Infigratinib in Early-Line and Salvage Therapy for FGFR3-Altered Metastatic Urothelial Carcinoma

The optimal sequencing of systemic treatments for metastatic urothelial cancer (mUC) is unknown. We assessed the efficacy of infigratinib, a fibroblast growth factor receptor (FGFR) 1 to 3 inhibitor, in 67 patients with FGFR3-altered mUC by line of therapy. Objective response rates were 31% (early-line setting) and 24% (≥2nd-line setting). Infigratinib has notable activity in mUC regardless of line of therapy. INTRODUCTION: To describe the efficacy of infigratinib, a potent, selective fibroblast growth factor receptor (FGFR) 1–3 tyrosine kinase inhibitor, across lines of therapy (LOT) in patients with metastatic urothelial cancer (mUC). PATIENTS AND METHODS: Eligible patients had mUC and prior platinum-based chemotherapy, unless contraindicated, and activating FGFR3 mutation/fusion. Patients received infigratinib 125 mg orally daily (3 weeks on/1 week off) in a single-arm, open-label study. Primary endpoint: investigator-assessed confirmed objective response rate (ORR). Disease control rate (DCR), progression-free survival (PFS), best overall response (BOR) that included unconfirmed responses, and overall survival (OS) were also assessed. Subgroup analysis of efficacy and safety outcomes by LOT was performed. RESULTS: Sixty-seven patients were enrolled; 13 (19.4%) received infigratinib as early-line therapy for mUC due to ineligibility to receive platinum-based chemotherapy. Overall, ORR was 25.4% (95% CI 15.5–37.5) and DCR was 64.2% (95% CI 51.5–75.5). ORR was 30.8% (95% CI 9.1–61.4) with early-line infigratinib and 24.1% (95% CI 13.5–37.6) for ≥2 LOT. DCR was 46.2% (95% CI 19.2–74.9) for early-line and 68.5% (95% CI 54.4–80.5) for ≥2 LOT. PFS and OS appeared similar in both groups. Thirteen of 59 patients with a bladder primary tumor received early-line treatment with an ORR of 30.5% (95% CI 9.1–61.4), and 46 received ≥2 LOT with an ORR of 20.3% (95% CI 9.4–33.9); BOR was 38.5% (95% CI: 13.9–68.4%) and 42.6% (95% CI: 29.2–56.8%) in the early-line and salvage settings, respectively. Eight patients with upper tract urothelial carcinoma received salvage therapy (ORR, 50.0%; DCR, 100.0%). No significant differences in toxicities between LOT were observed. CONCLUSION: Infigratinib has notable activity in patients with mUC regardless of LOT. The findings support the evaluation of infigratinib across different settings in mUC.