Within the next year or so, depending on how quickly the FDA acts, the U.S. may be getting its first therapeutic agent specifically indicated for the treatment of premature ejaculation.
Even as data from two pivotal phase III trials were being discussed at the AUA annual meeting, Shionogi Pharma, Inc., was preparing a new drug application for PSD502, a metered aerosolized formulation of lidocaine and priolocaine applied to the glans penis 5 minutes before intercourse.
Improvement seen on IPE scores
The improvement in IELT produced a corresponding improvement in Index of Premature Ejaculation (IPE) scores. Men using the agent showed a 6.1-point improvement over those in the control group in the ejaculatory control domain of the IPE. They also showed a 5.3-point improvement in the IPE satisfaction domain compared to controls and a 2.6-point improvement in the distress domain versus controls.
Current treatments for PE include selective serotonin reuptake inhibitors such as fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft), and topical creams containing lidocaine and prilocaine. The antidepressants must be taken at least an hour, if not 3 or more, before intercourse. The creams are wiped on, allowed to remain until the anesthetic actions take effect, and then wiped off.
The men in the two studies were instructed to administer three quick sprays to the head of their penis, wait for 5 minutes, and wipe off the spray just before vaginal penetration.
"This agent [PSD502] is absorbed through the relatively poorly keratinized surface of the glans penis, but only the non-ionized form passes through. The ionized form remains on the surface, but this is not absorbed and is unable to penetrate the vaginal mucosa," Dr. Sharlip explained.
The findings Dr. Sharlip reported were drawn from two separate studies. A total of 539 patients were evaluable, one-third of whom were randomized to a placebo and the remaining two-thirds to the treatment. The men or their partners recorded the time from penetration to ejaculation with a hand-held stopwatch.
A little over 6% of the men in the treatment group reported adverse events, the most common of which was desensitization, which 3% of the treated men noted. Nearly 7% of their partners reported adverse events, most of which (5%) were a vulvovaginal burning sensation.
"One of the big questions is whether patients will find a topical treatment as acceptable as an oral agent. My guess is that they will if it is shown that the treatment is effective and safe," Dr. Sharlip said.
Dr. Sharlip is an investigator for Shionogi, and several of his co-authors have investigatory and/or other relationships with Shionogi and Plethora Solutions, both of which provided funding for the studies.