A Study of Erdafitinib in Participants With Advanced Solid Tumors and Fibroblast Growth Factor Receptor (FGFR) Gene Alterations

Inclusion Criteria

• Histologic demonstration of an unresectable, locally advanced, or metastatic solid tumor malignancy with an fibroblast growth factor receptor (FGFR) mutation or FGFR gene fusion
• Measurable disease
• Participant must have received at least one prior line of systemic therapy in the advanced, unresectable, or metastatic setting; or is a child or adolescent participant with a newly-diagnosed solid tumor and no acceptable standard therapies
• Documented progression of disease, defined as any progression that requires a change in treatment, prior to full study screening

Exclusion Criteria

• Has had prior chemotherapy, targeted therapy, or treatment with an investigational anticancer agent within 15 days or less than or equal to (<=) 5 half-lives of the agent (whichever is longer) and up to a maximum of 30 days before the first dose of erdafitinib
• The presence of FGFR gatekeeper and resistance mutations
• Histologic demonstration of urothelial carcinoma
• Hematologic malignancy (i.e., myeloid and lymphoid neoplasms
• For non-small cell lung cancer participants only: pathogenic somatic mutations or gene fusions in the following genes: EGFR, ALK, ROS1, NTRK, BRAF V600E and KRAS
• Active malignancies other than for disease requiring therapy