Erdafitinib or Erdafitinib Plus Cetrelimab for Patients With Metastatic Urothelial Carcinoma and FGFR Alterations: Final Results From the Phase II NORSE Study

PURPOSE – First-line treatment options for cisplatin-ineligible patients with metastatic urothelial cancer (mUC) are limited. We conducted a phase II study of erdafitinib, alone or with cetrelimab, in FGFR-altered mUC.METHODS – Adults with mUC and select FGFR alterations who are ineligible for cisplatin were randomly assigned 1:1 in a noncomparative design to once-daily erdafitinib 8 mg (with pharmacodynamically guided uptitration to 9 mg) or erdafitinib 8 mg plus intravenous cetrelimab 240 mg once every 2 weeks at cycles 1-4 and 480 mg once every 4 weeks thereafter. Primary end points were investigator-assessed confirmed overall response rate (ORR) and safety; secondary end points included duration of response (DOR), progression-free survival, and overall survival (OS). No statistical hypotheses were tested.RESULTS – At data cutoff, 87 patients were randomly assigned and treated (erdafitinib, n = 43; erdafitinib plus cetrelimab, n = 44). Of 64 patients with PD-L1 expression data, 56 (87.5%) had low levels of PD-L1 expression (combined positive score <10). Median survival follow-up was 14.2 months. Investigator-assessed confirmed ORR for erdafitinib was 44.2% (95% CI, 29.1 to 60.1) with one complete response (CR); median DOR and median OS were 9.7 months (95% CI, 4.6 to not estimable [NE]) and 16.2 months (95% CI, 8.3 to NE), respectively. Investigator-assessed confirmed ORR for erdafitinib plus cetrelimab was 54.5% (95% CI, 38.8 to 69.6), with six (13.6%) CRs; median DOR and median OS were 11.1 months (95% CI, 8.8 to NE) and 20.8 months (95% CI, 12.0 to NE), respectively. The most frequent treatment-related adverse events (TRAEs) were hyperphosphatemia (83.7% and 68.2% in erdafitinib and erdafitinib plus cetrelimab groups, respectively), stomatitis (69.8% and 56.8%), and dry mouth (37.2% and 56.8%). Grade ≥3 TRAEs occurred in 46.5% and 45.5% of patients receiving erdafitinib and erdafitinib plus cetrelimab, respectively.CONCLUSION – First-line erdafitinib monotherapy and erdafitinib plus cetrelimab demonstrated antitumor activity and a manageable safety profile in cisplatin-ineligible patients with mUC.