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Clinical Trial Methodology in Premature Ejaculation Observational, Interventional, and Treatment Preference Studies—Part II—Study Design, Outcome Measures, Data Analysis, and Reporting


Chris G. McMahon, MBBS, FAChSHM, Australian Center for Sexual Health, St Leonards, New South Wales, Australia. Tel: +61 (02) 94373906; Fax: +61 (02) 99065900; E-mail:


Introduction.  Regulatory approval of new drug treatments for premature ejaculation (PE) demands evaluation in well-designed clinical efficacy and safety randomized clinical trials (RCTs).

Aims.  The objective of this article was to make recommendations for trial design and efficacy outcome measures which comprise ideal PE observational, interventional, and treatment preference trial methodology.

Main Outcome Measures.  Published data on clinical trial design, epidemiology, definitions, dimensions, and psychological impact of PE.

Methods.  Data on the epidemiology, definitions, dimensions, and psychological impact of PE were reviewed, critiqued, and incorporated into a series of recommendations for standardization of PE clinical trial design, outcome measures, and reporting using the principles of evidence-based medicine.

Results.  PE observational trials should be prospective and should provide quantitative or qualitative data derived from objective outcome measurements and/or the results of subject interview and other trial-specific investigations for analysis. PE drug trials should employ a double-blind RCT methodology and should include placebo control, active standard drug control, and/or dose comparison trials. Application of the placebo concept to psychotherapy intervention trials is complex and fraught with both conceptual and pragmatic problems. Criteria for the ideal PE preference trial are not yet determined but are likely to be a double-blind, crossover RCT of treatment-naive subjects using randomized drug sequences of equivalent drug doses. Ejaculatory latency time (ELT) and subject/partner outcome measures of control, personal/partner/relationship distress, and other study-specific outcome measures should be used as outcome measures. There is currently no published literature which identifies a clinically significant threshold response to intervention.

Conclusion.  Data from PE observational, interventional, and preference studies are only reliable, interpretable, and capable of being generalized to patients with PE when derived from well-designed observational studies or intervention RCTs using ELT and subject/partner-reported outcome measures of perceived ejaculatory control and personal/partner/relationship distress are used as trial outcome measures. McMahon CG. Clinical trial methodology in premature ejaculation observational, interventional, and treatment preference studies—Part II—Study design, outcome measures, data analysis, and reporting. J Sex Med 2008;5:1817–1833.

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