Electrochemotherapy combined with immunotherapy - a promising potential in the treatment of cancer

Electrochemotherapy in metastatic epidural spinal cord compression: a review and technical update

This review aims to analyse the safety and clinical efficacy in terms of pain relief and local tumour control, in patients with metastatic epidural spinal cord compression undergoing electrochemotherapy (ECT). Moreover, a recommendation detailing optimal electrodes insertion is proposed with the intent of improving treatment planning. Clinical studies published between 2015 and 2023 were included since this time window is consistent with recent developments in the field of ECT of spinal metastases. In the whole, 3 articles were included. Results showed that percutaneous image-guided ECT provides effective pain relief with limited procedure-related morbidity, along with local tumour control (complete response 28.5%, 38% partial response, 24% stable disease) at 3-month follow-up in the largest published series so far. In conclusion, ECT should integrate the armamentarium of therapies that are currently being proposed to patients with painful metastatic epidural disease.

Advances in the Functionalization of Vaccine Delivery Systems: Innovative Strategies and Translational Perspectives

The development of effective vaccines requires a rational design that considers the interaction between antigens, their vectors, and the immune system in addition to the activation of pathways that induce a safe and specific immune response. The efficacy of a vaccine formulation depends on the nature of the antigen, the protection offered by the delivery system, the ability to potentiate the immune response, and the precise release of the immunogen. Carrier systems such as lipid nanoparticles, polymers, exosomes, and microorganisms can be functionalized by chemical, physical, or biological methods to generate selective and improved biodistribution profiles. These methods enhance interaction with target cells, thereby improving immunological efficacy. The conjugation of specific ligands or the modification of parameters such as shape, charge, and size of vectors can enhance the specificity, stability, and efficiency of antigen transport to cellular compartments, thereby facilitating a robust immune response. This study examines modifications in vaccine delivery systems, focusing on biomolecules and physicochemical changes that enhance antigen presentation. Additionally, we examine innovative methods, including microneedles, electroporation, and needle-free systems that show potential for enhancing the immune response.

Phase I trial of phIL12 plasmid intratumoral gene electrotransfer in patients with basal cell carcinoma in head and neck region

INTRODUCTION

In the treatment of cancer, immunomodulatory approaches are developed to support the organism in fighting cancer or to enhance the immunomodulatory effects of local ablative techniques. To this end, we conducted an interventional, open-label, single-arm Phase I trial to evaluate the safety and tolerability of intratumoral phIL12 plasmid DNA gene electrotransfer as primary objectives.

METHODS

The study was dose-escalating with 3 consecutive cohorts of 3 patients per phIL12 dose level (0.5 mg/ml, 1 mg/ml or 2 mg/ml) according to a matched 3 + 3 design. Recruitment of patients was staggered. The waiting period was 30 days after treatment of the previous patient, based on the expected duration of acute and subacute toxicity.

RESULTS

The results of this phase I clinical trial in basal cell carcinoma demonstrated the feasibility and safety of the phIL12 plasmid by gene electrotransfer. We were able to demonstrate that phIL12 gene electrotransfer induced local IL-12 production, which was accompanied with IFN-γ expression. Triggering of the immune response was demonstrated by increased infiltration of immune cells and some antitumor effect. Based on these data, we would recommend the use of a concentration of 2 mg/ml of the plasmid in future trials.

CONCLUSION

The trial lays the foundation for future Phase II clinical trials in which phIL12 gene electrotransfer is used in combination with local tumor-ablative approaches, such as electrochemotherapy or radiotherapy.

Reversible electroporation for cancer therapy

Reversible electroporation (EP) refers to the use of high-voltage electrical pulses on tissues to increase cell membrane permeability. It allows targeted delivery of high concentrations of chemotherapeutic agents including cisplatin and bleomycin, a process known as electrochemotherapy (ECT). It can also be used to deliver toxic concentrations of calcium and gene therapies that stimulate an anti-tumour immune response. ECT was validated for palliative treatment of cutaneous tumours. Evidence to date shows a mean objective response rate of ∼80% in these patients. Regression of non-treated lesions has also been demonstrated, theorized to be from an in situ vaccination effect. Advances in electrode development have also allowed treatment of deep-seated metastatic lesions and primary tumours, with safety demonstrated in vivo. Calcium EP and combination immunotherapy or immunogene electrotransfer is also feasible, but research is limited. Adverse events of ECT are minimal; however, general anaesthesia is often necessary, and improvements in modelling capabilities and electrode design are required to enable sufficient electrical coverage. International collaboration between preclinical researchers, oncologists, and interventionalists is required to identify the most effective combination therapies, to optimize procedural factors, and to expand use, indications and assessment of reversible EP. Registries with standardized data collection methods may facilitate this.

