A Study in Erectile Dysfunction

Tadalafil Once Daily Following As-Needed Phosphodiesterase Type 5 Inhibitor Treatment, an Assessment of Return to Normal Erectile Function

The purpose of this trial is to evaluate if treatment with tadalafil once daily will allow men to return to normal erectile function in those who did not have normal erectile function following as-needed (PRN) Phosphodiesterase Type 5 (PDE5) Inhibitor treatment.

Inclusion Criteria:

• At least a 3-month history of erectile dysfunction (ED).
• Are able to read, understand and provide signed informed consent.
• Have an International Index of Erectile Function-Erectile Function (IIEF-EF) domain score that is greater than or equal to 17 and less than 26 at screening.
• Have been taking a maximum dose of sildenafil citrate (100 milligram [mg]), vardenafil (20 mg), or tadalafil (20 mg) on as needed basis for at least one month prior to screening.
• Anticipate having the same female sexual partner during the study who is willing to participate in the required number of sexual intercourse attempts and complete study measures during the study.
• Agree to make at least four sexual intercourse attempts during both the 4-week as needed run-in period and the 4-week non-drug run-in period.
• Agree not to use any other erectile dysfunction (ED) treatment, including herbal therapy during the 4-week non-drug, run-in, the double-blind treatment period, the open label period and for 96 hours after the end of the study.

Partner Inclusion Criteria:

• Are female and at least 18 years of age at screening.
• Anticipate having the same male study subject as her sexual partner during the study.
• Able to read, understand and provide signed informed consent.
• Agree to make the required number of sexual intercourse attempts with the male sexual study partner during the study.
• Willing to participate in recording responses to the treatment satisfaction scale.

Exclusion Criteria:

• Have an IIEF-EF domain score of greater than or equal to 26 at screening.
• Prior ineffective treatment with (or nonresponder to) any PDE5 Inhibitor
• Have previously used or are currently using any PDE5 inhibitor once daily.
• Present with ED caused by other primary disorders or ED caused by untreated/inadequately treated endocrine disease.
• Partner unwilling to complete all study requirements.
• History of radical prostatectomy or other pelvic surgery or penile implant, or a clinically significant penile deformity, in the opinion of the investigator
• Exhibit evidence of clinically significant renal insufficiency or hepatobiliary disease, or significant cardiac history as determined by the investigator
• Currently receive treatment with nitrates, cancer chemotherapy, or antiandrogens
• Have previously completed or withdrawn from this study or any other study investigating tadalafil for once-daily use.