Study to Investigate Effect of a New Drug (PF-00446687) in Males Suffering From Erectile Dysfunction

A 2-Cohort, Multi-Centre, Randomised, Double Blind, Placebo Controlled 4-Way Crossover Study To Assess The Efficacy Of Single Oral Doses Of PF-00446687 On Erectile Function In Men Suffering From Erectile Dysfunction, Using 100 Mg Sildenafil As A Positive Control.

The purpose of this study is to investigate the effect of up to 200 mg of PF-00446687 on erectile activity in males suffering from erectile dysfunction as well as examining the safety and toleration of the drug.

Inclusion Criteria:

• Males aged 18-65 years who has given written informed consent to participate in the study and who suffers moderate to severe erectile dysfunction who has a current or recent successful response to treatment with phosphodiesterase type 5 inhibitors

Exclusion Criteria:

• Males with a history of significant cardiac disease; unstable angina or recent myocardial infarction.
• Males suffering from treated or untreated hypo- or hypertension
• Males currently receiving vasoactive medication
• Males taking medications contraindicated, or cautioned with sildenafil or MC4 agonists