This extension trial of SP668 consists of two phases: double-blind treatment and open-label extension. The trial provides subjects the option of long-term treatment with sustained release (SR) fesoterodine (SPM 907) and to assess long-term subject safety, tolerability and efficacy.

Double-Blind: Subjects remained on either fesoterodine 4mg, 8mg or 12mg depending on their dose assignment in SP668. Previous SP668 placebo subjects received fesoterodine 4mg.

Open-Label: Subjects received fesoterodine 8mg with a one time option to reduce the dose to 4mg and a one time option to increase again to 8mg.

The primary variables focus on long-term safety and tolerability and include the observation and assessment of adverse events, residual urinary volumes, laboratory parameters, changes in ECG, physical and urological examinations and subject's assessment of treatment tolerance.

Secondary efficacy variables include various parameters derived from micturition diaries, count of subjects and their dose choice throughout the trial and subject's assessment of treatment efficacy.

Inclusion Criteria:

• Overactive bladder