Drugs of interest to pathologists
Drugs related to surgical pathology

Author: Him G. Kwee, M.D. (see Authors page)

Revised: 5 December 2017, last major update January 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Panitumumab [title] review

Cite this page: Kwee, H.G. Panitumumab. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/drugspanitumumab.html. Accessed October 22nd, 2018.
Definition / general
  • Fully human monoclonal antibody directed against EGFR (epidermal growth factor receptor)
Trade name
  • Vectibix®
Clinical information
Approved by US Food and Drug Administration:
  • As monotherapy for metastatic colorectal carcinoma after disease progression on or following standard fluoropyrimidine, oxaliplatin and irinotecan chemotherapy regimens (National Cancer Institute: Panitumumab [Accessed 4 December 2017])
  • Cost: approximately $3,000 per 2 weeks treatment in 2007, $950 for 100 mg/5 ml solution, 5 ml vial at drugstore.com in March 2012
  • Side effects: infusion reactions, dermatologic toxicity which can be fatal, acne-like rash, skin photosensitivity, pulmonary fibrosis, eye toxicity (keratitis, ulcerative keratitis), hypomagnesemia and hypocalcemia (National Cancer Institute: Panitumumab [Accessed 4 December 2017])
Molecular pathology - theory
  • Like cetuximab (Erbitux), panitumumab inhibits the extracellular domain of EGFR but cetuximab is a chimeric (human / mouse) antibody and panitumumab is a full human monoclonal antibody
  • With cetuximab, there is a high incidence of IgE mediated anaphylactic reactions; these reactions have not been seen with panitumumab (BMC Clin Pharmacol 2011;11:17)
  • Cetuximab is an IgG1 antibody but panitumumab is an IgG2 antibody; IgG1 can activate the complement pathway and mediate antibody dependent cellular cytotoxicity (Wikipedia: Panitumumab [Accessed 4 December 2017])
  • KRAS mutational analysis must be performed before treatment with cetuximab or panitumumab; these drugs cannot be used if there is a KRAS mutation in codons 12 or 13 (Arch Pathol Lab Med 2012;136:26)