SUO 2022: Comparison of Administration Route for UGN-101 on Upper Tract Urothelial Carcinoma: A Multi Center Evaluation

(UroToday.com) A poster session focusing on Bladder and Kidney cancer was held at the Annual Meeting of the Society of Urologic Oncology and in this session, Dr. Josh Gottlieb presented results of a multi-center study examining alternative routes of administration for UGN-101. 

UGN-101 is a mitomycin-containing reverse thermal gel. This novel delivery system allows for the topical treatment of upper tract urothelial cancer (UTUC), addressing issues associated with dwell time for standard topical treatments in liquid formulation. UGN-101 provides a kidney-sparing alternative for patients with low grade, non-invasive tumors or in patients whose renal function would be severely compromised after nephroureterectomy. Following a pivotal, single arm trial, UGN-101 was approved for small volume residual low-grade UTUC. The gel can be administered retrograde through ureteral catheter or antegrade through nephrostomy tube. These authors sought to evaluate if outcomes differed for patients treated with differing approaches.

To do so, they performed a retrospective review of all patients treated with UGN-101 from 15 institutions in the United States. The authors of this report focused on administration patterns, efficacy, and adverse effects, comparing those patients who received treatment via retrograde approach through ureteral catheter or antegrade through nephrostomy tube. Categorical outcome variables were compared between groups using the chi-squared test.

With a database lock of February 20, 2022, included patients had a median follow up of 7.1 months following treatment (interquartile range=3.6-11.3 months). Among the 132 patients with 136 renal units treated with UGN-101, 78 received treatment via retrograde instillation and 58 received antegrade instillations. Of the 78 retrograde instillations, 29 were performed in the operating room and 49 in clinic.

The authors did not identify differences in tumor size or multiplicity between those patients who received retrograde versus antegrade treatment. However, in patients with tumor in the ureter or both ureter and renal pelvis, a greater proportion received retrograde instillation of UGN-101 (n=34, 43%) than antegrade instillation (n=13, 22%). Further, a greater proportion of patients receiving antegrade treatment had undergone complete endoscopic ablation (n=32, 55%) compared to those receiving retrograde treatment (n=28, 36%).

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Assessing treatment response as determined by endoscopic evaluation and cytology, this was achieved more commonly in those treated with an antegrade approach (n=30, 60%) than a retrograde approach (n=29, 45%) though the difference was not statistically significant (n=0.06) and is likely affected by the differences in tumor burden prior to therapy.

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Considering the toxicity of therapy and potential for adverse events, the authors could evaluate for ureteral stenosis in 65 of 78 renal units treated with retrograde approach. Among these, 21 (32%) had Grade 3 ureteral stenosis requiring intervention. Conversely, among the 51 (of 58) renal units treated by antegrade approach that were evaluable, 6 patients (12%) developed grade 3 stenosis. The differences between these proportions was significant (p<0.01).

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Thus, the authors conclude that this preliminary data suggests that antegrade administration of UGN-101 was be associated with decreased stricture/stenosis formation. Further, there is a potential, albeit non-significant, signal of improved oncologic efficacy. However, this may be confounded by more extensive endoscopic ablation prior to treatment.

Presented by: Josh Gottlieb, DO, Robotics/Urologic Oncology Fellow, Santa Monica, California

 
Written by: Christopher J.D. Wallis, MD, Ph.D., Assistant Professor in the Division of Urology at the University of Toronto, @WallisCJD on Twitter during the 23rd Annual Meeting of the Society of Urologic Oncology (SUO), Nov 30 – Dec 2, 2022. San Diego, CA

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