A drug in development at US drugmaker Johnson & Johnson has taken a step closer to becoming the first treatment for the estimated third of men who suffer from premature ejaculation, if positive results from a Phase III trial are backed up in further studies.

The drug, called dapoxetine, is a member of the selective serotonin reuptake inhibitor class, the widely used antidepressant group that includes drugs such as GlaxoSmithKline’s Paxil (paroxetine) and Eli Lilly’s Prozac (fluoxetine). J&J’s decision to develop dapoxetine for premature ejaculation stemmed from the discovery that delayed ejaculation was a side effect of SSRIs used to treat depression.

The results of the 12-week Phase III trial, presented at the American Urological Association annual meeting in San Antonio, Texas, showed that dapoxetine tripled the duration of intercourse in men who had been with the same partner for at least six months and persistently suffered from PE. The men were given either 30mg dapoxetine, a 60m dose or placebo for 12 weeks, and the results suggested that the beneficial effect on premature ejaculation was observed after the first dose and increased over the course of the study period.

Dapoxetine has already been filed for approval in the USA by J&J subsidiary Ortho-McNeil Pharmaceuticals, but the company says it has not yet decided whether to make similar applications in Europe. It is perhaps mindful of the difficulties Pfizer had in persuading European health systems to reimburse its erectile dysfunction treatment Viagra (sildenafil) on the grounds that it was a so-called ‘lifestyle’ drug [[16/10/01g]].

The lead researcher in the study, Dr Jon Pryor of the University of Minnesota, said: “The impact premature ejaculation can have on men and their partners can be devastating for a relationship and, currently, there are no truly optimal therapies for premature ejaculation

Premature ejaculation is estimated to affect between 27% and 34% of men, according to the AUA, two to three times the incidence of erectile dysfunction.