Electrochemotherapy with bleomycin, oxaliplatin, or cisplatin in mouse tumor models, from tumor ablation to in situ vaccination

Introduction

In addition to its direct cytotoxic effects, ablative therapies as electrochemotherapy (ECT) can elicit indirect antitumor effects by triggering immune system responses. Here, we comprehensively analyzed this dual effectiveness of intratumoral ECT with chemotherapeutic drugs bleomycin (BLM), oxaliplatin (OXA), and cisplatin (CDDP). Our aim was to determine if ECT can act as in situ vaccination and thereby induce an abscopal effect. By evaluating ECT's potential for in situ vaccination, our goal was to pave the way for future advancements for its combination with emerging (immuno)therapies, leading to enhanced responses and outcomes.

Methods

We employed two mouse tumor models, the immunologically cold B16F10 melanoma and 4T1 mammary carcinoma, to explore both local and systemic (i.e., abscopal) antitumor effects following equieffective intratumoral ECT with BLM, OXA, and CDDP. Through histological analyses and the use of immunodeficient and metastatic (for abscopal effect) mouse models, we identified and compared both the cytotoxic and immunological components of ECT's antitumor efficiency, such as immunologically recognizable cell deaths (immunogenic cell death and necrosis) and immune infiltrate (CD11+, CD4+, CD8+, GrB+).

Results

Differences in immunological involvement after equieffective intratumoral ECT were highlighted by variable kinetics of immunologically recognizable cell deaths and immune infiltrate across the studied tumor models. Particularly, the 4T1 tumor model exhibited a more pronounced involvement of the immune component compared to the B16F10 tumor model. Variances in the antitumor (immune) response were also detected based on the chemotherapeutic drug used in ECT. Collectively, ECT demonstrated effectiveness in inducing in situ vaccination in both tumor models; however, an abscopal effect was observed in the 4T1 tumor model only.

Conclusions

This is the first preclinical study systematically comparing the immune involvement in intratumoral ECT's efficiency using three distinct chemotherapeutic drugs in mouse tumor models. The demonstrated variability in immune response to ECT across different tumor models and chemotherapeutic drugs provides a basis for future investigations aimed at enhancing the effectiveness of combined treatments.

Stereotactic Percutaneous Electrochemotherapy as a New Minimal Invasive Treatment Modality for Primary and Secondary Liver Malignancies

Background and Objectives: To report on the first results of safety, efficacy, and outcome of CT-navigated stereotactic percutaneous electrochemotherapy (SpECT) in patients with primary and secondary liver malignancies. Methods: This retrospective study included 23 consecutive lesions in 22 patients who underwent SpECT for primary and secondary malignant liver lesions with locally curative intention. The endpoints were primary technique efficacy (PTE), local tumor progression (LTP), time to progression (TTP), and occurrence of adverse events. Results: The mean maximum diameter of the treated lesions was 42 mm (range: 16 mm-72 mm). Eight lesions were hepatocellular carcinoma (34.8%), five lesions were colorectal liver metastases (21.7%), three lesions were cholangiocellular carcinoma (13.0%), and the other seven lesions were liver metastases from different primary cancers (30.4%). PTE was achieved for 22 lesions (95.7%). The mean follow-up time was 15 months (0-39 months). No LTP was observed. In six patients (27.3%), hepatic tumor progression was observed during follow-up with a mean TTP of 3.8 months (2-8 months). In 10 procedures (43.5%), minor complications (1 CIRSE Grade 2) and side effects occurred, but no major complications were observed. Conclusions: SpECT seems to be a safe and effective new local treatment modality for primary and secondary liver malignancies.

Review of Role of Surgery with Electroporation in Melanoma: Chemotherapy, Immunotherapy, and Gene Delivery

Electroporation with chemotherapy (ECT) is currently offered as a treatment in Europe for locoregional or metastatic melanoma with cutaneous lesions. However, the role of surgery and other forms of electroporation in melanoma requires further evaluation. Two reviewers used two databases to conduct a literature search and review, and 51 publications related to electroporation with chemotherapy, immunotherapy, or gene delivery were found. ECT appears to be effective in reducing tumor burden for surgical resection, replacing surgical intervention with evidence of complete regression in some lesions, and inducing both local and systemic immune effects. These immune effects are pronounced when ECT is combined with immunotherapy, with a statistically significant improvement in overall survival (OS). Other forms of electroporation, such as those using calcium chloride, an IL-12 plasmid, and vaccination, require further study. However, IL-12 plasmid electroporation may be inferior to ECT based on the evidence available. Furthermore, irradiation of the tumor prior to ECT treatment is negatively correlated with local response. Access to ECT is restricted in the US and requires further evaluation. More randomized controlled trials of ECT and electroporation treatment in locoregional melanoma are recommended.