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ORIGINAL RESEARCH—ED PHARMACOTHERAPY: Efficacy and Safety of Tadalafil Across Ethnic Groups and Various Risk Factors in Men with Erectile Dysfunction: Use of a Novel Noninferiority Study Design


Abraham Morgentaler, MD, Harvard Medical School, 1 Brookline Place, Suite 624, Brookline, MA 02445, USA. Tel: (617) 277-5000; Fax: (617) 277-5444; E-mail:


Aim.  This U.S. multicenter open-label study used a noninferiority trial design to assess the efficacy of tadalafil 20 mg to treat erectile dysfunction (ED) in the black American and Hispanic groups compared with a reference group of Caucasians. A secondary objective was to demonstrate the efficacy and safety of tadalafil 20 mg in various populations of men with ED.

Methods.  A total of 1,911 patients with ED were enrolled into eight predefined groups: (1–3) Caucasian (Reference group), Black American, or Hispanic patients, ≤65 years of age with no diabetes mellitus or depression; (4) patients with depression, ≤65 years of age, no diabetes; (5) patients with diabetes, ≤65 years of age, no depression; (6) patients >65 years of age, no diabetes or depression; (7) patients who met enrollment criteria but were not included in any other group; and (8) patients with ED due to traumatic spinal cord injury. The study had a 4-week run-in period, followed by a 12-week treatment period with tadalafil taken as needed, up to one dose/day, prior to sexual activity. Change from baseline to endpoint in the Erectile Function (EF) domain of the International Index of Erectile Function (IIEF) was used to determine noninferiority of groups 2 and 3 from group 1. Secondary efficacy measures included other IIEF domains and Sexual Encounter Profile (SEP).

Results.  Noninferiority analyses based on the EF domain score showed that tadalafil was as efficacious in the Hispanic and Black American groups as in the Reference group. Patients in each of the eight groups had a significant change from baseline (P < 0.001) in the IIEF EF domain score and positive responses to SEP Questions 1–5. The most common treatment-emergent adverse events reported by patients in all eight groups were headache, nasal congestion, dyspepsia, flushing, and back pain.

Conclusion.  Tadalafil 20 mg was as efficacious in the Hispanic and black American groups as in the Caucasian/Reference group. Tadalafil was efficacious and well tolerated in each of the groups studied in this trial. Morgentaler A, Barada J, Niederberger C, Donatucci C, Garcia CS, Natanegara F, Ahuja S, and Wong DG. Efficacy and safety of tadalafil across ethnic groups and various risk factors in men with erectile dysfunction: Use of a novel noninferiority study design. J Sex Med 2006;3:492–503.