Evaluation of Calcium Electroporation for the Treatment of Cutaneous Metastases: A Double Blinded Randomised Controlled Phase II Trial

The comparison of the dynamics of Ca2+ and bleomycin intracellular delivery after cell sonoporation and electroporation in vitro

Ca2+, in combination with SP or EP, induces cell cytotoxicity much faster compared to BLM. The application of BLM in combination with, SP or EP, reaches the level of cell death, induced by similar combination with Ca2+, only after 72 h. The methods of SP and EP were calibrated according to the level of differential cytotoxicity, determined after 6 days (using cell clonogenic assay). The combination of Ca2+ SP induces cell death faster than Ca2+ EP - after Ca2+ SP it increases to a maximum level after 15 min and remains constant for up to 6 days, while the cytotoxic efficiency after Ca2+ EP increases to the level of Ca2+ SP only after 72 h. The combination of BLM SP shows a very similar dynamics to BLM EP - both reach maximal level of cytotoxicity after 48-72 h. Ca2+ and BLM in combination with SP have shown similar levels of cytotoxicity at higher acoustic pressures (≥250 kPa); therefore, Ca2+ SP can be used to induce immediate and maximal level of cytotoxic effect. The faster cytotoxic efficiency of Ca2+ in combination with SP than EP was determined to be due to the involvement of microbubble inertial cavitation.

Cutaneous metastases: From epidemiology to therapy

Cutaneous metastases are seen in up to 10% of all oncology patients and can occur in different locations depending on the entity. Cutaneous metastases are often associated with a high psychological burden and, especially in the case of exulceration, with shame and social withdrawal. This review discusses the diagnostic and therapeutic options. The most common tumor entities in which cutaneous metastases are observed are discussed, and local and systemic treatment options are presented according to the current state of research.

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.

Immune cell populations in the tumour environment following calcium electropora-tion for cutaneous metastasis: a histopathological study

BACKGROUND AND PURPOSE

Calcium electroporation (CaEP) involves injecting calcium into tumour tissues and using electrical pulses to create membrane pores that induce cell death. This study assesses resultant immune responses and histopathological changes in patients with cutaneous metastases.

PATIENTS/MATERIALS AND METHODS

The aimed cohort comprised 24 patients with metastases exceeding 5 mm. Tumours were treated once with CaEP (day 0) or twice (day 28). Biopsies were performed on days 0 and 2, with additional samples on days 7, 28, 30, 35, 60, and 90 if multiple tumours were treated. The primary endpoint was the change in tumour-infiltrating lymphocytes (TILs) two days post-treatment, with secondary endpoints evaluating local and systemic immune responses via histopathological analysis of immune markers, necrosis, and inflammation.

RESULTS

Seventeen patients, with metastases primarily from breast cancer (14 patients), but also lung cancer (1), melanoma (1), and urothelial cancer (1), completed the study. Of the 49 lesions treated, no significant changes in TIL count or PD-L1 expression were observed. However, there was substantial necrosis and a decrease in FOXP3-expression (p = 0.0025) noted, with a slight increase in CD4+ cells but no changes in CD3, CD8, or CD20 expressions. Notably, four patients showed reduced tumour invasiveness, including one case of an abscopal response.

INTERPRETATION

This exploratory study indicates that CaEP can be an effective anti-tumour therapy potentially enhancing immunity. Significant necrosis and decreased regulatory lymphocytes were observed, although TIL count remained unchanged. Several patients exhibited clinical signs of immune response following treatment.

An Explorative Study on Calcium Electroporation for Low-risk Basal Cell Carcinoma

In electrochemotherapy, permeabilization of the cell membrane by electric pulses increases the anti-tumour effect of chemotherapeutics. In calcium electroporation, chemotherapy is replaced by calcium chloride with obvious benefits. This study explores the effect and underlying mechanisms of calcium electroporation on basal cell carcinomas using either high- or low-frequency electroporation. Low-risk primary basal cell carcinomas were treated in local anaesthesia with intratumoral calcium chloride followed by electroporation with high (167 kHz) or low (5 kHz) frequencies. Non-complete responders were retreated after 3 months. The primary endpoint was tumour response 3 months after last calcium electroporation. Plasma membrane calcium ATPase was examined in various cell lines as plasma membrane calcium ATPase levels have been associated with calcium electroporation efficacy. Twenty-two out of 25 included patients complete the study and 7 of these (32%) achieved complete response at 3 months with no difference in efficacy between high- and low-frequency pulses. High-frequency calcium electroporation was significantly less painful (p=0.03). Plasma membrane calcium ATPase was increased 16-32-fold in basal cell carcinoma cell lines compared with 4 other cancer cell lines. Calcium electroporation for low-risk basal cell carcinomas does not fulfil the requirements of a new dermatological basal cell carcinoma treatment but may be useful as adjuvant treatment to surgery in more advanced basal cell carcinomas. The elevated PMCA levels in basal cell carcinomas may contribute to low efficacy.

Calcium electroporation of esophageal cancer induces gene expression changes: a sub-study of a phase I clinical trial

PURPOSE

In this study, we aim to investigate gene expression changes in tumor samples obtained from patients with esophageal cancer treated with calcium electroporation. Previously, local treatment with calcium electroporation has been shown to induce gene expression alterations, potentially contributing to a more tumor-hostile microenvironment.

METHODS

In this sub-study of a phase I clinical trial, we included five patients with esophageal cancer treated with calcium electroporation. We compared cancer-associated gene expression patterns in tumor samples before and after treatment. Furthermore, we used linear support vector regression to predict the cellular composition of tumor samples.

