Researchers have performed the first postmarkert analysis of a novel delivery system of mitomycin—a gel formation, also known as UGN-101—to treat upper tract urothelial cancers, according to a novel study published by Woldu et al in Urologic Oncology. Their findings showcase how the treatment is being used and its potential to prevent patients from losing a kidney and undergoing lifelong dialysis.
UGN-101 is a unique reformulation of mitomycin, a chemotherapy used to treat patients with bladder cancer; however, treatment with mitomycin has proven ineffective for patients with upper tract urothelial cancer as a result of the limited contact the chemotherapeutic agent has with the tumors. Without an effective chemotherapy for these tumors, patients must typically undergo removal of the diseased kidneys and ureters—which can necessitate dialysis in patients with preexisting kidney impairment.
To solve this problem, UGN-101 incorporates mitomycin into a gel that is liquid at cold temperatures but thickens at body temperature. Therefore, this mitomycin gel can remain in the upper urinary tract long enough to kill tumor cells and gradually breaks down over time, researchers discovered.
“[Mitomycin gel] was approved based on a trial with a limited number of patients. Our new study is the first postmarket analysis to see how [clinicians] are using this drug in routine practice and what their patient outcomes are,” explained lead study author Solomon Woldu, MD, Assistant Professor of Urology at the University of Texas Southwestern Harold C. Simmons Comprehensive Cancer Center.
Study Methods and Results
To better understand the use of mitomycin gel—which received approval from the U.S. Food and Drug Administration in April 2020—the researchers analyzed patient outcomes at 15 medical centers that treat a high volume of patients with upper tract urothelial cancers. They gathered data on 132 patients treated for 136 cancers, 4 of whom had bilateral disease. Approximately 67% of the patients received an induction course of mitomycin gel that involved six weekly doses, and 27% of them received monthly maintenance doses. About 43% of the patients had tumors that had already been ablated and were seeking treatment to prevent recurrence—which is common for upper tract urothelial cancers.
Approximately 3 months after the initial treatment course, about 69% of patients whose tumors had been ablated prior to treatment did not experience disease recurrence. In those with low-grade tumors measuring less than 1.5 cm, 70% of them were cleared of tumors. Even among patients with tumors larger than 3 cm, tumors disappeared in about 25% of the cases.
About 15% of patients developed urinary tract infections during treatment—a common side effect of this drug—and about 25% of them developed ureteral stenosis. Although these adverse events were significant, the researchers noted that they were minimal in comparison to losing a kidney and requiring dialysis. Only five patients needed surgery to remove their diseased kidney.
“Patients with upper tract urothelial cancers are often left with the choice of lifelong dialysis or untreated cancers,” Dr. Woldu stressed. “[Mitomycin gel] has enormous potential to save them from either of these fates.”
Disclosure: For full disclosures of the study authors, visit sciencedirect.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.