Amgen Inc.’s metastatic colorectal cancer drug Vectibix won approval for a label expansion from the U.S. Food and Drug Administration, the company announced Thursday.

The Thousand Oaks biotech said Vectibix is now approved for patients with wild-type RAS in colorectal cancer.

There are few biomarkers in colorectal cancer. Doctors usually study mutations in a gene that’s about to become cancerous (KRS), or enzymes encoded by genes (NRAS). When there is a mutation in both KRS and NRAS, it’s defined as wild-type RAS.

In short, Vectibix is now approved to treat patients with different types of metastatic colorectal cancer, possibly increasing the use of the drug.

Shares of Amgen (AMGN) on Friday closed down 36 cents, or less than 1 percent, to $172.23 on the Nasdaq.