Evaluating the safety and potential activity of URO‐902 (hMaxi‐K) gene transfer by intravesical instillation or direct injection into the bladder wall in female participants with idiopathic (non‐neurogenic) overactive bladder syndrome and detrusor overactivity from two double‐blind, imbalanced, placebo‐controlled randomized phase 1 trials

Aims Two phase 1 trials were performed in healthy women with the overactive bladder (OAB) syndrome and urodynamically demonstrated detrusor overactivity (DO), with the aim to demonstrate the safety and potential efficacy of URO‐902, which comprises a gene therapy plasmid vector expressing the human big potassium channel α subunit. Methods ION‐02 (intravesical instillation) and ION‐03 (direct injection) were double‐blind, placebo‐controlled, multicenter studies without overlap in enrollment between studies. Active doses were administered and evaluated sequentially (lowest dose first) for safety. ION‐02 participants received either 5000 µg or 10 000 µg URO‐902, or placebo. ION‐03 participants received either 16 000 or 24 000 µg URO‐902, or placebo, injected directly into the bladder wall using cystoscopy. Primary outcome variables were safety parameters occurring subsequent to URO‐902 administration; secondary efficacy variables also were evaluated. Results Among the safety outcomes, there were no dose‐limiting toxicities or significant adverse events (AEs) preventing dose escalation during either trial, and no participants withdrew due to AEs. For efficacy, in ION‐02 (N = 21), involuntary detrusor contractions on urodynamics at 24 weeks in patients receiving URO‐902 (P