A Phase II Study to Evaluate: Delay in Intravaginal Ejaculatory Latency Time (IELT), Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Two Oral Doses of GSK557296 in a Randomized, Double Blind, Placebo-Controlled, Parallel Group Study in Men With Premature Ejaculation

To determine if an on demand dosing of 50 mg or 150 mg of GSK557296 demonstrates superior efficacy with respect to duration of intra vaginal ejaculatory latency time (IELT) during an 8 week study period compared to placebo in men with primary premature ejaculation. An assessment of the safety and tolerability of all doses of GSK557296 will be performed as well as an assessment for change in the Index of Premature Ejaculation (IPE) from baseline and at the end of the 8 weeks of treatment. During the active treatment period study participants will be limited to a maximum of 40 doses of GSK557296, or placebo, spilt as 20 doses for both 4 week intervals.