The U.S. Food and Drug Administration approved Xiaflex (collagenase clostridium histolyticum) as the first drug to treat a progressive hand disease known as Dupuytren's contracture, which can affect a person's ability to straighten and properly use their fingers.

Dupuytren's contracture affects the connective tissue found beneath the skin in the palm of the hand. Too much collagen can build up, forming thick, rope-like cords of tissue that can prevent the fingers from being able to relax and straighten normally. The disorder is most common in Caucasians and in men over age 50.

Xiaflex is a biologic drug made from the protein product of a living organism. It works by breaking down the excessive buildup of collagen in the hand.

Xiaflex is injected directly into the collagen cord of the hand and should be administered only by a health care professional experienced with injections of the hand, because tendon ruptures may occur.

The most common adverse reactions in patients treated with Xiaflex were fluid build up, swelling, bleeding, and pain in the injected area. Although no serious allergic reactions have been observed, such a response would not be unexpected because this foreign protein could prompt an immune system reaction.

In one 66-patient study, 44 percent of those injected with Xiaflex were treated successfully, compared to 5 percent for patients who received a placebo. In a separate 306-patient study, 64 percent of patients given Xiaflex were treated successfully, compared to only 7 percent of patients receiving the placebo.

Xiaflex is manufactured by Auxilium Pharmaceuticals Inc., a specialty biopharmaceutical company based in Malvern, Penn.