caused apoptosis in Jurkat cells, which was inhibited by B1C4. B1C4 reversed the immunosuppression of Jurkat cells resulted from co-cultured with HePG2 cells through inhibiting PTEN and activating PI3K/AKT/mTOR signaling pathways.

CONCLUSION

Our study demonstrated that anti-PD-1 mAb B1C4 could inhibit the apoptosis of Jurkat cells induced by HePG2 hepatoma cells and reverse the immunosuppressive effect of HePG2 cells on Jurkat cells. The study provides a vital basis for applying PD-1 monoclonal antibodies in the treatment of HCC and provides antibody selection for the development of novel PD-1 mAb with blocking activity.

Rationale and Outcomes for Neoadjuvant Immunotherapy in Urothelial Carcinoma of the Bladder

CONTEXT

Immune therapy has emerged as a powerful treatment of metastatic urothelial carcinoma. Over 20 ongoing studies are exploring this strategy in the neoadjuvant setting in patients with localized muscle-invasive bladder cancer.

OBJECTIVE

To summarize the rationale and the clinical outcomes regarding the use of immune checkpoint blockade in the neoadjuvant setting before radical cystectomy.

EVIDENCE ACQUISITION

A systematic review of the literature in the MEDLINE database was performed. The central search strategy used the terms bladder cancer, urothelial carcinoma, mice, human, immunotherapy, neoadjuvant therapy, atezolizumab, pembrolizumab, durvalumab, nivolumab, avelumab, ipilimumab, and tremelimumab. The search was limited to publications between January 2008 and February 2020. Publicly available relevant abstracts from recent meetings were also included.

EVIDENCE SYNTHESIS

Phase II trials investigating neoadjuvant immune checkpoint blockade as a single agent before radical cystectomy reported a rate of pathological complete response (CR), ranging from 31% with an anti-PD-L1 monoclonal antibody (mAb) atezolizumab (n = 27/88) to 37% with anti-PD-1 mAb pembrolizumab (n = 42/114). Overall, 92% (n = 87/95) and 98% (n = 112/114) of the patients underwent radical cystectomy. Neoadjuvant immune checkpoint blockade did not delay planned surgery. Checkpoint inhibitor monotherapy was well tolerated, with no unexpected toxicity in the presurgical setting. Early phase I/II trials investigating neoadjuvant combination chemotherapy strategies with immune checkpoint blockers reported enhanced antitumor efficacy, with a pathological CR ranging from 33% to 50%.

CONCLUSIONS

Although limited clinical data are available on long-term survival, neoadjuvant immune checkpoint blockade demonstrated effective antitumor efficacy for localized muscle-invasive bladder cancer. Phase III trials are currently investigating this strategy in the presurgical setting.

PATIENT SUMMARY

Immunotherapy prior to surgery has been evaluated for patients with muscle-invasive bladder cancer. Although long-term survival benefit is unknown, such treatment strategy revealed a promising antitumor response rate for patients who underwent radical cystectomy. Ongoing prospective clinical trials will define the potential advantage of this approach over current cisplatin-based chemotherapeutic regimens alone or in combination.

A guide to cancer immunotherapy: from T cell basic science to clinical practice

The T lymphocyte, especially its capacity for antigen-directed cytotoxicity, has become a central focus for engaging the immune system in the fight against cancer. Basic science discoveries elucidating the molecular and cellular biology of the T cell have led to new strategies in this fight, including checkpoint blockade, adoptive cellular therapy and cancer vaccinology. This area of immunological research has been highly active for the past 50 years and is now enjoying unprecedented bench-to-bedside clinical success. Here, we provide a comprehensive historical and biological perspective regarding the advent and clinical implementation of cancer immunotherapeutics, with an emphasis on the fundamental importance of T lymphocyte regulation. We highlight clinical trials that demonstrate therapeutic efficacy and toxicities associated with each class of drug. Finally, we summarize emerging therapies and emphasize the yet to be elucidated questions and future promise within the field of cancer immunotherapy.

