Immune Modulation Plus Tumor Ablation: Adjuvants and Antibodies to Prime and Boost Anti-Tumor Immunity In Situ

Efficacy and safety of microwave ablation and its synergistic potential in the treatment of early-stage non-small cell lung cancer

Lung cancer remains the primary cause of cancer-related mortality globally. In the case of early-stage non-small cell lung cancer (NSCLC), surgical resection, such as lobectomy and sub-lobectomy, continues to be the established standard treatment. However, for patients with insufficient cardiopulmonary function and multiple comorbidities who are unable to undergo surgical resection, nonoperative local therapies, including radiotherapy and thermal ablation, are preferred. In recent years, microwave ablation (MWA) has gained popularity for treating early-stage NSCLC due to its high heating efficiency, good tissue conductance, and heat conduction capabilities. This review provides a comprehensive summary of the current efficacy and safety data regarding MWA for early-stage NSCLC and discusses the potential benefits of combining MWA with other therapies.

Therapeutic In Situ Cancer Vaccine Using Pulsed Stereotactic Body Radiotherapy-A Translational Model

Both radiation and cancer therapeutic vaccine research are more than 100 years old, and their potential is likely underexplored. Antiangiogenics, nanoparticle targeting, and immune modulators are some other established anticancer therapies. In the meantime, immunotherapy usage is gaining momentum in clinical applications. This article proposes the concept of a pulsed/intermittent/cyclical endothelial-sparing single-dose in situ vaccination (ISVRT) schedule distinguishable from the standard therapeutic stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) plans. This ISVRT schedule can repeatedly generate tumor-specific neoantigens and epitopes for primary and immune modulation effects, augment supplementary immune enhancement techniques, activate long-term memory cells, avoid extracellular matrix fibrosis, and essentially synchronize with the vascular normalized immunity cycle. The core mechanisms of ISVRT impacting in situ vaccination would be optimizing cascading antigenicity and adjuvanticity. The present proposed hypothesis can be validated using the algorithm presented. The indications for the proposed concept are locally progressing/metastatic cancers that have failed standard therapies. Immunotherapy/targeted therapy, chemotherapy, antiangiogenics, and vascular-lymphatic normalization are integral to such an approach.

Bispecific antibodies revolutionizing breast cancer treatment: a comprehensive overview

Breast cancer (BCa) is known as a complex and prevalent disease requiring the development of novel anticancer therapeutic approaches. Bispecific antibodies (BsAbs) have emerged as a favorable strategy for BCa treatment due to their unique ability to target two different antigens simultaneously. By targeting tumor-associated antigens (TAAs) on cancer cells, engaging immune effector cells, or blocking critical signaling pathways, BsAbs offer enhanced tumor specificity and immune system involvement, improving anti-cancer activity. Preclinical and clinical studies have demonstrated the potential of BsAbs in BCa. For example, BsAbs targeting human epidermal growth factor receptor 2 (HER2) have shown the ability to redirect immune cells to HER2-positive BCa cells, resulting in effective tumor cell killing. Moreover, targeting the PD-1/PD-L1 pathway by BsAbs has demonstrated promising outcomes in overcoming immunosuppression and enhancing immune-mediated tumor clearance. Combining BsAbs with existing therapeutic approaches, such as chemotherapy, targeted therapies, or immune checkpoint inhibitors (ICIs), has also revealed synergistic effects in preclinical models and early clinical trials, emphasizing the usefulness and potential of BsAbs in BCa treatment. This review summarizes the latest evidence about BsAbs in treating BCa and the challenges and opportunities of their use in BCa.

Mechanisms and therapeutic strategies to combat the recurrence and progression of hepatocellular carcinoma after thermal ablation

Thermal ablation (TA), including radiofrequency ablation (RFA) and microwave ablation (MWA), has become the main treatment for early-stage hepatocellular carcinoma (HCC) due to advantages such as safety and minimal invasiveness. However, HCC is prone to local recurrence, with more aggressive malignancies after TA closely related to TA-induced changes in epithelial-mesenchymal transition (EMT) and remodeling of the tumor microenvironment (TME). According to many studies, various components of the TME undergo complex changes after TA, such as the recruitment of innate and adaptive immune cells, the release of tumor-associated antigens (TAAs) and various cytokines, the formation of a hypoxic microenvironment, and tumor angiogenesis. Changes in the TME after TA can partly enhance the anti-tumor immune response; however, this response is weak to kill the tumor completely. Certain components of the TME can induce an immunosuppressive microenvironment through complex interactions, leading to tumor recurrence and progression. How the TME is remodeled after TA and the mechanism by which the TME promotes HCC recurrence and progression are unclear. Thus, in this review, we focused on these issues to highlight potentially effective strategies for reducing and preventing the recurrence and progression of HCC after TA.

