Inclusion Criteria:

          1. BCG-unresponsive NMIBC with carcinoma in situ (CIS) with or without resected papillary
             tumors who are indicated for, ineligible for, or have elected not to undergo
             cystectomy:

               1. persistent high-grade disease (Ta, T1, or Tis) or recurrence within 6 months of
                  receiving at least 2 courses of intravesical BCG (at least 5 of 6 induction doses
                  and at least 2 of 3 maintenance doses).

               2. T1 high grade disease residual at the first evaluation following induction BCG
                  (at least 5 of 6 doses).

          2. Patients who have previously been treated with an investigational or approved
             checkpoint inhibitor (e.g. pembrolizumab) and failed treatment are eligible for
             inclusion 30 days post-treatment (Phase 1) or 3 months post-treatment (Phase 2).

          3. Male or non-pregnant, non-lactating female, 18 years or older.

          4. Women of childbearing potential must have a negative pregnancy test at Screening. A
             female patient is considered to be of child-producing potential unless she:

               1. has had a hysterectomy or bilateral oophorectomy or

               2. is age ≥ 60 years and is amenorrhoeic or

               3. is age < 60 years and has been amenorrhoeic for ≥ 12 months (including no
                  irregular menses or spotting) in the absence of any medication which induces a
                  menopausal state and has documented ovarian failure by serum oestradiol and
                  follicle-stimulating hormone levels within the institutional laboratory
                  postmenopausal range).

          5. All patients of childbearing potential must be willing to consent to using effective
             double-barrier contraception, i.e., intrauterine device, birth control pills,
             depo-provera, and condoms while on treatment and for 3 months after their
             participation in the study ends.

          6. Performance Status: Eastern Cooperative Oncology Group (ECOG) 0, 1, and 2.

          7. Hematologic inclusion within 2 weeks of start of treatment:

               1. Absolute neutrophil count >1,500/mm3.

               2. Hemoglobin >9.0 g/dl.

               3. Platelet count >100,000/mm3.

          8. Hepatic inclusion within 2 weeks of Day 1:

               1. Total bilirubin must be ≤1.5 x the upper limit of normal (ULN).

               2. Adequate renal function with creatinine clearance >30 mL/min (measured using
                  Cockcroft-Gault equation or the estimated glomerular filtration rate from the
                  Modification of Diet in Renal Disease Study).

               3. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5 x ULN
                  for the institution, alkaline phosphatase ≤2.5 x ULN for the institution, unless
                  bone metastasis is present in the absence of liver metastasis.

          9. Prothrombin time and partial thromboplastin time within the normal limits at
             Screening.

         10. Must have satisfactory bladder function with ability to retain study drug for a
             minimum of 60 minutes.

         11. Must be willing and able to comply with all protocol requirements.

         12. Must be willing and able to give informed consent and any authorizations required by
             local law for participation in the study.

        Exclusion Criteria:

          1. Any other malignancy diagnosed within 1 year of study entry (except basal or squamous
             cell skin cancers or noninvasive cancer of the cervix) is excluded.

          2. Concurrent treatment with any chemotherapeutic agent.

          3. Treatment with pembrolizumab within 30 days (Phase 1) or 3 months (Phase 2) prior to
             Screening.

          4. Treatment with last therapeutic agent within 30 days of Screening (Phase 1 and Phase
             2) or treatment with an investigational checkpoint inhibitor within 3 months of
             Screening (Phase 2 only).

          5. Women who are pregnant or lactating.

          6. History of vesicoureteral reflux or an indwelling urinary stent.

          7. Participation in any other research protocol involving administration of an
             investigational agent within 1 month prior to Day 1.

          8. History of radiation to the pelvis.

          9. History of interstitial lung disease and/or pneumonitis in patients who have
             previously received a PD-1 or PD-L1 inhibitor therapy.

         10. Evidence of metastatic disease.

         11. History of difficult catheterization that in the opinion of the Investigator will
             prevent administration of EG-70.

         12. History of interstitial cystitis.

         13. Active, uncontrolled bacterial, viral, or fungal infection(s) requiring systemic
             therapy.

         14. Known human immunodeficiency virus (HIV), Hepatitis B, or Hepatitis C infection.

         15. Significant cardiovascular risk (e.g., coronary stenting within 8 weeks, myocardial
             infarction within 6 months).