RESULTS

Using differential expression analysis, we identified the downregulation of CXCL14 and upregulation of CCL21, ANGPTL4, and CRABP2 genes. We also found a decreased predicted proportion of dendritic cells while the proportion of neutrophils was increased.

CONCLUSION

This study provides evidence that calcium electroporation for esophageal cancer induces local transcriptional changes and possibly alters the cellular composition of the tumor microenvironment. The results are explorative, larger studies are needed to confirm and further correlate our findings with clinical outcomes.

[Electrochemotherapy in metastatic melanoma]

INTRODUCTION

In metastatic melanoma, despite the increased survival rates with new innovative therapies, therapeutic response is still quite heterogenous, not always durable. In the case of oligoprogression, several additional therapeutic modalities are available such as electrochemotherapy in the local treatment of cutaneous or subcutaneous metastases.

OBJECTIVE

Analysis of our experiences with electrochemotherapy in patients with metastatic melanoma.

METHOD AND RESULTS

23 patients with metastatic melanoma (10 male and 13 female) were treated with electrochemotherapy, between 2016 and 2021 in our Institute. Median age was 74.5 years. The location of metastases varied. 13 of our patients (57%) had metastases on the lower limbs, in 5 cases (22%) metastases were located in the head and neck region, in 4 cases (17%) on the upper limbs, and one (4%) patient received electrochemotherapy for metastases located on the chest. Prior to electrochemotherapy, 7 patients (30%) received chemotherapy, 6 patients (26%) were treated with immunotherapy and 2 patients (9%) received targeted therapy, while electrochemotherapy was first-line treatment for 8 patients (35%). Complete remission was achieved in 12 cases (52%), and partial remission in 6 cases (26%). In 1 case (4%) stable disease was observed, and in 4 patients (35%) progression was detected. We continued the previous systemic therapy which was effective in other localizations after the electrochemotherapy in 8 patients (35%) and in the case of 4 patients (17%) no further systemic therapy was needed. Side effects were observed in 8 patients (35%), 1 had severity of G3.

CONCLUSION

Electrochemotherapy in melanoma results in effective local tumor control, improved quality of life, and survival advantage in most of the patients, with tolerable side effects. Orv Hetil. 2023; 164(35): 1381-1386.

Calcium electroporation in cutaneous metastases - A non-randomised phase II multicentre clinical trial

BACKGROUND

Cutaneous metastases can cause distressing symptoms and be challenging to treat. Local therapies are essential in management. Calcium electroporation uses calcium and electrical pulses to selectively kill cancer cells. This multicentre study aimed to define response in cutaneous metastases across different cancer types.

METHODS

Patients with tumours ≤3 cm of any histology were included (stable or progressing on current therapy ≥2 months), at three centres. Tumours were treated with 220 mM calcium chloride injection and manual application of eight 0.1 ms pulses with 1 kV/cm and 1Hz with a handheld electrode, in local or general anaesthesia. Clinical response was evaluated after 1, 2, 3, 4, 5, 6, and 12 months. Primary endpoint was response at two months. The overall response rate (ORR) was partial- and complete responses of treated tumours. MR-imaging and qualitative interviews were performed in respective subsets.

RESULTS

Nineteen patients with disseminated cancer (breast n = 4, lung n = 5, pancreatic n = 1, colorectal n = 2, gastric n = 1, and endometrial cancer n = 1) were enrolled, and 58 metastases were treated (50 once, 8 retreated). The ORR was 36% (95% CI 22-53) after two months. Best ORR was 51% (CR 42%; PR 9%). Previous irradiation improved outcomes (p = 0.0004). Adverse events were minimal. Median pain score was reduced after two months (p = 0.017). Treatment may relieve symptoms according to qualitative interviews. MRI showed restriction in treated tissue.

CONCLUSION

The majority of tumours were treated only once with calcium electroporation, achieving an ORR of 36% after two months and best ORR of 51%. Efficacy, symptom-relief and safety support calcium electroporation as a palliative treatment option for cutaneous metastases.

Pulsed Electric Fields in Oncology: A Snapshot of Current Clinical Practices and Research Directions from the 4th World Congress of Electroporation

The 4th World Congress of Electroporation (Copenhagen, 9-13 October 2022) provided a unique opportunity to convene leading experts in pulsed electric fields (PEF). PEF-based therapies harness electric fields to produce therapeutically useful effects on cancers and represent a valuable option for a variety of patients. As such, irreversible electroporation (IRE), gene electrotransfer (GET), electrochemotherapy (ECT), calcium electroporation (Ca-EP), and tumour-treating fields (TTF) are on the rise. Still, their full therapeutic potential remains underappreciated, and the field faces fragmentation, as shown by parallel maturation and differences in the stages of development and regulatory approval worldwide. This narrative review provides a glimpse of PEF-based techniques, including key mechanisms, clinical indications, and advances in therapy; finally, it offers insights into current research directions. By highlighting a common ground, the authors aim to break silos, strengthen cross-functional collaboration, and pave the way to novel possibilities for intervention. Intriguingly, beyond their peculiar mechanism of action, PEF-based therapies share technical interconnections and multifaceted biological effects (e.g., vascular, immunological) worth exploiting in combinatorial strategies.

