Erdafitinib (FGFR1–4 inhibitor) Extends OS vs Chemo in FGFR3‑Altered Metastatic Urothelial Cancer

Erdafitinib (Balversa) is an oral pan‑FGFR tyrosine kinase inhibitor targeting susceptible FGFR3 alterations and was evaluated in THOR/BLC3001 Cohort 1 (NCT03390504), an open‑label Phase 3 trial in previously treated locally advanced/metastatic urothelial carcinoma. In 266 patients randomized 1:1 to erdafitinib vs investigator’s choice chemotherapy (docetaxel or vinflunine), erdafitinib improved median OS to 12.1 months vs 7.8 months (HR 0.64, p=0.0050), median PFS to 5.6 vs 2.7 months (HR 0.58, p=0.0002), and confirmed ORR to 35.3% vs 8.5% (p<0.001)—a clear step up from typical post‑platinum/post‑IO single‑agent chemo activity (KEYNOTE‑045 control arm mOS ~7.4 months). The January 19, 2024 FDA traditional approval includes a limitation of use because THOR Cohort 2 did not show an OS benefit vs pembrolizumab (HR 1.18), so erdafitinib is not recommended for PD‑(L)1–eligible patients who have not yet received prior PD‑(L)1 therapy.