Erdafitinib versus Chemotherapy in Fibroblast Growth Factor Receptor-Altered Advanced or Metastatic Urothelial Cancer After Progression on Anti-programmed Death-(Ligand) 1 Therapy: An Exploratory Analysis of the Asian Subpopulation in the THOR Phase 3 Study.

INTRODUCTION

The randomized phase 3 THOR study showed significantly longer survival with erdafitinib (pan-fibroblast growth factor receptor [FGFR] inhibitor) over chemotherapy in adults with FGFR-altered locally advanced or metastatic urothelial cancer (la/mUC) who had progressed during or after anti-programmed death-(ligand) 1 (anti-PD-[L]1) therapy (Cohort 1). This exploratory post-hoc analysis was conducted to evaluate the efficacy and safety of erdafitinib in the Asian subpopulation within THOR Cohort 1.

PATIENTS AND

METHODS

Eligible patients were randomized in a 1:1 ratio to receive erdafitinib (8 mg once daily with pharmacodynamically guided up-titration to 9 mg) or chemotherapy (vinflunine or docetaxel once every 3 weeks). The primary endpoint was overall survival (OS).

RESULTS

Seventy-six patients were included in the Asian subpopulation: 37 were randomized to erdafitinib and 39 to docetaxel. The median follow-up for survival was 15.7 months. The median OS was longer with erdafitinib than chemotherapy (23.3 months vs.11.3 months; hazard ratio [HR], 0.47; 95% confidence interval [CI], 0.23-0.96). One patient (2.7%) in the erdafitinib arm and 5 patients (15.2%) in the chemotherapy arm had grade 3 or 4 treatment-related serious adverse events (SAEs). One patient (2.7%) in the erdafitinib arm and 4 patients (12.1%) in the chemotherapy arm discontinued treatment due to treatment-related AEs.

CONCLUSIONS

Erdafitinib showed improved survival compared with chemotherapy, with no new safety concerns in the Asian subpopulation. These findings were consistent with those for the overall study population in THOR Cohort 1 who received prior anti-PD-(L)1 therapy.