• Age ≥ 18 years at the time of study consent.

• ECOG Performance Status of 0, 1 or 2 (see Appendix A).

• Histologically confirmed muscle-invasive UC originating in the bladder, ureter, or renal pelvis. Variant histology, except small cell carcinoma, is allowed.

• Underwent curative-intent surgery (i.e. RC or nephroureterectomy), performed within 180 days prior to study treatment initiation.

• Radiographic disease-free status as determined by imaging within 28 days of C1D1 of study treatment.

• Prior platinum-based NAC is allowed. If chemotherapy-naive, patient must be Cisplatin-ineligible (based on Galsky et al 2011 \[10\]) or refuse platinum AC.

• Prior treatment with neoadjuvant investigational agents is allowed (except PD-1/PD-L1 inhibitors or sacituzumab govitecan). No washout from neoadjuvant therapy is required.

• If NAC was given, patient must be considered at high risk for cancer recurrence due to having pathologic T2, T3, T4, or N+ disease on RC or nephroureterectomy surgical spec-imen.

• If no NAC was given, patient must be considered at high risk for cancer recurrence due to having pathologic T3, T4, or N+ disease on RC or nephroureterectomy surgical speci-men.

• Adequate organ and marrow function as defined below:

• ANC ≥ 1000/mcL

• Platelets ≥ 100,000/mcL

• Total bilirubin ≤ 1.5 × institutional ULN (or ≤ 3.0 × ULN for subjects with Gilbert's disease)

• AST/ALT ≤ 3 × institutional ULN

• Alkaline phosphatase ≤ 3 × institutional ULN

• Serum albumin ≥ 2.8 g/dL

• Creatinine Creatinine clearance of ≥30 mL/min (calculated with Cockroft-Gault formula)

• Hemoglobin ≥ 9.0 g/dL

• aPTT ≤ 1.5 × institutional ULN

• Sexually active fertile subjects and their partners must agree to use medically accepted methods of contraception (i.e. barrier methods including male condom, female condom, or diaphragm with spermicidal gel, etc.) that are approved by the Investigator. Contra-ception must be used during the course of the treatment and for 6 months after the last dose of study treatment.

• Female subjects of childbearing potential must not be pregnant following signing the study consent form. Female subjects are considered to be of childbearing potential unless one of the following criteria are met: documented permanent sterilization (hysterectomy, bilateral salpingectomy, or bilateral oophorectomy) or documented postmenopausal sta-tus (defined as at least 12 months of amenorrhea in a woman ≥ 45 years-of-age in the ab-sence of other biological or physiological causes).

• Recovery to ≤ Grade 1 of CTCAE version 5 toxicities related to any prior treatment for UC, unless the AE(s) is clinically non-significant and/or stable on supportive therapy as per discretion of the Investigator.

• Subjects with any type of genitourinary catheters (i.e. nephrostomy, Foley, etc) are al-lowed.

• Ability to understand and the willingness to sign a written informed consent. Both men and women and members of all races and ethnic groups are eligible for this trial. Non-English speaking, hard of hearing, and illiterate individuals are eligible for this trial.