Study of Erdafitinib Intravesical Delivery System for Localized Bladder Cancer

The purpose of the study in Part 1 (dose escalation) and in Part 2 (dose expansion) is to determine the recommended Phase 2 dose(s) (RP2D\[s\]) and evaluate preliminary clinical efficacy. Part 3 (dose expansion) will confirm safety and preliminary clinical activity at the RP2D. Part 4 (RP2D expansion; MoonRISe-2) will assess the overall complete response (CR) in participants with intermediate-risk-non-muscle invasive bladder cancer (IR-NMIBC; means the cancer cells are only in the bladder's inner lining).

Inclusion Criteria: Parts 1-3: * Muscle-invasive or recurrent, non-muscle-invasive urothelial carcinoma of the bladder * For selected Cohorts: Activating tumor pan-fibroblast growth factor receptor (FGFR) mutation or fusion, as determined by local or central testing, approved by the sponsor prior to the start of study treatment. Local tissue-based results (if already existing) from next-generation sequencing (NGS) or polymerase chain reaction (PCR) tests performed in Clinical Laboratory Improvement Amendments (CLIA) -certified or equivalent laboratories, or results from commercially available PCR or NGS tests * Cohorts 1 and 2: Bacillus Calmette-Guérin (BCG) experienced, or participants with no BCG experience because BCG was not available as a treatment option in the participant's location within the previous 2 years and is currently unavailable. Participants who received an abbreviated course of BCG due to toxicity are still eligible * Cohort 1 only: Refuses or is not eligible for radical cystectomy (RC) * Cohorts 2 and 4: Willing and eligible for RC Part 4: * Have histologically confirmed diagnosis of recurrent Intermediate-risk-non-muscle invasive bladder cancer (IR-NMIBC) Ta LG tumors * Must not have undergone tumor debulking or selective ablation of visible lesions; partial tumor biopsy to confirm diagnosis and provide tissue for biomarker testing is permitted as long as remaining tumor is at least 5 millimeter (mm) in size * Must submit tissue and urine for FGFR testing * Can have a prior or concurrent second malignancy which natural history or treatment is unlikely to interfere with any study endpoints of safety or the efficacy of the study treatment Exclusion Criteria: Parts 1-3: * Concurrent extra-vesical (that is, urethra, ureter, renal pelvis) transitional cell carcinoma of the urothelium * Prior treatment with an pan-fibroblast growth factor receptor (FGFR) inhibitor * Received pelvic radiotherapy \)6 months prior to the start of study treatment, there must be no cystoscopic evidence of radiation cystitis * Presence of any bladder or urethral anatomic feature that in the opinion of the investigator may prevent the safe use of Erdafitinib intravesical delivery system * Indwelling urinary catheter. Intermittent catheterization is acceptable Part 4: * Histologically confirmed diagnosis of T1 NMIBC, HR NMIBC (HG/G2 or HG/G3 or CIS) or MIBC, locally advanced, non-resectable, or metastatic urothelial carcinoma at any time prior to enrollment. Previous high grade (HG) disease is accepted as long as diagnosis date is greater than or equal to (\>=5) years ago and there is documentation of low grade (LG) Ta thereafter * Known allergies, hypersensitivity, or intolerance to any study component or its excipients * Has a current diagnosis of newly diagnosed IR-NMIBC * Received an investigational treatment for bladder cancer after Transurethral Resection of the Bladder Tumor (TURBT) for the current NMIBC diagnosis or within 4 weeks or the agent/therapy washout period, whichever is longer, before the planned first dose of study treatment, or is currently enrolled in an investigational study * Evidence of current bladder perforation by cystoscopy or imaging