Mitomycin Exhibits Sustained 36-Month Responses in LG-IR-NMIBC

Treatment with mitomycin (Zusduri) produced sustained 36-month responses among patients with low-grade intermediate-risk non-muscle invasive bladder cancer (LG-IR-NMIBC) in the phase 3 ENVISION trial (NCT05243550), according to news release from the developer, UroGen Pharma.¹

Specifically, the median duration of response (DOR) among patients who achieved a complete response (CR) within 3 months of treatment with mitomycin (79.6%) was not reached after a median follow-up of 35.5 months. Additionally, the 36-month DOR rate was 64.5% (95% CI, 54.6%-72.8%) per Kaplan-Meier estimate.

“This update from the pivotal ENVISION trial shows that many patients who achieve a [CR] with [mitomycin] remain disease-free through 3 years,” Sandip Prasad, MD, MPhil, director of Genitourinary Surgical Oncology and vice chair of Urology at Morristown Medical Center/Atlantic Health System, NJ, and principal investigator of the ENVISION trial, stated in the news release.¹ “Among patients who achieved a [CR], the event rate over time has remained stable. Importantly, [mitomycin’s] durability was achieved without maintenance therapy, supporting a treatment approach that can provide lasting disease control while reducing ongoing treatment burden for patients.”

Moreover, findings previously published in The Journal of Urology revealed that among 191 responders to treatment, sustained event-free survival (EFS) outcomes were observed, with 12- and 24-month rates of 82% (95% CI, 76%-87%) and 72% (95% CI, 64%-79%), respectively.The respective CR rates at 12 and 24 months for the 3-month responders were 76% (95% CI, 69%-82%) and 59% (95% CI, 51%-66%).

Among patients who underwent 1 or fewer transurethral resection of bladder tumor (TURBT) procedures (n = 123), the 12- and 24-month EFS rates were 86% (95% CI, 79%-91%) and 78% (95% CI, 68%-85%). Among those who received 2 or more TURBT procedures, these rates were 75% (95% CI, 63%-84%) and 61% (95% CI, 47%-73%).

Patients with a history of low-grade NMIBC requiring TURBT were enrolled on the study and underwent 6 weekly intravesical instillations of mitomycin. Those who experienced a CR returned for follow-up every 3 months for up to 24 months, and those who remained disease-free returned every 6 months for an additional 36 months thereafter. Maintenance treatment was not given following the 6-week course of mitomycin.

The prespecified primary end point was the 3-month CR rate. A key prespecified secondary end point was DOR, with additional secondary end points including durable CR rate and safety. An exploratory analysis was DOR based on receipt of prior TURBT and number of tumors at baseline.

Adverse reactions occurring in at least 10% of patients included dysuria, creatinine increases, hemoglobin decreases, aspartate aminotransferase increases, and alanine aminotransferase increases, among others. These events were primarily mild to moderate in severity, with serious adverse reactions occurring in 12% of patients.

Previously reported safety data showed treatment-emergent adverse effects (TEAEs) leading to discontinuation of the study, discontinuation of treatment, or death occurred in 4.6%, 2.9%, and 2.9% of patients, respectively. All TEAE-related deaths were deemed unrelated to study treatment, and events included septic shock, acute myocardial infarction, pneumonia, cardiac failure, sepsis, cardiopulmonary failure, and an unknown cause.

“The ENVISION 36-month DOR data reinforce [mitomycin’s] potential to shift the treatment paradigm for recurrent LG-IR-NMIBC,” Mark Schoenberg, MD, chief medical officer of UroGen, said in the news release.¹ “By delivering durable responses without maintenance therapy, [mitomycin] provides an opportunity to move beyond the cycle of repeated surgical interventions and toward a more durable, lower-burden treatment approach over time.”

References

1. ZUSDURI median duration of response still not reached with 64.5% 36-month duration of response in the pivotal ENVISION trial. News release. UroGen Pharma. May 13, 2026. Accessed May 13, 2026. https://tinyurl.com/4p93tsmd
2. Prasad SM, Shishkov D, Mihaylov NH, et al. UGN-102 for recurrent low-grade intermediate-risk non-muscle invasive bladder cancer: 24-month duration of response results from the phase 3 ENVISION trial. J Urol. Published March 25, 2026. doi:10.1097/JU.0000000000005041