Clinical Outcome and Safety of Combined Radiation Therapy and Maintenance Avelumab for Bladder Cancer: A Case Series

The combination of maintenance avelumab and radiation therapy (RT) has emerged as a promising approach for enhancing therapeutic efficacy. However, clinical evidence on the use of this combination therapy is limited. This single-institution case series includes five patients with locally advanced or metastatic urothelial carcinoma who received maintenance avelumab combined with RT for primary bladder cancer. The characteristics of the patients, number of avelumab cycles received upon RT initiation, RT dose/delivery approach, severity and type of avelumab or radiation treatment-related adverse events, and response to RT were recorded. The primary site in all patients was the bladder. Among the patients receiving avelumab maintenance therapy, four underwent RT to the primary lesion for local control and one for bladder preservation. The patients only developed grade 1 RT-related adverse events without treatment interruptions. All patients had a complete response at the irradiation site of the primary bladder cancer. One patient died of community-acquired pneumonia, and the others are still being treated. The combination of maintenance avelumab and RT to the primary site could be effective and safe for local control in patients with bladder cancer.