Long-Term Outcomes of Primary Chemoablation of Low-Grade Upper Tract Urothelial Carcinoma (LG UTUC) with UGN-101, A Mitomycin Reverse Thermal Gel.

Purpose: To evaluate long-term outcomes of primary chemoablation using a mitomycin reverse thermal gel (UGN-101) in patients with low-grade upper tract urothelial carcinoma.

Materials and methods: Patients who participated in the OLYMPUS trial (TC-UT-03, NCT02793128) and achieved a complete response after 6 weekly doses of UGN-101 were followed up to 12 months after initial complete response. Those with complete response at study completion were eligible for long-term follow-up for up to 5 years or until disease recurrence, progression, or death.

Results: Of the 71 patients enrolled in the OLYMPUS trial, 42 patients achieved complete response 4-6 weeks after completing ≥1 instillation of UGN-101. Amongst the 41 patients followed after initial complete response, median follow-up was 28.1 months (95% CI 13.1, 57.5), and median duration of response was 47.8 months (95% CI 13.0, not estimable).Twenty patients (49%) had long-term follow-up (median 53.3 months [95% CI 27.9, 65.3]). Seventy-five percent of patients had no evidence of recurrence at last follow-up, with median duration of response not estimable (95% CI 43.5, not estimable) due to a low event rate.

Conclusions: Primary intracavitary chemoablation with UGN-101 for low-grade upper tract urothelial carcinoma is associated with favorable long-term durability.