Mon 4 Jun, 2012 02:47 pm
June 3, 2012
Treatment for Penis Curvature Sees Results
By ANDREW POLLACK
It can be painful and embarrassing for men: a disease that causes a curvature of the penis that makes intercourse difficult or impossible.
Now a drug company says it may have an effective treatment.
Auxilium Pharmaceuticals says that its drug Xiaflex succeeded in two late-stage clinical trials, which could put the product on a path to become the first medicine approved on the basis of solid evidence for the condition, Peyronie’s disease.
In both trials, injections of Xiaflex reduced the curvature by significantly more than placebo injections, according to a news release expected to be issued by the company Monday morning. And in both trials the drug also reduced how bothered the men felt about their condition significantly more than the placebo did.
The results “are not overwhelming and dramatic,” said Dr. Culley C. Carson III, a professor of urology at the University of North Carolina and an investigator in the trial. But, he added, “it’s a major advantage over what we have now, which is nothing.”
Named after the French surgeon who described it in 1743, Peyronie’s disease is identified by a fibrous plaque in the penis that can cause curvature during an erection.
Auxilium, which is based in Malvern, Pa., says that 5 percent of men have Peyronie’s, though estimates vary, and many men who have it are thought not to reveal that. Only a fraction of those with plaque have curvature, however. Citing medical claims data, Auxilium estimates that 65,000 to 120,000 American men receive such a diagnosis each year.
Various oral or injected treatments are used, though the evidence in support of them is weak, Dr. Carson said. A drug called Potaba, which reached the market before the Food and Drug Administration required proof of effectiveness, says on its label that it is “possibly effective.” For severe cases, surgery is an option, although it can lead to erectile dysfunction and a shortening of the penis.
The two trials, each with more than 400 patients in the United States and Australia, were virtually identical in design and had fairly similar results.
In one trial, for instance, the average curvature for men treated with Xiaflex went from 48.8 degrees at the start of the study to 31.0 degrees a year later, an improvement of 37.6 percent. A 20 percent improvement is considered medically meaningful.
In the control group the curvature went from 49.0 degrees to 39.0 degrees, an improvement of 21.3 percent.
Xiaflex is derived from an enzyme that a gangrene-causing bacterium uses to eat away at the tissues of its victims. The enzyme breaks down collagen, a component of the penile plaques.
Treatment could involve up to eight injections into the penile plaque over the course of several months. The injections can cause pain, swelling and hematomas, a collection of blood. The doctor would also manipulate the penis by hand to help break up the plaque.
Xiaflex was approved in 2010 to treat Dupuytren’s contracture, a disease in which fingers are permanently bent inward toward the palm. Sales of $42 million last year in the United States fell short of expectations, though the company expects the figure to grow to around $60 million this year.
Pfizer sells the drug outside the United States. BioSpecifics Technologies of Lynbrook, N.Y., which initially developed the drug, earns royalties on its sales.
One reason for the disappointing sales is that hand surgeons, the doctors mainly using the drug, are reluctant to give up surgery, for which they get paid more than for injecting Xiaflex. That might not be such a problem for Peyronie’s because the surgery is not attractive to either doctors or their patients.