Immune Checkpoint Inhibitors in 10 Years: Contribution of Basic Research and Clinical Application in Cancer Immunotherapy

Neoadjuvant chemoradiotherapy up-regulates PD-L1 in radioresistant colorectal cancer

Background

Combining radiotherapy (RT) with immune checkpoint inhibitors (ICIs) is a promising strategy that can enhance the therapeutic efficacy of ICIs. However, little is known about RT-induced changes in the expression of immune checkpoints, such as PD-L1, and their clinical implications in colorectal cancer (CRC). This study aimed to investigate the association between responsiveness to RT and changes in PD-L1 expression in human CRC tissue and cell lines.

Methods

Tissue specimens from preoperative biopsy via sigmoidoscopy and surgical resection were obtained from 24 patients with locally advanced rectal cancer (LARC) who underwent neoadjuvant chemoradiation therapy (CRT) between August 2016 and December 2017. Immunohistochemistry for PD-L1 in formalin-fixed paraffin-embedded tissue was performed from the endoscopic biopsy and surgical specimens. RNA sequencing was performed using 11 pairs of human LARC tissues before and after irradiation. After exposing human CRC cells to radiation, we investigated changes in the expression levels of PD-L1 and its regulatory signaling pathways.

Results

Patients were classified by tumor regression grade into responders (grade 2; 9 patients, 37.5 %) and non-responders (grades 3, 4, or 5; 15 patients, 62.5 %). In the non-responder group, 13 patients had low PD-L1 expression, but neoadjuvant CRT increased PD-L1 expression in 7 patients (53.9 %) (McNemar's test, p=0.034). CRT up-regulated PD-L1 in non-responder LARC tissues. Similarly, radiation increased PD-L1 in radioresistant DLD-1 cells more than in radiosensitive HCT116 cells, also affecting PD-L1-regulating genes and immune checkpoints in CRC cells. Conventional fractionated radiation treatment further increased PD-L1 in DLD-1 cells compared to HCT116 cells.

Conclusions

This study demonstrated that radiation induces an increase in PD-L1 expression, which is more pronounced in radioresistant CRC, proving the theoretical framework for a combined treatment strategy with a PD-L1 blockade for locally advanced rectal cancer.

Immune biomarkers and predictive signatures in gastric cancer: Optimizing immunotherapy responses

Gastric cancer is a malignant disease with a poor prognosis and few therapeutic options once it has advanced. Immunotherapy using ICIs has emerged as a viable therapeutic method; nevertheless, reliable immunological biomarkers are required to identify who may benefit from these therapies. It focuses on key immune biomarkers and predictive signatures in gastric cancer, such as PD-L1 expression, microsatellite instability (MSI), tumor mutational burden (TMB), and Epstein-Barr virus (EBV) status, to optimize gastric cancer patients' immunotherapy responses. PD-L1 expression is a popular biomarker for ICI effectiveness. Tumors with high MSI-H and TMB are the most susceptible to ICIs because they are highly immunogenic. EBV-positive stomach tumors are highly immunogenic, and immunotherapy has a high response rate. Combining composite biomarker panels with multi-omics-based techniques improved patient selection accuracy. In recent years, machine learning models have been integrated into next-generation sequencing. Dynamic, real-time-monitorable biomarkers for real-time immune response monitoring are also being considered. Thus, enhancing biomarker-driven immunotherapy is critical for improving clinical outcomes with gastric cancer. There is still more work to be done in this field, and verifying developing biomarkers will be an important component in the future of customized cancer therapy.

Fulminant immune checkpoint inhibitor-associated myocarditis bridged to recovery with a temporary left ventricular assist device: a case report

Background

Immune checkpoint inhibitors (ICIs) are effective antineoplastic agents but can cause adverse effects in many organ systems. Cardiovascular toxicities include arrhythmias, myocarditis, heart failure, takotsubo syndrome, pericarditis, coronary artery disease, and vasculitis.

Case summary

A 66-year-old woman with Stage 3C2 endometrial carcinoma presented for her second cycle of pembrolizumab, carboplatin, and paclitaxel. She subsequently suffered cardiac arrest and was brought to the emergency department. Spontaneous circulation returned following resuscitation, but she was haemodynamically unstable. An electrocardiogram revealed complete heart block. Initial management included intubation, vasopressor support, and transcutaneous pacing before transfer to the catheterization lab. Coronary angiography revealed no coronary artery disease. Right heart catheterization confirmed severe cardiogenic shock despite inotropic support and a temporary transvenous pacemaker in place. A micro-axial flow pump (Impella CP) was implanted for deteriorating cardiogenic shock. She was treated with high-dose corticosteroids (dexamethasone 190 mg i.v.) for suspected ICI-associated myocarditis, with significant improvement in cardiac function. The Impella was weaned and removed on Day 5. Cardiac magnetic resonance imaging showed elevated T1 and T2 signal intensities, consistent with the 2018 Lake Louise Criteria for myocarditis. The complete heart block was resolved, but a leadless pacemaker was implanted due to pre-existing conduction abnormalities.

Discussion

Early recognition of ICI-associated myocarditis can be achieved with biochemical testing, electrocardiography, imaging, and expedited investigation of alternative causes for cardiac decompensation. Our case demonstrates that temporary left ventricular assist devices can support cardiac output for patients in cardiogenic shock due to ICI-associated myocarditis, allowing for recovery following high-dose corticosteroids.

Factors associated with immune‑related severe adverse events (Review)

Immune checkpoint inhibitors (ICIs) are frequently used in cancer treatment. Despite their clinical benefits, they can also cause a wide range of immune-related adverse events (ir-AEs). The overall incidence of irAEs in cancer patients treated with immunotherapy ranges from 70-90%, while that of immune-related severe adverse events (ir-SAEs) is 10-43%. ir-SAEs pose a significant risk to patient safety as they are extremely frequent and lethal. Due to non-specific manifestations, rapid progression and significant morbidity, it is essential to identify factors associated with ir-SAEs early to predict high-risk groups for treatment safety. However, less information is available on the factors causing ir-SAEs, and further research is needed. The present study reviews the factors associated with ir-SAEs in terms of demographic characteristics, disease-related information and laboratory examinations to provide a clinical reference. In terms of demographic characteristics, age, body mass index, smoking, ethnicity and cancer family history may influence the incidence of ir-SAEs. Regarding disease-related information, the risks factors associated with ir-SAEs may include disease history, treatment regimen and cancer type. For laboratory examinations, risk factors associated with ir-SAEs include the laboratory examination parameters of peripheral blood cells, immunocytes, cytokines/chemokines, genetics, gut microbia, proteins and brain injury markers. All of these risk factors can stimulate the body's inflammatory response, leading to over proliferation of T cells and other inflammatory factors. In addition, the use of ICIs may disrupt gut microbial homeostasis and dysregulate the pre-existing intestinal ecology, which may therefore trigger inflammatory signaling pathways, affect overall immune function and increase the occurrence of ir-SAEs. In response to the aforementioned risk factors, it is recommended that medical professionals incorporate their analysis into routine patient testing for early identification of patient ir-SAEs and to create early individualized interventions to improve the safety for immunotherapy patients.

Targeting the aminopeptidase ERAP enhances antitumor immunity by disrupting the NKG2A-HLA-E inhibitory checkpoint

The aminopeptidase, endoplasmic reticulum aminopeptidase 1 (ERAP1), trims peptides for loading into major histocompatibility complex class I (MHC class I), and loss of this activity has broad effects on the MHC class I peptidome. Here, we investigated the impact of targeting ERAP1 in immune checkpoint blockade (ICB), as MHC class I interactions mediate both activating and inhibitory functions in antitumor immunity. Loss of ERAP sensitized mouse tumor models to ICB, and this sensitivity depended on CD8+ T cells and natural killer (NK) cells. In vivo suppression screens revealed that Erap1 deletion inactivated the inhibitory NKG2A-HLA-E checkpoint, which requires presentation of a restricted set of invariant epitopes (VL9) on HLA-E. Loss of ERAP altered the HLA-E peptidome, preventing NKG2A engagement. In humans, ERAP1 and ERAP2 showed functional redundancy for the processing and presentation of VL9, and loss of both inactivated the NKG2A checkpoint in cancer cells. Thus, loss of ERAP phenocopies the inhibition of the NKG2A-HLA-E pathway and represents an attractive approach to inhibit this critical checkpoint.

