Adding the targeted therapy cetuximab to chemotherapy and radiation treatment does not improve overall survival for patients with esophageal cancer, according to new research published online in the journal JAMA Oncology.

More than 340 patients were enrolled in the National Cancer Institute–sponsored Phase III clinical study led by the Radiation Therapy Oncology Group (now NRG Oncology) from 2008 to 2013. A total of 328 patients from institutions across the country were evaluated. All of the patients received weekly doses of two chemotherapy drugs, paclitaxel and cisplatin, plus daily radiation treatments. About half of the patients also received cetuximab.

Cetuximab is a monoclonal antibody that inhibits a protein called epidermal growth factor receptor (EGFR). In esophageal and other cancers, the protein seems to encourage tumor growth. The drug has been approved to treat advanced head and neck cancer and metastatic colorectal cancer and is under investigation for several other cancers.

"Our findings are consistent with other Phase III studies that have failed to demonstrate an improvement in overall survival by adding an EGFR inhibitor to concurrent chemoradiation regimens for various solid tumors," says lead author Mohan Suntha, MD, MBA, the Marlene and Stewart Greenebaum professor of radiation oncology at the University of Maryland School of Medicine and president and chief executive officer of the University of Maryland Medical Center.

“Taken together, these trial results highlight the need to identify prognostic variables that may provide insight into which patient populations will benefit from EGFR inhibition,” says Dr. Suntha, adding that mutations in the p53 gene and KRAS protein may be key factors in determining who will benefit. Dr. Suntha, a radiation oncologist, treats patients at the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center.

The median overall survival for the patients in the study who received cetuximab was 19.7 months, compared to 19 months for those who received chemoradiation alone. After two years, the patients in the experimental arm had an overall survival rate of 45 percent compared to a 44 percent survival rate for the control group. The survival rate after three years was similar for both groups – 34 percent for the cetuximab arm and 28 percent for the control group.

The response to treatment between the two groups was also about the same – 56 percent in the experimental arm initially had a complete response to the treatment, compared to 58 percent in the group that received only chemotherapy and radiation.