Development and Validation of an Immuno-PET Tracer as a Companion Diagnostic Agent for Antibody-Drug Conjugate Therapy to Target the CA6 Epitope
| Autor: | Richard H. Kimura, Ataya Sathirachinda, Sharon S. Hori, Arutselvan Natarajan, Jochen Kruip, Chantal Carrez, Susanta K. Sarkar, Ohad Ilovich, Ingo Focken, Mathias Gebauer, Ingrid Sassoon, Veronique Blanc, Sanjiv S. Gambhir, Christian Lange, Ananth Srinivasan |
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| Rok vydání: | 2015 |
| Předmět: |
Validation study
Antibody-Drug Conjugate Therapy Immunologic Tests Epitope Epitopes Mice Drug Therapy In vivo Animals Humans Medicine Radiology Nuclear Medicine and imaging Radioactive Tracers Immunoglobulin Fragments Cells Cultured Original Research Immuno pet biology business.industry Copper Radioisotopes Positron-Emission Tomography Immunology Cancer research biology.protein Antibody business Companion diagnostic Conjugate |
| Zdroj: | Radiology. 276:191-198 |
| ISSN: | 1527-1315 0033-8419 |
| Popis: | To develop and compare three copper 64 ((64)Cu)-labeled antibody fragments derived from a CA6-targeting antibody (huDS6) as immuno-positron emission tomography (immuno-PET)-based companion diagnostic agents for an antibody-drug conjugate by using huDS6.Three antibody fragments derived from huDS6 were produced, purified, conjugated to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), and evaluated in the following ways: (a) the affinity of the fragments and the DOTA conjugates was measured via flow cytometry, (b) the stability of the labeled fragments was determined ex vivo in human serum over 24 hours, and (c) comparison of the in vivo imaging potential of the fragments was evaluated in mice bearing subcutaneous CA6-positive and CA6-negative xenografts by using serial PET imaging and biodistribution. Isotype controls with antilysozyme and anti-DM4 B-Fabs and blocking experiments with an excess of either B-Fab or huDS6 were used to determine the extent of the antibody fragment (64)Cu-DOTA-B-Fab binding specificity. Immunoreactivity and tracer kinetics were evaluated by using cellular uptake and 48-hour imaging experiments, respectively. Statistical analyses were performed by using t tests, one-way analysis of variance, and Wilcoxon and Mann-Whitney tests.The antibody fragment (64)Cu-DOTA-B-Fab was more than 95% stable after 24 hours in human serum, had an immunoreactivity of more than 70%, and allowed differentiation between CA6-positive and CA6-negative tumors in vivo as early as 6 hours after injection, with a 1.7-fold uptake ratio between tumors. Isotype and blocking studies experiments showed tracer-specific uptake in antigen-positive tumors, despite some nonspecific uptake in both tumor models.Three antibody fragments were produced and examined as potential companion diagnostic agents. (64)Cu-DOTA-B-Fab is a stable and effective immuno-PET tracer for CA6 imaging in vivo. |
| Databáze: | OpenAIRE |
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