Optimal control of combination immunotherapy for a virtual murine cohort in a glioblastoma-immune dynamics model

The immune checkpoint inhibitor anti-PD-1, commonly used in cancer immunotherapy, has not been successful as a monotherapy for the highly aggressive brain cancer glioblastoma. However, when used in conjunction with a CC-chemokine receptor-2 (CCR2) antagonist, anti-PD-1 has shown efficacy in preclinical studies. In this paper, we aim to optimize treatment regimens for this combination immunotherapy using optimal control theory. We extend a treatment-free glioblastoma-immune dynamics ODE model to include interventions with anti-PD-1 and the CCR2 antagonist. An optimized regimen increases the survival of an average mouse from 32 days post-tumor implantation without treatment to 111 days with treatment. We scale this approach to a virtual murine cohort to evaluate mortality and quality of life concerns during treatment, and predict survival, tumor recurrence, or death after treatment. A parameter identifiability analysis identifies five parameters suitable for personalizing treatment within the virtual cohort. Sampling from these five practically identifiable parameters for the virtual murine cohort reveals that personalized, optimized regimens enhance survival: 84% of the virtual mice survive to day 100, compared to 60% survival in a previously studied experimental regimen. Subjects with high tumor growth rates and low T cell kill rates are identified as more likely to die during and after treatment due to their compromised immune systems and more aggressive tumors. Notably, the MDSC death rate emerges as a long-term predictor of either disease-free survival or death.

Next-generation combination approaches for immune checkpoint therapy

Immune checkpoint therapy has revolutionized cancer treatment, leading to dramatic clinical outcomes for a subset of patients. However, many patients do not experience durable responses following immune checkpoint therapy owing to multiple resistance mechanisms, highlighting the need for effective combination strategies that target these resistance pathways and improve clinical responses. The development of combination strategies based on an understanding of the complex biology that regulates human antitumor immune responses has been a major challenge. In this Review, we describe the current landscape of combination therapies. We also discuss how the development of effective combination strategies will require the integration of small, tissue-rich clinical trials, to determine how therapy-driven perturbation of the human immune system affects downstream biological responses and eventual clinical outcomes, reverse translation of clinical observations to immunocompetent preclinical models, to interrogate specific biological pathways and their impact on antitumor immune responses, and novel computational methods and machine learning, to integrate multiple datasets across clinical and preclinical studies for the identification of the most relevant pathways that need to be targeted for successful combination strategies.

The HDAC6 inhibitor AVS100 (SS208) induces a pro-inflammatory tumor microenvironment and potentiates immunotherapy

Histone deacetylase 6 (HDAC6) inhibition is associated with an increased pro-inflammatory tumor microenvironment and antitumoral immune responses. Here, we show that the HDAC6 inhibitor AVS100 (SS208) had an antitumoral effect in SM1 melanoma and CT26 colon cancer models and increased the efficacy of anti-programmed cell death protein 1 treatment, leading to complete remission in melanoma and increased response in colon cancer. AVS100 treatment increased pro-inflammatory tumor-infiltrating macrophages and CD8 effector T cells with an inflammatory and T cell effector gene signature. Acquired T cell immunity and long-term protection were evidenced as increased immunodominant T cell clones after AVS100 treatment. Last, AVS100 showed no mutagenicity, toxicity, or adverse effects in preclinical good laboratory practice studies, part of the package that has led to US Food and Drug Administration clearance of an investigational new drug application for initiating clinical trials. This would be a first-in-human combination therapy of pembrolizumab with HDAC6 inhibition for locally advanced or metastatic solid tumors.

Oncolytic Virotherapies and Adjuvant Gut Microbiome Therapeutics to Enhance Efficacy Against Malignant Gliomas

Glioblastoma (GBM) is the most prevalent malignant brain tumor. Current standard-of-care treatments offer limited benefits for patient survival. Virotherapy is emerging as a novel strategy to use oncolytic viruses (OVs) for the treatment of GBM. These engineered and non-engineered viruses infect and lyse cancer cells, causing tumor destruction without harming healthy cells. Recent advances in genetic modifications to OVs have helped improve their targeting capabilities and introduce therapeutic genes, broadening the therapeutic window and minimizing potential side effects. The efficacy of oncolytic virotherapy can be enhanced by combining it with other treatments such as immunotherapy, chemotherapy, or radiation. Recent studies suggest that manipulating the gut microbiome to enhance immune responses helps improve the therapeutic efficacy of the OVs. This narrative review intends to explore OVs and their role against solid tumors, especially GBM while emphasizing the latest technologies used to enhance and improve its therapeutic and clinical responses.

Efficacy and Safety of Biosimilar Cetuximab Versus Innovator Cetuximab in Indian Patients With Head and Neck Cancer: A Multicenter, Randomized, Double-Blind, Phase III Trial

PURPOSE

Squamous cell carcinoma of the head and neck (SCCHN) is the sixth most common cancer, with approximately 225,419 new cases with over 125,000 deaths annually in India. This trial compared the efficacy and safety of biosimilar cetuximab versus innovator cetuximab (IC) in combination with platinum-based chemotherapy in patients with recurrent locoregional or metastatic SCCHN.

METHODS

This phase III trial is a multicenter, randomized, double-blind and parallel group study performed in Indian patients with recurrent locoregional or metastatic SCCHN. Patients were randomly assigned in 2:1 ratio to receive biosimilar cetuximab and IC in combination with cisplatin and fluorouracil via intravenous infusions. The primary end points were disease control rate (DCR) and overall response rate (ORR) as per response evaluation criteria in solid tumors version 1.1. The secondary end points included pharmacokinetics (PK), immunogenicity, safety, and tolerability.

RESULTS

Of 180 patients enrolled, 120 patients received biosimilar cetuximab and 60 patients received IC treatment. No significant statistical difference was observed in the primary outcomes between two groups. Treatment difference in DCR and ORR response was found to be -5.21 (90% CI, -8.94 to -1.48) and -4.79 (90% CI, -19.42 to 9.84), respectively, indicating noninferiority to reference product. The incidence of treatment-emergent adverse events (AEs; biosimilar cetuximab: 89.2% v IC: 91.7%; P = .8364) and serious AEs (biosimilar cetuximab: 23.3% v IC: 13.3%; P = .0603) and PK parameters were comparable between treatment groups. The immunogenicity findings showed higher incidence of anticetuximab antibodies in the biosimilar cetuximab group compared with the IC group at the end of Study.

CONCLUSION

The findings of this study demonstrated noninferiority along with comparable PK, safety, and immunogenicity of biosimilar cetuximab and IC in patients with recurrent or metastatic SCCHN.

CRISPR/Cas9-mediated knockout strategies for enhancing immunotherapy in breast cancer

Breast cancer, a prevalent disease with significant mortality rates, often presents treatment challenges due to its complex genetic makeup. This review explores the potential of combining Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) gene knockout strategies with immunotherapeutic approaches to enhance breast cancer treatment. The CRISPR/Cas9 system, renowned for its precision in inducing genetic alterations, can target and eliminate specific cancer cells, thereby minimizing off-target effects. Concurrently, immunotherapy, which leverages the immune system's power to combat cancer, has shown promise in treating breast cancer. By integrating these two strategies, we can potentially augment the effectiveness of immunotherapies by knocking out genes that enable cancer cells to evade the immune system. However, safety considerations, such as off-target effects and immune responses, necessitate careful evaluation. Current research endeavors aim to optimize these strategies and ascertain the most effective methods to stimulate the immune response. This review provides novel insights into the integration of CRISPR/Cas9-mediated knockout strategies and immunotherapy, a promising avenue that could revolutionize breast cancer treatment as our understanding of the immune system's interplay with cancer deepens.

Recent Advances in Artificial Intelligence to Improve Immunotherapy and the Use of Digital Twins to Identify Prognosis of Patients with Solid Tumors

To date, the public health system has been impacted by the increasing costs of many diagnostic and therapeutic pathways due to limited resources. At the same time, we are constantly seeking to improve these paths through approaches aimed at personalized medicine. To achieve the required levels of diagnostic and therapeutic precision, it is necessary to integrate data from different sources and simulation platforms. Today, artificial intelligence (AI), machine learning (ML), and predictive computer models are more efficient at guiding decisions regarding better therapies and medical procedures. The evolution of these multiparametric and multimodal systems has led to the creation of digital twins (DTs). The goal of our review is to summarize AI applications in discovering new immunotherapies and developing predictive models for more precise immunotherapeutic decision-making. The findings from this literature review highlight that DTs, particularly predictive mathematical models, will be pivotal in advancing healthcare outcomes. Over time, DTs will indeed bring the benefits of diagnostic precision and personalized treatment to a broader spectrum of patients.

