In this population, conventional chemotherapy is often limited by altered pharmacokinetics and the risk of heightened toxicity, highlighting an important unmet clinical need.<h4>Case summary</h4>We report the case of a 46-year-old woman with metastatic CLDN18.2-positive, HER2-negative gastric adenocarcinoma who subsequently developed end-stage renal disease (ESRD) secondary to tumor progression, necessitating regular hemodialysis. The gene discussed is ERBB2; the disease is chronic kidney disease.