Potential biomarkers for predicting immune response and outcomes in lung cancer patients undergoing thermal ablation

Thermal ablation is a promising alternative treatment for lung cancer. It disintegrates cancer cells and releases antigens, followed by the remodeling of local tumor immune microenvironment and the activation of anti-tumor immune responses, enhancing the overall effectiveness of the treatment. Biomarkers can offer insights into the patient's immune response and outcomes, such as local tumor control, recurrence, overall survival, and progression-free survival. Identifying and validating such biomarkers can significantly impact clinical decision-making, leading to personalized treatment strategies and improved patient outcomes. This review provides a comprehensive overview of the current state of research on potential biomarkers for predicting immune response and outcomes in lung cancer patients undergoing thermal ablation, including their potential role in lung cancer management, and the challenges and future directions.

Fluorocarbon Modified Chitosan to Enable Transdermal Immunotherapy for Melanoma Treatment

Despite the rapid development of the immune checkpoint blockade (ICB) in melanoma treatment, the immunosuppressive tumor microenvironment (TME) still hinders the efficacy of immunotherapy. Recently, using agonists to modulate the TME have presented promising clinical responses in combination with ICB therapies. However, local intratumoral injection as the commonly used administration route for immune agonists would lead to low patient compliance. Herein, it is demonstrated that fluorocarbon modified chitosan (FCS) can self-assemble with immune adjuvant polyriboinosinic:polyribocytidylic acid (poly(I:C)), forming nanoparticles that can penetrate through cutaneous barriers to enable transdermal delivery. FCS/poly(I:C) can efficiently activate various types of cells presented on the transdermal route (through the skin into the TME), leading to IRF3-mediated IFN-β induction in the activated cells for tumor repression. Furthermore, transdermal FCS/poly(I:C) treatment can significantly magnify the efficacy of the programmed cell death protein 1 (PD-1) blockade in melanoma treatment through activating the immunosuppressive TME. This study approach offered an attractive transdermal approach in combined with ICB therapy for combined immunotherapy, particularly suitable for melanoma treatment.

Autophagy-amplifying nanoparticles evoke immunogenic cell death combined with anti-PD-1/PD-L1 for residual tumors immunotherapy after RFA

Incomplete radiofrequency ablation (IRFA) triggers mild protective autophagy in residual tumor cells and results in an immunosuppressive microenvironment. This accelerates the recurrence of residual tumors and causes resistance to anti-PD-1/PDL1 therapy, which bringing a great clinical challenge in residual tumors immunotherapy. Mild autophagy activation can promote cancer cell survival while further amplification of autophagy contributes to immunogenic cell death (ICD). To this regard, we constructed active targeting zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) loaded with STF62247 or both STF62247 and BMS202, namely STF62247@ZIF-8/PEG-FA (SZP) or STF62247-BMS202@ZIF-8/PEG-FA (SBZP) NPs. We found that SZP NPs inhibited proliferation and stimulated apoptosis of residual tumor cells exposed to sublethal heat stress in an autophagy-dependent manner. Further results discovered that SZP NPs could amplify autophagy in residual tumor cells and evoke their ICD, which dramatically boosted the maturation of dendritic cells (DCs). Through vaccination experiments, we found for the first time that vaccination with heat + SZP treatment could efficiently suppress the growth of new tumors and establish long-term immunological memory. Furthermore, SBZP NPs could remarkably promote the ICD of residual tumor cells, obviously activate the anti-tumor immune microenvironment, and significantly inhibit the growth of residual tumors. Thus, amplified autophagy coupled with anti-PD-1/PDL1 therapy is potentially a novel strategy for treating residual tumors after IRFA.