Nanotechnology Applications in Breast Cancer Immunotherapy

Next-generation cancer treatments are expected not only to target cancer cells but also to simultaneously train immune cells to combat cancer while modulating the immune-suppressive environment of tumors and hosts to ensure a robust and lasting response. Achieving this requires carriers that can codeliver multiple therapeutics to the right cancer and/or immune cells while ensuring patient safety. Nanotechnology holds great potential for addressing these challenges. This article highlights the recent advances in nanoimmunotherapeutic development, with a focus on breast cancer. While immune checkpoint inhibitors (ICIs) have achieved remarkable success and lead to cures in some cancers, their response rate in breast cancer is low. The poor response rate in solid tumors is often associated with the low infiltration of anti-cancer T cells and an immunosuppressive tumor microenvironment (TME). To enhance anti-cancer T-cell responses, nanoparticles are employed to deliver ICIs, bispecific antibodies, cytokines, and agents that induce immunogenic cancer cell death (ICD). Additionally, nanoparticles are used to manipulate various components of the TME, such as immunosuppressive myeloid cells, macrophages, dendritic cells, and fibroblasts to improve T-cell activities. Finally, this article discusses the outlook, challenges, and future directions of nanoimmunotherapeutics.

State of the art and perspectives of chimeric antigen receptor T cells cell therapy for neuroblastoma

Neuroblastoma (NB) is a solid, neuroendocrine pediatric solid tumor with divergent clinical behavior. Patients with high-risk diseases have poor prognoses despite complex multimodal therapy, which requires the search for new therapeutic approaches. Chimeric antigen receptor T cells (CAR-T) have led to dramatic improvements in the survival of cancer patients, most notably those with hematologic malignancies. Early-phase clinical trials of CAR-T cell therapy for NB have proven safe and feasible, but limited clinical efficacy. At the same time, multiple experimental and preclinical studies have shown that the most common in clinical trials single 2nd or 3rd generation CAR structure is not sufficient for a complete response in solid tumors. Here, we review the recent advances and future perspectives associated with engineered receptors, including several antigens binding, armored CAR-T of 4th and 5th generation and CAR-T cell combination strategies with other immunotherapy. We also summarize the results and shortcomings of ongoing clinical trials of CAR-T therapy for NB.

Fucoidan from Durvillaea Antarctica enhances the anti-cancer effect of anti-PD-L1 antibody by activating dendritic cells and T cells

Immune checkpoint inhibitors are showing groundbreaking results in tumor immunotherapy. However, there are cases where treatment efficiency is insufficient due to limitations in immune activity, and various trials to overcome this are being studied. In this study, we investigated the immune activation ability of fucoidan extracted from Durvillaea antarctica (FDA) and whether it can enhance the anti-cancer effects of immune checkpoint inhibitors. FDA treatment resulted in an elevation of co-stimulator and major histocompatibility complex molecule expression, as well as the production of pro-inflammatory cytokines in bone marrow-derived and splenic dendritic cells (DCs). Administration of 50 mg/kg FDA increased the number of splenic CD8 T cells by >1.4-fold compared to PBS administration. Additionally, 50 mg/kg FDA increased the production of IFN-γ in CD4 and CD8 T cells by 4.3-fold and 7.2-fold, respectively, compared to the PBS control. FDA promoted immune cell activation was TLR4 dependent. Furthermore, anti-PD-L1 antibody administration inhibited CT-26 tumor growth by approximately 3-fold compared to the PBS control group, whereas combined treatment with FDA and anti-PD-L1 antibody showed an 8.4-fold tumor growth inhibition effect compared to the PBS control group. Therefore, FDA may be used to enhance the anti-cancer effects of immune checkpoint inhibitors.

Strategies to Overcome Hurdles in Cancer Immunotherapy

Despite marked advancements in cancer immunotherapy over the past few decades, there remains an urgent need to develop more effective treatments in humans. This review explores strategies to overcome hurdles in cancer immunotherapy, leveraging innovative technologies including multi-specific antibodies, chimeric antigen receptor (CAR) T cells, myeloid cells, cancer-associated fibroblasts, artificial intelligence (AI)-predicted neoantigens, autologous vaccines, and mRNA vaccines. These approaches aim to address the diverse facets and interactions of tumors' immune evasion mechanisms. Specifically, multi-specific antibodies and CAR T cells enhance interactions with tumor cells, bolstering immune responses to facilitate tumor infiltration and destruction. Modulation of myeloid cells and cancer-associated fibroblasts targets the tumor's immunosuppressive microenvironment, enhancing immunotherapy efficacy. AI-predicted neoantigens swiftly and accurately identify antigen targets, which can facilitate the development of personalized anticancer vaccines. Additionally, autologous and mRNA vaccines activate individuals' immune systems, fostering sustained immune responses against cancer neoantigens as therapeutic vaccines. Collectively, these strategies are expected to enhance efficacy of cancer immunotherapy, opening new horizons in anticancer treatment.

Anti-4-1BB×PDL1 Bispecific Antibody Reinvigorates Tumor-Specific Exhausted CD8+ T Cells and Enhances the Efficacy of Anti-PD1 Blockade

PURPOSE

To overcome the limited efficacy of immune checkpoint blockade, there is a need to find novel cancer immunotherapeutic strategies for the optimal treatment of cancer. The novel anti-4-1BB×PDL1 bispecific antibody-ABL503 (also known as TJ-L14B)-was designed to simultaneously target PDL1 and 4-1BB and demonstrated strong antitumor T-cell responses without considerable toxicity. In this study, we investigated the mechanisms by which the combination of ABL503 and anti-PD1 blockade affected the reinvigoration of exhausted tumor-infiltrating CD8+ T cells (CD8+ TIL) and antitumor efficacy.

EXPERIMENTAL DESIGN

Single-cell suspensions of hepatocellular carcinoma and ovarian cancer tissues from treatment-naïve patients were used for immunophenotyping of CD8+ TILs and in vitro functional assays. Humanized hPD1/hPDL1/h4-1BB triple-knock-in mice were used to evaluate the effects of ABL503 and anti-PD1 blockade in vivo.

RESULTS

We observed that ABL503 successfully restored the functions of 4-1BB+ exhausted CD8+ TILs, which were enriched for tumor-specific T cells but unresponsive to anti-PD1 blockade. Importantly, compared with anti-PD1 blockade alone, the combination of ABL503 and anti-PD1 blockade further enhanced the functional restoration of human CD8+ TILs in vitro. Consistently, the combination of ABL503 with anti-PD1 in vivo significantly alleviated tumor growth and induced enhanced infiltration and activation of CD8+ TILs.

CONCLUSIONS

ABL503, a PDL1 and 4-1BB dual-targeting bispecific antibody, elicits pronounced additive tumor growth inhibition, with increased infiltration and functionality of exhausted CD8+ T cells, which in turn enhances the anticancer effects of anti-PD1 blockade. These promising findings suggest that ABL503 (TJ-L14B) in combination with PD1 inhibitors will likely further enhance therapeutic benefit in clinical trials. See related commentary by Molero-Glez et al., p. 3971.

Janus kinase inhibitor overcomes resistance to immune checkpoint inhibitor treatment in peritoneal dissemination of gastric cancer in C57BL/6 J mice

BACKGROUND

Cancer immunotherapy aims to unleash the immune system's potential against cancer cells, providing sustained relief for tumors responsive to immune checkpoint inhibitors (ICIs). While promising in gastric cancer (GC) trials, the efficacy of ICIs diminishes in the context of peritoneal dissemination. Our objective is to identify strategies to enhance the impact of ICI treatment specifically for cases involving peritoneal dissemination in GC.

METHODS

The therapeutic efficacy of anti-PD1, CTLA4 treatment alone, or in combination was assessed using the YTN16 peritoneal dissemination tumor model. Peritoneum and peritoneal exudate cells were collected for subsequent analysis. Immunohistochemical staining, flow cytometry, and bulk RNA-sequence analyses were conducted to evaluate the tumor microenvironment (TME). A Janus kinase inhibitor (JAKi) was introduced based on the pathway analysis results.

RESULTS

Anti-PD1 and anti-CTLA4 combination treatment (dual ICI treatment) demonstrated therapeutic efficacy in certain mice, primarily mediated by CD8 + T cells. However, in mice resistant to dual ICI treatment, even with CD8 + T cell infiltration, most of the T cells exhibited an exhaustion phenotype. Notably, resistant tumors displayed abnormal activation of the Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) pathway compared to the untreated group, with observed infiltration of macrophages, neutrophils, and Tregs in the TME. The concurrent administration of JAKi rescued CD8 + T cells function and reshaped the immunosuppressive TME, resulting in enhanced efficacy of the dual ICI treatment.

CONCLUSION

Dual ICI treatment exerts its anti-tumor effects by increasing tumor-specific CD8 + T cell infiltration, and the addition of JAKi further improves ICI resistance by reshaping the immunosuppressive TME.

