The Food and Drug Administration (FDA) approved Auxilium Pharmaceuticals Inc.’s Xiaflex (collagenase clostridium histolyticum) for the treatment of Peyronie’s disease, a painful curvature of the penis. This repurposed drug was first approved by the FDA in 2010 and has been used since then to successfully treat Dupuytren’s contracture, a progressive hand disease that affects a person’s ability to straighten their fingers. Xiaflex is the first FDA-approved medicine to treat Peyronie’s disease.

“Today’s approval expands the available treatment options for men experiencing Peyronie’s disease, and enables them, in consultation with their doctor, to choose the most appropriate treatment option,” Dr. Audrey Gassman, deputy director of FDA’s Division of Bone, Reproductive and Urologic Products, stated in a press release.

In the case of Peyronie’s disease, Xiaflex works by breaking down the scar tissue, made of collagen, that develops under the skin of the penis and causes an abnormal bend of at least 30 degrees upon erection. Xiaflex is a biologic; such medicines are not chemically synthesized but created from biological processes. In this case, Xiaflex is made from collagenase clostridium histolyticum, which is an enzyme produced by a bacteria known to destroy collagen. The drug is administered by injection with no surgery or general anesthesia required.

"In my practice, treating [Peyronie's disease] has been a challenge as, until now, we have had few options to offer our patients," Dr. Martin K. Gelbard, UCLA School of Medicine, Department of Urology, stated in a press release

Two studies in 832 men with Peyronie’s disease established the safety and effectiveness of Xiaflex for the treatment of Peyronie’s disease. After participants were given up to four treatment cycles of Xiaflex or placebo, they were followed for a year. Compared with a placebo, Xiaflex treatment significantly reduced penile curvature deformity and related bothersome effects. The most common side effects associated with use of Xiaflex for Peyronie’s disease included penile hematoma, penile swelling, and penile pain. When prescribed for the treatment of Peyronie’s disease, Xiaflex is available only through a restricted program because of the risks of serious reactions, including penile fracture and other serious injury.

The cause of Peyronie's disease is unknown and though the condition is uncommon it usually affects men over the age of 40. It is known that fracture or injury during intercourse can lead to this condition. It can also occur in conjunction with Dupuytren’s contracture, however, relatively few people with Dupuytren's contracture develop Peyronie’s. Men with this condition have a certain type of immune cell marker, which indicates that it may be inherited. When newborn males have a curvature of the penis, it is different from Peyronie’s disease and may be part of another abnormality known as hypospadias in which the opening of the urethra is on the underside of the penis, instead of at the tip.

Auxilium Pharmaceuticals, which is based in Pennsylvania, was founded in 1999 to develop and market pharmaceutical products that focus on urology and sexual health.