The effectiveness of calcium electroporation combined with gene electrotransfer of a plasmid encoding IL-12 is tumor type-dependent

Introduction

In calcium electroporation (CaEP), electroporation enables the cellular uptake of supraphysiological concentrations of Ca2+, causing the induction of cell death. The effectiveness of CaEP has already been evaluated in clinical trials; however, confirmatory preclinical studies are still needed to further elucidate its effectiveness and underlying mechanisms. Here, we tested and compared its efficiency on two different tumor models to electrochemotherapy (ECT) and in combination with gene electrotransfer (GET) of a plasmid encoding interleukin-12 (IL-12). We hypothesized that IL-12 potentiates the antitumor effect of local ablative therapies as CaEP and ECT.

Methods

The effect of CaEP was tested in vitro as well as in vivo in murine melanoma B16-F10 and murine mammary carcinoma 4T1 in comparison to ECT with bleomycin. Specifically, the treatment efficacy of CaEP with increasing calcium concentrations alone or in combination with IL-12 GET in different treatment protocols was investigated. We closely examined the tumor microenvironment by immunofluorescence staining of immune cells, as well as blood vessels and proliferating cells.

Results

In vitro, CaEP and ECT with bleomycin reduced cell viability in a dose-dependent manner. We observed no differences in sensitivity between the two cell lines. A dose-dependent response was also observed in vivo; however, the efficacy was better in 4T1 tumors than in B16-F10 tumors. In 4T1 tumors, CaEP with 250 mM Ca resulted in more than 30 days of growth delay, which was comparable to ECT with bleomycin. In contrast, adjuvant peritumoral application of IL-12 GET after CaEP prolonged the survival of B16-F10, but not 4T1-bearing mice. Moreover, CaEP with peritumoral IL-12 GET modified tumor immune cell populations and tumor vasculature.

Conclusions

Mice bearing 4T1 tumors responded better to CaEP in vivo than mice bearing B16-F10 tumors, even though a similar response was observed in vitro. Namely, one of the most important factors might be involvement of the immune system. This was confirmed by the combination of CaEP or ECT with IL-12 GET, which further enhanced antitumor effectiveness. However, the potentiation of CaEP effectiveness was also highly dependent on tumor type; it was more pronounced in poorly immunogenic B16-F10 tumors compared to moderately immunogenic 4T1 tumors.

Endoscopic calcium electroporation for colorectal cancer: a phase I study

Background and study aims  Colorectal cancer is one of the most common malignancies, with approximately 20 % of patients having metastatic disease. Local symptoms from the tumor remain a common issue and affect quality of life. Electroporation is a method to permeabilize cell membranes with high-voltage pulses, allowing increased passage of otherwise poorly permeating substances such as calcium. The aim of this study was to determine the safety of calcium electroporation for advanced colorectal cancer. Patients and methods  Six patients with inoperable rectal and sigmoid colon cancer were included, all presenting with local symptoms. Patients were offered endoscopic calcium electroporation and were followed up with endoscopy and computed tomography/magnetic resonance scans. Biopsies and blood samples were collected at baseline and at follow-up, 4, 8, and 12 weeks after treatment. Biopsies were examined for histological changes and immunohistochemically with CD3/CD8 and PD-L1. In addition, blood samples were examined for circulating cell-free DNA (cfDNA). Results  A total of 10 procedures were performed and no serious adverse events occurred. Prior to inclusion, patients reported local symptoms, such as bleeding (N = 3), pain (N = 2), and stenosis (N = 5). Five of six patients reported symptom relief. In one patient, also receiving systemic chemotherapy, clinical complete response of primary tumor was seen. Immunohistochemistry found no significant changes in CD3 /CD8 levels or cfDNA levels after treatment. Conclusions  This first study of calcium electroporation for colorectal tumors shows that calcium electroporation is a safe and feasible treatment modality for colorectal cancer. It can be performed as an outpatient treatment and may potentially be of great value for fragile patients with limited treatment options.

Electric Fields Regulate In Vitro Surface Phosphatidylserine Exposure of Cancer Cells via a Calcium-Dependent Pathway

Cancer is the second leading cause of death worldwide after heart disease. The current treatment options to fight cancer are limited, and there is a critical need for better treatment strategies. During the last several decades, several electric field (EF)-based approaches for anti-cancer therapies have been introduced, such as electroporation and tumor-treating fields; still, they are far from optimal due to their invasive nature, limited efficacy and significant side effects. In this study, we developed a non-contact EF stimulation system to investigate the in vitro effects of a novel EF modality on cancer biomarkers in normal (human astrocytes, human pancreatic ductal epithelial -HDPE-cells) and cancer cell lines (glioblastoma U87-GBM, human pancreatic cancer cfPac-1, and MiaPaCa-2). Our results demonstrate that this EF modality can successfully modulate an important cancer cell biomarker-cell surface phosphatidylserine (PS). Our results further suggest that moderate, but not low, amplitude EF induces p38 mitogen-activated protein kinase (MAPK), actin polymerization, and cell cycle arrest in cancer cell lines. Based on our results, we propose a mechanism for EF-mediated PS exposure in cancer cells, where the magnitude of induced EF on the cell surface can differentially regulate intracellular calcium (Ca²⁺) levels, thereby modulating surface PS exposure.

