Considerations in the design of clinical trials for erectile dysfunction

The naissance of the phosphodiesterase-5 inhibitors has dramatically fueled the research engine in pursuit of novel therapies for erectile dysfunction (ED). The epidemiological product of reports on penile implants, to multicenter, randomized, double-blinded, placebo-controlled trials on oral therapy and intracavernosal/intraurethral injection therapy, has translated into substantial assets for the treatment of patients with ED. However, at the heart of this issue, is that prior to the imbursement of effective and safe advents, investigators must consider several key points in the design stages of clinical trials. The scope of the following review of the ED literature over the past two decades represents a methodological approach and a prospective quest for enriching current quality of evidence, focusing on considerations in the design stages of Phase III clinical trials of ED and highlighting the emphasis that needs to be placed in the process of subject enrollment, partner involvement and standardization of outcome assessment.