Study suggests potential diuretic effect with nadofaragene firadenovec

In the following interview, conducted at the 2026 American Urological Association Annual Meeting in Washington, DC, Abigail Keller, MD, discusses findings from a retrospective analysis suggesting that intravesical nadofaragene firadenovec (Adstiladrin) is associated with an increase in urine production during instillation. This increase was not observed with equivalent volume and dwell time with gemcitabine/docetaxel (Gem/Doce).¹

Keller is a clinical research assistant with the department of urology at the Fox Chase – Temple Urologic Institute.

According to Keller, the study originated from a clinical observation that despite using instillation volumes and dwell times comparable to other intravesical therapies, patients who recieved nadofaragene were producing unexpectedly large volumes of urine during dwell time. They also frequently reported irritative symptoms such as urgency, bladder spasms, dysuria, pressure, and discomfort. Given the limited data available regarding the tolerability profile and intravesical dwelling dynamics of nadofaragene, the investigators sought to systematically evaluate urine production during treatment.

To that end, the investigators conducted a retrospective, single-institution study of patients who received nadofaragene between May 2024 and July 2025. To minimize interpatient variability, only patients who had previously undergone Gem/Doce therapy were included, allowing the investigators to use each patient's 3 most recent Gem/Doce treatments as an internal control. Eight patients met the study criteria.

Urine production volume was calculated by subtracting the instilled volume from the voided volume, and urine production rates were normalized to dwell time. Using paired statistical analyses, the team found that nadofaragene was associated with significantly greater post-treatment urine volumes than Gem/Doce, with median volumes of 275 mL vs 75 mL, respectively (P = .0033).

The findings also highlighted treatment-related irritation. Half of nadofaragene instillations were associated with symptoms including bladder spasms, pain, pressure, or dysuria. Symptoms often began within the first 15 minutes of treatment and, in some cases, prompted a need to void during dwell time.

REFERENCE

1. Keller A, Chung R, Kishore J, et al. DIURETIC EFFECT ASSOCIATED WITH NADOFARAGENE FIRADENOVEC INSTILLATION THERAPY - INSIGHT INTO TREATMENT TOLERABILITY. J Urol. 2026;215(5S):e1036. doi:10.1097/01.JU.0001191584.85292.ee.19