Qualitative Investigation of Experience and Quality of Life in Patients Treated with Calcium Electroporation for Cutaneous Metastases

(1) Background: Calcium electroporation is a novel cancer treatment. It includes injecting calcium-solution and applying electric pulses to tumour tissue. Data on quality of life for patients with cutaneous metastases treated with calcium electroporation is limited. We evaluated quality of life in patients with skin metastases treated with calcium electroporation using qualitative interviews. (2) Methods: This investigation featured a subgroup from a non-randomised phase II study (CaEP-R) at Zealand University Hospital, Denmark, studying response to calcium electroporation in cutaneous metastasis (ClinicalTrials no. NCT04225767). Participants were interviewed at baseline before calcium electroporation treatment and after two months. Data was analysed phenomenologically; (3) Results: Interviews were conducted February 2020-November 2021. Nine patients were included, of which seven participated in both interviews. All seven patients expected treated tumours to disappear, symptom relief and minimal side effects. Most patients requested peer accounts. All patients found the treatment uncomfortable but acceptable; all thought their fears of electric pulses exceeded their experience. All would repeat the treatment if effective. Successful treatment had a positive effect on pain, symptomatic wounds, sleep, vigour and social inclination; (4) Conclusions: Calcium electroporation enhanced health-related quality of life by reducing symptoms and increasing social inclination. Peer accounts provide patients with a shortcut to confidence in treatment on top of doctors' recommendations.

Nanosecond pulsed electric field suppresses growth and reduces multi-drug resistance effect in pancreatic cancer

Nanosecond pulsed electric fields (nsPEF) have been shown to exert anticancer effects; however, little is known about the mechanisms triggered in cancer cells by nanosecond-length pulses, especially when low, sub-permeabilization voltage is used. In this study, three human pancreatic cancer cell lines were treated with nsPEF and molecular changes at the cellular level were analyzed. Further, we assessed the efficacy of paclitaxel chemotherapy following nsPEF treatment and correlated that with the changes in the expression of multi-drug resistance (MDR) proteins. Finally, we examined the influence of nsPEF on the adhesive properties of cancer cells as well as the formation and growth of pancreatic cancer spheroids. Cell line response differed with the application of a 200 ns, 100 pulses, 8 kV/cm, 10 kHz PEF treatment. PEF treatment led to (1) the release of microvesicles (MV) in EPP85-181RDB cells, (2) electropermeabilization in EPP85-181RNOV cells and (3) cell shrinkage in EPP85-181P cells. The release of MV's in EPP85-181RDB cells reduced the membrane content of P-gp and LRP, leading to a transient increase in vulnerability of the cells towards paclitaxel. In all cell lines we observed an initial reduction in size of the cancer spheroids after the nsPEF treatment. Cell line EPP85-181RNOV exhibited a permanent reduction in the spheroid size after nsPEF. We propose a mechanism in which the surface tension of the membrane, regulated by the organization of actin fibers, modulates the response of cancer cells towards nsPEF. When a membrane's surface tension remains low, we observed some cells form protrusions and release MVs containing MDR proteins. In contrast, when cell surface tension remains high, the cell membrane is being electroporated. The latter effect may be responsible for the reduced tumor growth following nsPEF treatment.

Synergistic In Vitro Anticancer Toxicity of Pulsed Electric Fields and Glutathione

Despite continuous advancement in skin cancer therapy, the disease is still fatal in many patients, demonstrating the need to improve existing therapies, such as electrochemotherapy (ECT). ECT can be applied in the palliative or curative setting and is based on the application of pulsed electric fields (PEF), which by themselves exerts none to low cancer toxicity but become potently toxic when combined with low-dosed chemotherapeutics such as bleomycin and cisplatin. Albeit their favorable side-effect profiles, not all patients respond to standard ECT, and some responders experience tumor recurrence. To identify potential adjuvant or alternative agents to standard electrochemotherapy, we explored the possibility of combining PEF with a physiological compound, glutathione (GSH), to amplify anticancer toxicity. GSH is an endogenous antioxidant and is available as a dietary supplement. Surprisingly, neither GSH nor PEF mono treatment but GSH + PEF combination treatment exerted strong cytotoxic effects and declined metabolic activity in four skin cancer cell lines in vitro. The potential applicability to other tumor cells was verified by corroborating results in two leukemia cell lines. Strikingly, GSH + PEF treatment did not immediately increase intracellular GSH levels, while levels 24 h following treatment were enhanced. Similar tendencies were made for intracellular reactive oxygen species (ROS) levels, while extracellular ROS increased following combination treatment. ROS levels and the degree of cytotoxicity could be partially reversed by pre-incubating cells with the NADPH-oxidase (NOX) inhibitor diphenyleneiodonium (DPI) and the H₂O₂-degrading enzyme catalase. Collectively, our findings suggest a promising new "endogenous" drug to be combined with PEF for future anticancer research approaches.

Palliative Treatment of Esophageal Cancer Using Calcium Electroporation

Simple Summary

Calcium electroporation is a new cancer therapy wherein a high, rapid influx of calcium, facilitated by electrical pulses, is used to kill cancer cells. This pilot study aimed to evaluate the safety and feasibility of this new treatment for patients with non-curable esophageal cancer. The treatment was administrated during an endoscopic examination, under general anesthesia, and in an outpatient setting. Eight patients were treated. One severe adverse event occurred (requiring a single blood transfusion) and another three mild side effects were seen. Two patients reported dysphagia relief after treatment and one patient had a partial response evaluated by CT. Six months after treatment, the same patient was still in good condition, without the need for further treatment. Calcium electroporation was conducted in eight patients with only a few side effects. More studies are warranted to evaluate clinical efficacy.

