Journal of Clinical Case Reports

Successful Treatment with Panitumumab and Irinotecan in a Colorectal Cancer Patient with a Severe Hypersensitivity Reaction to Cetuximab

Abstract

Leila R Mohassel, Andrew Whitman, Kara Zacholski and William B Ershler

Infusion-related reactions resulting from administration of monoclonal antibodies targeting the epidermal growth factor receptor (EGFR) are well defined in the literature. Although these reactions occur more frequently with earlier generation antibodies such as cetuximab, which contains 34% murine protein, the risk of immunogenicity is still present with fully human and humanized antibodies. Panitumumab is the first fully human monoclonal antibody approved by the US Food and Drug Administration for the treatment of patients with metastatic colorectal cancer. It is associated with a lower risk of hypersensitivity reactions and premedications are not routinely required. Because of the inherent differences in protein sequence between the two agents, patients who experience infusion reactions with cetuximab may tolerate panitumumab administration. There are however limited data on the safety of panitumumab in patients with prior infusion reactions to cetuximab. We report a case of a 62-year-old patient with metastatic colorectal cancer who was treated successfully with panitumumab and irinotecan after developing a grade 4 infusion reaction to cetuximab therapy. Treatment with panitumumab was initiated approximately five weeks after the single dose of cetuximab resulted in respiratory failure, cardiac arrest and intensive care management. The patient was premedicated prior to first and all subsequent doses. To date, the patient has not experienced any hypersensitivity reactions and continues to receive panitumumab in combination with chemotherapy with objective improvement in his overall condition. This case suggests that panitumumab maybe safely administered in patients with prior infusion reactions to cetuximab.