Role of inflammasome activation in tumor immunity triggered by immune checkpoint blockers

Immune checkpoint blockers improve the overall survival of a limited number of patients among different cancers. Identifying pathways that influence the immunological and clinical response to treatment is critical to improve the therapeutic efficacy and predict clinical responses. Recently, a key role has been assigned to innate immune mechanisms in checkpoint blockade-driven anti-tumor responses. However, inflammatory pathways can both improve and impair anti-tumor immunity. In this review, we discuss how different inflammatory pathways, particularly inflammasome activation, can influence the clinical outcome of immune checkpoint blockers. Inflammasome activation may reinforce anti-tumor immunity by boosting CD8⁺ T cell priming as well as by enhancing T helper type 17 (Th17) responses. In particular, we focus on the modulation of the cation channel transmembrane protein 176B (TMEM176B) and the ectonucleotidase CD39 as potential targets to unleash inflammasome activation leading to reinforced anti-tumor immunity and improved efficacy of immune checkpoint blockers. Future studies should be aimed at investigating the mechanisms and cell subsets involved in inflammasome-driven anti-tumor responses.

Intratumoral Immunotherapy: From Trial Design to Clinical Practice

Systemic immunotherapies such as immune checkpoint blockade targeted at PD(L)1 and CTLA4 have demonstrated their ability to provide durable tumor responses and long-term overall survival benefits for some patients in several solid tumor types. However, a majority of patients remain resistant to these treatments and a significant proportion of them develop severe autoimmune and inflammatory adverse events. Preclinical studies have demonstrated that intratumoral injections of immunostimulatory products (oncolytics, pattern recognition receptor agonists,…) that are able to trigger type I IFN release and enhance tumor antigen presentation on immune cells could generate a strong antitumor immunity and overcome the resistance to systemic immune checkpoint blockade therapies. The intratumoral immunotherapy strategies that are currently in clinical development offer a unique therapeutic and exploratory setting to better understand the immune contexture across tumor lesions of patients with metastatic cancer. Also these local therapeutic products could turn cold tumors into hot and improve the response rates to cancer immunotherapies while diminishing their systemic exposure and toxicities. Intratumoral immunotherapies could prime or boost the immunity against tumors and therefore radically change the combinatorial therapeutic strategies currently pursued for metastatic and local cancers to improve their long-term survival. We aimed to review and discuss the scientific rationale for intratumoral immunotherapy, the challenges raised by this strategy in terms of drug development within clinical trials and the current state-of-the-art regarding the clinical practice of this innovative approach.

Advances in engineering local drug delivery systems for cancer immunotherapy

Cancer immunotherapy aims to leverage the immune system to suppress the growth of tumors and to inhibit metastasis. The recent promising clinical outcomes associated with cancer immunotherapy have prompted research and development efforts towards enhancing the efficacy of immune checkpoint blockade, cancer vaccines, cytokine therapy, and adoptive T cell therapy. Advancements in biomaterials, nanomedicine, and micro-/nano-technology have facilitated the development of enhanced local delivery systems for cancer immunotherapy, which can enhance treatment efficacy while minimizing toxicity. Furthermore, locally administered cancer therapies that combine immunotherapy with chemotherapy, radiotherapy, or phototherapy have the potential to achieve synergistic antitumor effects. Herein, the latest studies on local delivery systems for cancer immunotherapy are surveyed, with an emphasis on the therapeutic benefits associated with the design of biomaterials and nanomedicines. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Adjuvant Effect of Toll-Like Receptor 9 Activation on Cancer Immunotherapy Using Checkpoint Blockade

Immunotherapy using checkpoint blockade has revolutionized cancer treatment, improving patient survival and quality of life. Nevertheless, the clinical outcomes of such immunotherapy are highly heterogeneous between patients. Depending on the cancer type, the patient response rates to this immunotherapy are limited to 20–30%. Based on the mechanism underlying the antitumor immune response, new therapeutic strategies have been designed with the aim of increasing the effectiveness and specificity of the antitumor immune response elicited by checkpoint blockade agents. The activation of toll-like receptor 9 (TLR9) by its synthetic agonists induces the antitumor response within the innate immunity arm, generating adjuvant effects and priming the adaptive immune response elicited by checkpoint blockade during the effector phase of tumor-cell killing. This review first describes the underlying mechanisms of action and current status of monotherapy using TLR9 agonists and immune checkpoint inhibitors for cancer immunotherapy. The rationale for combining these two agents is discussed, and evidence indicating the current status of such combination therapy as a novel cancer treatment strategy is presented.

