In the first human trial to investigate gene transfer as a treatment for impotence, also referred to as erectile dysfunction, the approach appeared to be safe and provided some evidence that it is effective, according to findings presented at the American Urological Association annual meeting in Atlanta.
The advantage of gene transfer over treatment with drugs, such as sildenafil, is that "you don't need to plan to take the drug before you want to have sex," lead researcher Dr. Arnold Melman, a urology professor at Albert Einstein College of Medicine in New York and co-founder of Ion Channel Innovations, told Reuters Health.
Nine men with erectile dysfunction received a penile injection of a DNA formulation that contained a gene for a subunit of a potassium channel (hMaxi-K). The men were divided into three groups and given a dose of 500, 1000, or 5000 micrograms of hMaxi-K.
The findings from animal studies have suggested that increased expression of this gene can improve smooth muscle relaxation and restore erectile function. The main focus of this study, however, was to simply "establish the feasibility and safety of gene transfer for erectile dysfunction in humans," Melman said during a media briefing.
During the 6-month study, none of the men experienced adverse events or changes in laboratory tests suggesting possible harm. In addition, there was no evidence that hMaxi-K wound up in the semen.
Although establishing the safety of this gene transfer method was the major study objective, significant improvements in erectile dysfunction were noted, particularly at the higher doses, Melman said.
These findings pave the way for phase II studies to establish the effectiveness of this gene transfer approach, he concluded.