Harnessing IL-2 for immunotherapy against cancer and chronic infection: a historical perspective and emerging trends

IL-2 therapy, which enhances the function of CD8 + T cells, was initially employed as the cornerstone of immunotherapy against cancer. However, the impact of this therapy extends beyond CD8 + T cells to cells expressing IL-2R, such as endothelial cells and regulatory T cells (Tregs), resulting in various side effects. Consequently, IL-2 therapy has taken a step back from the forefront of treatment. Immune checkpoint inhibitors (ICIs), such as anti-PD-1/PD-L1 antibodies and CTLA-4 antibodies, are used because of their durable therapeutic responses and the reduced incidence of side effects. Nevertheless, only a small fraction of cancer patients respond to ICIs, and research on IL-2 as a combination treatment to improve the efficacy of these ICIs is ongoing. To mitigate side effects, efforts have focused on developing IL-2 variants that do not strongly bind to cells expressing IL-2Rα and favor signaling through IL-2Rβγ. However, recent studies have suggested that, in the context of persistent antigen stimulation models, effective stimulation of antigen-specific exhausted CD8 + T cells in combination with PD-1 inhibitors requires either 1) binding to IL-2Rα or 2) delivery via a fusion with PD-1. This review explores the historical context of IL-2 as an immunotherapeutic agent and discusses future directions for its use in cancer immunotherapy.

Optimal control of combination immunotherapy for a virtual murine cohort in a glioblastoma-immune dynamics model

The immune checkpoint inhibitor anti-PD-1, commonly used in cancer immunotherapy, has not been successful as a monotherapy for the highly aggressive brain cancer glioblastoma. However, when used in conjunction with a CC-chemokine receptor-2 (CCR2) antagonist, anti-PD-1 has shown efficacy in preclinical studies. In this paper, we aim to optimize treatment regimens for this combination immunotherapy using optimal control theory. We extend a treatment-free glioblastoma-immune dynamics ODE model to include interventions with anti-PD-1 and the CCR2 antagonist. An optimized regimen increases the survival of an average mouse from 32 days post-tumor implantation without treatment to 111 days with treatment. We scale this approach to a virtual murine cohort to evaluate mortality and quality of life concerns during treatment, and predict survival, tumor recurrence, or death after treatment. A parameter identifiability analysis identifies five parameters suitable for personalizing treatment within the virtual cohort. Sampling from these five practically identifiable parameters for the virtual murine cohort reveals that personalized, optimized regimens enhance survival: 84% of the virtual mice survive to day 100, compared to 60% survival in a previously studied experimental regimen. Subjects with high tumor growth rates and low T cell kill rates are identified as more likely to die during and after treatment due to their compromised immune systems and more aggressive tumors. Notably, the MDSC death rate emerges as a long-term predictor of either disease-free survival or death.

Significant Association of PD-L1 With CD44 Expression and Patient Survival: Avenues for Immunotherapy and Cancer Stem Cells Downregulation in Pancreatic Cancers

Background: Pancreatic cancers are known for their aggressive nature. This aggressiveness may be attributed to the presence of cancer stem cells (CSCs), which promote relapse, metastasis, and resistance to chemotherapy. Targeting CSCs is essential to reverse this aggressiveness in pancreatic malignancies. Literature highlights the association of PD-L1 expression with CSCs in various cancers, suggesting immunotherapy as a promising therapeutic approach. This study is aimed at investigating the potential of immunotherapy in pancreatic cancers by examining its association with selected CSC marker expression. Method: A retrospective cohort study was conducted involving 56 patients with confirmed diagnoses of pancreatic cancers at Aga Khan University Hospital from January 2015 to October 2022. After exclusions, based on refusal to provide consent or incomplete follow-up data, 38 patients were enrolled in the study. Immunohistochemistry was performed on formalin-fixed paraffin-embedded (FFPE) tumor tissue samples to assess the expression of CSC markers (CD133, CD44, and L1CAM) and immune checkpoint inhibitor marker (PD-L1). Statistical analysis was employed to determine associations between marker expression, clinical factors, and overall survival. Results: The study revealed that 86.8% of pancreatic cancer cases exhibited positive PD-L1 expression. Moreover, a significant association of PD-L1 expression was observed with the presence of CD44 protein (p = 0.030), as well as with the overall survival of patients (p = 0.023). Conclusion: Our findings show a significant association of PD-L1 with CD44 marker expression as well as patient survival. This research shows the potential to serve as the foundation for investigating the efficacy of immunotherapy in reducing CD44-expressing CSCs in pancreatic cancer, potentially enhancing patient outcomes.

Mutant ARID1A: igniting cancer immunotherapy

Maxwell et al. show that ARID1A loss enhances antitumor immunity by triggering a type I IFN response through the cGAS-STING pathway, thereby promoting T cell infiltration and cytotoxicity. These findings highlight SWI/SNF inhibitors as a strategy to augment immunotherapy efficacy by potentially transforming non-responsive tumors into responders and advancing approaches to cancer treatment.

Multi-Layered Mechanisms of Immunological Tolerance at the Maternal-Fetal Interface

Pregnancy represents an immunological paradox where the maternal immune system must tolerate the semi-allogeneic fetus expressing paternally-derived Ags. Accumulating evidence over decades has revealed that successful pregnancy requires the active development of robust immune tolerance mechanisms. This review outlines the multi-layered processes that establish fetomaternal tolerance, including the physical barrier of the placenta, restricted chemokine-mediated leukocyte trafficking, lack of sufficient alloantigen presentation, the presence of immunosuppressive regulatory T cells and tolerogenic decidual natural killer cells, expression of immune checkpoint molecules, specific glycosylation patterns conferring immune evasion, and unique metabolic/hormonal modulations. Interestingly, many of the strategies that enable fetal tolerance parallel those employed by cancer cells to promote angiogenesis, invasion, and immune escape. As such, further elucidating the mechanistic underpinnings of fetal-maternal tolerance may reciprocally provide insights into developing novel cancer immunotherapies as well as understanding the pathogenesis of gestational complications linked to dysregulated tolerance processes.

Advancements in Immunotherapy for Breast Cancer: Mechanisms, Efficacy, and Future Directions

Breast cancer is a major global health challenge characterized by its diverse biological behavior and varying treatment responses. Traditional therapies, including surgery, radiation, chemotherapy, hormonal therapy, and targeted therapy, have significantly advanced breast cancer treatment but are often limited by issues such as resistance, side effects, and variable efficacy. Immunotherapy has emerged as a transformative approach, leveraging the body's immune system to target and eliminate cancer cells. This review provides a comprehensive overview of recent advancements in immunotherapy for breast cancer, detailing the mechanisms of various therapeutic strategies, including checkpoint inhibitors, monoclonal antibodies, cancer vaccines, adoptive cell therapy, and oncolytic virus therapy. We evaluate the efficacy of these approaches in different stages of breast cancer, highlighting successes and challenges encountered in clinical settings. The review also addresses the current limitations of immunotherapy, such as treatment-related adverse effects, resistance mechanisms, and issues of cost and accessibility. We discuss promising future directions, including emerging targets, combination therapies, and personalized medicine approaches. By integrating recent research and clinical trial data, this review aims to elucidate the potential of immunotherapy to revolutionize breast cancer treatment, offering insights into its future role in improving patient outcomes and shaping the landscape of oncological care.

Myocarditis Induced by Immune Checkpoint Inhibitors: An Exploratory Review

Checkpoints are essential proteins in the immune system that regulate the intensity and duration of immune responses, preventing damage to healthy tissues during the fight against pathogens and abnormal cells. While these mechanisms are crucial in cancer defense, this disease can alter the functionality of these proteins. This is why checkpoint inhibitors have emerged as an important class of drugs to potentiate the antitumor immune response. However, it has been observed that these drugs can trigger adverse effects, among which myocarditis is one of the most prevalent. This article explores the signaling pathways associated with checkpoint inhibitors, their adverse effects, and their impact on the development of myocarditis, as well as potential therapeutic strategies.

Hepatobiliary complications of immune checkpoint inhibitors in cancer

Immune checkpoint inhibitors (ICIs) have dramatically changed the landscape of cancer therapy. Over the last decade, both their primary focus in trials and clinical application have exponentially risen, with repeated demonstrations of their efficacy in improving survival in various cancer types. The adverse effects of these drugs on various organ systems were recognised in early phase studies. Given their relatively new emergence on the market, there has been increasing interest into short- and long-term effects and management of ICIs in real-world settings. ICI-related hepatobiliary toxicities are often challenging to diagnose and difficult to distinguish from other causes of deranged liver biochemical tests. The aim of this review is to provide an up-to-date and detailed exploration of the hepatobiliary complications of ICIs, including pathogenesis and approaches to diagnosis and management.

Immune Checkpoint Inhibitors for Pediatric Cancers: Is It Still a Stalemate?

