Antibody-drug conjugate therapy in a renal transplant patient with bladder cancer: A case report.

This case report presents the clinical course and treatment outcomes of a 61-year-old male renal transplant patient who developed recurrent bladder cancer while receiving long-term immunosuppressive therapy. Computed tomography (CT) revealed two tumors in the bladder trigone (largest diameter 8.4 mm). After initial treatment with transurethral resection of the bladder tumor (TURBT), the patient underwent regular bladder instillations of epirubicin. However, a follow-up examination 1 month later revealed disease recurrence, leading to a second TURBT. Due to the patient's renal impairment (baseline creatinine 107.8 µmol/L, glomerular filtration rate (GFR) 79.19 mL/min/1.73m2) and human epidermal growth factor receptor 2 (HER2) overexpression (2+), the decision was made to employ an antibody-drug conjugate (ADC) targeting HER2 (disitamab vedotin, 120 mg intravenously). The report outlines the patient's background, the progression of his disease, the decision-making process behind the use of ADC therapy, and the subsequent response to treatment. The successful control of the disease with ADC therapy in this complex patient population highlights its potential as an effective and less toxic alternative to conventional chemotherapy, particularly in patients with recurrent bladder cancer after renal transplantation.