Immunotherapy for Head and Neck Cancer

The immune system has a vital role in the development, establishment, and progression of head and neck squamous cell carcinoma (HNSCC). Immune evasion of cancer cells leads to progression of HNSCC. An understanding of this mechanism provides the basis for improved therapies and outcomes for patients. Through the tumor's influence on the microenvironment, the immune system can be exploited to promote metastasis, angiogenesis, and growth. This article provides an overview of the interaction between immune infiltrating cells in the tumor microenvironment, and the immunologic principles related to HNSCC. Current immunotherapeutic strategies and emerging results from ongoing clinical trials are presented.

Sensitizing the Tumor Microenvironment to Immune Checkpoint Therapy

Immune checkpoint blockade (ICB) has revolutionized cancer treatment, providing remarkable clinical responses in some patients. However, the majority of patients do not respond. It is therefore crucial both to identify predictive biomarkers of response and to increase the response rates to immune checkpoint therapy. In this review we explore the current literature about the predictive characteristics of the tumor microenvironment and discuss therapeutic approaches that aim to change this toward a milieu that is conducive to response. We propose a personalized biomarker-based adaptive approach to immunotherapy, whereby a sensitizing therapy is tailored to the patient's specific tumor microenvironment, followed by on-treatment verification of a change in the targeted biomarker, followed by immune checkpoint therapy. By incorporating detailed knowledge of the immunological tumor microenvironment, we may be able to sensitize currently non-responsive tumors to respond to immune checkpoint therapy.

Safety and Efficacy of Durvalumab With or Without Tremelimumab in Patients With PD-L1-Low/Negative Recurrent or Metastatic HNSCC: The Phase 2 CONDOR Randomized Clinical Trial

Importance

Dual blockade of programmed death ligand 1 (PD-L1) and cytotoxic T-lymphocyte associated protein 4 (CTLA-4) may overcome immune checkpoint inhibition. It is unknown whether dual blockade can potentiate antitumor activity without compromising safety in patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) and low or no PD-L1 tumor cell expression.

Objective

To assess safety and objective response rate of durvalumab combined with tremelimumab.

Design, Setting, and Participants

The CONDOR study was a phase 2, randomized, open-label study of Durvalumab, Tremelimumab, and Durvalumab in Combination With Tremelimumab in Patients With R/M HNSCC. Eligibility criteria included PD-L1-low/negative disease that had progressed after 1 platinum-containing regimen in the R/M setting. Patients were randomized (N = 267) from April 15, 2015, to March 16, 2016, at 127 sites in North America, Europe, and Asia Pacific.

Interventions

Durvalumab (20 mg/kg every 4 weeks) + tremelimumab (1 mg/kg every 4 weeks) for 4 cycles, followed by durvalumab (10 mg/kg every 2 weeks), or durvalumab (10 mg/kg every 2 weeks) monotherapy, or tremelimumab (10 mg/kg every 4 weeks for 7 doses then every 12 weeks for 2 doses) monotherapy.

Main Outcomes and Measures

Safety and tolerability and efficacy measured by objective response rate.

Results

Among the 267 patients (220 men [82.4%]), median age (range) of patients was 61.0 (23-82) years. Grade 3/4 treatment-related adverse events occurred in 21 patients (15.8%) treated with durvalumab + tremelimumab, 8 (12.3%) treated with durvalumab, and 11 (16.9%) treated with tremelimumab. Grade 3/4 immune-mediated adverse events occurred in 8 patients (6.0%) in the combination arm only. Objective response rate (95% CI) was 7.8% (3.78%-13.79%) in the combination arm (n = 129), 9.2% (3.46%-19.02%) for durvalumab monotherapy (n = 65), and 1.6% (0.04%-8.53%) for tremelimumab monotherapy (n = 63); median overall survival (95% CI) for all patients treated was 7.6 (4.9-10.6), 6.0 (4.0-11.3), and 5.5 (3.9-7.0) months, respectively.

Conclusions and Relevance

In patients with R/M HNSCC and low or no PD-L1 tumor cell expression, all 3 regimens exhibited a manageable toxicity profile. Durvalumab and durvalumab + tremelimumab resulted in clinical benefit, with minimal observed difference between the two. A phase 3 study is under way.

