Main Inclusion Criteria:

1. Patient is at least 18 years of age.
2. Naive or recurrent patients with LG, non-invasive UTUC in the pyelocalyceal system.
3. Patient has at least one (1) measurable and biopsy-confirmed papillary LG tumor, evaluated visually, ≤ 15 mm. The largest lesion should not exceed 15mm.
4. Following biopsy patient should have at least one remaining lesion with a diameter of 5 mm.
5. Patient with bilateral LG UTUC may be enrolled if at least one side meets the inclusion criteria for the trial and if the other kidney does not require further treatments (The other kidney can be treated prior to the beginning of the study).

Main Exclusion Criteria:

1. Patient received BCG treatment for UC during the 6 months prior to Visit 1.
2. The patient has untreated concurrent urothelial cancer in other locations other than the target area (unless treated during screening)
3. CIS in the past in the urinary tract.
4. Patient has a history of invasive urothelial carcinoma in the urinary tract during the past 5 (Five) years.
5. Patient has a history of high grade papillary urothelial carcinoma in the urinary tract during the past 2 (Two) years.
6. Patient is actively being treated or intends to be treated with systemic chemotherapy during the duration of the trial.