New head to head study proves non-inferiority of Levitra® (vardenafil HCI) in comparison to Viagra® (sildenafil) for the treatment of erectile dysfunction
Vardenafil achieved nominal statistical superiority to sildenafil for several frequently used efficacy measures
Wednesday - September 20, 2006 - Cairo, Egypt – Launched today, a new medical study shows that in those men who expressed a preference, 53% preferred vardenafil compared to 47% who preferred sildenafil, in patients with erectile dysfunction and risk factors for cardiovascular disease. This study demonstrated non-inferiority to sildenafil for overall preference and achieved nominal statistical superiority to sildenafil for several frequently used efficacy measures. Non-inferiority shows that Levitra is at least as good as Viagra, while SEP 2 and 3 efficacy shows a superior effect for vardenafil.
Comparative clinical trials can be difficult to design in an unbiased way however the CONFIRMED study has been consciously designed to be truly unbiased towards either treatment. The CONFIRMED Study (COmparing vardeNafil and sildenaFil In the tReatment of Men with Erectile Dysfunction (ED)) is a randomised, double-blind, pooled crossover study. This study compared patient preference and satisfaction with the two treatments in men with ED and diabetes, hypertension and/or hyperlipidaemia from Europe, USA and Mexico.
A total of 1057 men were recruited to the study. 38.9% of men expressed an overall preference for Levitra over Viagra (34.5%) and 26.6% of patients had no treatment preference. As this difference found was not statistically significant, this result confirms the non-inferiority of vardenafil. However vardenafil achieved nominal statistical superiority to sildenafil for several frequently used efficacy measures: Levitra achieved better response for men responding to the Sexual Encounter Profile questions 2 and 31 ; 83.9% of men taking Levitra responded positively to SEP2 (p=0.0389) compared with 82.2% for Viagra and 74% of men reported a positive response to Levitra for the question SEP3 (p=0.0038) against 72% for Viagra.
The CONFIRMED study minimized bias seen in other comparative trials by consciously creating an unbiased methodology that included 13 separate criteria. Trial results that are more likely to be accepted by the medical community are usually randomised (patients are chosen randomly to be given one treatment or the other), double-blind (neither the researcher nor patient know which treatment the patient is taking until the end of the study), cross-over design (each patient tries one treatment and then the other). This trial additionally used equivalent drug doses, had a randomised treatment sequence, used a neutral consent form, and assessed preference after each treatment period and, importantly, did not eliminate previous non-responders or only include naïve patients (patients who had never used an ED treatment before).
“The CONFIRMED study represents an important step forward in our understanding of the clinical differences between PDE5 inhibitors, confirming the efficacy of Levitra for men with erectile dysfunction,” explains Irwin Goldstein, study co-author and Editor in Chief of the Journal of Sexual Medicine.
About the CONFIRMED Study
The CONFIRMED Study (COmparing vardeNafil and sildenaFil In the tReatment of Men with Erectile Dysfunction) is a randomised, double-blind, pooled crossover study. This is a study of 1057 men aged ≥18 years with ED for more than 6 months according to NIH criteria; and risk factors for cardiovascular disease (diabetes mellitus, hypertension and/or hyperlipidaemia). Another requirement was a stable, heterosexual relationship for more than the last 6 months. Patients underwent two 4-week treatment periods, study medication being either vardenafil 20 mg or sildenafil 100 mg. Preference questions were asked after completion of each treatment period. As well as overall preference, 11 other preference questions were asked. Additionally, efficacy questions were asked including the erectile function (EF) domain score of the International Index of Erectile Function (IIEF); Sexual Encounter Profile (SEP) diary questions 2 and 3; Global Assessment Questions (GAQ) and Treatment Satisfaction Scale (TSS).
Further information and full results of this study can be found in the Journal of Sexual Medicine (available online 19 September 2006 http://jsm.issir.org).
About Erectile Dysfunction
Erectile dysfunction (ED) is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual performance.1 It is estimated that some degree of ED affects about half of all men over the age of 40 and that worldwide an estimated 152 million men suffer from ED.2 The number of men with ED is expected to more than double to 322 million by 2025.3 Despite the high prevalence of sexual dysfunction, experts estimate that only 15-20 percent of men with ED are currently treated.4
1. Jardin A, Wagner G, Khory S et al. Recommendations of the 1st International Consultation on Erectile Dysfunction. Co-sponsored by the World Health Organisation (WHO), International Consultation on Urological Diseases (ICUD) and Societé Internationale D’Urologie (SIU). p.713
2. Rosen RC, Fisher W, Eardley I, Neiderberger C, Nada A, Sand M: The Multinational Men’s Attitudes to Life Events and Sexuality (MALES) Study I, Prevalence of Erectile Dysfunction and Related Health Concerns in the General Population. Cur Med Res Op.
3. Aytac IA, McKinlay JB, Krane RJ: The likely world increase in erectile dysfunction between 1995 and 2065 and some possible policy consequences. BJU International 1999; 84:50-56
4. Southgate J: New rivals to Viagra expand the market. Scrip World Pharmaceutical News, 2002
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1SEP2 -‘Were you able to insert your penis into your partner’s vagina?’; SEP3, ‘Did your erection last long enough for you to have sexual intercourse?’ Response to SEP expressed as least-squared mean positive result.
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