Trial Registration

clinicaltrials.gov Identifier: NCT02319044.

TLR9 activation cooperates with T cell checkpoint blockade to regress poorly immunogenic melanoma

Tumors that lack pre-existing immune infiltration respond poorly to T cell checkpoint blockade immunotherapy. These cancers often surround themselves with high densities of suppressive myeloid stroma while excluding immunostimulatory dendritic cells. Tumor-resident myeloid cells and selected lymphocyte populations retain expression of Toll-like Receptors (TLR) that sense common features of pathogens and activate innate immunity in response. We explored whether agonists of TLR9 could augment innate immunity to promote tumor regression alone or in combination with T cell checkpoint blockade. In the setting of the immunogenic B16-Ova (Ovalbumin) expressing melanoma model, local injection of the CpG oligonucleotide TLR9 agonist ODN1826 combined with systemic CTLA-4 blockade cured 45% of mice of both their treated and an untreated tumor on the opposite flank demonstrating the synergistic potential of this combination. Next, in the non-immunogenic B16-F10 melanoma model, we showed that only intra-tumoral, but not systemic TLR9 activation augments the therapeutic potential of checkpoint blockade. In this setting, intra-tumoral TLR9 activation cooperated equally with either CTLA-4 or PD-1 blockade co-administered locally or given systemically; however, the uninjected tumor rarely regressed. Anti-CTLA-4 combinations were associated with improved intra-tumoral CD8 to regulatory T cell ratios, while anti-PD-1 combinations elicited improved ratios of CD8 T cells relative to suppressive myeloid stroma. Using both a TLR9 agonist (MGN1703) and a CTLA-4 antibody (9D9-IgG2a) of increased potency cured 50% of bi-lateral B16-F10 melanoma. These findings suggest that intra-tumoral TLR9 agonists can improve sensitivity of poorly immunogenic tumors to T cell checkpoint blockade, and that newer, higher potency TLR agonists and checkpoint antibodies can raise the therapeutic ceiling for this combination therapy.

Beneficial modulation of the tumor microenvironment and generation of anti-tumor responses by TLR9 agonist lefitolimod alone and in combination with checkpoint inhibitors

Activation of Toll-like receptor 9 (TLR9) is known to foster innate and adaptive immune responses and thus improve immune-mediated control of malignant disease. Lefitolimod is a potent TLR9 agonist without chemical modification developed for immunotherapeutic strategies. Modulation of the tumor microenvironment (TME) is a crucial requirement for the response to various immunotherapies: Immunogenic (“hot”) tumors, characterized by their T cell-infiltrated TME, respond better compared to non-immunogenic (“cold”) tumors. It has been speculated that the mode-of-action of lefitolimod provides the necessary signals for activation of immune cells, their differentiation into anti-tumor effector cells and their recruitment into the TME. We investigated the effect of lefitolimod on TME, and its potency to induce synergistic anti-tumor effects when combined with immune checkpoint inhibitory antibodies (CPI) in a murine model. Indeed, we could show that treatment with single-agent lefitolimod beneficially modulated the TME, via infiltration of activated CD8+ cells and a shift in the macrophage population toward M1 phenotype. The result was a pronounced anti-tumor effect correlated with the magnitude of infiltrated immune cells and tumor-specific T cell responses. In line with this, lefitolimod led to persistent anti-tumor memory in the EMT-6 model after tumor re-challenge. This was accompanied by an increase of tumor-specific T cell responses and cross-reactivity against different tumor cells. Lefitolimod clearly augmented the limited anti-tumor effect of the CPI anti-PD1 in an A20 and anti-PD-L1 in a CT26 model. These properties of potent immune surveillance reactivation render lefitolimod an ideal candidate as therapeutic agent for immuno-oncology, e.g. improving CPI strategies.

Harnessing immune checkpoints for cancer therapy

Immunomodulatory antibodies that directly trigger and reawaken suppressed T-cell effector function are termed 'checkpoint inhibitors'. CTLA-4 and PD-1/PD-L1 molecules are the most studied inhibitory immune check points against cancer and because of this therapeutic property have entered the clinic for treating a variety of tumor types. The results so far demonstrate a positive impact on cancer remission. Preclinical studies have demonstrated that targeting a number of other T-cell surface molecules including both positive and negative immune regulators, also possesses strong antitumor activity. Some of these molecules have already entered clinical trials. In this report, we briefly highlight the status of these immune checkpoint inhibitors and discuss their side effects and future directions for their use.

