title: An anti-insulin-like growth factor I receptor antibody that is a potent inhibitor of cancer cell proliferation.
abstract: An antagonistic monoclonal antibody, designated EM164, has been developed which binds specifically to the human insulin-like growth factor I receptor (IGF-IR) and inhibits the proliferation and survival functions of the receptor in cancer cells. EM164 was initially selected by a rapid cell-based screen of hybridoma supernatants to identify antibodies that bind to IGF-IR but not to the homologous insulin receptor and that show maximal inhibition of IGF-I-stimulated autophosphorylation of IGF-IR. EM164 binds tightly to IGF-IR with a dissociation constant K(d) of 0.1 nM, inhibits binding of IGF-I and antagonizes its effects on cells completely, and has no agonistic activity on its own. EM164 inhibits IGF-I-, IGF-II-, and serum-stimulated proliferation and survival of diverse human cancer cell lines in vitro, including breast, lung, colon, cervical, ovarian, pancreatic, melanoma, prostate, neuroblastoma, rhabdomyosarcoma, and osteosarcoma cancer lines. It also suppresses the autocrine or paracrine proliferation of several cancer cell lines. EM164 was the most potent antagonistic anti-IGF-IR antibody tested when compared with several commercially available antibodies. The in vitro inhibitory effect could be extended to in vivo tumor models, where EM164 caused regression of established BxPC-3 human pancreatic tumor xenografts in SCID mice. The antitumor effect of treatment with EM164 could be enhanced by combining it with the cytotoxic agent gemcitabine. These data support the development of EM164 as a candidate therapeutic agent that targets IGF-IR function in cancer cells.
authors.affiliation: ImmunoGen, Inc., 128 Sidney Street, Cambridge, Massachusetts 02139, USA.
authors.forename: Erin K
authors.initials: EK
authors.lastname: Maloney
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: McLaughlin
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Dagdigian
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Garrett
authors.forename: Katherine M
authors.initials: KM
authors.lastname: Connors
authors.forename: Xiao-Mai
authors.initials: XM
authors.lastname: Zhou
authors.forename: Walter A
authors.initials: WA
authors.lastname: Blättler
authors.forename: Thomas
authors.initials: T
authors.lastname: Chittenden
authors.forename: Rajeeva
authors.initials: R
authors.lastname: Singh
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology / Q000627:therapeutic use*; D002453:Cell Cycle; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D016513:Mice, SCID; D009374:Neoplasms, Experimental / Q000473:pathology / Q000628:therapy*; D010766:Phosphorylation; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015398:Signal Transduction; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1