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Restorative therapy clinical trials for erectile dysfunction: a scoping review of endpoint measures


Given the lack of regulatory approval for restorative therapies for the treatment of erectile dysfunction, we hypothesized that clinical trials would vary in methodology and endpoint measurements. Our objective was to analyze methodological approaches and outcome measures of clinical trials evaluating restorative therapies for erectile dysfunction. Data was extracted from on trials which contained the keywords “erectile dysfunction”. We evaluated trials initiated between 2004 and 2021 which listed a restorative therapy intervention. We identified 95 trials investigating energy-based/shockwave therapies (60/95), stem cell therapies (25/95), platelet-based therapies (6/95), and others (4/95). Only 41.1% of the trials evaluated safety. The most common efficacy endpoint was International Index of Erectile Function and Sexual Health Inventory for Men, and only 29.5% utilized penile Doppler. Thirty (31.6%) trials had been completed yet only 3 (3.2%) have published results. We found substantial heterogeneity in methodological approach in the trials. Subjective measures of erectile function were commonly reported, but definitions of inclusion criteria and objective outcome measures were inconsistent. These results provide a basis for the design of future clinical trials to improve the quality of trial data and aid in the development of standardized criteria for erectile dysfunction clinical trials.

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Fig. 1: Restorative therapies used in clinical trials.
Fig. 2: Common endpoints assessed in clinical trials.

Data availability

The data that support the findings of this study are available from


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This work was supported by National Institutes of Health Grant R01 DK130991 and Clinician Scientist Development Grant from the American Cancer Society.

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RS conceived of the research question that led to the submission, acquired data, and helped draft the manuscript. RG acquired data and helped draft the manuscript. TM contributed to interpretation of the results and revised the manuscript. AS helped with interpretation of results and revised the manuscript. RR helped interpret the results and revised the manuscript. All authors approved of the final version of the manuscript and agreed to be accountable for all aspects of the work to ensure that questions related to accuracy or integrity of any part of the work are appropriately investigated and resolved.

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Correspondence to Ranjith Ramasamy.

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Saltzman, R.G., Golan, R., Masterson, T.A. et al. Restorative therapy clinical trials for erectile dysfunction: a scoping review of endpoint measures. Int J Impot Res (2022).

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