Nanoplatforms Potentiated Ablation-Immune Synergistic Therapy through Improving Local Control and Suppressing Recurrent Metastasis

Minimally invasive ablation has been widely applied for treatment of various solid tumors, including hepatocellular carcinoma, renal cell carcinoma, breast carcinomas, etc. In addition to removing the primary tumor lesion, ablative techniques are also capable of improving the anti-tumor immune response by inducing immunogenic tumor cell death and modulating the tumor immune microenvironment, which may be of great benefit to inhibit the recurrent metastasis of residual tumor. However, the short-acting activated anti-tumor immunity of post-ablation will rapidly reverse into an immunosuppressive state, and the recurrent metastasis owing to incomplete ablation is closely associated with a dismal prognosis for the patients. In recent years, numerous nanoplatforms have been developed to improve the local ablative effect through enhancing the targeting delivery and combining it with chemotherapy. Particularly, amplifying the anti-tumor immune stimulus signal, modulating the immunosuppressive microenvironment, and improving the anti-tumor immune response with the versatile nanoplatforms have heralded great application prospects for improving the local control and preventing tumor recurrence and distant metastasis. This review discusses recent advances in nanoplatform-potentiated ablation-immune synergistic tumor therapy, focusing on common ablation techniques including radiofrequency, microwave, laser, and high-intensity focused ultrasound ablation, cryoablation, and magnetic hyperthermia ablation, etc. We discuss the advantages and challenges of the corresponding therapies and propose possible directions for future research, which is expected to provide references for improving the traditional ablation efficacy.

Combining energy-based focal ablation and immune checkpoint inhibitors: preclinical research and clinical trials

Energy-based focal therapy (FT) uses targeted, minimally invasive procedures to destroy tumors while preserving normal tissue and function. There is strong emerging interest in understanding how systemic immunity against the tumor can occur with cancer immunotherapy, most notably immune checkpoint inhibitors (ICI). The motivation for combining FT and ICI in cancer management relies on the synergy between the two different therapies: FT complements ICI by reducing tumor burden, increasing objective response rate, and reducing side effects of ICI; ICI supplements FT by reducing local recurrence, controlling distal metastases, and providing long-term protection. This combinatorial strategy has shown promising results in preclinical study (since 2004) and the clinical trials (since 2011). Understanding the synergy calls for understanding the physics and biology behind the two different therapies with distinctive mechanisms of action. In this review, we introduce different types of energy-based FT by covering the biophysics of tissue-energy interaction and present the immunomodulatory properties of FT. We discuss the basis of cancer immunotherapy with the emphasis on ICI. We examine the approaches researchers have been using and the results from both preclinical models and clinical trials from our exhaustive literature research. Finally, the challenges of the combinatory strategy and opportunities of future research is discussed extensively.

The CXCL10/CXCR3 Pathway Contributes to the Synergy of Thermal Ablation and PD-1 Blockade Therapy against Tumors

As a practical local therapeutic approach to destroy tumor tissue, thermal ablation can activate tumor-specific T cells via enhancing tumor antigen presentation to the immune system. In the present study, we investigated changes in infiltrating immune cells in tumor tissues from the non-radiofrequency ablation (RFA) side by analyzing single-cell RNA sequencing (scRNA-seq) data of tumor-bearing mice compared with control tumors. We showed that ablation treatment could increase the proportion of CD8⁺T cells and the interaction between macrophages and T cells was altered. Another thermal ablation treatment, microwave ablation (MWA), increased the enrichment of signaling pathways for chemotaxis and chemokine response and was associated with the chemokine CXCL10. In addition, the immune checkpoint PD-1 was especially up-regulated in the infiltrating T cells of tumors on the non-ablation side after thermal ablation treatment. Combination therapy of ablation and PD-1 blockade had a synergistic anti-tumor effect. Furthermore, we found that the CXCL10/CXCR3 axis contributed to the therapeutic efficacy of ablation combined with anti-PD-1 therapy, and activation of the CXCL10/CXCR3 signaling pathway might improve the synergistic effect of this combination treatment against solid tumors.

Macrophage activity at the site of tumor ablation can promote murine urothelial cancer via transforming growth factor-β1

