Perrigo Co. said Wednesday it filed an application with the Food and Drug Administration to make a generic version of the Abbott Laboratories testosterone gel Androgel 1 percent.
Perrigo, based in Allegan, Mich., said the gel had $900 million in annual sales last year.
It treats men with low levels of testosterone. Low testosterone is associated with fatigue, depression and various sexual dysfunctions.
Androgel is one of the oldest testosterone replacement products on the market. It was first launched in 2000.
In April, North Chicago-based Abbott said it received regulatory approval for a more potent formulation of the gel, Androgel 1.62 percent.
Drug companies are increasingly targeting low testosterone as a new market opportunity. About 14 million American men are believed to have irregularly low testosterone levels.
Perrigo said Abbott has filed a lawsuit against it in the U.S. District Court for the District of New Jersey alleging patent infringement.
Shares of Perrigo climbed 96 cents to $89.11 in afternoon trading, while the Nasdaq exchange rose less than 1 percent. Abbott shares were up 12 cents to $52.88.