This open-label (all people know identity of intervention) and multicenter (when more than one hospital or medical school team work on a medical research study) study to establish the recommended phase 2 dose (RP2D) for erdafitinib and cetrelimab and/or platinum (cisplatin or carboplatin) chemotherapy, and to evaluate the safety of erdafitinib in combination with cetrelimab and platinum chemotherapy in Phase 1b and to evaluate the safety and efficacy of the RP2D of erdafitinib plus cetrelimab versus erdafitinib in Phase 2 in participants with advanced urothelial cancer with select fibroblast growth factor receptor (FGFR) gene alterations. Participants enrolled in Phase 1b erdafitinib + cetrelimab cohort may have received any number of lines of prior therapy, and participants enrolled in Phase 1b erdafitinib + cetrelimab + platinum chemotherapy cohort will have had no prior systemic therapy for metastatic disease and participants enrolled in Phase 2 will have had no prior systemic therapy for metastatic disease and will be cis-ineligible. Part 1 (Phase 1b: Dose Escalation) will identify safety and RP2Ds of erdafitinib + cetrelimab and erdafitinib + cetrelimab + platinum (cisplatin or carboplatin) chemotherapy, and Part 2 (Phase 2: Dose Expansion) will evaluate erdafitinib monotherapy and the RP2D regimen of the erdafitinib + cetrelimab combination to further characterize safety and clinical activity. The study will be conducted in 3 phases: screening phase, treatment phase, and follow-up phase. Study evaluations include efficacy, pharmacokinetics, pharmacodynamics, immunogenicity, biomarkers, and safety.
The purpose of this study is to: (a) characterize the safety and tolerability of and to identify the recommended Phase 2 dose (RP2D) and schedule for erdafitinib in combination with cetrelimab, and for erdafitinib in combination with cetrelimab and platinum (cisplatin and carboplatin) chemotherapy and; (b) to evaluate the safety and clinical activity of erdafitinib alone and in combination with cetrelimab in cisplatin-ineligible participants with metastatic or locally advanced urothelial cancer (UC) with select fibroblast growth factor receptor (FGFR) gene alterations and no prior systemic therapy for metastatic disease.