Chemoablation of low-grade upper tract urothelial carcinoma (UTUC) using a novel mitomycin gel results in durable response for up to 12 months in most patients who achieve initial complete response, according to investigators presenting at SUO 2020, the virtual annual meeting of the Society of Urologic Oncology.

In the OLYMPUS phase 3 trial (Optimized Delivery of Mitomycin for Primary UTUC Study), 71 patients with low-grade UTUC with a tumor diameter of 5 to 15 mm above the ureteropelvic junction received at least 1 dose of the mitomycin gel (4 mg/mL). The gel, which is marketed as Jelmyto®, was instilled into the renal pelvis as a viscous liquid that  turned into a gel at body temperature, providing 4-6 hours of drug exposure.

After 6 weekly instillations, 41 patients (58%) achieved complete response the following month. They then received monthly maintenance treatments (0 to 11 doses) for up to 11 months.

At 12 months, 23 of the 41 patients (56%) maintained a complete response, Surena F. Matin, MD, of MD Anderson Cancer Center in Houston, Texas, reported. According to a Kaplan-Meier analysis, the probability a patient would remain disease-free at 12 months was 81.8%, he said.


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Maintenance treatment did not appear to affect durability of response. Median time to recurrence was not reached, and no one died from treatment.

The most common adverse events with UGN-101 were ureteric stenosis, urinary tract infection, hematuria, flank pain, nausea, dysuria, renal dysfunction, abdominal pain, and vomiting. Nonetheless, patients who received the induction treatment had a lower rate of ureteric stenosis compared with the overall population (29% vs 44%).

“[Mitomycin gel]offers a kidney-sparing alternative for the treatment for [low-grade] UTUC that reduces disease recurrence and avoids the morbidity associated with radical nephroureterectomy,” Dr Matin stated. “These data serve as a new benchmark for kidney-preserving treatment…”

Disclosure: This clinical trial was supported by UroGen Pharma. Please see the original reference for a full list of authors’ disclosures.

Reference

Lerner S, Matin S, Kleinmann N, et al.Durability of response to chemoablative treatment of low-grade upper tract urothelial carcinoma with a mitomycin-containing reverse thermal hydrogel: final results of the Olympus trial. Presented at: SUO 2020, December 3-5, 2020.