Introduction: Given the current lack of regulatory agency approval for any restorative therapies for the treatment of erectile dysfunction (ED), the American Urological Association (AUA) and Sexual Medicine Society of North America (SMSNA) established positions statements on the use of restorative therapies for ED. Restorative therapies should only be “conducted under research protocols in compliance with Institutional Review Board approval”. Our objective was to analyze methodological approaches and outcome measures of clinical trials evaluating restorative therapies for ED.
Methods: Data was extracted from clinicaltrials.gov, the largest database of clinical trials overseen by the US FDA, on 10/27/2021 and included all trials which contained the study disease keywords ‘erectile dysfunction’. We evaluated trials initiated between 2004 and 2021 which listed a restorative therapy as the intervention, including energy-based/shockwave therapies, platelet-rich plasma, and stem cell therapy (SCT), among others. We examined multiple parameters to provide our descriptive analysis.
Results: We identified 515 trials for ED in the clinicaltrials.gov database. Of these, 95 (18%) investigated a restorative therapy. The trials investigated the effects of energy-based therapies (60/95), SCT (25/95), platelet-based therapies (6/95) or others (4/95). A total of 15,839 male participants were enrolled or are anticipated for enrollment into these restorative therapy trials.
The majority of these trials were conducted at a single-center (81%) and were open-label (49.5%). Only 31% were double-blinded, 63% included randomization, and 51% were conducted in an academic setting. Only 41% of the trials evaluated safety. The most common efficacy endpoint was International Index of Erectile Function (IIEF) and Sexual Health Inventory for Men (SHIM), and only 30% utilized penile Doppler.
A total of 30 (31.5%) trials were completed yet only 3 (3.2%) have available results. Among these, enrollment (=80% planned sample size) was achieved in one trial (1/3), and retention (=75% enrolled subjects) occurred in 2 of the 3 trials.
Conclusions: There is substantial heterogeneity in methodological approach in clinical trials evaluating restorative therapies for ED. Subjective measures of erectile function are commonly reported, but definitions of inclusion criteria and objective outcome measures are 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 ED clinical trials.
Source of Funding: This work was supported by National Institutes of Health Grant R01 DK130991 and Clinician Scientist Development Grant from the American Cancer Society to RR.
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