WEDNESDAY, Sept. 27 (HealthDay News) -- Amgen's Vectibix (panitumumab) was approved by the U.S. Food and Drug Administration on Wednesday for people with colorectal cancer that has spread to other body sites.

Vectibix -- a type of drug known as a monoclonal antibody -- binds to a protein on certain cancer cells and may slow or stop the growth of some tumors.

In clinical testing involving 463 people who had undergone chemotherapy due to metastatic cancer of the colon or rectum, the average time to disease progression or death was 96 days, versus 60 days among people who didn't get the drug, the FDA said in a statement. In addition, 8 percent of users experienced a shrinkage in tumor size -- in some cases by more than 50 percent.

As a condition of approval, Amgen is required to conduct additional research to find out whether survival will improve among Vectibix users with fewer chemotherapy sessions than participants in previous studies.

This year, an estimated 150,000 new cases of colorectal cancer will be diagnosed, causing 55,000 deaths, the agency said.

More information

To learn more about colorectal cancer, go to the American Cancer Society.