The knowledge surrounding the application of immune checkpoint inhibitors (ICIs) in the treatment of pediatric cancers is continuously expanding and evolving. These therapies work by enhancing the body's natural immune response against tumors, which may have been suppressed by certain pathways. The effectiveness of ICIs in treating adult cancers has been widely acknowledged. However, the results of early phase I/II clinical trials that exclusively targeted the use of ICIs for treating different pediatric cancers have been underwhelming. The response rates to ICIs have generally been modest, except for cases of pediatric classic Hodgkin lymphoma. There seems to be a notable disparity in the immunogenicity of childhood cancers compared to adult cancers, potentially accounting for this phenomenon. On average, childhood cancers tend to have significantly fewer neoantigens. In recent times, there has been a renewed sense of optimism regarding the potential benefits of ICI therapies for specific groups of children with cancer. In initial research, individuals diagnosed with pediatric hypermutated and SMARCB1-deficient cancers have shown remarkable positive outcomes when treated with ICI therapies. This is likely due to the underlying biological factors that promote the expression of neoantigens and inflammation within the tumor. Ongoing trials are diligently assessing the effectiveness of ICIs for pediatric cancer patients in these specific subsets. This review aimed to analyze the safety and effectiveness of ICIs in pediatric patients with different types of highly advanced malignancies.

The efficacy outcomes in non-small cell lung cancer patients treated with PD axis inhibitor agents - a population-based study of the Vojvodina region

Background: By 2021, the FDA approved the use of the drugs pembrolizumab and atezolizumab in the first-line treatment of patients with high positivity of programmed death ligand-1 (PD-L1) in locally advanced and metastatic non-small-cell-lung cancer (NSCLC). This approval was the result of statistically significant evidence from international, multicentric clinical studies that all reported increasing progression-free survival (PFS) and overall survival (OS) in these patients. Methods: In our study, we reported the demographic and clinical characteristics of 79 patients diagnosed with NSCLC with expression of PD-L1 ≥50% from January 2019 to December 2022 at the Institute for Pulmonary Diseases of Vojvodina, who received pembrolizumab therapy as the first-line treatment. Patients were divided according to the histological type of lung cancer as adenocarcinoma (ADC) or squamous cell carcinoma (SCC) of the lung. In 52 of the 79 patients, PFS and in 32 of them overall survival (censored OS) was shown according to the histological type of tumor, the tumor proportion score (TPS) of PDL-1 expression, and the metastatic status within the Tumor Nodes Metastasis (TNM) disease classification. Independent factors of death outcome were shown by multivariable proportional hazard regression analysis. Results: The study included 79 patients diagnosed with NSCLC with an expression of PD-L1 ≥50%, 50 (63.3%) patients with ADC, and 29 (36.7%) patients with SCC, whose 55 (69.6%) PDL-1 expression was obtained from broncho biopsy (BB). The majority of patients, 49 (62%), had a TPS PD-L1 score of 51%-79%. Median, PFS for adenocarcinoma was 22 months and censored OS was 27 months, while for squamous cell carcinoma, median PFS was 12 months, and censored OS was 21 months. M1b disease stage, which was the most common in patients, had a PFS of 16 months and a censored OS of 18 months. Conclusion: Pembrolizumab monotherapy in patients with NSCLC in the fourth stage of the disease and with the positivity of the immune checkpoint protein TPS PD-L1 above 50% represents a safe therapy that allows a satisfactory period without disease progression and overall survival with acceptable treatment complications.

Immune Checkpoint Inhibition-related Neuroinflammation Disrupts Cognitive Function

Combinatorial blockade of Cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and Programmed Cell Death Protein 1 (PD-1) significantly improve the progression-free survival of individuals with metastatic cancers, including melanoma. In addition to unleashing anti-tumor immunity, combination immune checkpoint inhibition (ICI) disrupts immune-regulatory networks critical for maintaining homeostasis in various tissues, including the central nervous system (CNS). Although ICI- and cancer-related cognitive impairments (CRCI) in survivors are increasingly becoming evident, our understanding of ICI-induced immune-related adverse effects (IREA) in the CNS remains incomplete. Here, our murine melanoma model reveals that combination ICI impairs hippocampal-dependent learning and memory, as well as memory consolidation processes. Mechanistically, combination ICI disrupted synaptic integrity, and neuronal plasticity, reduced myelin, and further predisposed CNS for exaggerated experimental autoimmune encephalomyelitis. Combination ICI substantially altered both lymphoid and myeloid cells in the CNS. Neurogenesis was unaffected, however, microglial activation persisted for two-months post- ICI, concurrently with cognitive deficits, which parallels clinical observations in survivors. Overall, our results demonstrate that blockade of CTLA-4 and PD-1 alters neuro-immune homeostasis and activates microglia, promoting long-term neurodegeneration and driving cognitive impairments. Therefore, limiting microglial activation is a potential avenue to mitigate CNS IRAE while maintaining the therapeutic benefits of rapidly evolving ICIs and their combinations.

SIGNIFICANCE

Despite the superior therapeutic efficacy of immune checkpoint inhibition (ICI) for cancers, its undesired effects on brain function are not fully understood. Here, we demonstrate that combination ICI elevates neuroinflammation, activates microglia, leading to detrimental neurodegenerative and neurocognitive sequelae.

Unaddressed Challenges in the Treatment of Cutaneous Melanoma?

Background and Objectives: While the management of noninvasive cutaneous melanoma (CM) is typically limited to a secondary excision to reduce recurrence risk and periodic follow-up, treating patients with advanced melanoma presents ongoing challenges. Materials and Methods: This review provides a comprehensive examination of both established and emerging pharmacologic strategies for advanced CM management, offering an up-to-date insight into the current therapeutic milieu. The dynamic landscape of advanced CM treatment is explored, highlighting the efficacy of immune checkpoint inhibitors and targeted therapies, either in monotherapy or combination regimens. Additionally, ongoing investigations into novel treatment modalities are thoroughly discussed, reflecting the evolving nature of melanoma management. Results: The therapeutic landscape for melanoma management is undergoing significant transformation. Although various treatment modalities exist, there remains a critical need for novel therapies, particularly for certain stages of melanoma or cases resistant to current options. Conclusions: Consequently, further studies are warranted to identify new treatment avenues and optimize the utilization of existing drugs.

Immunomodulatory Precision: A Narrative Review Exploring the Critical Role of Immune Checkpoint Inhibitors in Cancer Treatment

An immune checkpoint is a signaling pathway that regulates the recognition of antigens by T-cell receptors (TCRs) during an immune response. These checkpoints play a pivotal role in suppressing excessive immune responses and maintaining immune homeostasis against viral or microbial infections. There are several FDA-approved immune checkpoint inhibitors (ICIs), including ipilimumab, pembrolizumab, and avelumab. These ICIs target cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed death ligand 1 (PD-L1). Furthermore, ongoing efforts are focused on developing new ICIs with emerging potential. In comparison to conventional treatments, ICIs offer the advantages of reduced side effects and durable responses. There is growing interest in the potential of combining different ICIs with chemotherapy, radiation therapy, or targeted therapies. This article comprehensively reviews the classification, mechanism of action, application, and combination strategies of ICIs in various cancers and discusses their current limitations. Our objective is to contribute to the future development of more effective anticancer drugs targeting immune checkpoints.

Update on Neuro-ophthalmic Manifestations of Immune Checkpoint Inhibitors

PURPOSE OF REVIEW

Immune checkpoint inhibitor (ICI) use has been on the rise for treatment of many different malignancies. Subsequently, more has been learned about immune-related adverse events (irAEs) that occur up to 12 months after treatment. This review summarizes the latest findings and management of neuro-ophthalmic associated irAEs.

RECENT FINDINGS

irAEs can affect the afferent and efferent neuro-ophthalmic pathways, thereby targeting central and peripheral nervous systems. As more cases are being reported, it is becoming apparent that neuro-ophthalmic irAEs often present with atypical features when compared to their spontaneous autoimmune counterparts. These neuro-ophthalmic presentations can also be signs of a more extensive inflammatory process that spans other organ systems, such as myopathies, endocrinopathies, and paraneoplastic syndromes. Awareness of neuro-ophthalmic irAEs and their atypical presentations can lead to early detection, termination of ICI treatment, and immunosuppressant therapy initiation.

