Anika Therapeutics Inc. said the U.S. Food and Drug Administration approved its drug to treat pain and improve joint mobility in patients with osteoarthritis of the knee.

The company said the drug will be marketed in the United States by Depuy Synthes, a unit of Johnson & Johnson.

Anika said it would receive a $5 million milestone payment from DePuy Synthes on the first sale of the drug, Monovisc.

The company said it would also get milestone payments as well as product transfer and royalty fees.

In aftermarket trading Tuesday, the company's shares were up 20 percent at $41.40, after ending the regular Nasdaq session little changed.