Vardenafil To Challenge Viagra

May 9, 2001 -- Move over Viagra - here comes Vardenafil. Men over age 65 experienced improved erections after taking vardenafil, Bayer's investigational treatment to improve erectile function. The results presented this week at the annual American Geriatrics Society meeting in Chicago also showed vardenafil was generally well tolerated.

``Vardenafil enhanced erectile function in older men,'' said Christopher P. Steidle, M.D., a clinical associate professor of urology at Indiana University School of Medicine and co-author of the analysis. ``This is an important finding because men over age 65 are more likely to suffer from impaired erectile function and also are more difficult to treat.''

According to the Massachusetts Males Aging Study, the prevalence of erectile dysfunction increases dramatically with age. In fact, according to the study, 57 percent of men in the U.S. ages 60-69 experience some type of ED(1).

The latest analysis of the large Phase II vardenafil study compared 65 older men (> 65 years) and 134 younger men (18 to 45 years). All had reported mild to severe impaired erectile function for more than six months. The patients were randomized into four groups and were given 5 mg, 10 mg, or 20 mg doses of vardenafil (a phosphodiesterase 5 [PDE-5] inhibitor) or placebo on demand.

The study participants were evaluated using the erectile function domain, part of the International Index of Erectile Function (IIEF), a standard sexual function questionnaire used by urologists. The men answered the questionnaire after a four-week pre-treatment period and again after 12 weeks of treatment. Each answer is assigned a points value, with a maximum of 30 points possible. Anyone scoring between 26 and 30 points is considered to have normal sexual function.

In this study, the average change in scores for patients taking vardenafil was similar among the older and younger age groups. The average improvement for older patients on vardenafil was between 2.5 and 10.3 points, depending on the dose they were given. The average improvement for younger patients on vardenafil was between 7.9 and 8.4 points, depending on dose. In contrast, there was very little improvement in scores for the placebo-treated patients. The average improvement for older patients on placebo was 0.5 points, the average improvement for younger patients on placebo was 1.1 points.

The occurrence of adverse events also was similar in older and younger patients. Those adverse events included headache, nasal congestion, upset stomach, and flushing.

An earlier, separate pharmacokinetic (PK) study evaluated vardenafil clearance in the same age groups. A 40 mg dose was given -- higher than that used in the Phase II trial. Peak levels were reached at a similar time in both older and younger subjects (mean times of 30 minutes and 36 minutes, respectively). Vardenafil took slightly longer to clear from the blood in older men than in younger men. The drug's half-life was six hours for older men and 4.8 hours for younger men.

``This study suggests that vardenafil is cleared from the body in a similar timeframe for older and younger men. That is especially important for older men because you don't want any drug remaining in their bodies longer than needed,'' said Dr. Steidle.

Last month at the European Association of Urology meeting in Geneva, Switzerland, data was presented showing vardenafil improved erectile function in men regardless of age, cause, or the severity of erectile impairment. In addition, the study showed vardenafil not only improved erections in up to 80 percent of men, but also increased their ability to complete sexual intercourse with ejaculation(2).

Vardenafil is an oral treatment currently under investigation to improve erectile function. Bayer plans to submit a new drug application (NDA) for this compound to the U.S. Food and Drug Administration later this year.