Activity of panitumumab alone or with chemotherapy in non-small cell lung carcinoma cell lines expressing mutant epidermal growth factor receptor.
Epidermal growth factor receptor (EGFR) kinase domain mutations cause hyperresponsiveness to ligand and hypersensitivity to small-molecule tyrosine kinase inhibitors. However, little is known about how these mutations respond to antibodies against EGFR. We investigated the activity of panitumumab, a fully human anti-EGFR monoclonal antibody, in vitro in mutant EGFR-expressing non-small cell lung carcinoma (NSCLC) cells and in vivo with chemotherapy in xenograft models. Mutant EGFR-expressing NSCLC cells (NCI-H1975 [L858R+T790M] and NCI-H1650 [Delta746-750]) and CHO cells were treated with panitumumab before EGF stimulation to assess the inhibition of EGFR autophosphorylation. Established tumors were treated with panitumumab (25, 100, or 500 mug/mouse twice a week) alone or with docetaxel (10 or 20 mg/kg once a week) or cisplatin (7.5 mg/kg once a week). Antitumor activity and levels of proliferation markers were analyzed. Treatment of mutant EGFR-expressing CHO and NSCLC cells with panitumumab inhibited ligand-dependent autophosphorylation. In NCI-H1975 and NCI-H1650 xenografts, treatment with panitumumab alone or with cisplatin inhibited tumor growth compared with control (P < 0.0003). With panitumumab plus docetaxel, enhanced antitumor activity was seen in both xenografts versus panitumumab alone. Panitumumab treatment alone decreased Ki-67 and phospho- mitogen-activated protein kinase (pMAPK) staining in both xenografts compared with control. Docetaxel enhanced panitumumab activity in NCI-H1650 xenografts (decreased Ki-67 and pMAPK staining by >60%) when compared with either agent alone. Panitumumab inhibits ligand-induced EGFR phosphorylation, tumor growth, and markers of proliferation alone or with docetaxel in NSCLC cell lines that express clinically observed EGFR kinase domain mutations, including the small-molecule tyrosine kinase inhibitor-resistant T790M mutation.
Freeman
Daniel J
DJ
Department of Oncology Research, Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA 91320, USA. dfreeman@amgen.com
Bush
Tammy
T
Ogbagabriel
Selam
S
Belmontes
Brian
B
Juan
Todd
T
Plewa
Cherylene
C
Van
Gwyneth
G
Johnson
Carol
C
Radinsky
Robert
R
D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D015153:Blotting, Western; D016466:CHO Cells; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000008:administration & dosage; D006224:Cricetinae; D003412:Cricetulus; D000077143:Docetaxel; D066246:ErbB Receptors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D000077544:Panitumumab; D010766:Phosphorylation / Q000187:drug effects; D043823:Taxoids / Q000008:administration & dosage; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
D000911:Antibodies, Monoclonal; D019394:Ki-67 Antigen; D043823:Taxoids; D000077143:Docetaxel; D000077544:Panitumumab; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; D002945:Cisplatin