Introduction: Calcium electroporation (CaEP) is a novel anti-cancer treatment where a high influx of calcium, induced by local injection of a calcium solution and locally applied reversible electroporation, leads to tumor necrosis. In this ongoing first-in-man trial, CaEP is administered in patients with advanced esophageal cancer. The primary aim of this exploratory study is to establish safety and feasibility.

Methods: The trial aims to treat eight patients. In an outpatient setting, all patients are put in general anesthesia. For the endoscopic procedure, we use a pulse generator (ePORE®, Mirai Medical) and a single-use probe with two parallel electrodes (EndoVE®, Mirai Medical) connected to a gastroscope. The calcium solution (Calcium gluconate, B.Braun 0.23 mmol/ml) is injected into the tumor followed by locally applied electrical pulses (bipolar pulses of 5000 kilohertz/1000 Volt). After treatment, adverse events, pain, and dysphagia are registered and all patients are followed with computed tomography scans and upper endoscopies for up to three months.

Results: To date, seven patients have been treated. One serious adverse event (one day hospitalization due to anemia, requiring a single blood transfusion) and four adverse events have been registered including anemia, local pain, and oral thrush. Initially, five patients suffered from dysphagia, two reported dysphagia relief and three reported no change. Imaging response evaluation is pending.

Conclusion: In this preliminary analysis, CaEP in patients with advanced esophageal cancer has so far been conducted without major safety concerns. This study opens the way for larger studies evaluating tumor regression and symptom palliation.