No safety problems were seen in the 11 men with ED who got the gene therapy treatment two years ago, notes Arnold Melman, MD, professor and chairman of the urology department at New York's Albert Einstein College of Medicine.
The men got an injection of a human gene, called the Maxi-K gene, into their penis.
"The gene produces a protein that makes the Maxi-K channel. And when that channel is open, it causes the smooth muscle cells to relax," helping to facilitate erections, Melman tells WebMD. "What we're doing is correcting a problem that's induced by aging and disease."
The tests on people have been primarily focused on safety. Tests on monkeys show that the therapy does increase erectile function and other measures of sexual behavior.
Melman predicts that men with ED would get the gene therapy treatment twice a year, based on research on animals and people showing that the treatment last for about six months.
"The advantage of it is that you don't have to plan on doing anything," Melman says. "It naturalizes the event, so people can have sex without having to take a pill or inject themselves."
The gene therapy also appears to work "synergistically" with drugs such as Viagra and Cialis, "so that you can perhaps use a lower dose ... if you have these genes on board," Melman says.
Melman is a directing member of Ion Channel Innovations, the company that is developing the gene therapy treatment. He and his colleagues are also studying the Maxi-K gene therapy for the treatment of overactive bladder.