The primary purpose of this study is to evaluate objective response rate (ORR) as per Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 of erdafitinib in a molecularly-defined subset of Asian participants with non-small-cell lung cancer (NSCLC), urothelial cancer, esophageal cancer and cholangiocarcinoma.

This is an open-label (all people know the identity of the intervention), multicenter, phase 2 study to evaluate the clinical efficacy, safety and pharmacokinetics of erdafitinib in Asian participants with advanced NSCLC, urothelial cancer, esophageal cancer and cholangiocarcinoma.

Inclusion Criteria:

• Pathologically or cytologically confirmed, advanced or refractory tumors (there are no restriction on the total number of lines of prior therapies, but participant should have received at least 1 line of anti-cancer therapy [as per local standard of care]): Squamous and non-squamous non-small-cell lung cancer (NSCLC), esophageal cancer, urothelial cancer and cholangiocarcinoma
• Participants must meet the following molecular eligibility criteria (diagnosed at a central or local laboratory using either a tumor tissue based assay, which must indicate: at least one of following): a) fibroblast growth factor receptor (FGFR) gene translocations b) FGFR gene mutations c) Participants with evidence of FGFR pathway activation or other potential target/pathway inhibited by erdafitinib may also be considered and allowed for enrollment if supported by emerging biomarker data.
• The presence of measurable disease according to the RECIST, Version 1.1 Criteria, and documented disease progression as defined by RECIST (Version 1.1) at baseline
• Eastern Cooperative Oncology Group (ECOG) performance status score 0 or 1
• Female participants (of child bearing potential and sexually active) and male participants (with a partner of child bearing potential) must use medically acceptable methods of birth control. Male participants must use highly effective birth control measurements when sexually active and must not donate sperm
• Adequate bone marrow, liver, and renal function within the 14 days prior to Day 1 of Cycle 1 up until pre-dose of Cycle 1

Exclusion Criteria:

• Chemotherapy, targeted therapies, immunotherapy, or treatment with an investigational anticancer agent within 2 weeks or at least 5 half-lives of the drug whichever is longer up to a maximum of 4 weeks before the first administration of study drug. Localized palliative radiation therapy (but should not include radiation to target lesions) and ongoing luteinizing hormone-releasing hormone (LHRH) agonists, bisphosphonates and denosumab, are permitted
• Participants with persistent phosphate greater than (>) upper limit of normal (ULN) during Screening (within 14 days prior to Day 1 of Cycle 1 up until pre-dose of Cycle 1) and despite medical management of phosphate levels
• Participants taking medications known to have a significant risk of causing QTc prolongation and Torsades de Pointes. Participants who have discontinued any of these medications must have a wash-out period of at least 5 days or at least 5 half-lives of the drug (whichever is longer) prior to the first dose of study drug
• Left ventricular ejection fraction (LVEF) less than (<) 50% as assessed by echocardiography (or multi-gated acquisition [MUGA]) performed at Screening
• Uncontrolled inter-current illness including, but not limited to, poorly controlled hypertension or diabetes, ongoing active infection requiring antibiotics, psychiatric illness, or at risk of gastrointestinal perforation as per investigators' assessment
• Received prior selective FGFR inhibitor treatment or RET inhibitor treatment, respectively according to the biomarker prescreening result, or if the participant has known allergies, hypersensitivity, or intolerance to Erdafitinib or its excipients
• Any corneal or retinal abnormality likely to increase risk of eye toxicity