Inclusion Criteria:

- Histologic diagnosis of transitional cell cancer of the bladder must have completed a
transurethral resection of all visible bladder tumors, and have completed two
previous 6-week courses with intravesical BCG.

- Evidence of disease recurrence within 1 year of previous BCG treatment

- Tumor tissue must be available from biopsy for study related immunohistochemical
analysis

- If sexually active must use reliable form of contraception while on study and for 4
weeks after last treatment

- ECOG performance status of <2

- Life expectancy of at least 6 months

- Adequate hematologic, renal and liver function

- Informed consent

Exclusion Criteria:

- No evidence of immunosuppression or treated with immunosuppressive therapy within 6
months

- No prior radiation to the pelvis

- No gross hematuria within 1 week prior to planned week 1 treatment

- Cannot have previous intolerance to BCG

- Cannot be seropositive for HIV, hepatitis B(HBV) or hepatitis C(HCV) per patient
history

- No evidence of metastatic disease

- No prior treatment with anti-CTLA-4 monoclonal antibody

- Can not be pregnant or lactating

- No history of autoimmune disorder

- No history of thyroid or adrenal insufficiency

- No history of inflammatory bowel conditions, including diverticulitis, ulcerative
colitis, Crohn's or celiac disease, intractable urinary tract infection