Abstract

Calcium electroporation (CaEP) is a novel cancer therapy wherein high intracellular calcium levels, facilitated by reversible electroporation, trigger tumor necrosis. This study aimed to establish safety with CaEP within esophageal cancer. Patients with non-curable esophageal cancer were included at Copenhagen University Hospital Rigshospitalet in 2021 and 2022. In an outpatient setting, calcium gluconate was injected intratumorally followed by reversible electroporation applied with an endoscopic electrode. The primary endpoint was the prevalence of adverse events, followed by palliation of dysphagia. All patients were evaluated with CT and upper endoscopies up to two months after treatment. The trial was registered at ClinicalTrials.gov (NCT04958044). Eight patients were treated. One serious adverse event (anemia, requiring a single blood transfusion) and three adverse events (mild retrosternal pain (two) and oral thrush (one)) were registered. Initially, six patients suffered from dysphagia: two reported dysphagia relief and four reported no change. From the imaging evaluation, one patient had a partial response, three patients had no response, and four patients had progression. Six months after treatment, the patient who responded well was still in good condition and without the need for further oncological treatment. CaEP was conducted in eight patients with only a few side effects. This study opens the way for larger studies evaluating tumor regression and symptom palliation.

Calcium Electroporation for Management of Cutaneous Metastases in HER2-Positive Breast Cancer: A Case Report

We report a case of successful treatment of cutaneous metastases in HER2-positive breast cancer with calcium electroporation (CaEP), in addition to trastuzumab, over a period of 5 years. CaEP is performed in local or general anesthesia, by injecting calcium chloride intratumorally and then electroporating cells in the area. Using a handheld needle electrode, a series of short, high-voltage electric pulses are delivered, which transiently permeabilizes cell membranes, causing toxic intracellular calcium levels. The treatment causes cancer cell death, while normal cells are less affected, making the treatment useful for local management of cutaneous lesions. This case presents a 66-year-old female, who had mastectomy surgery followed by adjuvant chemo- and radiotherapy for an ER-negative, HER2-positive breast cancer on her right side in 2003, and a mastectomy followed by endocrine therapy for an ER-positive, HER2 normal breast cancer on her left side in 2006. In 2015, the patient presented local cutaneous recurrence of the ER-negative, HER2-positive breast cancer. The patient was treated with trastuzumab alone, trastuzumab emtansine (TDM1), and a combination of trastuzumab and CaEP. TDM1 was found to have a slightly better effect on the cutaneous metastases than trastuzumab, but the side effects of TDM1 were not acceptable to the patient. The combination of continuous HER2-inhibition and intermittent CaEP, when needed, has been effective in keeping the cutaneous metastases under control for 5 years, and presumably more tolerable for the patient than chemotherapy. An interesting finding was local sparing of calcium electroporated skin from new recurrences, otherwise seen in the general area, which could be a sign of local immunity. This warrants further studies investigating local immunomodulation following CaEP. The patient reported appreciation of a treatment option without chemotherapy, and satisfaction with the outcome of the combination of HER2 inhibition and CaEP treatment. CaEP treatment is currently phase II treatment, and mechanisms and possible applications still need investigation. This novel anticancer treatment could potentially benefit many patients, due to its efficacy, low cost, and accessibility. This case provides observations, which may inspire future trials with CaEP for skin metastases of HER2-positive breast cancer.

Treatment of Basal Cell Carcinoma with Electrochemotherapy: Insights from the InspECT Registry (2008–2019)

This prospective registry-based study aims to describe electrochemotherapy (ECT) modalities in basal cell carcinoma (BCC) patients and evaluate its efficacy, safety, and predictive factors. The International Network for Sharing Practices of Electrochemotherapy (InspECT) multicentre database was queried for BCC cases treated with bleomycin-ECT between 2008 and 2019 (n = 330 patients from seven countries, with 623 BCCs [median number: 1/patient; range: 1–7; size: 13 mm, range: 5–350; 85% were primary, and 80% located in the head and neck]). The procedure was carried out under local anaesthesia in 68% of cases, with the adjunct of mild sedation in the remaining 32%. Of 300 evaluable patients, 242 (81%) achieved a complete response (CR) after a single ECT course. Treatment naïvety (odds ratio [OR] 0.35, 95% confidence interval [C.I.] 0.19–0.67, p = 0.001) and coverage of deep tumour margin with electric pulses (O.R. 5.55, 95% C.I. 1.37–21.69, p = 0.016) predicted CR, whereas previous radiation was inversely correlated (O.R. 0.25, p = 0.0051). Toxicity included skin ulceration (overall, 16%; G3, 1%) and hyperpigmentation (overall, 8.1%; G3, 2.5%). At a 17-month follow-up, 28 (9.3%) patients experienced local recurrence/progression. Despite no convincing evidence that ECT confers improved outcomes compared with standard surgical excision, it can still be considered an opportunity to avoid major resection in patients unsuitable for more demanding treatment. Treatment naïvety and coverage of the deep margin predict tumour clearance and may inform current patient selection and management.

Phase 1/2 study of topical submicron particle paclitaxel for cutaneous metastases of breast cancer

Purpose

This Phase 1/2 study evaluated safety and efficacy of a topical submicron particle paclitaxel (SPP) in an anhydrous ointment base (SOR007), primarily in breast cancer patients with cutaneous metastases (CM).

