Comparative Efficacy of Avelumab Maintenance Therapy Versus Continued Chemotherapy Followed by Pembrolizumab in Metastatic Urothelial Carcinoma With No Progression After 4 Cycles of Chemotherapy: A Retrospective Study Using Propensity Score Matching.

INTRODUCTION: In cases of metastatic and unresectable urothelial carcinoma with no disease progression after 4 cycles of chemotherapy, including platinum agents, treatment options include continuation of chemotherapy or switching to maintenance therapy with avelumab. This study compared the treatment outcomes of avelumab maintenance therapy with those of pembrolizumab in urothelial carcinoma using propensity score matching.

PATIENTS AND METHODS: Between January 2017 and December 2022, 243 patients with metastatic and unresectable urothelial carcinoma were treated with either avelumab or pembrolizumab at the Yamaguchi University Hospital and its affiliated institutions. We retrospectively compared the oncological outcomes and adverse events by aligning patient characteristics and treatment backgrounds using propensity score matching.

RESULTS: The analysis compared 36 cases receiving avelumab maintenance therapy after chemotherapy to 49 cases where patients, after receiving 4 courses of chemotherapy including platinum-based agents without disease progression, were subsequently administered pembrolizumab as a second-line treatment following disease progression. Using propensity score matching, 27 cases from each group were selected for comparison. From the initiation of prechemotherapy to disease progression on immune checkpoint inhibitors, the median progression-free survival was 20.7 and 23.3 months in the avelumab and pembrolizumab groups, respectively, with no statistically significant difference observed (P = .358). However, avelumab tended to have a lower rate of high-dose glucocorticoid treatment compared to pembrolizumab.

CONCLUSION: Progression-free survival was similar for avelumab maintenance therapy and the sequence of continued chemotherapy followed by pembrolizumab after no disease progression at four chemotherapy courses. Avelumab may require less high-dose glucocorticoid treatment, potentially enhancing safety.