Gene transfer appears safe as treatment for erectile dysfunction

[unseennude]

In the first human trial to investigate gene transfer as a treatment for erectile dysfunction (ED), this new modality appeared safe and showed some evidence of efficacy, according to findings presented Monday at the American Urological Association annual meeting in Atlanta.

"The advantage of gene transfer over PDE5 inhibitors (like 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. The benefits of a single treatment are maintained for several months.

In the current study, 9 men with established ED were given an intracavernous injection of a naked DNA plasmid vector (hMaxi-K) containing a gene for a subunit of a potassium channel. The men were divided into three groups and given a dose of 500, 1000, or 5000 micrograms of hMaxi-K.

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 the present study, however, was simply "to establish the feasibility and safety of gene transfer for ED in humans," Dr. Melman said during a media briefing.

During the 6-month study, none of the men experienced gene transfer-related adverse events or significant changes in laboratory tests. In addition, there was no evidence that hMaxi-K wound up in the semen.

Although safety was the principal endpoint for the study, significant improvements in ED were noted, particularly at the higher doses of hMaxi-K, Dr. Melman said.

The current findings pave the way for phase II studies designed to establish the efficacy of hMaxi-K gene transfer over placebo, he concluded.