This is a 12 week study in which different doses and formulations of UK-369,003 will be administered to patients with a diagnosis of enlarged prostate. Patients will complete a series of questionnaires before, during and after treatment to assess if UK-369,003 has improved their urinary symptoms and erectile function . There will be several blood samples taken during the study to asses the level of drug in the blood and correlate it with the responses to the questionnaires.

Inclusion Criteria:

1. Male subjects aged 40 years and above, with documented LUTS with an International Prostate Symptom Score (IPSS) ≥13
2. Clinical diagnosis of BPH.
3. Qmax 5 to 15ml/sec with a voided volume of ≥150ml at visit 1 (screening).

Exclusion Criteria:

1. Urinary tract infection
2. Primary neurological conditions affecting bladder function