Route of Administration for UGN-101 and Impact on Oncological and Safety Outcomes

Background: UGN-101 can be used for chemoablation of low-grade upper tract urothelial carcinoma (UTUC). The gel can be administered via a retrograde route through a ureteral catheter or an antegrade route via a nephrostomy tube. Objective: To report outcomes of UGN-101 by route of administration. Design, setting, and participants: We performed a retrospective review of 132 patients from 15 institutions who were treated with UGN-101 for low-grade UTUC via retrograde versus antegrade administration. Outcome measurements and statistical analysis: Survival outcomes are reported per patient. Treatment, complications, and recurrence outcomes are reported per renal unit. Statistical analysis was performed for primary endpoints of oncological response and ureteral stricture occurrence. Results and limitations: A total of 136 renal units were evaluated, comprising 78 retrograde and 58 antegrade instillations. Median follow-up was 7.4 mo. There were 120 cases (91%) of biopsy-proven low-grade UTUC. Tumors were in the renal pelvis alone in 89 cases (65%), in the ureter alone in 12 cases (9%), and in both in 35 cases (26%). Seventy-six patients (56%) had residual disease before UGN-101 treatment. Chemoablation with UGN-101 was used in 50/78 (64%) retrograde cases and 26/58 (45%) antegrade cases. A complete response according to inspection and cytology was achieved in 31 (48%) retrograde and 30 (60%) antegrade renal units (p = 0.1). Clavien grade 3 ureteral stricture occurred in 21 retrograde cases (32%) and only six (12%) antegrade cases (p < 0.01). Limitations include treatment bias, as patients in the antegrade group were more likely to undergo endoscopic mechanical ablation before UGN-101 instillation. Conclusions: These preliminary results show a significantly lower rate of stricture occurrence with antegrade administration of UGN-101, with no apparent impact on oncological efficacy. Patient summary: We compared results for two different delivery routes for the drug UGN-101 for treatment of cancer in the upper urinary tract. For the antegrade route, a tube is inserted through the skin into the kidney. For the retrograde route, a catheter is inserted past the bladder into the upper urinary tract. Our results show a lower rate of narrowing of the ureter (the tube draining urine from the kidney into the bladder) using the antegrade route, with no difference in cancer control.