Vardenafil demonstrates first-dose success and reliability of penetration and maintenance of erection in men with erectile dysfunction. Discussion
The objective of this study was to evaluate the 12-week reliability, efficacy and safety of vardenafil 20 mg in men with ED who reported a first-dose success of vaginal penetration. This placebo-controlled trial was conducted after the similarly designed RELY-I study that evaluated vardenafil 10 mg in patients with less severe ED and fewer associated comorbidities. Study limitations included the lack of investigator and patient blinding during the open-label challenge phase and the potential bias toward positive efficacy effects on patients in the placebo group at randomization. These are similar to the limitations found in the RELY-I study (owing to the shared study design) and should be considered when the results of this study are reviewed. Results from our study demonstrated 12-week reliability with vardenafil 20 mg and showed that this treatment regimen was highly successful, compared with placebo, as first-dose therapy for ED patients both with and without comorbidities. This also confirms earlier results reported by the RELY-I study. At the end of the RELY-I trial, the least squares mean reliability rate by dose in terms of SEP2 was 83.4% and in terms of SEP3, 76.5%. Rates at the end of the RELY-II trial (SEP2, 85.0%; SEP3, 78.5%) were comparable and slightly higher than those in the RELY-I trial, despite the more severely ill patient population and corresponding lower baseline values. First-dose success rates were slightly lower overall in this study, compared with the RELY-I trial, which can be explained by the more severely ill patient population. However, considering the improved reliability rates discussed earlier, these lower first-dose success values with vardenafil 20 mg have no impact on the reliability profile of this dose. It is important to remember when comparing data from clinical trials having the same or similar study designs that differences in baseline characteristics of patients enrolled in the trials may often produce clinical outcomes that are not expected or the same as those seen earlier. Therefore, evaluation of baseline patient characteristics is an essential facet and should be done while data from such studies are reviewed. Vardenafil 20 mg was safe and well tolerated in patients with and without comorbidities. The AEs reported during the study were consistent with those seen in the RELY-I study.
RELY-II IIEF-EF data further support the time-after-time efficacy, that is, consistent and maintained improvement in erectile function parameters over time, reported in an earlier vardenafil trial that used IIEF questions 3 and 4 as the primary efficacy end points. A retrospective analysis of these results examined efficacy in terms of specific subgroup patient populations defined according to ED causes, ED severity and patient age. Similar future subgroup analyses from the RELY-I and RELY-II studies might shed more light on the reliability of vardenafil (generic levitra) 10 mg and 20 mg in these and other subgroup patient populations.
Sustained efficacy and tolerability have been demonstrated with vardenafil 10 mg and 20 mg in men with ED over a longer period of 2 years. Long-term efficacy also has been demonstrated for sildenafil in a 1- to 3-year postobservational study. For tadalafil, there are no published data from studies with a similar long-term follow-up.
Interestingly, in the RELY-II study, 78% of patients had used sildenafil, and 9% tadalafil, before enrolment. A growing consensus in recent literature now suggests that ED patients whose PDE5-inhibitor treatment fails should be rechallenged with another agent. For instance, in this study, vardenafil (generic levitra) significantly improved all efficacy parameters in patients who did not respond to sildenafil therapy.
Canadian Vardenafil is the only PDE5 inhibitor for which first-dose success as assessed by key erectile function parameters has been studied exclusively in placebo-controlled trials rather than in retrospective analysis studies alone. Previously, first-dose success and/or reliability data for PDE5 inhibitors were available only from retrospective analysis of studies. In our study, with 34% of the men having severe ED, 41% having hypertension, 28% having dyslipidemia and 24% having diabetes, vardenafil 20 mg demonstrated comparable if not superior reliability and first-time success in terms of SEP2 and SEP3 rates, compared with both sildenafil and tadalafil.