Amgen's (NASDAQ:AMGN) cancer drug Nexavar is going to reach a broader market. Today, the Food and Drug Administration widened its approval for the drug to include its use in the treatment of several forms of late-stage differentiated thyroid cancer. The decision follows a priority review by the regulator, a process reserved for treatments that "may offer a significant improvement in treatment over existing options," in Amgen's words.

The thyroid is a gland located in the neck. Nexavar functions by inhibiting multiple proteins in cancer cells. This limits the growth and division of such cells.

There is a patient base for the drug. According to the FDA, for 2013 around 60,220 Americans will be diagnosed with thyroid cancer. Of that number, roughly 1,850 will die from it.