The purpose of the study is to determine the tolerability of erdafitinib intravesical delivery system (TAR-210) in Japanese participants.

Inclusion Criteria:

• Histologically confirmed non-muscle-invasive urothelial carcinoma of the bladder
• All visible tumors must be completely resected prior to the start of study treatment and documented on screening cystoscopy
• Confirmed recurrence of non-muscle invasive bladder cancer (NMIBC) after prior therapy that meet either one: a. Recurrence of high-risk NMIBC (high-grade Ta or any-grade T1) within 12 months after adequate Bacillus Calmette-Guerin (BCG), or any-grade T1 within 3 months after 1st induction course, refusing or ineligible for radical cystectomy (RC). b. Recurrence of intermediate- or high-risk NMIBC (any-grade Ta/T1) after prior BCG regardless of the timing of recurrence, refusing or ineligible for RC and considering no other effective treatment options. c. Recurrence of intermediate-risk NMIBC (low grade Ta) after intravesical chemotherapy including maintenance therapy following a single dose after operation, no other effective intravesical chemotherapy is available and refusing BCG treatment
• At least 1 of the study protocol defined activating fibroblast growth factor receptors (FGFR) mutation or fusion, as determined by local or central testing using either tumor tissue or urine sample collected prior to trans urethral resection of bladder tumour (TURBT)
• Eastern Cooperative Oncology Group (ECOG) performance status score of less than or equal to (<=) 2

Exclusion Criteria:

• Histologically confirmed muscle-invasive (T2 or higher stage) urothelial carcinoma of the bladder.
• Prior treatment with an fibroblast growth factor receptor (FGFR) inhibitor
• Presence of any bladder or urethral anatomic feature that in the opinion of the investigator may prevent the safe placement, indwelling use, or removal of erdafitinib intravesical delivery system
• Participants with active bladder stones or history of bladder stones less than [< 6] months prior to the start of study treatment
• Participants have concurrent or second malignancy other than the disease which natural history or treatment is unlikely to interfere with any study endpoints of safety or the efficacy of the study treatment(s); -Bladder post-void residual volume (PVR) >350 mL after second voided urine, -Current central serous retinopathy or retinal pigment epithelial detachment of any-grade

The data sharing policy of the Janssen Pharmaceutical Companies of Johnson & Johnson is available at www.janssen.com/clinical-trials/transparency. As noted on this site, requests for access to the study data can be submitted through Yale Open Data Access (YODA) Project site at yoda.yale.edu