Inclusion Criteria:

- Histologically confirmed, non-muscle invasive urothelial carcinoma with carcinoma in
situ (CIS) (with or without papillary disease).

- Predominant histologic component (> 50 percent) must be urothelial (transitional cell)
carcinoma.

- Participants must have high-risk Bacillus Calmette-Guerin (BCG) - unresponsive
disease, defined as:

- Persistent or recurrent CIS alone or with recurrent Ta/T1 disease within 12
months of completion of adequate BCG therapy. (Ta/T1: noninvasive papillary
disease/tumor invades the subepithelial connective tissue). Adequate BCG therapy
is defined as one of the following:

- 5 of 6 doses of an initial induction course + at least 2 of 3 doses maintenance
therapy;

- 5 of 6 doses of an initial induction course + at least 2 of 6 doses of a second
induction course.

- Participant must be ineligible for or refusing a radical cystectomy.

- All visible papillary Ta/T1 tumors must be completely resected within 60 days prior to
enrollment.

- Eastern Cooperative Oncology Group Performance Status score of 0, 1, or 2.

Exclusion Criteria:

- Current or prior history of muscle-invasive urothelial carcinoma or metastatic
disease.

- Nodal or metastatic disease as noted on computed tomography (CT) or magnetic resonance
imaging (MRI) within 3 months prior to study treatment.

- Concomitant upper tract urothelial carcinoma as noted on CT or MRI urogram performed
within 3 months prior to study treatment.

- Prior or concomitant urothelial carcinoma of the prostatic urethra within 6 months
prior to study treatment.

- Participants with tumor-related hydronephrosis.

- Participant has received other systemic anticancer therapy including chemotherapy,
biologic therapy, immunotherapy, targeted therapy, endocrine therapy, and/or
investigational agent within 4 weeks or intravesical therapy within 6 weeks of first
dose of study treatment.

- Subject has had any prior radiation to the bladder for urothelial cancer.