In this renewal application, we seek to adapt our labeling strategies designed to minimize dehalogenation and maximize entrapment of radioactivity within tumor cells after receptor-mediated internalization of intact antibodies to nanobodies (Nbs) - the smallest naturally occurring antibody fragment. The small size (~15 kDa), nM-range affinity and low immunogenicity of these proteins make them a very attractive platform for the development of radiotheranostic agents. The goal of this proposal is to increase the clinical utility of labeled Nbs for cancer diagnosis and therapy by developing more effective strategies for labeling internalizing Nbs with radioiodine nuclides and 211At. Iodine-131 remains the most widely used radionuclide in clinical radioimmunotherapy; 211At emits ?-particles that have a greater cytotoxic effectiveness than conventional radiation and have a range in tissue of only a few cell diameters. Based on potential clinical impact and promising preliminary results, our strategy will be to focus on the development of HER2-targeted Nbs as molecular radiotherapeutics for HER2-positive breast carcinoma, particularly for patients with central nervous system (CNS) metastatic disease. Particularly in patients that respond to systemic treatments such as trastuzumab, there has been a rapid increase in the incidence of neoplastic meningitis (NM) and brain metastases (BM) to which these patients quickly succumb because of the lack of efficacy of these drugs against disease sites in the CNS. Unfortunately, these patients face a dim prognosis because current treatment options such as external beam radiotherapy are often dose limited because of CNS toxicity concerns. Our hypothesis is that by combining a HER2-targeted Nb construct with an optimized labeling method and radionuclide, this barrier will be overcome, thereby providing an effective strategy for the treatment of breast cancer patients with CNS metastases. In support of this approach, the results that we have obtained to date labeling the anti-HER2 Nb 5F7 using radio iodination methods originally designed for internalizing mAbs demonstrated enhanced retention of radioactivity in HER2-expressing tumor cells compared with conventional methods. Studies using N-succinimidyl 4-guanidinomethyl-3-[131I]iodobenzoate (SGMIB) were particularly encouraging, demonstrating a more than twofold tumor xenograft delivery advantage compared with and previously reported radionuclide/labeling method/Nb combination.
Our Specific Aims are: 1) to label HER2 targeted Nb monomers and dimers with 131I and 211At using SGMIB and N-succinimidyl 3-[211At] astato-4- guanidinomethylbenzoate and to evaluate their potential as targeted radiotherapeutics: 2) to investigate strategies for improving Nb labeling; and 3) to evaluate the therapeutic efficacy of promising 131I- and 211At- labeled Nb conjugates in athymic rodents with subcutaneous, intracranial and neoplastic meningitis HER2- expressing xenografts.

Public Health Relevance

The goal of this research is to develop more effective methods for treating metastatic disease, particularly in the central nervous system, of patients with HER2-positive breast cancer. Our strategy is to combine the promising characteristics of nanobodies, the smallest naturally occurring functional antibody fragment, with optimized radiolabeling technologies and radionuclides to develop a targeted radiotherapeutic that will permit the selective elimination of HER2-positive cancer cells while leaving normal cells unharmed.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
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Clinical Molecular Imaging and Probe Development (CMIP)
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Prasanna, Pat G
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Duke University
Schools of Medicine
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Zhou, Zhengyuan; Chitneni, Satish K; Devoogdt, Nick et al. (2018) Fluorine-18 labeling of an anti-HER2 VHH using a residualizing prosthetic group via a strain-promoted click reaction: Chemistry and preliminary evaluation. Bioorg Med Chem 26:1939-1949
Choi, Jaeyeon; Vaidyanathan, Ganesan; Koumarianou, Eftychia et al. (2018) Astatine-211 labeled anti-HER2 5F7 single domain antibody fragment conjugates: radiolabeling and preliminary evaluation. Nucl Med Biol 56:10-20
Pruszynski, Marek; Kang, Choong Mo; Koumarianou, Eftychia et al. (2018) d-Amino Acid Peptide Residualizing Agents for Protein Radioiodination: Effect of Aspartate for Glutamate Substitution. Molecules 23:
Pozzi, Oscar R; Zalutsky, Michael R (2017) Radiopharmaceutical chemistry of targeted radiotherapeutics, part 4: Strategies for211At labeling at high activities and radiation doses of211At ?-particles. Nucl Med Biol 46:43-49
D'Huyvetter, Matthias; De Vos, Jens; Xavier, Catarina et al. (2017) 131I-labeled Anti-HER2 Camelid sdAb as a Theranostic Tool in Cancer Treatment. Clin Cancer Res 23:6616-6628
Raghavan, Raghu; Howell, Roger W; Zalutsky, Michael R (2017) A model for optimizing delivery of targeted radionuclide therapies into resection cavity margins for the treatment of primary brain cancers. Biomed Phys Eng Express 3:
Zhou, Zhengyuan; Vaidyanathan, Ganesan; McDougald, Darryl et al. (2017) Fluorine-18 Labeling of the HER2-Targeting Single-Domain Antibody 2Rs15d Using a Residualizing Label and Preclinical Evaluation. Mol Imaging Biol 19:867-877
Vaidyanathan, Ganesan; McDougald, Darryl; Choi, Jaeyeon et al. (2016) N-Succinimidyl 3-((4-(4-[(18)F]fluorobutyl)-1H-1,2,3-triazol-1-yl)methyl)-5-(guanidinomethyl)benzoate ([(18)F]SFBTMGMB): a residualizing label for (18)F-labeling of internalizing biomolecules. Org Biomol Chem 14:1261-71
Vaidyanathan, Ganesan; McDougald, Darryl; Choi, Jaeyeon et al. (2016) Preclinical Evaluation of 18F-Labeled Anti-HER2 Nanobody Conjugates for Imaging HER2 Receptor Expression by Immuno-PET. J Nucl Med 57:967-73
Vaidyanathan, Ganesan; McDougald, Darryl; Koumarianou, Eftychia et al. (2015) Synthesis and evaluation of 4-[18F]fluoropropoxy-3-iodobenzylguanidine ([18F]FPOIBG): A novel 18F-labeled analogue of MIBG. Nucl Med Biol 42:673-84

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