Calcium Electroporation for Urinary Bladder Tumors: A First-in-Human Feasibility, Safety, and Early Response Trial

Inclusion Criteria: * Age ≥ 18 years and able to understand participant information and give informed consent * Histologically verified urothelial bladder tumor * Unfit for cystectomy and/or radiotherapy * Patients with recurrence after radiotherapy unfit for salvage cystectomy * Disease where other treatments are considered unsuitable or have been declined by the patient * The patient may receive simultaneous systemic treatment * Selected high-burden non-muscle-invasive bladder tumors after MDT assessment * Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) ≤ 2 * Life expectancy of ≥ 3 months * Patients must be deemed able to tolerate general anesthesia * Sexually active participants in the reproductive age must use contraception. Accepted contraception includes the use of intrauterine device (IUD), oral contraceptives, male or female condom, vasectomy or female sterilization * Patients must stop treatment with anticoagulants before surgery in accordance with national guidelines * Plasma ionized Ca2+ must be within the normal upper limit. Correction is allowed * Hematology * Thrombocytes ≥ 50 billion/L * International normalized ratio (INR) ≤ 1.5. Correction is allowed Exclusion Criteria: * Pregnancy (confirmed by a blood sample) or lactation * Allergy to calcium gluconate or any of its excipients * Any clinical condition or previous treatment, that in the investigators' opinion made the patient ineligible * Contraindications to treatment with calcium gluconate as described: * Hypersensitivity to calcium gluconate or any of its excipients * Hypercalcemia (e.g. due to hyperparathyroidism, hypervitaminosis D, decalcifying malignancies, renal insufficiency, immobilization osteoporosis, sarcoidosis, milk-alkali syndrome)