Methods

One of three concentrations of SOR007 SPP (0.15%, 1.0%, or 2.0%) was applied twice daily over an area of 50 cm² under a 3 + 3 phase 1 design for up to 28 days, with the option for expansion to an additional 28 days at the highest dose under a Phase 2a once safety was established. Efficacy was analyzed by lesion measurements and photographs to determine overall response rate (ORR), complete response (CR), and progression free survival by day 28 or 56.

Results

Twenty-three subjects were enrolled, 21 with cutaneous metastases of breast cancer (CMOBC). Four subjects received SOR007 0.15% for a median of 28 days (range = 17–29), three at a dose of 1.0% for a median of 28 days (range = 6–29), and sixteen at 2.0% for a median of  55 days (range = 6–60). All doses were well tolerated, and 19 subjects were evaluable for efficacy. At day 28 across all dose levels, 16% (95% CI 3.4 to 39.6%) of subjects achieved an ORR and another 63% (95% CI 34.9–96.8%) had stable disease (SD). The proportion of patients being progression free at 28 days across all treatments was 79% (95 CI 54–94%).

Conclusion

Application of SOR007 0.15%, 1.0%, and 2.0% to CM was safe and well tolerated with some reduction in lesion pain, and minimal systemic absorption of paclitaxel. Lesion stabilization was observed in most subjects over the study period. A randomized, placebo-controlled trial to confirm these findings is warranted.

ClinicalTrials.gov identifier

NCT03101358.

Prospektive Kohortenstudie von InspECT zur Sicherheit und Wirksamkeit der Elektrochemotherapie bei Hauttumoren und Metastasen in Abhängigkeit von Ulzeration

HINTERGRUND

Elektrochemotherapie (ECT) ist eine wirksame lokale Behandlung von Hauttumoren. Ziel dieser Studie war es, die Wirksamkeit der ECT bei ulzerierten gegenüber nichtulzerierten Tumoren zu vergleichen und den Effekt auf tumorassoziierte Symptome zu untersuchen.

METHODIK

20 Krebszentren des International Network for Sharing Practices on Electrochemotherapy (InspECT) sammelten prospektiv Daten. Die ECT wurde nach dem ESOPE-Protokoll durchgeführt. Das Therapieansprechen wurde anhand der Entwicklung der Läsionsgröße bewertet. Zusätzlich wurden Schmerzen, Symptome, Leistungsstatus (ECOG-Index) und Gesundheitszustand (EQ-5D-Fragebogen) untersucht.

ERGEBNISSE

716 Patienten mit ulzerierten (n = 302) und nichtulzerierten (n = 414) Hauttumoren und Metastasen wurden eingeschlossen (Mindest-Nachsorge 45 Tage). Nicht-ulzerierte Läsionen sprachen besser auf die ECT an als ulzerierte Läsionen (vollständiges Ansprechen: 65 % gegenüber 51 %, p = 0,0061). Nur 38 % (115/302) der Patienten mit ulzerierten Läsionen vor der ECT wiesen bei der letzten Nachuntersuchung ulzerierte Läsionen auf. Patienten mit ulzerierten Läsionen berichteten über stärkere Schmerzen und schwerere Symptome im Vergleich zu Patienten mit nichtulzerierten Läsionen, die sich nach der ECT signifikant und kontinuierlich besserten. Bei Patienten mit nichtulzerierten Läsionen hingegen nahmen die Schmerzen während der Behandlung vorübergehend zu. Es wurden keine schwerwiegenden Nebenwirkungen beobachtet.

SCHLUSSFOLGERUNGEN

Die ECT ist eine sichere und wirksame lokale Behandlung von Hauttumoren. Während die ECT die Symptome insbesondere bei Patienten mit ulzerierten Läsionen verbessert, sollte auf Basis der Daten die Implementation eines perioperativen Schmerzmanagements besonders bei nichtulzerierten Läsionen während der ECT erwogen werden.

Electroporation and Electrochemotherapy in Gynecological and Breast Cancer Treatment

Gynecological carcinomas affect an increasing number of women and are associated with poor prognosis. The gold standard treatment plan is mainly based on surgical resection and subsequent chemotherapy with cisplatin, 5-fluorouracil, anthracyclines, or taxanes. Unfortunately, this treatment is becoming less effective and is associated with many side effects that negatively affect patients’ physical and mental well-being. Electroporation based on tumor exposure to electric pulses enables reduction in cytotoxic drugs dose while increasing their effectiveness. EP-based treatment methods have received more and more interest in recent years and are the subject of a large number of scientific studies. Some of them show promising therapeutic potential without using any cytotoxic drugs or molecules already present in the human body (e.g., calcium electroporation). This literature review aims to present the fundamental mechanisms responsible for the course of EP-based therapies and the current state of knowledge in the field of their application in the treatment of gynecological neoplasms.

Prospective cohort study by InspECT on safety and efficacy of electrochemotherapy for cutaneous tumors and metastases depending on ulceration

BACKGROUND

Electrochemotherapy (ECT) is an effective local treatment for cutaneous tumors. The aim of this study was to compare the effectiveness of ECT in ulcerated vs. non-ulcerated tumors and investigate the effect on tumor-associated symptoms.

METHODS

Twenty cancer centers in the International Network for Sharing Practices on Electrochemotherapy (InspECT) prospectively collected data. ECT was performed following ESOPE protocol. Response was evaluated by lesion size development. Pain, symptoms, performance status (ECOG-Index) and health status (EQ-5D questionnaire) were evaluated.

