Switching Off Resistant Colon Cancer

Colorectal cancer resistant to cetuximab is treatable with panitumumab

(RxWiki News) A study shows that patients who have colon cancer that is no longer responding to therapy may benefit from switching to a similar drug in the same class.

Of the two colon cancer drugs, Erbitux (cetuximab) is more commonly used. However, resistance to the drug is also common.

Now researchers have shown that for these patients with a resistant cancer, switching to Vectibix (panitumumab) is a valid option.

"Ask your oncologist about the medications you're taking."

A team from Spain's Hospital del Mar has demonstrated that while both Erbitux and Vectibix target the same molecule in colon cancer, resistance to one drug does not mean the end of treatment.

A newer class of drugs called a monoclonal antibody, both of these drugs target the growth signal molecule EGFR, which is commonly found on cancer cells.

Clara Montagut, M.D., a researcher from the Institut Municipal de Investigacion Medica (IMIM) in Spain, concluded, "These results justify developing tests to detect this mutation in patients that are being treated with cetuximab for colorectal cancer.

Later studies shall also have to validate whether this mutation contributes to acquiring a resistance to cetuximab in tumors for which it is also used, such as head and throat cancer," Dr. Montagut said.

Both drugs were approved by the FDA in 2006. Erbitux costs about $15,000 a month, while Vectibix runs close to $8,000 per month.

Results were published in the journal Nature Medicine.

Authors of the study declared no competing financial interests.