Complete Response after Avelumab Maintenance Therapy: Successful Management of Metastatic Urothelial Carcinoma.

Urothelial carcinoma is one of the most frequently diagnosed cancer types in the world and despite progress in treatment, it remains a lethal disease in the metastatic stage. Because of its high programmed cell death ligand 1 protein expression, it is associated with an increased response to immune checkpoints inhibitors. In the past few years, the gold standard for first-line treatment of metastatic urothelial carcinoma has been platinum-based chemotherapy, and avelumab (PD-1 inhibitor) maintenance therapy for non-progressing tumours. After the remarkable benefit demonstrated in the EV-302 study, the guidelines were recently revised to include enfortumab vedotin plus pembrolizumab as the new standard of care in this setting. Despite the new recommendations, in some countries, this combination is still pending approval. Furthermore, for patients who are ineligible for enfortumab vedotin plus pembrolizumab, platinum-based chemotherapy followed by avelumab maintenance therapy continues to be a preferred treatment option. This report presents a woman diagnosed with metastatic urothelial carcinoma with histologically confirmed complete response after cisplatin and gemcitabine chemotherapy and avelumab as maintenance therapy, which has been reported in only a few cases in the literature. LEARNING POINTS: Urothelial carcinoma is associated with high mortality despite significant progresses in treatment.In metastatic urothelial carcinoma the first-line treatment was recently changed, with enfortumab vedotin plus pembrolizumab being approved by the US Food and Drug Administration and European Medicines Agency. Until now, platinum-based chemotherapy and avelumab maintenance therapy for non-progressing tumours was the only standard of care for these patients.In the literature, few cases have been reported with complete response to avelumab maintenance therapy.