Variability in Methodology of Erectile Dysfunction Regenerative Therapy Trials on ClinicalTrials.gov

To evaluate the variability in the criteria of erectile dysfunction (ED) regenerative therapy trials registered on ClinicalTrials.gov.

Interventional trials on ClinicalTrials.gov with the keywords "erectile dysfunction" and variations of "shockwave," "platelet rich plasma," "stem cell," "regenerative," and "restorative" were examined. Inclusion/exclusion criteria and primary/secondary outcomes were compared between extracorporeal shockwave therapy (ESWT), platelet rich plasma and stem cell injections (PRP/SC), and other regenerative therapies (ORT) groups.

Of the 92 trials analyzed, International Index of Erectile Function (IIEF) score was the most common primary outcome (72%), with a higher prevalence in ESWT trials than PRP/SC or ORT trials (89% vs 44% and 58%, P <.001). Safety/tolerability was a primary outcome for 44% of PRP/SC trials and 25% of ORT trials but no ESWT trials (P <.001). ESWT trials more frequently had sexual/romantic relationship-based inclusion criteria and cancer treatment-related exclusion criteria than PRP/SC and ORT trials.

There is substantial variability in the inclusion/exclusion criteria and outcome measures among ED regenerative therapy trials. ESWT trials most frequently utilized IIEF and had the strictest inclusion/exclusion criteria, suggesting more rigorous and functional outcome-based studies. Conversely, PRP/SC and ORT trials, but not ESWT trials, had safety/tolerability as a primary outcome, likely due to the experimental nature of these therapies. The variability in inclusion/exclusion criteria and outcome measures limits comparison of the various ED regenerative therapies.