The first clinical study to evaluate Levitra (vardenafil HCl) in men with erectile dysfunction (ED) who were unresponsive by history to Viagra (sildenafil citrate)+ (as identified by six criteria) showed that men were three times more likely to complete sexual intercourse successfully on Levitra than on placebo.1 Results from the study, referred to as the PROVEN (Patient RespOnse with VardENafil in Sildenafil Non-Responders) trial, presented on October 11 at the 5th Annual Fall Research Meeting of the Sexual Medicine Society of North America (SMSNA) in Denver. The SMSNA deemed the study abstract a Prize Essay Winner.
"In my clinical experience, a number of men with ED are not successful with Viagra. Results from the PROVEN study clearly demonstrated that Levitra was effective in many men who reported lack of success with Viagra," said Culley C. Carson, III, MD, lead study investigator and president of SMSNA. "These findings confirm the need for new treatments and support Levitra as an excellent choice for many men with ED." Dr Carson is chief of Urology at the University of North Carolina Hospital, Chapel Hill, and Rhodes distinguished Professor of Urology.
Levitra PROVEN Study Demonstrated Three-Fold Increase in Success Rates. This prospective, multicenter, double-blind, flexible-dose trial studied men with ED who had a documented history of non-response to Viagra. Unresponsiveness to Viagra was defined by patient reported history and they were not re-challenged with Viagra.
All study participants met rigorous criteria, including failing at least four of the last six attempts at successful intercourse with Viagra and having at least one unsuccessful attempt with the highest available dose of Viagra (100 mg). These men were considered to be unresponsive to Viagra in the medical opinion of the study physician. A total of 463 men with moderate to severe ED were randomized to Levitra 10 mg or placebo for four weeks. At weeks four and eight of the trial, physicians could adjust the starting dose of Levitra 10 mg to 20 mg or 5 mg based on the efficacy and tolerability of the drug.
All primary endpoints showed statistically and clinically significant improvements compared with placebo. Results showed that after 12 weeks, men were three times more likely to complete sexual intercourse successfully on Levitra than on placebo (46.1 per cent vs. 16.1 per cent, respectively). When compared with baseline, men were four times more likely to complete sexual intercourse successfully on Levitra (46.1 per cent vs. 10.1 per cent, respectively). Among those taking placebo, there were no clinically or statistically significant differences in success in maintaining erections to completion of successful intercourse after taking the sugar pill as compared with baseline (16.1 per cent vs. 11.6 per cent, respectively).
"Men with ED want to be confident that their treatment is reliable," said Dr. Dimitris Hatzichristou, PROVEN study investigator and assistant Professor, Centre for Sexual Dysfunction of the Aristotle University of Thessaloniki, Greece. "These impressive findings show that many men with ED can rely on Levitra to improve their erectile function, even those men who are difficult to treat or are dissatisfied with other treatments," he added.
In the clinical trial, the most commonly reported adverse events were generally mild to moderate and included headache, flushing, nasal congestion and upset stomach.
Other studies have shown that Levitra works as quickly as 15 minutes2 (most men by 25 minutes), is effective from the first time that most men take it, and provides a reliable improvement in erection quality for many men with ED.
Levitra, researched and discovered by Bayer AG, is marketed by Bayer and GlaxoSmithKline plc (GSK) through a worldwide co-promotion and co-development agreement. Levitra was approved on 6 March 2003 by the European Commission based on the quality, safety and efficacy data submitted. These data included results from more than 3,750 men representing a broad patient population. The US Food and Drug Administration (FDA) approved Levitra for the treatment of ED on 19 August 2003.