Cell death and injury at the site of tumor ablation attracts macrophages. We sought to understand the status and activity of these cells while focusing on transforming growth factor-β1 (TGF-β1), a potent immunosuppressive and tumorigenic cytokine. Patients with urothelial cancer who underwent ablation using electrocautery or laser demonstrated increased infiltration and numbers of CD8+ T cells, along with FoxP3+ regulatory T cells, CD68+ macrophages and elevated levels of TGF-β1 in recurrent tumors. Similar findings were reproduced in a mouse model of urothelial cancer (MB49) by partial tumor ablation with irreversible electroporation (IRE). Stimulation of bone marrow derived macrophages with MB49 cell debris produced using IRE elicited strong M2 polarization, with exuberant secretion of TGF-β1. The motility, phenotypic markers and cytokine secretion by macrophages could be muted by treatment with Pirfenidone (PFD), a clinically approved drug targeting TGF-β1 signaling. MB49 cancer cells exposed to TGF-β1 exhibited increased migration, invasiveness and upregulation of epithelial-mesenchymal transition markers α-Smooth Muscle Actin and Vimentin. Such changes in MB49 cells were reduced by treatment with PFD even during stimulation with TGF-β1. IRE alone yielded better local tumor control when compared with control or PFD alone, while also reducing the overall number of lung metastases. Adjuvant PFD treatment did not provide additional benefit under in vivo conditions.

Knowledge mapping of image-guided tumor ablation and immunity: A bibliometric analysis

Background

Various ablation techniques have been successfully applied in tumor therapy by locally destroying tumor. In the process of tumor ablation, a large number of tumor cell debris is released, which can be used as a source of tumor antigens and trigger a series of immune responses. With the deepening of the research on the immune microenvironment and immunotherapy, researches exploring tumor ablation and immunity are continuously published. However, no research has systematically analyzed the intellectual landscape and emerging trends for tumor ablation and immunity using scientometric analysis. Therefore, this study aimed to conduct a bibliometric analysis to quantify and identify the status quo and trend of tumor ablation and immunity.

Methods

Data of publications were downloaded from the Web of Science Core Collection database. CiteSpace and VOSviewer were used to conduct bibliometric analysis to evaluate the contribution and co-occurrence relationship of different countries/regions, institutions and authors in the field, and to determine the research hotspots in this field.

Results

By searching in the database, a total of 3531 English articles published between 2012 and 2021 were obtained. We observed rapid growth in the number of publications since 2012. The two most active countries were China and the United States, with more than 1,000 articles. Chinese Academy of Sciences contributed the most publications (n = 153). Jibing Chen and Xianzheng Zhang might have a keen interest in tumor ablation and immunity, with more publications (n = 14; n = 13). Among the top 10 co-cited authors, Castano AP (284 citations) was ranked first, followed by Agostinis P (270 citations) and Chen Qian (246 citations). According to the co-occurrence and cluster analysis, the results indicated that the focus of research was "photothermal therapy" and "immune checkpoint blockade".

Conclusions

In the past decade, the neighborhood of tumor ablation domain immunity has been paid more and more attention. Nowadays, the research hotspots in this field are mainly focused on exploring the immunological mechanism in photothermal therapy to improve its efficacy, and the combination of ablation therapy and immune checkpoint inhibitor therapy.

Combinatory local ablation and immunotherapies for hepatocellular carcinoma: Rationale, efficacy, and perspective

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related death worldwide. Local ablation, such as radiofrequency ablation, microwave ablation, cryoablation and irreversible electroporation, etc., are well established in elimination and control of HCC. However, high recurrence rate after local ablation remains the biggest challenge for HCC management. Novel and effective therapeutic strategies to improve long-term survival are urgently needed. Accumulating studies have reported the role of ablation in modulating the tumor signaling pathway and the immune microenvironment to both eliminate residual/metastatic tumor and promote tumor progression. Ablation has been shown to elicit tumor-specific immune responses by inducing massive cell death and releasing tumor antigen. Immunotherapies that unleash the immune system have the potential to enhance the anti-tumor immunity induced by ablation. Multiple combinatory strategies have been explored in preclinical and clinical studies. In this review, we comprehensively summarize the latest progress on different mechanisms underlying the effects of ablation on tumor cells and tumor microenvironment. We further analyze the clinical trials testing the combination of ablation and immunotherapies, and discuss the possible role of immunomodulation to boost the anti-tumor effects of ablation and prevent HCC recurrence.

