Inclusion Criteria:

          1. Be willing and able to provide a written Informed Consent Form ("ICF") for the Study.

          2. Be > 18 years of age on day of signing ICF.

          3. Have histologically confirmed NMIBC CIS with or without resected papillary disease
             (Ta, T1) (high grade) according to the 2004 World Health Organization ("WHO") /
             International Society of Urologic Pathology classification system up to 8 weeks prior
             to the treatment procedure.

             • Confirmation of histology, grade and stage will be performed by local review and
             must be completed prior to enrolment.

          4. Patients with Ta, or T1 disease, must have undergone complete Trans-Urethral Resection
             of the Bladder Tumour ("TURBT") defined as the absence of resectable disease after at
             least 1 cystoscopy or TURBT procedure.

             • The most recent cystoscopy must have been performed no longer than 8 weeks prior to
             the treatment procedure.

          5. Considered BCG-Unresponsive, which is at least one of the following:

               -  At least five of six doses of an initial induction course, plus at least two of
                  three doses of maintenance therapy

               -  At least five of six doses of an initial induction course, plus at least two of
                  six doses of a second induction course

               -  Patients experiencing disease relapse less than 12 months after finishing the
                  second course of BCG therapy are also considered BCG-Unresponsive.

          6. Are not candidates for cystectomy on medical grounds or refuse radical cystectomy.

          7. Have an Eastern Cooperative Oncology Group ("ECOG") performance score of 0 to 1.

          8. Have satisfactory bladder function. Ability to retain Study Drug for a minimum of 1
             hour.

          9. Are available for the duration of the Study including follow-up (approximately 12
             months).

         10. Female patients of childbearing potential must have a negative Human Chorionic
             Gonadotropin ("HCG") pregnancy test taken during the screening visit and confirmed
             prior to the treatment procedure.

         11. Female patients of childbearing potential must be willing to use 2 methods of birth
             control (i.e.: oral contraceptive, pills, diaphragm or condoms) or be surgically
             sterile, or abstain from heterosexual activity for two weeks after the treatment
             procedure. Patients of childbearing potential are those who have not been surgically
             sterilized or have not been free from menses for >1 year.

         12. Intolerance of BCG therapy

        Exclusion Criteria:

          1. Past or current muscle invasive (i.e.: T2, T3, T4) or metastatic urothelial carcinoma.

          2. Has concurrent extravesical (i.e.: urethra, ureter, renal pelvis, prostate or
             prostatic ducts) non-muscle invasive transitional cell carcinoma of the urothelium.
             (confirmed by staging to exclude extravesical disease, which may include radiological
             imaging and/or biopsy) within 3 months of enrollment:

             If previous work up occurred more than 3 months prior to enrollment, staging for
             extravesical disease must be repeated prior to enrolment in order to determine
             eligibility.

          3. Active gross hematuria.

          4. Have a known additional malignancy that is progressing or requires active treatment.
             Exceptions include basal cell carcinoma of the skin, squamous cell carcinoma of the
             skin that has undergone potentially curative therapy, in situ cervical cancer or
             localized prostate cancer under active surveillance with Gleason 6 disease. A history
             of prostate cancer that was treated with definitive intent (surgically or through
             radiation therapy) is acceptable, provided that the following criteria are met: Stage
             T2N0M0 or lower; prostate-specific antigen (PSA) undetectable for 2 years while off
             androgen deprivation therapy or no more than 2 consecutive rising PSAs.

          5. Have a history or current evidence of any condition, therapy, surgery or laboratory
             abnormality that, in the opinion of the PI, might confound the results of the Study,
             interfere with the patient's participation in the Study, or is not in the best
             interest of the patient to participate.

          6. Currently receiving treatment with a prohibited concomitant therapy (refer to 12.2.1,
             Prohibited Medications).

          7. Participated in a study with an investigational agent or device within 1 month from
             the first dose of current Study treatment.

          8. Prior treatment with an intravesical chemotherapeutic agent within 1 month of the
             first dose of current Study Drug, with the exception of a single perioperative dose of
             chemotherapy immediately post-TURBT (not considered treatment).

          9. Have an active infection requiring systemic therapy, including active or intractable
             Urinary Tract Infection ("UTI"), not resolved prior to the procedure.

         10. Has any contraindication to general or spinal anesthesia.

         11. Is pregnant or breastfeeding within the projected duration of the Study, starting with
             the screening visit through to two weeks following the second TLD-1433 instillation.