Cancer immunotherapy with immune checkpoint inhibitors and infections: A particular focus on mycobacterial infections

Cancer treatment is undergoing a major transformation with the advent of immunotherapy with immune checkpoint inhibitors. These drugs, which have a different mechanism of action from conventional cytotoxic chemotherapy, are transforming treatment paradigms for many patients suffering from advanced cancer. On the other hand, they are often complicated by specific adverse events, known as immune-related adverse events (irAEs). Infections occurring during immunotherapy with immune checkpoint inhibitors have recently received increasing attention and sometimes are seen as part of irAEs. Amongst these, mycobacterial infections have attracted particular attention. Recent reports have shown that infections occurring during immunotherapy can not only be caused by immunosuppression, but in addition new type of infections are observed that are not caused by immunosuppression. Specifically, tuberculosis (TB) has recently been shown to develop as a result of an imbalance in immunoregulation and an excessive immune response. This review highlights reports of infections during immunotherapy with immune checkpoint inhibitors, followed by a focus on the association with TB and nontuberculous mycobacteria. It concludes with a discussion of the possible mechanisms of pathogenesis and the implications for clinical practice.

Investigating the synergistic effects of immunotherapy and normalization treatment in modulating tumor microenvironment and enhancing treatment efficacy

We developed a comprehensive mathematical model of cancer immunotherapy that takes into account: i) Immune checkpoint blockers (ICBs) and the interactions between cancer cells and the immune system, ii) characteristics of the tumor microenvironment, such as the tumor hydraulic conductivity, interstitial fluid pressure, and vascular permeability, iii) spatial and temporal variations of the modeled components within the tumor and the surrounding host tissue, iv) the transport of modeled components through the vasculature and between the tumor-host tissue with convection and diffusion, and v) modeling of the tumor draining lymph nodes were the antigen presentation and the development of cytotoxic immune cells take place. Our model successfully reproduced experimental data from various murine tumor types and predicted immune system profiling, which is challenging to achieve experimentally. It showed that combination of ICB therapy and normalization treatments, that aim to improve tumor perfusion, decreases interstitial fluid pressure and increases the concentration of both innate and adaptive immune cells at the tumor center rather than the periphery. Furthermore, using the model, we investigated the impact of modeled components on treatment outcomes. The analysis found that the number of functional vessels inside the tumor region and the ICB dose administered have the largest impact on treatment outcomes.

Clinical and basic science aspects of innate lymphoid cells as novel immunotherapeutic targets in cancer treatment

Immunotherapy has revolutionised cancer treatment over the past decade, demonstrating remarkable efficacy across a broad range of cancer types. However, not all patients or cancer types respond to contemporary clinically-utilised immunotherapeutic strategies, which largely focus on harnessing adaptive immune T cells for cancer treatment. Accordingly, it is increasingly recognised that upstream innate immune pathways, which govern and orchestrate the downstream adaptive immune response, may prove critical in overcoming cancer immunotherapeutic resistance. Innate lymphoid cells (ILCs) are the most recently discovered major innate immune cell population. They have overarching roles in homeostasis and orchestrating protective immunity against pathogens. As innate immune counterparts of adaptive immune T cells, ILCs exert effector functions through the secretion of cytokines and direct cell-to-cell contact, with broad influence on the overall immune response. Importantly, dysregulation of ILC subsets have been associated with a range of diseases, including immunodeficiency disorders, allergy, autoimmunity, and more recently, cancer. ILCs may either promote or inhibit cancer initiation and progression depending on the cancer type and the specific ILC subsets involved. Critically, therapeutic targeting of ILCs and their associated cytokines shows promise against a wide range of cancer types in both preclinical models and early phase oncology clinical trials. This chapter provides a comprehensive overview of the current understanding of ILC subsets and the associated cytokines they produce in cancer pathogenesis, with specific focus on how these innate pathways are, or can be targeted, therapeutically to overcome therapeutic resistance and ultimately improve patient care.

Exploring the safety profile of tremelimumab: an analysis of the FDA adverse event reporting system

BACKGROUND

Despite the approval of tremelimumab in 2022, there is a lack of pharmacovigilance studies investigating its safety profile in real-world settings using the FDA Adverse Event Reporting System (FAERS) database.

AIM

This pharmacovigilance study aimed to comprehensively explore the adverse events (AEs) associated with tremelimumab using data mining techniques on the FAERS database.

METHOD

The study utilized data from the FAERS database, covering the period from the first quarter of 2004 to the third quarter of 2022. Disproportionality analysis, the Benjamini Hochberg adjustment method and volcano plots were used to identify and evaluate AE signals associated with tremelimumab.

RESULTS

The study uncovered 233 AE cases associated with tremelimumab. Among these cases, pyrexia (n = 39), biliary tract infection (n = 23), and sepsis (n = 21) were the three main AEs associated with tremelimumab use. The study also investigated the system organ classes associated with tremelimumab-related AEs. The top three classes were gastrointestinal disorders (17.9%), infections and infestations (16.6%), and general disorders and administration site infections (11.2%). Several AEs were identified that were not listed on the drug label of tremelimumab. These AEs included pyrexia, biliary tract infection, sepsis, dyspnea, infusion site infection, hiccup, appendicitis, hypotension, dehydration, localised oedema, presyncope, superficial thrombophlebitis and thrombotic microangiopathy.

CONCLUSION

This pharmacovigilance study identified several potential adverse events signals related to tremelimumab including some adverse events not listed on the drug label. However, further basic and clinical research studies are needed to validate these results.

Immune Cytolytic Activity and Strategies for Therapeutic Treatment

Intratumoral immune cytolytic activity (CYT), calculated as the geometric mean of granzyme-A (GZMA) and perforin-1 (PRF1) expression, has emerged as a critical factor in cancer immunotherapy, with significant implications for patient prognosis and treatment outcomes. Immune checkpoint pathways, the composition of the tumor microenvironment (TME), antigen presentation, and metabolic pathways regulate CYT. Here, we describe the various methods with which we can assess CYT. The detection and analysis of tumor-infiltrating lymphocytes (TILs) using flow cytometry or immunohistochemistry provide important information about immune cell populations within the TME. Gene expression profiling and spatial analysis techniques, such as multiplex immunofluorescence and imaging mass cytometry allow the study of CYT in the context of the TME. We discuss the significant clinical implications that CYT has, as its increased levels are associated with positive clinical outcomes and a favorable prognosis. Moreover, CYT can be used as a prognostic biomarker and aid in patient stratification. Altering CYT through the different methods targeting it, offers promising paths for improving treatment responses. Overall, understanding and modulating CYT is critical for improving cancer immunotherapy. Research into CYT and the factors that influence it has the potential to transform cancer treatment and improve patient outcomes.

A comprehensive analysis of CD47 expression in various histological subtypes of soft tissue sarcoma: exploring novel opportunities for macrophage-directed treatments

PURPOSE

The CD47 molecule, often referred to as the "do not eat me" signal, is frequently overexpressed in tumor cells. This signaling pathway limits phagocytosis by macrophages. Our objective was to determine CD47 abundance in various soft tissue sarcomas (STS) to investigate whether it could serve as a potential evasion mechanism for tumor cells. Additionally, we aimed to assess the prognostic value of CD47 expression by examining its association with different clinicopathological factors. This study aimed to elucidate the significance of CD47 in the context of emerging anti-tumor targeting approaches.

METHODS

In this retrospective study, formalin-fixed paraffine-embedded (FFPE) tumor tissues of 55 treatment-naïve patients were evaluated by immunohistochemistry for the abundance of CD47 molecule on tumor cells. The categorization of CD47 positivity was as follows: 0 (no staining of tumor cells), 1 + (less than 1/3 of tumor area positive), 2 + (between 1/3 and 2/3 of tumor area positive), and 3 + (more than 2/3 of tumor area positive for CD47). Next, we compared CD47 abundance between different tumor grades (G1-3). We used Kaplan-Meier survival curves with log-rank test to analyze the differences in survival between patients with different CD47 expression. Moreover, we performed Cox proportional hazards regression model to evaluate the clinical significance of CD47.

RESULTS

CD47 is widely prevalent across distinct STS subtypes. More than 80% of high grade undifferentiated pleiomorphic sarcoma (UPS), 70% of myxofibrosarcoma (MFS) and more than 60% of liposarcoma (LPS) samples displayed a pattern of moderate-to-diffuse positivity. This phenomenon remains consistent regardless of the tumor grade. However, there was a tendency for higher CD47 expression levels in the G3 group compared to the combined G1 + G2 groups when all LPS, MFS, and UPS were analyzed together. No significant associations were observed between CD47 abundance, death, and metastatic status. Additionally, high CD47 expression was associated with a statistically significant increase in progression-free survival in the studied cohort of patients.

CONCLUSION

This study highlights the potential of the CD47 molecule as a promising immunotherapeutic target in STS, particularly given its elevated expression levels in diverse sarcoma types. Our data showed a notable trend linking CD47 expression to tumor grade, while also suggesting an interesting correlation between enhanced abundance of CD47 expression and a reduced hazard risk of disease progression. Although these findings shed light on different roles of CD47 in STS, further research is crucial to assess its potential in clinical settings.

