Is biweekly treatment with cetuximab safe and effective for patients with metastatic colorectal cancer?

This study evaluated the efficacy and safety of administering biweekly (every 14 days) cetuximab (Erbitux) plus standard chemotherapy to patients with metastatic colorectal cancer (cancer that has spread to other organs).

Cetuximab is a drug that binds to the epidermal growth factor receptor (EGFR) protein. As EGRF is involved in cancer growth, cetuximab can help slow cancer. Previous studies have shown that adding weekly doses of cetuximab to chemotherapy regimens is an effective treatment for metastatic colorectal cancer. These benefits of cetuximab are only seen in tumors with a normal-KRAS gene (wild-type KRAS).

The standard treatment with cetuximab involves weekly doses. Biweekly administration would increase convenience for patients and healthcare providers, especially as standard chemotherapy is administered on a biweekly basis. It is unclear whether giving biweekly cetuximab in combination with chemotherapy is as safe and effective as weekly treatment.

This study included 99 metastatic colorectal cancer patients with wild-type KRAS tumors who had not previously been treated. Patients received cetuximab on day 1 of the study and every 14 days for the rest of the study. Patients also received biweekly FOLFOX-4 chemotherapy (oxaliplatin [Eloxatin] on day 1, leucovorin on days 1 and 2, and fluorouracil [Efudex] on day 1 and 2). Patient response (improvement) to treatment, overall survival (time until death from any cause), and progression free survival (time until the cancer gets worse) was assessed during the study. Adverse events following treatment were also assessed.

Overall, 60.6% of patients’ tumors improved following treatment with biweekly cetuximab and chemotherapy. The average time until the disease progressed was 10.1 months. The average patient survival time was 20.8 months from the beginning of the study.

Severe adverse events occurred in 77.8% of the patients. The most common severe adverse events included neutropenia (32.3%; low neutrophil cell count, a type of white blood cell needed to fight infections), acne-like rash (15.2%) and diarrhea (13.1%). Less severe adverse events occurred in 98% of patients and included acne-like rash (91.9%), diarrhea (58.6%), stomach-area pain (30.3%) and mouth sores (52.5%).

The authors concluded that the efficacy and safety of biweekly administration of cetuximab is similar the safety and efficacy previously reported after weekly administration. 

This study did not directly compare patients receiving weekly doses of cetuximab to patients receiving biweekly doses. This limits the value to the study and future trials are needed to ensure the accuracy of the results.