U.S. regulators approved the first drug treatment for Peyronie's disease, a painful condition causing severe curvature of the penis, mostly in older men, that often leads to depression and an inability to have sex.

Peyronie's is caused by untreated inflammation of the penis that occurs through injuries obtained during sex that don't heal correctly. The drug, called Xiaflex, works by breaking down a buildup of scar tissue underneath the skin that causes the penis to curve as much as 90 degrees when erect. Some men are treated...