Amgen Inc. on Friday announced its anemia drug Nplate received an orphan drug designation.

The designation refers to a drug in development to treat a medical condition so rare that it isn’t considered profitable to produce without government assistance.

If approved for treatment, Amgen’s drug would have seven years’ market exclusivity.

Shares of Amgen (AMGN) closed Friday up 18 cents, or a fraction of one percent, to $234.72 on the Nasdaq.