Cetuxa (Cetuximab) is a monoclonal antibody that targets the epidermal growth factor receptor (EGFR). It is primarily used to treat certain types of cancers, including metastatic colorectal cancer, head and neck squamous cell carcinoma (HNSCC), and non-small cell lung cancer (off-label in some cases). Cetuximab inhibits cancer cell proliferation and survival by blocking EGFR signaling pathways. Cetuximab binds specifically to the extracellular domain of EGFR, preventing the binding of natural ligands such as epidermal growth factor (EGF). This inhibition disrupts downstream signaling pathways responsible for cell growth, proliferation, angiogenesis, and survival. It also enhances immune system activity by promoting antibody-dependent cellular cytotoxicity (ADCC).

Uses

Metastatic Colorectal Cancer (mCRC):

• Used in combination with chemotherapy (e.g., irinotecan-based regimens) or as monotherapy in patients who have failed other treatments.

• Effective in patients with wild-type RAS (KRAS/NRAS) tumors; testing for RAS mutation is mandatory before treatment.

Head and Neck Squamous Cell Carcinoma (HNSCC):

• Used in combination with radiation therapy for locally advanced disease.

• Administered with platinum-based chemotherapy for recurrent or metastatic disease.

Off-label Uses:

• Non-small cell lung cancer (NSCLC) in certain clinical scenarios.

• Other cancers expressing EGFR under investigation in trials.

Cetuxa (Cetuximab) is a targeted therapy that has significantly improved outcomes in EGFR-expressing cancers such as metastatic colorectal cancer and head and neck cancer. However, its use requires careful patient selection, monitoring for side effects, and proactive management of infusion reactions and skin toxicity to maximize its benefits while minimizing risks.

Onset of Action- The therapeutic effects of Cetuximab may begin within weeks after initiation, but full benefits may take several treatment cycles.

Duration of Action- Cetuximab has a half-life of approximately 5–7 days, with dosing typically scheduled weekly or every two weeks depending on the regimen.