Global real-world experiences with pembrolizumab in advanced urothelial carcinoma after platinum-based chemotherapy: the ARON-2 study

Background: Immune checkpoint inhibitors have changed previous treatment paradigm of advanced urothelial carcinoma (UC). The ARON-2 study (NCT05290038) aimed to assess the real-world effectiveness of pembrolizumab in patients recurred or progressed after platinum-based chemotherapy. Patients and Methods: Medical records of patients with documented metastatic UC treated by pembrolizumab as second-line therapy were retrospectively collected from 88 institutions in 23 countries. Patients were assessed for overall survival (OS), progression-free survival (PFS) and overall response rate (ORR). Cox proportional hazards models were adopted to explore the presence of prognostic factors. Results: In total, 836 patients were included: 544 patients (65%) received pembrolizumab after progression to first-line platinum-based chemotherapy in the metastatic setting (cohort A) and 292 (35%) after recurring within < 12 months since the completion of adjuvant or neoadjuvant chemotherapy (cohort B). The median follow-up time was 15.3 months. The median OS and the ORR were 10.5 months and 31% in the overall study population, 9.1 months and 29% in cohort A and 14.6 months and 37% in cohort B. At multivariate analysis, ECOG-PS ≥ 2, bone metastases, liver metastases and pembrolizumab setting (cohort A vs B) proved to be significantly associated with worst OS and PFS. Stratified by the presence of 0, 1–2 or 3–4 prognostic factors, the median OS was 29.4, 12.5 and 4.1 months (p < 0.001), while the median PFS was 12.2, 6.4 and 2.8 months, respectively (p < 0.001). Conclusions: Our study confirms that pembrolizumab is effective in the advanced UC real-world context, showing outcome differences between patients recurred or progressed after platinum-based chemotherapy.