Dec 6 (Reuters) - U.S. health regulators on Friday approved Auxilium Pharmaceuticals Inc's Xiaflex injections to treat a condition that causes a painful curvature of the penis called Peyronie's disease.

It marks the second U.S. approval for Xiaflex, which in 2010 received a Food and Drug Administration nod to treat Dupuytren's contracture - a condition in which hardening of the connective tissue collagen in the hands bends fingers toward the palm, leaving a patient unable to straighten their hands or use their fingers properly.

Xiaflex is now the first FDA-approved non-surgical treatment option for men with Peyronie's disease who have a plaque buildup in the penis that results in a curvature deformity of at least 30 degrees upon erection, the agend.

The drug is injected directly into the collagen buildup to break it down in order to help restore normal function to the penis or hands.