Objective: To compare OAB symptom outcomes following initial randomised treatment with solifenacin 5 mg or tolterodine ER 4 mg at the 4-week clinic-visit and again at 12 weeks for patients choosing to remain on this treatment dose from 4 weeks.
Methods: A prospective, double blind, double-dummy, two-arm, parallel-group, 12-week study (The STAR study) was conducted to compare the efficacy and safety of solifenacin 5/10 mg and tolterodine extended release (ER) 4 mg in OAB patients.
Results: At 4 weeks mean improvements in OAB symptoms, including urgency, frequency (primary variable), incontinence and nocturia, were larger in patients randomised to solifenacin 5 mg; with the difference for incontinence being statistically significant (mean reduction in incontinence episodes/24 hrs in the solifenacin group of -1.30 vs. -0.90 (p=0.0181); the mean result for solifenacin 5 mg amounted to a 44% additional improvement.) There was an associated significant reduction in pad use (reduced by -1.21 vs. -0.80; p=0.0089); the mean result for solifenacin 5 mg amounted to a 51% additional improvement over that of tolterodine ER 4 mg. For patients choosing to remain on these treatments improvements in favour of solifenacin were maintained at study end (12-weeks). Treatments were well tolerated.
Conclusions: Within 4 weeks solifenacin 5mg was statistically significantly better than tolterodine ER 4 mg in improving incontinence and reducing incontinence pad use. Differences in efficacy in favour of solifenacin 5 mg were maintained from 4 weeks for the duration of the study for patients choosing to remain on their starting dose.