RESULTS

716 patients with ulcerated (n = 302) and non-ulcerated (n = 414) cutaneous tumors and metastases were included (minimum follow-up of 45 days). Non-ulcerated lesions responded to ECT better than ulcerated lesions (complete response 65 % vs. 51 %, p = 0.0061). Only 38 % (115/302) with ulcerated lesions before ECT presented with ulcerated lesions at final follow-up. Patients with ulcerated lesions reported higher pain and more severe symptoms compared to non-ulcerated lesions, which significantly and continuously improved following ECT. In non-ulcerated lesions however, pain spiked during the treatment. No serious adverse events were reported.

CONCLUSIONS

ECT is a safe and effective local treatment for cutaneous tumors. While ECT improves symptoms especially in patients with ulcerated lesions, data suggest the implementation of a perioperative pain management in non-ulcerated lesions during ECT.

Calcium ion effect on phospholipid bilayers as cell membrane analogues

Ion attachment can modify stability and structure of phospholipid bilayers. Of particular importance is the interaction of phospholipids with divalent cations, such as calcium ions playing an important role in numerous cellular processes. The aim of our study was to determine effects of calcium ions on phospholipid membranes employing two cell membrane analogues, liposomes and planar lipid bilayers, and for the first time the combination of two instrumental setups: gas-phase electrophoresis (nES GEMMA instrumentation) and electrical (capacitance and resistance) measurements. Liposomes and planar lipid bilayers consisted of phosphatidylcholine, cholesterol and phosphatidylethanolamine. Liposomes were prepared from dried lipid films via hydration while planar lipid bilayers were formed using a Mueller-Rudin method. Calcium ions were added to membranes from higher concentrated stock solutions. Changes in phospholipid bilayer properties due to calcium presence were observed for both studied cell membrane analogues. Changes in liposome size were observed, which might either be related to tighter packing of phospholipids in the bilayer or local distortions of the membrane. Likewise, a measurable change in planar lipid bilayer resistance and capacitance was observed in the presence of calcium ions, which can be due to an increased rigidity and tighter packing of the lipid molecules in the bilayer.

ROS Pleiotropy in Melanoma and Local Therapy with Physical Modalities

Metabolic energy production naturally generates unwanted products such as reactive oxygen species (ROS), causing oxidative damage. Oxidative damage has been linked to several pathologies, including diabetes, premature aging, neurodegenerative diseases, and cancer. ROS were therefore originally anticipated as an imperative evil, a product of an imperfect system. More recently, however, the role of ROS in signaling and tumor treatment is increasingly acknowledged. This review addresses the main types, sources, and pathways of ROS in melanoma by linking their pleiotropic roles in antioxidant and oxidant regulation, hypoxia, metabolism, and cell death. In addition, the implications of ROS in various physical therapy modalities targeting melanoma, such as radiotherapy, electrochemotherapy, hyperthermia, photodynamic therapy, and medical gas plasma, are also discussed. By including ROS in the main picture of melanoma skin cancer and as an integral part of cancer therapies, a greater understanding of melanoma cell biology is presented, which ultimately may elucidate additional clues on targeting therapy resistance of this most deadly form of skin cancer.

Electrochemotherapy and Other Clinical Applications of Electroporation for the Targeted Therapy of Metastatic Melanoma

Electrochemotherapy (ECT) is an effective bioelectrochemical procedure that uses controlled electrical pulses to facilitate the increase of intracellular concentration of certain substances (electropermeabilization/ reversible electroporation). ECT using antitumor drugs such as bleomycin and cisplatin is a minimally invasive targeted therapy that can be used as an alternative for oncologic patients not eligible for surgery or other standard therapies. Even though ECT is mainly applied as palliative care for metastases, it may also be used for primary tumors that are unresectable due to size and location. Skin neoplasms are the main clinical indication of ECT, the procedure reporting good curative results and high efficiency across all tumor types, including melanoma. In daily practice, there are many cases in which the patient’s quality of life can be significantly improved by a safe procedure such as ECT. Its popularity must be increased because it has a safe profile and minor local adverse reactions. The method can be used by dermatologists, oncologists, and surgeons. The aim of this paper is to review recent literature concerning electrochemotherapy and other clinical applications of electroporation for the targeted therapy of metastatic melanoma.

Study protocol designed to investigate tumour response to calcium electroporation in cancers affecting the skin: a non-randomised phase II clinical trial

INTRODUCTION

Skin malignancy is a distressing problem for many patients, and clinical management is challenging. This article describes the protocol for the Calcium Electroporation Response Study (CaEP-R) designed to investigate tumour response to calcium electroporation and is a descriptive guide to calcium electroporation treatment of malignant tumours in the skin. Calcium electroporation is a local treatment that induces supraphysiological intracellular calcium levels by intratumoural calcium administration and application of electrical pulses. The pulses create transient membrane pores allowing diffusion of non-permeant calcium ions into target cells. High calcium levels can kill cancer cells, while normal cells can restore homeostasis. Prior trials with smaller cohorts have found calcium electroporation to be safe and efficient. This trial aims to include a larger multiregional cohort of patients with different cancer diagnoses and also to investigate treatment areas using MRI as well as assess impact on quality of life.

METHODS AND ANALYSIS

This non-randomised phase II multicentre study will investigate response to calcium electroporation in 30 patients with cutaneous or subcutaneous malignancy. Enrolment of 10 patients is planned at three centres: Zealand University Hospital, University Hospital of Southern Denmark and University Hospital Schleswig-Holstein. Response after 2 months was chosen as the primary endpoint based on short-term response rates observed in a prior clinical study. Secondary endpoints include response to treatment using MRI and change in quality of life assessed by questionnaires and qualitative interviews.