Hyperthermia combined with immune checkpoint inhibitor therapy in the treatment of primary and metastatic tumors

According to the difference in temperature, thermotherapy can be divided into thermal ablation and mild hyperthermia. The main advantage of thermal ablation is that it can efficiently target tumors in situ, while mild hyperthermia has a good inhibitory effect on distant metastasis. There are some similarities and differences between the two therapies with respect to inducing anti-tumor immune responses, but neither of them results in sustained systemic immunity. Malignant tumors (such as breast cancer, pancreatic cancer, nasopharyngeal carcinoma, and brain cancer) are recurrent, highly metastatic, and highly invasive even after treatment, hence a single therapy rarely resolves the clinical issues. A more effective and comprehensive treatment strategy using a combination of hyperthermia and immune checkpoint inhibitor (ICI) therapies has gained attention. This paper summarizes the relevant preclinical and clinical studies on hyperthermia combined with ICI therapies and compares the efficacy of two types of hyperthermia combined with ICIs, in order to provide a better treatment for the recurrence and metastasis of clinically malignant tumors.

cGAS/cGAMP/STING signal propagation in the tumor microenvironment: key role for myeloid cells in antitumor immunity

Cyclic GMP-AMP synthase (cGAS), second messenger 2'3'-cyclic GMP-AMP (cGAMP) and stimulator of interferon genes (STING) are fundamental for sensing cytoplasmic double stranded DNA. Radiotherapy treatment induces large amounts of nuclear and mitochondrial DNA damage and results in the presence of DNA fragments in the cytoplasm, activating the cGAS/STING pathway. Triggering of the cGAS/STING pathway in the tumor microenvironment (TME) results in the production of type I interferons (IFNs). Type I IFNs are crucial for an effective antitumor defense, with myeloid cells as key players. Many questions remain on how these myeloid cells are activated and in which cells (tumor versus myeloid) in the TME the signaling pathway is initiated. The significance of cGAS/STING signaling in the onco-immunology field is being recognized, emphasized by the frequent occurrence of mutations in or silencing of genes in this pathway. We here review several mechanisms of cGAS/STING signal propagation in the TME, focusing on tumor cells and myeloid cells. Cell-cell contact-dependent interactions facilitate the transfer of tumor-derived DNA and cGAMP. Alternatively, transport routes via the extracellular space such as extracellular vesicles, and channel-mediated cGAMP transfer to and from the extracellular space contribute to propagation of cGAS/STING signal mediators DNA and cGAMP. Finally, we discuss regulation of extracellular cGAMP. Altogether, we provide a comprehensive overview of cGAS/cGAMP/STING signal propagation from tumor to myeloid cells in the TME, revealing novel targets for combinatorial treatment approaches with conventional anticancer therapies like radiotherapy.

How Compatible Are Immune Checkpoint Inhibitors and Thermal Ablation for Liver Metastases?

Simple Summary

Although immune checkpoint inhibitors (ICIs) have achieved great progression in cancer treatment, the efficacy of ICI monotherapy is still limited. Meanwhile, the negative efficacy of thermal ablation for liver metastases is the high rate of local tumor progression. Since thermal ablation-induced inflammation and increases in tumor antigens have been suggested to promote the cancer-immunity cycle, thermal ablation and ICI can boost the immune response against cancer cells as one of the positive synergy effects. The findings of preclinical and clinical research have provided supportive evidence for the combination of ICIs with thermal ablation reversing T-cell exhaustion and demonstrating synergy. However, the clinical feasibility of immune response activation by combination therapy with ICI monotherapy and thermal ablation appears to be limited, it may be not very common phenomena.

Abstract

Cancer immunotherapy, which reactivates the weakened immune cells of cancer patients, has achieved great success, and several immune checkpoint inhibitors (ICIs) are now available in clinical practice. Despite promising clinical outcomes, favorable responses are only observed in a fraction of patients, and resistance mechanisms, including the absence of tumor antigens, have been reported. Thermal ablation involves the induction of irreversible damage to cancer cells by localized heat and may result in the release of tumor antigens. The combination of immunotherapy and thermal ablation is an emerging therapeutic option with enhanced efficacy. Since thermal ablation-induced inflammation and increases in tumor antigens have been suggested to promote the cancer-immunity cycle, the combination of immuno-oncology (IO) therapy and thermal ablation may be mutually beneficial. In preclinical and clinical studies, the combination of ICI and thermal ablation significantly inhibited tumor growth, and synergistic antitumor effects appeared to prolong the survival of patients with secondary liver cancer. However, evidence for the efficacy of ICI monotherapy combined with thermal ablation is currently insufficient. Therefore, the clinical feasibility of immune response activation by ICI monotherapy combined with thermal ablation may be limited, and thermal ablation may be more compatible with dual ICIs (the IO–IO combination) to induce strong immune responses.

