cetuximab

Cetuximab is a chimeric monoclonal antibody that targets the epidermal growth factor receptor (EGFR). Marketed under the brand name Erbitux, it is used in the treatment of certain cancers and is administered by intravenous infusion.

Mechanism of action involves binding to the extracellular domain of EGFR, blocking ligand binding and receptor activation. This inhibition disrupts downstream signaling pathways that promote cell proliferation and survival. Cetuximab can also mediate antibody-dependent cellular cytotoxicity, contributing to anti-tumor activity.

In clinical use, cetuximab is indicated for metastatic colorectal cancer in patients whose tumors harbor wild-type KRAS, often in combination with chemotherapy or as a single agent in appropriate settings. It is also approved for squamous cell carcinoma of the head and neck (SCCHN) in recurrent or metastatic disease, and in some locally advanced cases in combination with radiotherapy or chemotherapy. The likelihood of response is reduced in tumors with activating KRAS or NRAS mutations, and biomarker testing is used to guide treatment in colorectal cancer.

Administration and safety considerations include intravenous dosing with monitoring for infusion reactions. Common adverse effects are an acneiform rash, infusion reactions, hypomagnesemia, hypokalemia, mucositis, diarrhea, and fatigue. Rare but serious hypersensitivity reactions can occur. Long-term use may affect wound healing and electrolyte balance; premedication and monitoring protocols are often employed to manage risks.

Overall, cetuximab is a targeted EGFR inhibitor whose effectiveness depends on tumor EGFR dependency and biomarker status, particularly KRAS wild-type in colorectal cancer.