Urogen reported three-year durability data from the ZUSDURI ENVISION trial reinforcing the clinical profile of mitomycin (Zusduri) as a non-surgical option for recurrent low-grade intermediate-risk non-muscle invasive bladder cancer. As per a press release from the firm, the median duration of response was still unreached at a median follow-up of 35.5 months.
The Phase III ENVISION trial is a single-arm, multinational, multicenter pivotal study that enrolled 240 adults with recurrent LG-IR-NMIBC across 56 sites. Participants received six once-weekly intravesical instillations of Zusduri, administered in an outpatient setting via urinary catheter using UroGen Pharma's (Nasdaq: URGN) proprietary RTGel sustained-release hydrogel technology. A total 79.6% of patients achieved a complete response at three months, the trial's primary endpoint. Among those complete responders, the Kaplan-Meier estimated probability of remaining event-free at 36 months was 64.5% (95% CI, 54.6%–72.8%), and the median duration of response had not been reached. Notably, this durability was observed without maintenance therapy following the initial six-week treatment course.
Serious adverse reactions occurred in 12% of patients, including urinary retention in 0.8% and urethral stenosis in 0.4%. The most common adverse reactions — occurring in 10% or more of patients — included dysuria, electrolyte and laboratory abnormalities, urinary tract infection, and hematuria, with the majority characterized as mild to moderate in severity.
The demand for alternatives to surgery
LG-IR-NMIBC affects approximately 82,000 people in the US each year, with an estimated 59,000 of those cases representing recurrent disease. The median age at diagnosis is 73 years, a demographic that carries elevated surgical risk from comorbidities and cumulative anesthetic exposure.
The current standard of care is transurethral resection of bladder tumor, or TURBT. Because up to 70% of NMIBC patients experience at least one recurrence, many undergo multiple TURBT procedures over their lifetime. The procedural cycle imposes a compounding burden: repeat surgeries, recovery periods, and the attendant risks that accumulate with each intervention, particularly in older patients.
Zusduri's mechanism addresses this directly. Mitomycin is a bioreductive alkylating agent that crosslinks DNA strands, inhibiting replication and inducing apoptosis in tumor cells. Delivered intravesically via RTGel — a hydrogel that remains liquid at room temperature and transitions to a gel at body temperature — the formulation is designed to maximize bladder contact time and sustained drug exposure, a pharmacokinetic advantage over conventional aqueous mitomycin C solutions that are cleared more rapidly.