[Current Status and Progress of Thermal Ablation Combined with Immunotherapy for Lung Tumors]

Recent studies have shown that tumor immune microenvironment is closely related to tumor progression, metastasis, recurrence and response to treatment. Some immunotherapies also offer hope for cancer patients. However, the efficacy of tumor immunotherapy is uncertain and has some side effects. In order to enhance its efficacy, tumor immunotherapy combined with tumor thermal ablation has been studied. Thermal ablation has the advantages of minimally invasive, rapid recovery, safety, fewer complications, conformation, reliable effect, repeatable, low cost, and has become the fourth tumor treatment measure after surgery, radiotherapy, and drug therapy. It can directly kill tumor cells and modulate the immune system through a variety of mechanisms, although the corresponding mechanisms are not well understood, but combined tumor immunotherapy has been proposed to treat several solid malignancies. In this review, the current status and progress of thermal ablation combined with immunotherapy for lung tumor were reviewed, and further studies on the efficacy and safety of thermal ablation combined with immunotherapy were expected.
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Clinical Applications and Anticancer Effects of Antimicrobial Peptides: From Bench to Bedside

Cancer is a multifaceted global health issue and one of the leading causes of death worldwide. In recent years, medical science has achieved great advances in the diagnosis and treatment of cancer. Despite the numerous advantages of conventional cancer therapies, there are major drawbacks including severe side effects, toxicities, and drug resistance. Therefore, the urgency of developing new drugs with low cytotoxicity and treatment resistance is increasing. Antimicrobial peptides (AMPs) have attracted attention as a novel therapeutic strategy for the treatment of various cancers, targeting tumor cells with less toxicity to normal tissues. In this review, we present the structure, biological function, and underlying mechanisms of AMPs. The recent experimental studies and clinical trials on anticancer peptides in different cancer types as well as the challenges of their clinical application have also been discussed.

Irreversible Electroporation and Nivolumab Combined with Intratumoral Administration of a Toll-Like Receptor Ligand, as a Means of In Vivo Vaccination for Metastatic Pancreatic Ductal Adenocarcinoma (PANFIRE-III). A Phase-I Study Protocol

Simple Summary

Metastatic pancreatic ductal adenocarcinoma has a dismal prognosis, and to date no curative treatment options exist. The image guided tumor ablation technique irreversible electroporation (IRE) employs high-voltage electrical pulses through the application of several needle electrodes in and around the tumor in order to induce cell death. IRE ablation of the primary tumor has the ability to reduce pancreatic tumor induced immune suppression while allowing the expansion of tumor specific effector T cells, hereby possibly shifting the pancreatic tumor microenvironment into a more immune permissive state. The addition of immune enhancing therapies to IRE might work synergistically and could potentially induce a clinically significant treatment effect. This study protocol describes the rationale and design of the PANFIRE-III trial that aims to assess the safety of the combination of IRE with IMO-2125 (toll-like receptor 9 ligand) and/or nivolumab in patients with metastatic pancreatic ductal adenocarcinoma.

Abstract

Irreversible electroporation (IRE) is a novel image-guided tumor ablation technique with the ability to generate a window for the establishment of systemic antitumor immunity. IRE transiently alters the tumor’s immunosuppressive microenvironment while simultaneously generating antigen release, thereby instigating an adaptive immune response. Combining IRE with immunotherapeutic drugs, i.e., electroimmunotherapy, has synergistic potential and might induce a durable antitumor response. The primary objective of this study is to assess the safety of the combination of IRE with IMO-2125 (a toll-like receptor 9 ligand) and/or nivolumab in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC). In this randomized controlled phase I clinical trial, 18 patients with mPDAC pretreated with chemotherapy will be enrolled in one of three study arms: A (control): nivolumab monotherapy; B: percutaneous IRE of the primary tumor followed by nivolumab; or C: intratumoral injection of IMO-2125 followed by percutaneous IRE of the primary tumor and nivolumab. Assessments include contrast enhanced computed tomography (ceCT), ¹⁸F-FDG and ¹⁸F-BMS-986192 (PD-L1) positron emission tomography (PET)-CT, biopsies of the primary tumor and metastases, peripheral blood samples, and quality of life and pain questionnaires. There is no curative treatment option for patients with mPDAC, and palliative chemotherapy regimens only moderately improve survival. Consequently, there is an urgent need for innovative and radically different treatment approaches. Should electroimmunotherapy establish an effective and durable anti-tumor response, it may ultimately improve PDAC’s dismal prognosis.