The role of initial success rates and other factors in determining reliability of outcomes of phosphodiesterase inhibitor therapy for erectile dysfunction: a pooled analysis of 17 placebo-controlled trials of tadalafil for use as needed.
BACKGROUND
Reliability of successful outcomes in men with erectile dysfunction (ED) on phosphodiesterase type 5 inhibitors is an important aspect of patient management.


OBJECTIVE
We examined reliability of successful outcomes in a large integrated dataset of randomized tadalafil trials.


METHODS
Success rates, time to success, subsequent success after first success, and probability of success were analyzed based on Sexual Encounter Profile questions 2 and 3.


METHODS
Data from 3,254 ED patients treated with tadalafil 10 mg (N = 510), 20 mg (N = 1,772), or placebo (N = 972) were pooled from 17 placebo-controlled studies.


RESULTS
Tadalafil patients had significantly higher first-attempt success rates vs. placebo. This effect was consistent across most subgroups; however, patients with severe ED experienced a greater response to tadalafil than patients with mild-moderate ED. Approximately 80% of patients achieved successful penile insertion within two attempts with either tadalafil dose and successful intercourse within eight attempts for tadalafil 10 mg and four attempts for tadalafil 20 mg. However, approximately 70% of tadalafil-treated patients achieved successful intercourse even by the second attempt. Subsequent success rates were higher for patients with first-attempt success (81.5% for 10 mg and 86.1% for 20 mg vs. 66.2% for placebo, P < 0.001) vs. patients with later initial success (53.2% for 10 mg and 56.4% for 20 mg vs. 39.9% for placebo, P < 0.001). Among patients treated with tadalafil, intercourse success rates at early attempts were similar to rates at later attempts (i.e., attempts 5 and 10 vs. 25), although insertion success rates were significantly lower earlier in treatment.


CONCLUSIONS
The findings affirm the reliability of successful outcomes with tadalafil treatment and that first-attempt success is a critical factor affecting subsequent outcomes. The results further show that even among men who did not succeed on first attempt, a substantial proportion will have successful outcomes if treatment is maintained.
Eli Lilly and Company, Indianapolis, IN 46285, USA. sontag_angelina@lilly.com
Angelina
A
Sontag
Raymond C
RC
Rosen
Heather J
HJ
Litman
Xiao
X
Ni
Andre B
AB
Araujo
D000328:Adult; D000368:Aged; D002243:Carbolines / Q000627:therapeutic use*; D003075:Coitus; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D007172:Erectile Dysfunction / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use*; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D000068581:Tadalafil; D016896:Treatment Outcome
D002243:Carbolines; D058986:Phosphodiesterase 5 Inhibitors; D000068581:Tadalafil