From immune checkpoints to vaccines: The past, present and future of cancer immunotherapy

Cancer is a worldwide medical problem with significant repercussions on individual patients and societies as a whole. In order to alter the outcomes of this deadly disease the treatment of cancer over the centuries has undergone a unique evolution. However, utilizing the best treatment modalities and achieving cures or long-term durable responses have been inconsistent and limited, that is until recently. Contemporary research has highlighted a fundamental gap in our understanding of how we approach treating cancer, by revealing the intricate relationship between the immune system and tumors. In this atmosphere, the growth of immunotherapy has not only forever changed our understanding of cancer biology, but the manner by which we treat patients. It's paradigm shifting success has led to the approval of over 10 different immunotherapeutic agents, including checkpoint inhibitors, vaccine-based therapies, oncolytic viruses and T cell directed therapies for nearly 20 different indications across countless tumor types. Despite the breakthroughs that have occurred in the field of immunotherapy, it has not been the panacea for all cancers. With a deeper understanding of the immune system we have been able to peer into tumor immune escape and therapy resistance. Simultaneously this understanding has paved the way for the investigation and development of novel immune system altering agents and combinatorial therapies. In this chapter we review the immune system and its intricate relationship with cancer, the evolution of immunotherapy, its current landscape, and future directions in the context of resistance mechanisms and the challenges faced by immunotherapy against cancer.

The CTLA-4 x OX40 bispecific antibody ATOR-1015 induces anti-tumor effects through tumor-directed immune activation

BACKGROUND

The CTLA-4 blocking antibody ipilimumab has demonstrated substantial and durable effects in patients with melanoma. While CTLA-4 therapy, both as monotherapy and in combination with PD-1 targeting therapies, has great potential in many indications, the toxicities of the current treatment regimens may limit their use. Thus, there is a medical need for new CTLA-4 targeting therapies with improved benefit-risk profile.

METHODS

ATOR-1015 is a human CTLA-4 x OX40 targeting IgG1 bispecific antibody generated by linking an optimized version of the Ig-like V-type domain of human CD86, a natural CTLA-4 ligand, to an agonistic OX40 antibody. In vitro evaluation of T-cell activation and T regulatory cell (Treg) depletion was performed using purified cells from healthy human donors or cell lines. In vivo anti-tumor responses were studied using human OX40 transgenic (knock-in) mice with established syngeneic tumors. Tumors and spleens from treated mice were analyzed for CD8+ T cell and Treg frequencies, T-cell activation markers and tumor localization using flow cytometry.

RESULTS

ATOR-1015 induces T-cell activation and Treg depletion in vitro. Treatment with ATOR-1015 reduces tumor growth and improves survival in several syngeneic tumor models, including bladder, colon and pancreas cancer models. It is further demonstrated that ATOR-1015 induces tumor-specific and long-term immunological memory and enhances the response to PD-1 inhibition. Moreover, ATOR-1015 localizes to the tumor area where it reduces the frequency of Tregs and increases the number and activation of CD8+ T cells.

CONCLUSIONS

By targeting CTLA-4 and OX40 simultaneously, ATOR-1015 is directed to the tumor area where it induces enhanced immune activation, and thus has the potential to be a next generation CTLA-4 targeting therapy with improved clinical efficacy and reduced toxicity. ATOR-1015 is also expected to act synergistically with anti-PD-1/PD-L1 therapy. The pre-clinical data support clinical development of ATOR-1015, and a first-in-human trial has started (NCT03782467).

