Cetuximab improved survival compared to bevacizumab when combined with FOLFIRI in metastatic colorectal cancer

This study compared the effectiveness of the chemotherapy FOLFIRI plus cetuximab (Erbitux) and FOLFIRI plus bevacizumab (Avastin). Researchers suggested that FOLFIRI plus cetuximab is associated with a higher effectiveness in treating metastatic (spread to other parts of the body) colorectal cancers.

FOLFIRI is the standard first-line treatment for metastatic colorectal cancer. Chemotherapy drugs attack cancer cells, slowing down cancer progression. Different chemotherapy drugs can be used and often are combined to increase effectiveness. FOLFIRI chemotherapy combines the agents 5-fluorouracil (Efudex), leucovorin and irinotecan (Camptostar).

More recently, the addition of targeted therapies like cetuximab and bevacizumab that block the tumor from growing has been shown to provide an additional benefit. Prior studies suggested an improved overall survival in patients receiving FOLFIRI plus cetuximab when compared with patients receiving FOLFIRI plus bevacizumab. However, in these studies, objective response to the treatment (such as tumor shrinkage) and progression-free survival (PFS; time from treatment to disease progression) did not change. This has raised questions about the validity of these factors to investigate overall survival.

The objective of this study was to investigate the effectiveness of these two different treatments on the overall survival of metastatic colorectal cancer patients. This study used other factors that better measured tumor response related to treatment. This study included 400 patients with metastatic colorectal cancer. Patient were randomly assigned to receive FOLFIRI treatment with either bevacizumab or cetuximab. Patients were followed for an average of 40.3 months. 

Average overall survival was increased in the FOLFIRI+cetuximab group (33.1 months) when compared to the FOLFIRI+bevacizumab group (25 months).

More patients in the FOLFIRI+cetuximab group showed an objective response (72%) compared to the FOLFIRI+bevacizumab group (56.1%). Additionally tumor shrinkage was seen in 68.2% of the patients in the FOLFIRI+cetuximab group and 49.1% in the FOLFIRI+bevacizumab group.

This study concluded that FOLFIRI plus cetuximab was associated with an improved overall survival when compared to FOLFIRI plus bevacizumab. This was associated with factors that better measured tumor response to treatment, such as objective response and tumor shrinkage.