LONDON, ONTARIO -- April 13, 2001 -- A clinical trial in men with a history of erectile dysfunction showed a return of spontaneous erections in 85 percent of the men using Caverject(R) (alprostadil for injection) over a 12-month period, a significant improvement from a baseline of 37 percent.
The study was published in the March issue of Urology, (57:536-541, 2001).
The study specifically looked at the flow of blood into the arteries of the penis. Blood flow through the cavernosal arteries engorges the penis, creating an erection suitable for sexual intercourse. Caverject works by relaxing the smooth muscle of the penis and the muscles surrounding the arteries, allowing for an increase in blood flow to the penis.
"A significant number of men in this study experienced a measurable improvement in blood flow, one of the most common physical contributors to erectile dysfunction," said Gerald Brock, MD, associate professor, Department of Urology, at the University of Western Ontario, St. Joseph's Health Care, London, and lead study investigator.
"A significant number of men also reported an increase in return of spontaneous erections. Both of these results offer particularly encouraging news for the many millions of men worldwide that suffer regularly from erectile dysfunction," he added.
Erectile dysfunction is characterized by the inability to achieve or maintain an erect penis sufficient for sexual intercourse. The inability to maintain an erection can be caused by physical (e.g., diabetes, heart disease and high blood pressure) or situational conditions that work alone or in combination to inhibit a successful erection. The vast majority of cases have been found to be treatable.
The open-label study involved 70 men, ages 18 and older with documented arteriogenic ED of at least four months who had not previously been treated for this condition. The study measured improvements in penile circulation and reported the reoccurrence of spontaneous erections experienced at four, eight and 12-months from baseline with regular use of Caverject.
The minimal dose necessary to obtain an erection suitable for intercourse was first determined in a clinical setting, followed by an in-home period during which study participants were instructed to administer Caverject by injection two to three times a week.
Diaries were completed in which the duration and overall quality of the erection and subsequent sexual activity was recorded. Of the 70 men entering the study, 63 men entered the home maintenance phase and 42 completed the 12-month treatment phase.
During 12 months, 85 percent of the men (46 of 54) reported experiencing spontaneous erections, a significant improvement from a baseline of 37 percent, with 74 percent of these episodes resulting in satisfactory intercourse as reported by the men and their partners. Penile circulation was significantly improved at four and eight months and still noted at 12 months based on duplex ultrasound data in 38 men.
Adverse events after administration of Caverject were generally regarded as tolerable, with temporary penile or injection site pain the most reported side effect in 23 percent of men in the trial, and six percent reported prolonged erection (spontaneously resolved).
"These results should also be of special interest for men who have difficulty obtaining desired results with current oral therapies for erectile dysfunction, or those who can not take oral medications due to a pre-existing condition," said Dr. Brock. "The administration of Caverject in this study yielded a significant increase in spontaneous erections and should be taken into consideration by physicians in the long-term treatment plan for their erectile dysfunction patients."
Caverject is a self-injection medication indicated for the treatment of erectile dysfunction due to neurologic, vasculogenic, psychogenic, or mixed etiology. Caverject is also indicated as an adjunct to other diagnostic tests in the diagnosis of erectile dysfunction.
Caverject is generally well tolerated. The most common side effect is mild to moderate penile pain that occurs in about a third of men. Caverject should not be used in men who have conditions that might predispose them to priapism (erections lasting longer than six hours that can cause permanent tissue damage if untreated), or in men with anatomical deformation of the penis or penile implants.