Dendritic Cells and Cancer: From Biology to Therapeutic Intervention

Inducing effective anti-tumor immunity has become a major therapeutic strategy against cancer. Dendritic cells (DC) are a heterogenous population of antigen presenting cells that infiltrate tumors. While DC play a critical role in the priming and maintenance of local immunity, their functions are often diminished, or suppressed, by factors encountered in the tumor microenvironment. Furthermore, DC populations with immunosuppressive activities are also recruited to tumors, limiting T cell infiltration and promoting tumor growth. Anti-cancer therapies can impact the function of tumor-associated DC and/or alter their phenotype. Therefore, the design of effective anti-cancer therapies for clinical translation should consider how best to boost tumor-associated DC function to drive anti-tumor immunity. In this review, we discuss the different subsets of tumor-infiltrating DC and their role in anti-tumor immunity. Moreover, we describe strategies to enhance DC function within tumors and harness these cells for effective tumor immunotherapy.

Immunotherapy for Head and Neck Cancer

The immune system has a vital role in the development, establishment, and progression of head and neck squamous cell carcinoma (HNSCC). Immune evasion of cancer cells leads to progression of HNSCC. An understanding of this mechanism provides the basis for improved therapies and outcomes for patients. Through the tumor's influence on the microenvironment, the immune system can be exploited to promote metastasis, angiogenesis, and growth. This article provides an overview of the interaction between immune infiltrating cells in the tumor microenvironment, and the immunologic principles related to HNSCC. Current immunotherapeutic strategies and emerging results from ongoing clinical trials are presented.

Mouse-Derived Isograft (MDI) In Vivo Tumor Models II. Carcinogen-Induced cMDI Models: Characterization and Cancer Therapeutic Approaches

In this second study, we established syngeneic in vivo models named carcinogen-induced mouse-derived isografts (cMDIs). Carcinogen-induced tumors were obtained during short-term observation (3–9 months) of CBA/J mice treated with various administration routes with 3-methylcholanthrene (MCA) or N-methyl-N-nitrosourea (MNU) as carcinogens. During necropsy, primary tumors and suspicious tissues were assessed macroscopically and re-transplanted (in PDX-like manner) into sex-matched syngeneic animals. Outgrowing tumors were histologically characterized as either spinocellular carcinoma (1/8) or various differentiated sarcomas (7/8). Growth curves of four sarcomas showed striking heterogeneity. These cMDIs were further characterized by flow cytometry, RNA sequencing, or efficacy studies. A variable invasion of immune cells into the tumors, as well as varying expression of tyrosine kinase receptor, IFN-γ signature, or immune cell population marker genes could be observed. Immune checkpoint inhibitor treatment (anti-mPD-1, anti-mCTLA-4, or a combination thereof) showed different responses in the various cMDI models. In general, cMDI models are carcinogen-induced tumors of low passage number that were propagated as tissue pieces in mice without any tissue culturing. Therefore, the tumors contained conserved tumor characteristics and intratumoral immune cell populations. In contrast to the previously described spontaneous MDI, carcinogen induction resulted in a greater number of individual but histologically related tumors, which were preferentially sarcomas.

Mouse-Derived Isograft (MDI) In Vivo Tumor Models I. Spontaneous sMDI Models: Characterization and Cancer Therapeutic Approaches

Syngeneic in vivo tumor models are valuable for the development and investigation of immune-modulating anti-cancer drugs. In the present study, we established a novel syngeneic in vivo model type named mouse-derived isografts (MDIs). Spontaneous MDIs (sMDIs) were obtained during a long-term observation period (more than one to two years) of naïve and untreated animals of various mouse strains (C3H/HeJ, CBA/J, DBA/2N, BALB/c, and C57BL/6N). Primary tumors or suspicious tissues were assessed macroscopically and re-transplanted in a PDX-like manner as small tumor pieces into sex-matched syngeneic animals. Nine outgrowing primary tumors were histologically characterized either as adenocarcinomas, histiocytic carcinomas, or lymphomas. Growth of the tumor pieces after re-transplantation displayed model heterogeneity. The adenocarcinoma sMDI model JA-0009 was further characterized by flow cytometry, RNA-sequencing, and efficacy studies. M2 macrophages were found to be the main tumor infiltrating leukocyte population, whereas only a few T cells were observed. JA-0009 showed limited sensitivity when treated with antibodies against inhibitory checkpoint molecules (anti-mPD-1 and anti-mCTLA-4), but high sensitivity to gemcitabine treatment. The generated sMDI are spontaneously occurring tumors of low passage number, propagated as tissue pieces in mice without any tissue culturing, and thus conserving the original tumor characteristics and intratumoral immune cell populations.