A Study of Withdrawal Effects With Dapoxetine in the Treatment of Premature Ejaculation

A Placebo-Controlled, Double-Blind, Randomized, Parallel Study of the Withdrawal Effects of Chronic Daily and As-Needed Dosing With Dapoxetine in the Treatment of Premature Ejaculation

The primary purpose of the study is to assess the possible withdrawal effects after abruptly stopping daily therapy with dapoxetine compared with continuing daily therapy in men with premature ejaculation (PE).

Premature ejaculation (PE) is a form of male sexual dysfunction. A measure of withdrawal effects associated with stopping therapy for PE is the Discontinuation-Emergent Signs and Symptoms (DESS), a series of questions for signs and symptoms experienced by the patient. This study of men with PE is a multicenter, randomized, double-blind trial consisting of 3 phases: pre-randomization phase (a screening visit and 1-week baseline period); 10-week double-blind treatment phase during which patients receive dapoxetine or placebo; and 2-week follow-up phase. The total duration of the study is approximately 13 weeks. During the double-blind phase patients receive study medication for once daily treatment and for use on as "as-needed" basis prior to sexual activity. After 9 weeks, some patients (half of the active patients) continue treatment with dapoxetine and other (another half of the active patients) are switched to placebo for the last week of therapy, abruptly stopping the study drug. Assessments of effectiveness include the incidence of withdrawal symptoms, assessed by changes in DESS; control over ejaculation, satisfaction with sexual intercourse, and severity of symptom impressions, based on questions asked at specified intervals during the study. Safety assessments include the incidence, severity, and type of adverse events throughout the study, as well as laboratory tests and questionnaires to monitor sexual function at specified times during the study.The study hypothesis is that abruptly stopping treatment with dapoxetine in men with PE does not result in an increase in withdrawal symptoms (as assessed by DESS), compared with the men who stay with the treatment. Oral tablets of dapoxetine (60 milligrams) taken once daily and also as needed during 10 weeks of treatment. No more than 1 tablet for daily treatment and 1 as-needed tablet within a 24-hour period.

Inclusion Criteria:

• Patient is in a stable, monogamous sexual relationship with the same woman for at least 6 months and plans to maintain this relationship for the duration of the study
• diagnosis of premature ejaculation (PE) according to the criteria of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) for at least 6 months before study initiation
• experience PE in the majority of sexual intercourse events
• good general health at study initiation
• patient and partner willing to avoid situations or activities that may have an effect o their sexual activity (for example, avoid pregnancy, refrain from any preplanned surgery)

Exclusion Criteria:

• Not taken dapoxetine or participated in another study investigating pharmacologic treatment of PE within the last 3 months
• no history of any medical events such as surgery, injury, infections, or neurological conditions that are associated with the development of PE
• not taken an investigational drug within 1 month, or used an experimental medical device within 6 months, of study initiation
• no positive diagnosis of depressive or anxiety disorder, manic episode, panic disorder, obsessive-compulsive disorder, posttraumatic stress disorder, alcohol abuse and dependence, schizophrenia, or other psychotic disorders
• no known allergy or hypersensitivity to selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs)