Udenafil also has shown the
Udenafil also has shown the ability to significantly inhibit the decrease of vascular endothelial cell function and inhibit the decrease in endothelial cell and smooth muscle contents, thus preventing their fibrosis within the penile corpus cavernosum in diabetic or hyperlipidemic animal models when administered once daily for a long period.11, 12, 13 Based on these findings and those of a clinical trial in patients with ED using a low dose of udenafil (25, 50, and 75 mg) once daily in addition to taking the drug on demand, udenafil 50 mg has been shown to be safe and effective, leading to its market approval for once-daily administration. Recently, we reported on the efficacy and safety of udenafil 50 and 75 mg once daily for 24 weeks in a therapeutic confirmatory clinical trial (parent study: DA8159_EDD_III), and the present clinical trial was conducted to evaluate the long-term safety (to 48 weeks) of administering udenafil 75 mg once daily.
Discussion All PDE5-Is including udenafil are “on-demand” forms of medication indicated for men with ED to administer orally before previously arranged sexual intercourse, which is a nuisance, if not a burden, for the two partners. Tadalafil, which has longer of course than other PDE5-Is, has been reported to have a time of action of up to 36 hours when taken at on-demand dosages and to be effective and safe in the treatment of ED when taken at once-daily dosages. A clinical trial of patients with ED using a low dose of udenafil (25, 50, and 75 mg) once daily investigated the pharmacokinetic characteristics of udenafil and found that udenafil had a half-life of approximately 11 to 13 hours, its accumulation factor of maximum plasma concentration was 1.1 when consistently administered once daily, and its accumulation factor of trough plasma concentration was approximately 1.23 to 1.46, leading to the marketing license of once-daily dosing of udenafil 50 mg in October 2010. Subsequently, once-daily dosing of udenafil 50 and 75 mg was confirmed safe and effective in a clinical trial conducted for 24 weeks, and this clinical trial was conducted to evaluate the long-term safety of udenafil 75 mg administered once daily for 24 weeks during this extension study. ED can be treated with erectogenic agents such as PDE5-Is before anticipated sexual intercourse, but fundamental ED cannot be treated with such on-demand treatments. Sommer et al conducted a study to confirm the improvement and maintenance of EF and arteriogenic reactivity in the penis in men who used sildenafil 50 mg once daily for 1 year before bedtime based on results of improved nocturnal erection with once-daily dosing of sildenafil before bedtime. Approximately 58% of subjects reported normal erections for 6 months after discontinuation of the drug, and this improvement was believed to be caused by increased arterial blood flow in the penis during the pharmacologically induced erection. Porst et al checked the efficacy of tadalafil 5 mg once daily for 12 months during a 4-week ED treatment-free period. IIEF-EF scores rapidly decreased to baseline levels, and only 24.6% of subjects who had reported normal erections at the 12-month time point maintained normal erections after completion of the 4-week ED treatment-free period. Thus, continual treatment of patients with ED is needed for a successful sexual life. After the 4-week ED treatment-free period to check the efficacy of udenafil 75 mg once daily during the 6-month extension and confirm the results of the previous study, 14.2% of subjects reported normal erections, and 25% of subjects who had reported normal erections at completion of the 6-month administration period reported maintaining normal erections without the use of udenafil for 4 weeks. For subjects administered udenafil 75 mg in the parent study, which administered udenafil 75 mg once daily for 12 months, 46.2% of subjects reported normal erections at completion of the 12-month administration period; of these subjects, 25.6% maintained normal erections without the use of udenafil for 4 weeks. In the present clinical trial, udenafil showed a similar result as tadalafil reported by Porst et al.