Gene Therapy and Erectile Dysfunction
The first three patients participating in an early test of a "revolutionary" human gene therapy for erectile dysfunction have not developed any treatment-related side effects, according to preliminary results released here this week at a meeting of the International Society for Sexual and Impotence Research.
Dr. Albert Melman, of the Albert Einstein College of Medicine in New York, and colleagues are testing the safety of a single penile injection of a gene called maxi-K. The trial was launched in the spring of 2004 at the Mount Sinai School of Medicine in New York.
Maxi-K "channels" on the surface of cells are involved in diminishing smooth muscle contraction, which eventually leads to relaxation and erection.
The approach has already been tested successfully in rats with induced erectile dysfunction.
The three volunteers in the initial trial had moderate to severe erectile dysfunction. They were given injections of low doses of the maxi-K. After 1 and 5 months, none of the men had developed any side effects, the researchers found.
According to Melman, six more patients will be recruited and tested by the end of this year. A trial to test effectiveness of the erectile dysfunction therapy might start by the end of 2005, and eventually about 400 patients will participate in clinical trials before the treatment is submitted for FDA approval.
The therapy might become available "within the next 7 to 8 years," Melman said. It is estimated that each dose will cost around $400, and booster injections might be needed every 6 months.
"In the best case, the method will work by itself. On the other hand, you might be able to use lower doses of Viagra, Cialis or Levitra or improve their efficacy," Melman said.
"If it works, it will be revolutionary ", he added.
"Dr. Melman is a pioneer," commented Dr. Nestor Gonzalez-Cadavid, a UCLA researcher. "If he succeeds, the whole field of gene therapy for erectile dysfunction treatment will be stimulated."
Gonzalez-Cadavid is studying the effects of another gene therapy for erectile dysfunction in rats, and plans to begin his own clinical trials within the next 2 to 3 years.