Phase I and phase II clinical trials for the treatment of male sexual dysfunction—a systematic review of the literature

ABSTRACT

Introduction: The prevalence of sexual dysfunctions has increased over the last decades; despite a number of available treatments for erectile dysfunction (ED), premature ejaculation (PE), and Peyronie’s disease (PD), still several unmet therapeutic needs deserve to be fulfilled. The aim of this review is to detail on phase I and II clinical trials investigating novel medical treatments for ED, PE, and PD.

Areas covered: We conducted a systematic review of the literature including both published and ongoing phase I and II registered trials focused on medical treatment of ED, PE, and PD during the last 5 years. A total of 35 trials have been identified. Most studies (63%) investigated ED treatments and 26% were still ongoing. Stem cells (SCs) therapy was assessed in 28% of trials.

Expert opinion: SCs therapy represent a promising treatment for ED although only few patients have been treated to date. Likewise, the oral selective oxytocin receptor antagonists for treating PE showed excellent safety profile and deserve further investigations in phase III trials. Preliminary results of novel topical treatments for PD with fibrinolytic and antiinflammatory drugs are encouraging, but urgently need to be confirmed in large placebo-controlled trials.

KEYWORDS:

• Sexual dysfunction
• drugs
• erectile dysfunction
• premature ejaculation
• Peyronie’s disease

Article Highlights

• There are several unmet needs in the field of ED, PE, and PD treatment.

• The first four human trials on SCs therapy for ED showed promising results. Overall, a small number of patients have been treated to date, but further trials are still ongoing.

• The first human trial on gene transfer therapy for ED has been recently published, showing the overall safety of this novel therapeutic strategy. Future phase II and III trials are deserved.

• Clinical research in the field of PE has been mainly focused on SSRIs; however, the novel selective oxytocin inhibitors showed a good tolerability profile and encouraging efficacy results in phase I and II trials.

• Current available medical treatments for Peyronie’s disease are still insufficient; novel topical antiinflammatory and fibrinolytic drugs look promising, but deserve validation in larger placebo-controlled trials. The results of the first human trial on SCs therapy for PD encourage the research in this field.

Declaration of Interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.