Update from 2008 ASCO Meeting in Chicago
Three studies reported during the 2008 American Society of Clinical Oncology found that colorectal cancer patients whose tumors have mutated KRAS genes do not benefit from treatment with the EGFR-inhibitor Erbitux® (cetuximab).
At the same time, patients with tumors that aren’t aren’t mutated (wild-type) have significantly better results when Erbitux is added to either FOLFIRI or FOLFOX chemotherapy.
Two randomized trials of initial treatment of chemotherapy with or without Erbitux found responses and improved progression-free survival only in patients with wild-type KRAS. The CRYSTAL Phase III study compared FOLFIRI to FOLFIRI with the addition of cetuximab. The Phase II OPUS trial used FOLFOX as chemotherapy and compared FOLFOX to FOLFOX plus cetuximab. Neither found benefit for patients whose tumor had mutated KRAS.
However, both trials found that adding cetuximab to chemotherapy improved both tumor shrinkage (response rates) and the time until the cancer got worse (progression free survival) for people with wild-type KRAS.
Tumors can be tested for mutated KRAS before beginning treatment providing information that can help patients and doctors make better decisions about the right therapy for each individual.