ETHICS AND DISSEMINATION

The trial is approved by the Danish Medicines Agency and The Danish Regional Committee on Health Research Ethics. All included patients will receive active treatment (calcium electroporation). Patients can continue systemic treatment during the study, and side effects are expected to be limited. Data will be published in a peer-reviewed journal and made available to the public.

TRIAL REGISTRATION NUMBERS

NCT04225767 and EudraCT no: 2019-004314-34.

Mechanisms of curcumin-based photodynamic therapy and its effects in combination with electroporation: An in vitro and molecular dynamics study

Photodynamic therapy (PDT) and electrochemotherapy (ECT) are two methods designed to enhance the anticancer potential of various drugs. Various clinical trials proved the efficacy of both ECT and PDT in melanoma treatment. Curcumin is a natural polyphenolic compound with high anticancer potential against melanoma due to its light absorption properties and toxicity towards cancer cells; however, high reactivity and amphipathic structure of curcumin are limiting its utility. This study aimed to propose the most effective protocol for antimelanoma combination of both therapies (PDT and ECT) in the context of curcumin. The in vitro studies were carried on melanotic melanoma (A375), amelanotic melanoma (C32) and fibroblast (HGF) cell lines. In molecular dynamics studies curcumin presented the single-layer localization in the water-membrane interphase. Further, the mass spectrometry studies exposed that during the PDT treatment curcumin is degraded to vanillin, feruloylmethane, and ferulic acid. Instant ECT with curcumin followed by PDT is the most efficient approach due to its selective genotoxicity towards malignant cells. The metabolic activity of fibroblasts decreased, however, at the same time the fragmentation of DNA did not occur. Additionally, instant PDT with curcumin followed by ECT after 3 h of incubation was a therapy selective towards melanotic melanoma.

In Vitro Study of Calcium Microsecond Electroporation of Prostate Adenocarcinoma Cells

Electroporation, applied as a non-thermal ablation method has proven to be effective for focal prostate treatment. In this study, we performed pre-clinical research, which aims at exploring the specific impact of this so-called calcium electroporation on prostate cancer. First, in an in-vitro study of DU 145 cell lines, microsecond electroporation (μsEP) parameters were optimized. We determined hence the voltage that provides both high permeability and viability of these prostate cancer cells. Subsequently, we compared the effect of μsEP on cells' viability with and without calcium administration. For high-voltage pulses, the cell death's mechanism was evaluated using flow-cytometry and confocal laser microscopy. For lower-voltage pulses, the influence of electroporation on prostate cancer cell mobility was studied using scratch assays. Additionally, we applied calcium-binding fluorescence dye (Fluo-8) to observe the calcium uptake dynamic with the fluorescence microscopy. Moreover, the molecular dynamics simulation visualized the process of calcium ions inflow during μsEP. According to our results calcium electroporation significantly decreases the cells viability by promoting apoptosis. Furthermore, our data shows that the application of pulsed electric fields disassembles the actin cytoskeleton and influences the prostate cancer cells' mobility.

Calcium Electroporation of Equine Sarcoids

Sarcoids are common equine skin tumors where the risk of recurrence after treatment is high, and better treatment options are warranted. Calcium electroporation is a novel anti-cancer treatment where lethally high calcium concentrations are introduced into the cells by electroporation, a method where short high-voltage pulses induce transient permeabilization of the cell membrane. This study investigated the safety and long-term response of calcium electroporation on sarcoids. Thirty-two sarcoids in eight horses were included. The study suggested that calcium electroporation is a safe and feasible treatment for sarcoids, including inoperable sarcoids. Horses were treated once (2/8) or twice (6/8) under general anesthesia, where sarcoids were injected with 220 mM calcium chloride followed by electroporation with 8 pulses of 100 μs, 1 kV/cm, and 1 Hz. Biopsies were taken prior to treatment. The sarcoid size was monitored for 12-38 weeks after the first treatment. Complete response was observed in 22% (6/27) of treated sarcoids, and partial response in 22% (6/27), giving a 44% total response. Treatment efficacy did not appear to be related to location, type, or size. In all non-biopsied lesions, a complete response was seen (4/4). In conclusion, in this small study, 44% of sarcoids responded with 22% of sarcoids disappearing.

A Comprehensive Review of Calcium Electroporation -A Novel Cancer Treatment Modality

Calcium electroporation is a potential novel anti-cancer treatment where high calcium concentrations are introduced into cells by electroporation, a method where short, high voltage pulses induce transient permeabilisation of the plasma membrane allowing passage of molecules into the cytosol. Calcium is a tightly regulated, ubiquitous second messenger involved in many cellular processes including cell death. Electroporation increases calcium uptake leading to acute and severe ATP depletion associated with cancer cell death. This comprehensive review describes published data about calcium electroporation applied in vitro, in vivo, and clinically from the first publication in 2012. Calcium electroporation has been shown to be a safe and efficient anti-cancer treatment in clinical studies with cutaneous metastases and recurrent head and neck cancer. Normal cells have been shown to be less affected by calcium electroporation than cancer cells and this difference might be partly induced by differences in membrane repair, expression of calcium transporters, and cellular structural changes. Interestingly, both clinical data and preclinical studies have indicated a systemic immune response induced by calcium electroporation. New cancer treatments are needed, and calcium electroporation represents an inexpensive and efficient treatment with few side effects, that could potentially be used worldwide and for different tumor types.