Inclusion Criteria:

          1. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1.

          2. Life expectancy greater than (>) 2 years in the view of the investigator.

          3. Participants must have biopsy proven transitional or predominantly transitional cell
             NMIBC.

          4. For the Dose Escalation part of the study, the following participants will be
             included:

               1. Both, lower and higher dose escalation cohorts:

                  Participants with intermediate risk NMIBC

               2. Only higher dose escalation cohorts:

             Participants with BCG Unresponsive NMIBC despite prior adequate treatment.
             Furthermore, all participants should be indicated for radical cystectomy as the
             standard of care for BCG unresponsive NMIBC. Participants who are undergoing radical
             cystectomy as well as participants who have refused to undergo radical cystectomy will
             be eligible to participate in the Dose Escalation part of the study. For participants
             who are undergoing radical cystectomy, date of surgery should not be delayed more than
             3 months after Day 1 of dosing.

             For the Dose Expansion part of the study, the following participants will be included:

             Participants with histologically confirmed

               1. CIS (with or without concomitant non-muscle invasive, Ta or T1 papillary disease)
                  (Arm 1) Or

               2. Non-muscle invasive high-grade Ta or T1 papillary disease without CIS (Arm 2)
                  that is deemed to be unresponsive to BCG therapy despite prior adequate
                  treatment. Furthermore, participants should be indicated for radical cystectomy
                  as the standard of care for BCG unresponsive NMIBC but have refused to undergo
                  radical cystectomy.

             Intermediate risk NMIBC: is defined as any participant with a high-grade Ta less than
             or equal to (<=) 3 cm or low-grade T1 tumor or with histologically confirmed multiple
             and/or recurrent low-grade Ta tumor with either 1 or 2 of the following 4 factors

               1. Multiple tumors

               2. Tumor >3 centimeter (cm)

               3. Early recurrence (less than [<] year)

               4. Frequent recurrences (>1 per year)

             BCG Unresponsive NMIBC is defined as being at least 1 of the following:

               1. Persistent or recurrent CIS alone or with recurrent Ta/T1 (noninvasive papillary
                  disease/tumor invades the subepithelial connective tissue) disease within 12
                  months of completion of adequate BCG therapy.

               2. Recurrent high-grade Ta/T1 disease within 6 months of completion of adequate BCG
                  therapy.

               3. T1 high-grade disease at the first evaluation following an induction BCG course

             Adequate BCG therapy is defined as at least 1 of the following:

               1. At least 5 of 6 doses of an initial induction course plus at least 2 of 3 doses
                  of maintenance therapy.

               2. At least 5 of 6 doses of an initial induction course plus at least 2 of 6 doses
                  of a second induction course.

          5. Participants must consent to repeat biopsies to allow the acquisition of fresh
             formalin-fixed paraffin embedded (FFPE) material (obtained within 8 weeks prior to
             treatment initiation with E7766)

          6. Participants must consent to repeat blood draws as indicated in the schedule of
             assessments.

          7. Participant must consent to providing cystectomy tumor sample in the event that
             cystectomy is performed following treatment with E7766.

          8. Immunosuppressive doses of systemic medications, such as steroids or absorbed topical
             steroids (doses >10 milligram per day (mg/d) prednisone or equivalent) must be safely
             discontinued at least 4 weeks before study drug administration.

          9. Participants with prior Hepatitis B or C are eligible if they have adequate liver
             function.

         10. Left ventricular ejection fraction (LVEF) >50 percent (%) on echocardiography or
             multiple gate acquisition (MUGA) scan.

         11. Adequate renal function, bone marrow function and liver function.

        Exclusion Criteria:

          1. Other malignancy active within the previous 2 years except for basal or squamous cell
             skin cancer, or CIS of the cervix or breast that has completed curative therapy.

          2. Participants with any active autoimmune disease or a documented history of autoimmune
             disease, except for participants with vitiligo or resolved childhood asthma/atopy

          3. Presence of concomitant upper tract urothelial carcinoma or urothelial carcinoma
             within the prostatic urethra or any other regional/metastatic disease.

          4. Known human immunodeficiency virus (HIV) infection.

          5. Active infection requiring therapy

          6. Major surgery within 4 weeks before the first dose of study drug.

          7. Concurrent medical condition requiring the use of immunosuppressive medications or
             immunosuppressive doses of systemic medications, such as steroids or absorbed topical
             steroids (doses >10 mg/d prednisone or equivalent).

          8. Prolongation of corrected QT (corrected for QTc interval using Frederica's correction
             factors [QTcF]) interval to >480 millisecond (msec) when electrolytes balance is
             normal.

          9. Significant cardiovascular impairment.

         10. Use of illegal recreational drugs.

         11. Females who are breastfeeding or pregnant at Screening or Baseline (as documented by a
             positive beta-human chorionic gonadotropin [ß-hCG] (or human chorionic gonadotropin
             [hCG]) test with a minimum sensitivity of 25 International Units Per Liter (IU/L) or
             equivalent units of ß-hCG [or hCG]). A separate baseline assessment is required if a
             negative screening pregnancy test was obtained more than 72 hours before the first
             dose of study drug.

         12. Currently enrolled in another clinical study or used any investigational drug or
             device within 28 days preceding Cycle 1 Day 1 (first dosing day).