Avelumab first-line maintenance (1LM) for advanced urothelial carcinoma (aUC): Long-term outcomes from JAVELIN Bladder 100 in patients (pts) with low tumor burden.

Abstract

4566 Background: In the JAVELIN Bladder 100 phase 3 trial, avelumab 1LM + best supportive care (BSC) significantly prolonged overall survival (OS) and progression-free survival (PFS) vs BSC alone in pts with aUC that had not progressed with 1L platinum-based chemotherapy (PBC). Results led to the incorporation of avelumab 1LM into international guidelines. Prior analyses have shown that low tumor burden (eg, nonvisceral metastases or lymph node [LN]-only disease) is associated with better outcomes in pts with aUC receiving immune checkpoint inhibitors. We report post hoc analyses of efficacy and safety in subsets of pts with low tumor burden from JAVELIN Bladder 100. Methods: Eligible pts with unresectable locally advanced (LA) or metastatic UC without progression after 1L PBC were randomized 1:1 to receive avelumab + BSC (n=350) or BSC alone (n=350). The primary endpoint was OS measured from randomization; secondary endpoints included PFS and safety. In this post hoc analysis, pts with nonvisceral metastases included those with LA disease or only nonvisceral disease, including bone metastasis, at randomization. Results: In the avelumab + BSC and BSC alone arms, 159 and 159 pts had nonvisceral metastases and 51 and 51 pts had LN-only disease, of whom 42 and 35 pts had LN-only disease in the pelvic/retroperitoneal area. At the efficacy data cutoff (June 4, 2021), median follow-up was ≥38 mo in both arms (≥2 y in all pts). In all subgroups, OS and PFS were prolonged with avelumab + BSC vs BSC alone (Table). Incidence of treatment-related adverse events (TRAEs) with avelumab were similar across subgroups. In the avelumab + BSC and BSC alone arms, subsequent anticancer drug treatment was received by 90 (56.6%) vs 119 pts (74.8%) with nonvisceral metastases, 27 (52.9%) vs 39 pts (76.5%) with LN-only disease, and 22 (52.4%) vs 27 pts (77.1%) with pelvic/retroperitoneal LN-only disease. Conclusions: Exploratory analyses suggest that avelumab 1LM has pronounced efficacy and manageable toxicity in pts with aUC who have low tumor burden, supporting its use as a standard of care in this setting. Clinical trial information: NCT02603432 . [Table: see text]