Avelumab maintenance therapy for advanced urothelial carcinoma: subgroup analyses by characteristics of first-line platinum-based chemotherapy from a real-world chart review study in Japan (JAVEMACS).

BACKGROUND: Avelumab maintenance therapy was approved in Japan in February 2021 for patients with unresectable locally advanced or metastatic urothelial carcinoma (la/mUC) without disease progression after platinum-based chemotherapy (PBC). We report subgroup analyses from the JAVEMACS chart review study of avelumab maintenance therapy in Japan by characteristics of first-line (1L) PBC. METHODS: This multicenter, retrospective study collected data from medical charts of patients with la/mUC who received avelumab maintenance after 1L PBC. Protocol-specified subgroups defined by 1L PBC characteristics (PBC regimen, number of PBC cycles, and best overall response to PBC) were analyzed. RESULTS: Between February 2021 and December 2023, 350 patients received avelumab maintenance. Patient characteristics were generally similar across subgroups defined by 1L PBC characteristics. In patients who received 1L gemcitabine + cisplatin (n = 196) or gemcitabine + carboplatin (n = 116), median overall survival (OS) was not reached (95% CI, 31.2 months-not estimable [NE]) and 24.3 months (95% CI, 19.5–30.6 months), respectively. In patients who received 1–3 cycles (n = 68), 4 cycles (n = 205), 5/6 cycles (n = 61), or ≥ 7 cycles (n = 16) of 1L PBC, median OS was 25.0 months (95% CI, 15.2 months-NE), not reached (95% CI, 29.3 months-NE), 31.2 months (95% CI, 18.0 months-NE), and 23.6 months (95% CI, 19.3 months-NE), respectively. In patients with complete response (n = 32), partial response (n = 180), or stable disease (n = 138) as best response to 1L PBC, median OS was not reached (95% CI, 30.6 months-NE), 31.2 months (95% CI, 22.6 months-NE), and 26.5 months (95% CI, 20.2 months-NE), respectively. Across all subgroups, enfortumab vedotin was the most common second-line treatment after discontinuation of avelumab. CONCLUSIONS: Results from these descriptive subgroup analyses from JAVEMACS suggest that real-world outcomes with avelumab maintenance therapy are generally consistent regardless of 1L PBC regimen, number of 1L PBC cycles, or best response to 1L PBC. These findings further support the use of avelumab maintenance therapy as a standard of care for patients with la/mUC without disease progression after 1L PBC. TRIAL REGISTRATION: NCT06412848.