Phase 1 clinical trial of vesicare™ (solifenacin) in the treatment of urinary incontinence after radical prostatectomy

Purpose: Permanent and prolonged incontinence following robot assisted radical prostatectomy (RARP) is known to result from injury to the external sphincter. We hypothesize that pre-existing detrusor overactivity may also contribute to delayed return of continence (>3 months). This pilot study examines the safety profile and efficacy of muscarinic receptor antagonist, solifenacin, in incontinent men after prostatectomy.

Materials and Methods: Men using three or more pads 7 days post catheter removal were invited to enroll into the study (5 mg daily of solifenacin for 3 months). All subjects received RARP under hypothermic conditions by one surgeon. Continence was defined as 0 pads.

Results: Forty men were enrolled, one excluded due to missing follow-up. Two men reported nonserious adverse events: one a vaso-vagal reaction when taking solifenacin with sildenafil, and the other was dehydration and dizziness after strenuous exercise. Additionally, four withdrew due to side effects. The efficacy outcomes show improved intermittency after prostatectomy, though unclear if due to the medication. At 3 months, 21 patients (53.8%) reached the primary continence outcome of zero pads. The median time to continence in this group was 95 days.

Conclusions: Solifenacin is well tolerated in post radical prostatectomy patients with a 15% withdrawal rate due to side effects. These results formed the basis of a large, prospectively randomized clinical trial comparing the effects of solifenacin versus placebo in a population of men incontinent after RARP.