Potent induction of antitumor immunity by combining cryo-thermal ablation with immune checkpoint inhibitors in hepatocellular carcinoma

BACKGROUND

The low response rate of immune checkpoint inhibitors (ICIs) prompts the exploration of novel combination therapies for patients with hepatocellular carcinoma (HCC). Here, we aimed to examine the efficiency and potential mechanism of cryo-thermal ablation (Cryo-A) combined with anti-programmed death protein 1 (αPD1) and/or cytotoxic T-lymphocyte antigen 4 (αCTLA4) inhibitors in a murine hepatoma model.

METHOD

Immunocompetent C57BL/6 mice inoculated with unilateral or bilateral H22 hepatic tumour cells were treated with Cryo-A and/or ICIs (αPD1 and/or αCTLA4). Flow cytometry, immunohistochemistry, ELISpot assay, time-of-flight cytometry, tumour rechallenging, and T-cell depletion assay were used to assess the dynamic changes of immune cell subsets following therapy.

RESULTS

We found Cryo-A resulted in immunogenic cell death of tumour cells, activation of dendritic cells, and enhancement of antitumor immunity. Cryo-A alone was insufficient to extend survival, combining Cryo-A with αPD1 and αCTLA4 further modulated the tumour microenvironment, inducing a durable antitumor immune response by tumour-reactive CD8+ T cells and significantly prolonged survival. Time-of-flight cytometry (CyTOF) data revealed that combination therapies reshaped the tumour microenvironment by the increase of intratumoral CD8+ T cells expressed higher levels of cytotoxic markers and immune checkpoint molecules, and by downregulation of intratumoral granulocytes. The combination also resulted in the eradication of remote unablated tumours (abscopal effect).

CONCLUSIONS

These findings suggested that Cryo-A turned HCC from "cold" tumours to "hot" tumours and the combination of Cryo-A with αPD1 and αCTLA4 may be a promising approach to improve the prognosis of HCC.

A narrative review of the controversy on the risk of mycobacterial infections with immune checkpoint inhibitor use: does Goldilocks have the answer?

Background and Objective

Immune checkpoint inhibitors (ICIs) have revolutionized oncologic treatment. Whether ICIs increase susceptibility to or provide protection against mycobacterial infections remains controversial. The objective of this narrative review is to summarize the literature on the link between ICI use and mycobacterial infections-tuberculosis and non-tuberculous mycobacterial (NTM) infections-and to critically discuss evidence linking ICIs with mycobacterial infections, the possible confounders, and, if indeed the ICIs predispose to such infections, the potential mechanisms of how this may occur.

Methods

We conducted a literature search on PubMed for relevant articles published from 2011 to current time [2024] utilizing specific keywords of "immune checkpoint inhibitors", "programmed cell death protein-1", "PD-1", "programmed death-ligand 1", "PD-L1", "cytotoxic T-lymphocyte-associated protein-4", or "CTLA-4" with that of "non-tuberculous mycobacterial lung disease", "tuberculosis", or "mycobacteria". The bibliographies of identified papers were perused for additional relevant articles.

Key Content and Findings

Ex vivo studies using human cells indicate that ICIs would be salubrious for the host against mycobacteria. Yet, many case reports associate ICI use with mycobacterial infections, mostly tuberculosis. Potential confounders include immunosuppression from the cancer, concomitant use of immunosuppressive drugs, lung injury and distortion from chemotherapeutics or radiation, and reporting bias. Mice with genetic disruption of the programmed cell death protein-1 (PD-1) gene are paradoxically more susceptible to Mycobacterium tuberculosis (M. tuberculosis). In contrast, mice administered neutralizing antibody to T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) or knocked out for TIM3 gene have greater capacity to control an M. tuberculosis infection. We posit that hosts with greater baseline immunodeficiency are more likely to derive benefit from ICIs against mycobacterial infections than those with more intact immunity, where ICIs are more likely to be detrimental.

Conclusions

Studies are needed to test the hypothesis that ICIs may either protect or predispose to mycobacterial infections, depending on the baseline host immune status. Prospective studies are required of patients on ICIs that control for potential confounders as anecdotal case reports are insufficient to provide a causal link. Murine studies with ICIs are also required to corroborate or refute studies of mice with genetic disruption of an immune checkpoint.

Importance of targeting various cell signaling pathways in solid cancers

Most adult human cancers are solid tumors prevailing in vital organs and lead to mortality all over the globe. Genetic and epigenetic alterations in cancer genes or genes of associated signaling pathways impart the most common characteristic of malignancy, that is, uncontrolled proliferation. Unless the mechanism of action of these cells signaling pathways (involved in cell proliferation, apoptosis, metastasis, and the maintenance of the stemness of cancer stem cells and cancer microenvironment) and their physiologic alteration are extensively studied, it is challenging to understand tumorigenesis as well as develop new treatments and precision medicines. Targeted therapy is one of the most promising strategies for treating various cancers. However, cancer is an evolving disease, and most patients develop resistance to these drugs by acquired mutations or mediation of microenvironmental factors or due to tumor heterogeneity. Researchers are striving to develop novel therapeutic options like combinatorial approaches targeting multiple responsible pathways effectively. Thus, in-depth knowledge of cell signaling and its components remains a critical topic of cancer research. This chapter summarized various extensively studied pathways in solid cancer and how they are targeted for therapeutic strategies.

Toripalimab, a therapeutic monoclonal anti-PD-1 antibody with high binding affinity to PD-1 and enhanced potency to activate human T cells

Over the past decade, US Food and Drug Administration (FDA)-approved immune checkpoint inhibitors that target programmed death-1 (PD-1) have demonstrated significant clinical benefit particularly in patients with PD-L1 expressing tumors. Toripalimab is a humanized anti-PD-1 antibody, approved by FDA for first-line treatment of nasopharyngeal carcinoma in combination with chemotherapy. In a post hoc analysis of phase 3 studies, toripalimab in combination with chemotherapy improved overall survival irrespective of PD-L1 status in nasopharyngeal carcinoma (JUPITER-02), advanced non-small cell lung cancer (CHOICE-01) and advanced esophageal squamous cell carcinoma (JUPITER-06). On further characterization, we determined that toripalimab is molecularly and functionally differentiated from pembrolizumab, an anti-PD-1 mAb approved previously for treating a wide spectrum of tumors. Toripalimab, which binds the FG loop of PD-1, has 12-fold higher binding affinity to PD-1 than pembrolizumab and promotes significantly more Th1- and myeloid-derived inflammatory cytokine responses in healthy human PBMCs in vitro. In an ex vivo system employing dissociated tumor cells from treatment naïve non-small cell lung cancer patients, toripalimab induced several unique genes in IFN-γ and immune cell pathways, showed different kinetics of activation and significantly enhanced IFN-γ signature. Additionally, binding of toripalimab to PD-1 induced lower levels of SHP1 and SHP2 recruitment, the negative regulators of T cell activation, in Jurkat T cells ectopically expressing PD-1. Taken together, these data demonstrate that toripalimab is a potent anti-PD-1 antibody with high affinity PD-1 binding, strong functional attributes and demonstrated clinical activity that encourage its continued clinical investigation in several types of cancer.

Mitigating non-genetic resistance to checkpoint inhibition based on multiple states of immune exhaustion

Despite the revolutionary impact of immune checkpoint inhibition on cancer therapy, the lack of response in a subset of patients, as well as the emergence of resistance, remain significant challenges. Here we explore the theoretical consequences of the existence of multiple states of immune cell exhaustion on response to checkpoint inhibition therapy. In particular, we consider the emerging understanding that T cells can exist in various states: fully functioning cytotoxic cells, reversibly exhausted cells with minimal cytotoxicity, and terminally exhausted cells. We hypothesize that inflammation augmented by drug activity triggers transitions between these phenotypes, which can lead to non-genetic resistance to checkpoint inhibitors. We introduce a conceptual mathematical model, coupled with a standard 2-compartment pharmacometric (PK) model, that incorporates these mechanisms. Simulations of the model reveal that, within this framework, the emergence of resistance to checkpoint inhibitors can be mitigated through altering the dose and the frequency of administration. Our analysis also reveals that standard PK metrics do not correlate with treatment outcome. However, we do find that levels of inflammation that we assume trigger the transition from the reversibly to terminally exhausted states play a critical role in therapeutic outcome. A simulation of a population that has different values of this transition threshold reveals that while the standard high-dose, low-frequency dosing strategy can be an effective therapeutic design for some, it is likely to fail a significant fraction of the population. Conversely, a metronomic-like strategy that distributes a fixed amount of drug over many doses given close together is predicted to be effective across the entire simulated population, even at a relatively low cumulative drug dose. We also demonstrate that these predictions hold if the transitions between different states of immune cell exhaustion are triggered by prolonged antigen exposure, an alternative mechanism that has been implicated in this process. Our theoretical analyses demonstrate the potential of mitigating resistance to checkpoint inhibitors via dose modulation.

