WASHINGTON (February 25, 2013)--The U.S. Food and Drug Administration is expanding approval of the Bayer cancer drug Stivarga to treat tumors of the intestinal tract that don't respond to other treatments.

Regulators approved the drug to treat gastrointestinal stromal tumors that cannot be surgically removed and that no longer respond to other FDA-approved drugs.

The FDA previously approved Stivarga to treat colorectal cancer.

It works by blocking several enzymes that promote cancer growth.

The FDA approved the drug for the new use based on a study of nearly 200 patients who were randomly assigned to take Stivarga or a placebo pill.

Patients taking the drug experienced a nearly four month delay in the growth of their tumors compared to taking placebo.