A Study of STM-416 Administered to Patients Undergoing TURBT for Recurrent Bladder Cancer

Inclusion Criteria:

1. Are aged 18 years or older;

2. Have a history of pathologically confirmed high-grade Ta or T1 NMIBC without CIS whohave completed SOC previously, with recurrent papillary disease seen on cystoscopy,and who are undergoing TURBT without perioperative intravesical chemotherapy;

3. Are considered high risk for recurrence;

4. Have Eastern Cooperative Oncology Group (ECOG) Performance Status of 0, 1, or 2;

5. Have adequate organ and marrow function as defined below:

• Hemoglobin 9.0 g/dL;

• Absolute neutrophil count 1.5 × 109/L (1500 per mm3);

• Platelet count 75 × 109/L (75,000 per mm3);

• Serum bilirubin 1.5 × institutional upper limit of normal (ULN);

• AST (serum glutamic-oxaloacetic transaminase)/ALT (serum glutamic-pyruvictransaminase) 2.5 × institutional ULN; and

• Creatinine CL 60 mL/min by the Cockcroft-Gault formula or by 24-hour urinecollection for determination of creatinine CL: Males: Creatinine CL (mL/min) =Weight (kg) × (140 - Age)/72 × serum creatinine (mg/dL); or Females: CreatinineCL (mL/min) = Weight (kg) × (140 - Age) × 0.85/72 × serum creatinine (mg/dL).

Exclusion Criteria:

1. Have a history of CIS or MIBC;

2. Are receiving any other investigational agents;

3. Have a history of allergic reactions attributed to compounds of similar chemical orbiologic composition to resiquimod (R848), or excipients used in STM-416 includingpoloxamer 407 and sodium hyaluronate;

4. Have an uncontrolled intercurrent illness including, but not limited to, ongoing oractive infection, symptomatic congestive heart failure, unstable angina pectoris,cardiac arrhythmia, or psychiatric illness/social situations that would limitcompliance with study requirements. Urinary tract infections are not exclusionary unless they are NCI-CTCAE Grade 3 orhigher;

5. Are a woman of childbearing potential regardless of contraceptive use; Note: Womenof childbearing potential are only to be excluded in Phase 1 and Phase 2a to avoidbias due to the low prevalence of NMIBC in this population. However, they will beincluded in subsequent Phase 2/3 studies.