Targeting Farnesoid X Receptor in Tumor and the Tumor Microenvironment: Implication for Therapy

The farnesoid-X receptor (FXR), a member of the nuclear hormone receptor superfamily, can be activated by bile acids (BAs). BAs binding to FXR activates BA signaling which is important for maintaining BA homeostasis. FXR is differentially expressed in human organs and exists in immune cells. The dysregulation of FXR is associated with a wide range of diseases including metabolic disorders, inflammatory diseases, immune disorders, and malignant neoplasm. Recent studies have demonstrated that FXR influences tumor cell progression and development through regulating oncogenic and tumor-suppressive pathways, and, moreover, it affects the tumor microenvironment (TME) by modulating TME components. These characteristics provide a new perspective on the FXR-targeted therapeutic strategy in cancer. In this review, we have summarized the recent research data on the functions of FXR in solid tumors and its influence on the TME, and discussed the mechanisms underlying the distinct function of FXR in various types of tumors. Additionally, the impacts on the TME by other BA receptors such as takeda G protein-coupled receptor 5 (TGR5), sphingosine-1-phosphate receptor 2 (S1PR2), and muscarinic receptors (CHRM2 and CHRM3), have been depicted. Finally, the effects of FXR agonists/antagonists in a combination therapy with PD1/PD-L1 immune checkpoint inhibitors and other anti-cancer drugs have been addressed.

The Defined TLR3 Agonist, Nexavant, Exhibits Anti-Cancer Efficacy and Potentiates Anti-PD-1 Antibody Therapy by Enhancing Immune Cell Infiltration

Nexavant was reported as an alternative to the TLR3 agonist of Poly(I:C) and its derivatives. The physicochemical properties, signaling pathways, anti-cancer effects, and mechanisms of Nexavant were investigated. The distinctive characteristics of Nexavant compared to that of Poly(I:C) were demonstrated by precise quantification, enhanced thermostability, and increased resistance to RNase A. Unlike Poly(I:C), which activates TLR3, RIG-I, and MDA5, Nexavant stimulates signaling through TLR3 and RIG-I but not through MDA5. Compared to Poly(I:C), an intratumoral Nexavant treatment led to a unique immune response, immune cell infiltration, and suppression of tumor growth in various animal cancer models. Nexavant therapy outperformed anti-PD-1 antibody treatment in all the tested models and showed a synergistic effect in combinational therapy, especially in well-defined cold tumor models. The effect was similar to that of nivolumab in a humanized mouse model. Intranasal instillation of Nexavant led to the recruitment of immune cells (NK, CD4+ T, and CD8+ T) to the lungs, suppressing lung metastasis and improving animal survival. Our study highlighted Nexavant's defined nature for clinical use and unique signaling pathways and its potential as a standalone anti-cancer agent or in combination with anti-PD-1 antibodies.

Mathematical modeling of intratumoral immunotherapy yields strategies to improve the treatment outcomes

Intratumoral injection of immunotherapy aims to maximize its activity within the tumor. However, cytokines are cleared via tumor vessels and escape from the tumor periphery into the host-tissue, reducing efficacy and causing toxicity. Thus, understanding the determinants of the tumor and immune response to intratumoral immunotherapy should lead to better treatment outcomes. In this study, we developed a mechanistic mathematical model to determine the efficacy of intratumorally-injected conjugated-cytokines, accounting for properties of the tumor microenvironment and the conjugated-cytokines. The model explicitly incorporates i) the tumor vascular density and permeability and the tumor hydraulic conductivity, ii) conjugated-cytokines size and binding affinity as well as their clearance via the blood vessels and the surrounding tissue, and iii) immune cells-cancer cells interactions. Model simulations show how the properties of the tumor and of the conjugated-cytokines determine treatment outcomes and how selection of proper parameters can optimize therapy. A high tumor tissue hydraulic permeability allows for the uniform distribution of the cytokines into the tumor, whereas uniform tumor perfusion is required for sufficient access and activation of immune cells. The permeability of the tumor vessels affects the blood clearance of the cytokines and optimal values depend on the size of the conjugates. A size >5 nm in radius was found to be optimal, whereas the binding of conjugates should be high enough to prevent clearance from the tumor into the surrounding tissue. In conclusion, development of strategies to improve vessel perfusion and tissue hydraulic conductivity by reprogramming the microenvironment along with optimal design of conjugated-cytokines can enhance intratumoral immunotherapy.

Histopathologic Manifestations of Immune Checkpoint Inhibitor Therapy-Associated Gastrointestinal Tract Injury: A Practical Review

Immune checkpoint inhibitors have revolutionized the management of many advanced cancers by producing robust remissions. They mostly target two immune regulatory pathways: cytotoxic T lymphocyte antigen-4 and programmed death-1 or its ligand. However, a flip side is the immune-related adverse events (irAEs) commonly affecting the gastrointestinal (GI) tract that can cause treatment interruptions or discontinuation. This practical review discusses the clinical and histopathologic findings of irAEs encountered in the luminal GI tract, along with histopathologic differentials that can mimic varied inflammatory, infectious, or other medication-associated etiologies and the importance of clinico-pathologic correlation for an accurate diagnosis.

Dissecting the Impact of the Gut Microbiome on Cancer Immunotherapy

The gut microbiome has emerged as a key regulator of response to cancer immunotherapy. However, there is a gap in our understanding of the underlying mechanisms by which the microbiome influences immunotherapy. To this end, we developed a mathematical model based on i) gut microbiome data derived from preclinical studies on melanomas after fecal microbiota transplant, ii) mechanistic modeling of antitumor immune response, and iii) robust association analysis of murine and human microbiome profiles with model-predicted immune profiles. Using our model, we could distill the complexity of these murine and human studies on microbiome modulation in terms of just two model parameters: the activation and killing rate constants of immune cells. We further investigated associations between specific bacterial taxonomies and antitumor immunity and immunotherapy efficacy. This model can guide the design of studies to refine and validate mechanistic links between the microbiome and immune system.

Immune checkpoint inhibitors in breast cancer: development, mechanisms of resistance and potential management strategies

The use of immune checkpoint inhibitors (ICIs) has increased exponentially in the past decade, although its progress specifically for breast cancer has been modest. The first U.S. Food and Drug Administration approval for ICI in breast cancer came in 2019, eight years after the first-ever approval of an ICI. At present, current indications for ICIs are relevant only to a subset of patients with triple-negative breast cancer, or those displaying high microsatellite instability or deficiency in the mismatch repair protein pathway. With an increasing understanding of the limitations of using ICIs, which stem from breast cancer being innately poorly immunogenic, as well as the presence of various intrinsic and acquired resistance pathways, ongoing trials are evaluating different combination therapies to overcome these barriers. In this review, we aim to describe the development timeline of ICIs and resistance mechanisms limiting their utility, and summarise the available approaches and ongoing trials relevant to overcoming each resistance mechanism.

Novel PD-L1- and collagen-expressing patient-derived cell line of undifferentiated pleomorphic sarcoma (JBT19) as a model for cancer immunotherapy

Soft tissue sarcomas are aggressive mesenchymal-origin malignancies. Undifferentiated pleomorphic sarcoma (UPS) belongs to the aggressive, high-grade, and least characterized sarcoma subtype, affecting multiple tissues and metastasizing to many organs. The treatment of localized UPS includes surgery in combination with radiation therapy. Metastatic forms are treated with chemotherapy. Immunotherapy is a promising treatment modality for many cancers. However, the development of immunotherapy for UPS is limited due to its heterogeneity, antigenic landscape variation, lower infiltration with immune cells, and a limited number of established patient-derived UPS cell lines for preclinical research. In this study, we established and characterized a novel patient-derived UPS cell line, JBT19. The JBT19 cells express PD-L1 and collagen, a ligand of the immune checkpoint molecule LAIR-1. JBT19 cells can form spheroids in vitro and solid tumors in immunodeficient nude mice. We found JBT19 cells induce expansion of JBT19-reactive autologous and allogeneic NK, T, and NKT-like cells, and the reactivity of the expanded cells was associated with cytotoxic impact on JBT19 cells. The PD-1 and LAIR-1 ligand-expressing JBT19 cells show ex vivo immunogenicity and effective in vivo xenoengraftment properties that can offer a unique resource in the preclinical research developing novel immunotherapeutic interventions in the treatment of UPS.