Introduction: The manufacturer of dapoxetine funded randomized clinical trials to study its effect in premature ejaculation (PE). Financial support by pharmaceutical companies, however, may jeopardize the neutrality of clinical research.
Aim: To investigate the scientific process that has been followed in dapoxetine treatment trials and reviews as compared to daily drug treatment trials and reviews with selective serotonin reuptake inhibitors (SSRIs) in men with PE.
Methods: A search of Medline and Embase was conducted using the search terms "dapoxetine" or "SSRI." References of retrieved articles were searched. Only studies describing the use of these drugs in men with PE were included. Main Outcome Measures. Compared fold-increase intravaginal ejaculation latency time (IELT), geometric mean IELT, and adverse effect profiles between dapoxetine and SSRIs in PE.
Results: Preclinical studies on dapoxetine, including a multicenter study (category A) and reviews (category B), were compared with clinical studies with daily conventional SSRIs in PE (category C). Categories A/B focused on patient-reported outcomes with less attention for the IELT. The ejaculation-delaying effect of dapoxetine was expressed as natural mean IELT rather than as geometrical mean IELT. Dapoxetine side effects were monthly scored. In contrast, a significant part of category C articles focused on IELT data, used geometric mean IELT outcomes, and one study reported the side effects measured 24-48 hours after drug intake using a validated questionnaire. Without the Food and Drug Administration approval, dapoxetine, as well as other SSRIs in PE, is an off-label drug for PE. However, the off-label use of dapoxetine has never been criticized by clinical investigators in contrast to commentaries against the off-label use of daily SSRI treatment in PE.
Conclusions: Manufacturer-funded drug treatment research (categories A and B) is advantageously treated by some authors as compared with nonfunded trials with daily conventional SSRIs (category C). PE drug treatment research is a young and dynamic field, and its development deserves transparency to its development.