A 64.5% probability of remaining disease-free at three years — with the median duration of response still not reached at 35.5 months of follow-up — is a harder number than most intravesical therapies have ever produced, and it arrives in a disease setting where the standard of care is literally a knife under general anesthesia repeated indefinitely.
The ENVISION trial enrolled 240 patients across 56 sites with a single-arm design, which means every durability claim stands alone without a comparator arm to prop it up. That design choice was a regulatory gamble that paid off: FDA cleared ZUSDURI on the strength of a 79.6% complete response rate at three months as the primary endpoint, with this rolling durability readout as the key secondary. What the 36-month data now establish is that among patients who hit that CR threshold, the hazard of recurrence is not accelerating over time — the event rate has remained stable, meaning the responder population is not eroding in the third year at a faster clip than the first or second. For a single-arm trial, that trajectory is the closest thing to a natural history control the design permits, and it holds.
The clinical logic here is more consequential than it first appears. The target population — recurrent low-grade intermediate-risk NMIBC — skews heavily toward patients aged 73 and older with significant comorbidity burdens. Each repeat TURBT carries incremental anesthetic risk, perioperative morbidity, and the psychological weight of cycling back into the operating room. ZUSDURI’s RTGel platform extends mitomycin’s bladder contact time through a reverse-thermal hydrogel, enabling chemoablation without resection. That the durability is achieved without any maintenance therapy is the design feature that separates this profile from BCG-based regimens, where maintenance schedules are long, adherence is imperfect, and supply has historically been unreliable. Twelve percent of patients experienced serious adverse reactions, predominantly urologic — urinary retention and urethral stenosis — which remain the exposure’s honest liabilities.
The metric that will determine whether this data translates into market displacement of TURBT is real-world complete response durability in community urology practices, where patient selection and instillation technique will almost certainly diverge from the trial’s 56 specialized sites.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
