Avelumab first-line maintenance plus best supportive care (BSC) vs. BSC alone for advanced urothelial carcinoma: JAVELIN Bladder 100 Asian subgroup analysis

Background: The phase 3 JAVELIN Bladder 100 trial showed significantly prolonged overall survival (OS) with avelumab first-line maintenance + best supportive care (BSC) vs. BSC alone in patients with advanced urothelial carcinoma (UC) that had not progressed with first-line platinum-containing chemotherapy. Here, efficacy and safety were assessed from the initial analysis of the JAVELIN Bladder 100 trial (data cutoff October 21, 2019) in patients enrolled in Asian countries. Methods: Patients with locally advanced or metastatic UC that had not progressed with 4 to 6 cycles of first-line platinum-containing chemotherapy (gemcitabine + cisplatin or carboplatin) were randomized 1:1 to receive avelumab first-line maintenance + BSC or BSC alone, stratified by best response to first-line chemotherapy and visceral vs. nonvisceral disease when initiating first-line chemotherapy. The primary endpoint was OS assessed from randomization in all patients and patients with PD-L1+ tumors (Ventana SP263 assay). Secondary endpoints included progression-free survival (PFS) and safety. Results: A total of 147 patients in JAVELIN Bladder 100 were enrolled in Asian countries (Hong Kong, India, Japan, South Korea, and Taiwan). In this Asian subgroup, 73 and 74 patients received avelumab + BSC or BSC alone, respectively. Median OS was 25.3 months (95% CI, 18.6 to not estimable [NE]) in the avelumab + BSC arm vs. 18.7 months (95% CI, 12.8–NE) in the BSC alone arm (hazard ratio [HR], 0.74 [95% CI, 0.43–1.26]); median PFS was 5.6 months (95% CI, 2.0–7.5) vs. 1.9 months (95% CI, 1.9–1.9), respectively (HR, 0.58 [95% CI, 0.38–0.86]). In the avelumab + BSC vs. BSC alone arms, grade ≥3 treatment-emergent adverse events (any causality) occurred in 44.4% vs. 16.2%, respectively. The most common grade ≥3 treatment-emergent adverse events in the avelumab + BSC arm were anemia (9.7%), amylase increased (5.6%), and urinary tract infection (4.2%). Conclusions: Efficacy and safety results for avelumab first-line maintenance in the Asian subgroup of JAVELIN Bladder 100 were generally consistent with those in the overall trial population. These data support the use of avelumab first-line maintenance as standard of care for Asian patients with advanced UC that has not progressed with first-line platinum-containing chemotherapy.