RecruitingDrug trialLow-grade UTUC Treated With Nadofaragene Firadenovec Administered to Renal PelvisThe primary purpose of this trial is to evaluate the safety \& tolerability of Nadofaragene Firadenovec in subjects with LG-UTUC. To help with this evaluation, a safety lead-in period will be conducted for the first 6 subjects. Complete response is at 3 or 6 months defined as absence of any UTUC in the renal pelvis.