Room 519-A | Sexual Dysfunction (ED) Monday, July 11, 2005 Time: 8:30 AM-10:30 AM |
Open Label, Crossover Study of Sildenafil Citrate and Tadalafil for the Treatment of Erectile Dysfunction in Patients Naive to Phosphodiesterase 5 Inhibitor Therapy.
Eardley, Ian1, Mirone, Vincenzo2, Montorsi, Francesco3, Kell, Phillip*,4, Zhao, Yanli5, Harrison, Mark5, Beardsworth, Anthony5, 1 Department of Urology, Leeds, UK2 Urology Department, Naples, Italy3 Cattedra di Urologia, Milan, Italy4 Archway Sexual Health Clinic, London, UK, UK5 Eli Lilly and Company, Indianapolis, IN
ABSTRACT- Introduction and Objectives: To directly compare the efficacy, choice of treatment, and tolerability of sildenafil citrate (sildenafil) and tadalafil for the treatment of erectile dysfunction (ED) in patients naive to phosphodiesterase 5 (PDE5) inhibitor therapy. Methods: Open label, crossover study of sildenafil and tadalafil, taken as needed. After a 4-wk baseline assessment, men with ED (N=367; mean age=54yrs) were randomized to sildenafil for 12 wks followed by tadalafil for 12 wks, or vice versa. Each 12-wk period included an 8-wk dose optimization phase and 4-wk assessment phase. During the dose optimization phase, patients started with 25 or 50 mg sildenafil, or 10 mg tadalafil (per the SPC) and could titrate up and down to find their optimum dose of 25, 50 or 100 mg sildenafil, or 10 or 20 mg tadalafil. Men completing both 12-wk periods chose which treatment to continue during an 8-wk extension phase (primary objective). Efficacy (secondary objective) was measured with the International Index of Erectile Function (IIEF) and Sexual Encounter Profile (SEP) diary. Treatment emergent adverse events were collected throughout the study. Results: At baseline, 39%, 30% and 31% of men had mild, moderate or severe ED. A total of 294 men completed both treatment periods. During the sildenafil assessment phase, 7%, 61%, and 32% chose 25, 50, and 100 mg doses, and during the tadalafil assessment phase, 52% and 48% chose 10 and 20 mg doses, respectively. Efficacy: IIEF and SEP diary results at baseline (B), post-sildenafil (S), and post-tadalafil (T); p values are for comparison between sildenafil and tadalafil: IIEF Erectile Function Domain (B=14.2, S=23.9, T=24.3; p=0.08); IIEF Q1-Erection Frequency (B=3.0, S=4.2, T=4.3; p=0.14); IIEF Q2-Erection Firmness (B=2.6, S=4.1, T=4.3; p=0.01); IIEF Q3-Penetration Ability (B=2.6, S=4.2, T=4.3; p=0.43); IIEF Q4-Maintenance Ability (B=2.0, S=4.0, T=4.0; p=0.15); IIEF Q5-Maintenance Ease (B=2.1, S=4.0, T=3.9; p=0.81); IIEF Q15-Erection confidence (B=1.9, S=3.4, T=3.5; p=0.01); SEP2-Successful Penetration (%) (B=46, S=82, T=85; p=0.06); SEP3-Successful Intercourse (%) (B=19, S=72, T=77; p=0.003); IIEF Intercourse Satisfaction Domain (B=6.8, S=11.3, T=11.5; p=0.20); IIEF Overall Satisfaction Domain (B=4.4, S=7.6, T=7.8; p=0.04). Treatment choice: Having completed both 12-wk treatment periods, 29% (n=85) of men chose to continue with sildenafil and 71% (n=206) of men chose to continue with tadalafil (p<0.001) for the 8 wk extension. The medication choice for the extension phase was not affected by treatment sequence, ED severity or etiology, age, or dosage. Tolerability: Sildenafil and tadalafil were well tolerated with 11 (3.0%) discontinuing for an adverse event and 3 (0.8%) for lack of efficacy. The most commonly reported adverse events were headache, flushing, nasal congestion, back pain and dyspepsia. Conclusions: Sildenafil and tadalafil were both effective and well tolerated for the treatment of men with ED naive to PDE5 inhibitor therapy. At the completion of two 12-wk treatment periods, 29% of men chose sildenafil and 71% chose tadalafil for an 8-wk extension phase.
Key words: erectile dysfunction, efficacy, choice, sildenafil, tadalafil