FDA Approves Mitomycin Solution for Recurrent Low-Grade Bladder Cancer

On June 12, 2025, the Food and Drug Administration (FDA) gave its approval to a new treatment option, mitomycin intravesical solution known as Zusduri, developed by UroGen Pharma. This solution is designed for adult patients dealing with recurrent low-grade intermediate-risk non-muscle invasive bladder cancer (LG-IR-NMIBC). The full prescribing details for Zusduri will be available on the FDA's website.

The approval was based on findings from a clinical trial named ENVISION (NCT05243550). This single-arm, multicenter study involved 240 adults who had experienced a recurrence of low-grade NMIBC following a previous treatment known as transurethral resection of bladder tumor (TURBT). To qualify for the trial, participants had to meet specific criteria, such as having multiple tumors, a solitary tumor exceeding 3 cm, or experiencing recurrence within a year. The patients were administered 75 mg of mitomycin intravesical solution weekly for six consecutive weeks.

The trial assessed the status of the tumors every three months through methods like cystoscopy, biopsies if necessary, and urine cytology. The primary focus of the study was on two key outcomes: complete response (CR) at three months and the duration of response (DOR). A CR was defined as the absence of detectable disease within the bladder, verified through cystoscopy and urine analysis, with biopsies conducted if required. Out of the 223 patients evaluated for their response to the treatment, 78% achieved a complete response, with a confidence interval of 95% ranging from 72% to 83%. The duration of response among these patients varied from zero to over 25 months, and notably, 79% of those who responded continued to show positive results for at least a year.

As with any medical treatment, there were several common adverse reactions reported by patients involved in the study. These reactions, occurring in 10% or more of participants, included increased levels of creatinine and potassium, painful urination (dysuria), decreased hemoglobin, elevated levels of liver enzymes such as aspartate aminotransferase and alanine aminotransferase, increased eosinophils, reduced lymphocytes, urinary tract infections, reduced neutrophils, and blood in urine (hematuria). Serious adverse effects were observed in 12% of patients, with specific instances of urinary retention and urethral stenosis. Unfortunately, there was also a case where a patient suffered a fatal cardiac failure.

The suggested dosage for mitomycin is 75 mg, equivalent to 56 mL, which is to be administered once a week for six weeks using a urinary catheter directly into the bladder. Healthcare providers are encouraged to report any serious adverse events they suspect are connected to any medication or device to the FDA’s MedWatch Reporting System.

This advancement offers a new hope for patients with recurrent bladder cancer, providing a treatment option that has shown promising efficacy while highlighting the importance of monitoring for possible side effects. As the medical community continues to explore and develop cancer treatments, the approval of Zusduri marks a significant step forward in managing a challenging condition.