Tuesday, March 16, 2010

Xiaflex - one more step towards use with Peyronie's

Years away for use with penile fibrosis, but still worth following...
Triumph for Xiaflex, Drug to Straighten Clenched Fingers - NYTimes.com

... The Food and Drug Administration approved ... Xiaflex, last month as a nonsurgical treatment for Dupuytren’s contracture, a condition in which one or more fingers cannot be straightened.

Xiaflex, an injectable drug that goes on sale later this month, will not be cheap, at an estimated average cost per course of treatment of $5,400. But analysts expect sales to reach hundreds of millions of dollars a year.

And that total could go higher, if Xiaflex eventually wins approval for a related condition known as Peyronie’s disease, in which a bent penis makes intercourse painful or even impossible.

About one in 20 men is estimated to have Peyronie’s, but figures are not precise because people with the condition tend not to discuss it publicly...

... Some people treated with Xiaflex in clinical trials for the Dupuytren’s hand condition said it had made a big difference in their lives, and had allowed them to avoid painful surgery.

“When I looked down and saw my finger straightened out, I cried,” said Kenneth Nelson, 65, of Indianapolis. “It was to me just like a miracle.”

Xiaflex is an enzyme produced by a gangrene-causing bacterium, Clostridium histolyticum, which uses it to eat away the tissues of its victims. The enzyme, called collagenase, breaks down collagen, a major component of the body’s connective tissue that is found in skin, tendons, cartilage and other organs.

But collagenase by itself does not cause gangrene. And there are times doctors need to break down collagen, such as when an excess builds up in the hand or penis, causing Dupuytren’s and Peyronie’s. The ailments are named for French surgeons who described the conditions in the 18th and 19th centuries...

... Auxilium sought approval for treating Dupuytren’s first because it was easier to measure success in straightening fingers. But the company hopes to begin late-stage trials of Xiaflex for Peyronie’s disease later this year. In a midstage trial, injections of Xiaflex into the collagen plaque in the penis reduced the curvature. But the drug did not reduce pain or discomfort during intercourse by a statistically significant amount.

While collagenase itself is not patented, the companies do have patents on the use of the enzyme to treat Dupuytren’s and Peyronie’s. They are also shielded from competition for seven years under a federal law aimed at spurring development of drugs for rare, or “orphan,” diseases — even though newer estimates suggest these two diseases are not as rare as thought when the drugs were given orphan status...
This has been discussed for some time, so this is more of a milestone than major news. My suspicion is that if it does work at all, it will work best for persons early in the disease. Penile fibrosis appears to destroy tissues that will not regenerate, so even clearing the fibrosis does not mean restoring function.