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Special Contribution |
1 Garden State Cancer Center, Center for Molecular Medicine and Immunology, Belleville, New Jersey; 2 IBC Pharmaceuticals, Inc., Morris Plains, New Jersey; and 3 Immunomedics, Inc., Morris Plains, New Jersey
Correspondence: For correspondence or reprints contact: David M. Goldenberg, ScD, MD, Garden State Cancer Center, CMMI, 520 Belleville Ave., Belleville, NJ 07109. E-mail: dmg.gscancer{at}att.net
The Dock-and-Lock (DNL) method, which makes bioactive molecules with multivalency and multifunctionality, is a new approach to develop targeting molecules for improved cancer imaging and therapy. It involves the use of a pair of distinct protein domains involved in the natural association between cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) and A-kinase anchoring proteins (AKAPs). The dimerization and docking domain found in the regulatory subunit of PKA and the anchoring domain (AD) of an interactive AKAP are each attached to a biologic entity, and the resulting derivatives, when combined, readily form a stably tethered complex of a defined composition that fully retains the functions of the individual constituents. The DNL method has generated several trivalent, bispecific, binding proteins, each consisting of 2 identical Fab fragments linked site-specifically to a different Fab fragment. For example, 2 identical Fabs reacting with carcinoembryonic antigen (CEA) are bound to a Fab reacting with a hapten peptide that bears a diagnostic or therapeutic radionuclide. Using a 2-step, pretargeting method that separates the bivalent anti-CEA antibody targeting of tumor from the delivery of the radioactive peptide that is captured by the second Fab of the tri-Fab construct, an improved method of cancer imaging and therapy has been developed and shows very sensitive and specific targeting of CEA-expressing tumors for either diagnostic imaging, such as with immunoSPECT and immunoPET, or radioimmunotherapy. Improved therapeutic efficacy is shown with pretargeting in a pancreatic cancer xenograft model given a tri-Fab to a pancreatic cancer MUC1 and the hapten peptide labeled with 90Y.
Key Words: bispecific antibodies cancer PET pretargeting radioimmunodetection radioimmunotherapy
Dr. Goldenberg is the recipient of the 2005 Paul C. Aebersold award of the SNM. He declares a financial interest in Immunomedics, Inc., and IBC Pharmaceuticals, Inc., as a stockholding officer of both corporations. Drs. Rossi, McBride, and Chang are employees and stockholders of Immunomedics and/or IBC Pharmaceuticals. Dr. Sharkey declares no financial interests.
COPYRIGHT © 2008 by the Society of Nuclear Medicine, Inc.
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D. V. Gold, D. M. Goldenberg, H. Karacay, E. A. Rossi, C.-H. Chang, T. M. Cardillo, W. J. McBride, and R. M. Sharkey A Novel Bispecific, Trivalent Antibody Construct for Targeting Pancreatic Carcinoma Cancer Res., June 15, 2008; 68(12): 4819 - 4826. [Abstract] [Full Text] [PDF] |
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