The impact of eligibility for maintenance immunotherapy on prognosis in patients with unresectable or metastatic urothelial carcinoma

OBJECTIVES: To investigate the eligibility for maintenance immunotherapy and its impact on the prognosis of advanced urothelial carcinoma treated with first‐line chemotherapy, as the selection biases of the eligible population in the JAVELIN Bladder 100 trial remain unclear. METHODS: We retrospectively evaluated 213 patients (median age, 71 years) with unresectable locally advanced or metastatic urothelial carcinoma treated with platinum‐based first‐line chemotherapy between May 2003 and April 2021. The patients were categorized into the following two groups: progressive disease (PD) within four cycles (trial ineligible group) and non‐PD within four cycles (trial eligible group). The primary outcomes were the estimated proportion of trial eligible patients for maintenance immunotherapy. The secondary outcomes were the comparison of the overall survival in the trial eligible and ineligible groups and the impact of radiologic response at the second cycle on the fourth cycle. RESULTS: Among the 213 patients, 81 (38%) were included in the trial eligible group. The trial eligible group had a significantly longer overall survival than the trial ineligible group (P < 0.001). Of 166 patients who had no PD within two cycles, 85 (51%) patients experienced PD within four cycles. Patients with a complete response or partial response at the second cycle had a significantly lower rate of PD at the fourth cycle (42%) than those with stable disease at the second cycle (59%, P = 0.031). CONCLUSION: We observed 38% of the trial eligible population. Overall survival was significantly different between the trial eligible and ineligible groups.