Study to Compare the Tolerability and Efficacy of Once Daily Vardenafil vs Vardenafil PRN vs Placebo in Men Immediately After Nerve-sparing Prostatectomy for Improving ED

Inclusion Criteria: At Screening * Males 18-64 years of age * Scheduled to undergo bilateral nerve-sparing radical retropubic BNSRRP, as selected according to the investigator's usual clinical practice * Surgery scheduled within about 1 month of screening (Visit 1) * Expressed an interest in resuming sexual activity as soon as possible after prostatectomy * Heterosexual relationship * No pre-operative erectile dysfunction: * International Index of Erectile Function (IIEF) Erectile Function Domain Score score EF domain =26 at screening without any therapy/devices for improvement of erections * No perforation of the prostate capsule by tumor At Randomization: Before being randomized subjects must still be meeting all Screening Inclusion Criteria, as well as the following criteria: * bilateral nerve-sparing during the retropubic prostatectomy documented on the operating report * BNSRRP occurred within approximately 1 month post screening (Visit 1) * No perforation of the prostate capsule by tumor: No positive tumor margins confirmed after surgery: =T2 stage on pathology report from the surgery Exclusion Criteria: * Subjects who are taking nitrates or nitric oxide donors * Subjects who are taking the following inhibitors of cytochrome P 450 CYP 3A4: very potent HIV protease inhibitors (ritonavir, indinavir), the anti-mycotic agents itraconazole and ketoconazole (topical forms are allowed) or erythromycin * Known hypersensitivity to Vardenafil * Presence of significant penile anatomical abnormalities (e.g. penile fibrosis or Peyronie's disease) * History of retinitis pigmentosa * Unstable angina pectoris * History of myocardial infarction, stroke or life-threatening arrhythmia within the prior 6 months * Severe chronic or acute liver disease * Symptomatic postural hypotension in the past 6 months * NYHA Class III or IV heart failure * Life expectancy \<3 years * Clinical diagnosis of significant untreated sleep apnea or working night shifts (e.g. 23:00h to 7:00 h) * Anti-androgens use * Residual prostate cancer, or requirement for radiotherapy or ADT after surgery