Radiolabelling and preclinical characterization of 89Zr-Df-radiolabelled bispecific anti-PD-L1/TGF-βRII fusion protein bintrafusp alfa
- 19 February 2021
- journal article
- research article
- Published by Springer Science and Business Media LLC in European Journal of Nuclear Medicine and Molecular Imaging
- Vol. 48 (10), 3075-3088
- https://doi.org/10.1007/s00259-021-05251-0
Abstract
Purpose Τhis study aimed to optimize the 89Zr-radiolabelling of bintrafusp alfa investigational drug product and controls, and perform the in vitro and in vivo characterization of 89Zr-Df-bintrafusp alfa and 89Zr-Df-control radioconjugates. Methods Bintrafusp alfa (anti-PD-L1 human IgG1 antibody fused to TGF-β receptor II (TGF-βRII), avelumab (anti-PD-L1 human IgG1 control antibody), isotype control (mutated inactive anti-PD-L1 IgG1 control antibody), and trap control (mutated inactive anti-PD-L1 human IgG1 fused to active TGF-βRII) were chelated with p-isothiocyanatobenzyl-desferrioxamine (Df). After radiolabelling with zirconium-89 (89Zr), radioconjugates were assessed for radiochemical purity, immunoreactivity, antigen binding affinity, and serum stability in vitro. In vivo biodistribution and imaging studies were performed with PET/CT to identify and quantitate 89Zr-Df-bintrafusp alfa tumour uptake in a PD-L1/TGF-β-positive murine breast cancer model (EMT-6). Specificity of 89Zr-Df-bintrafusp alfa was assessed via a combined biodistribution and imaging experiment in the presence of competing cold bintrafusp alfa (1 mg/kg). Results Nanomolar affinities for PD-L1 were achieved with 89Zr-Df-bintrafusp alfa and 89Zr-avelumab. Biodistribution and imaging studies in PD-L1- and TGF-β-positive EMT-6 tumour-bearing BALB/c mice demonstrated the biologic similarity of 89Zr-Df-bintrafusp alfa and 89Zr-avelumab indicating the in vivo distribution pattern of bintrafusp alfa is driven by its PD-L1 binding arm. Competition study with 1 mg of unlabelled bintrafusp alfa or avelumab co-administered with trace dose of 89Zr-labelled bintrafusp alfa demonstrated the impact of dose and specificity of PD-L1 targeting in vivo. Conclusion Molecular imaging of 89Zr-Df-bintrafusp alfa biodistribution was achievable and allows non-invasive quantitation of tumour uptake of 89Zr-Df-bintrafusp alfa, suitable for use in bioimaging clinical trials in cancer patients.Keywords
Funding Information
- EMD Serono
This publication has 45 references indexed in Scilit:
- Positron range in PET imaging: an alternative approach for assessing and correcting the blurringPhysics in Medicine & Biology, 2012
- In vivo biodistribution and accumulation of 89Zr in miceNuclear Medicine and Biology, 2011
- Expression patterns of connective tissue growth factor and of TGF-β isoforms during glomerular injury recapitulate glomerulogenesisAmerican Journal of Physiology-Renal Physiology, 2010
- Conjugation and radiolabeling of monoclonal antibodies with zirconium-89 for PET imaging using the bifunctional chelate p-isothiocyanatobenzyl-desferrioxamineNature Protocols, 2010
- Mechanisms of Immune Evasion by TumorsAdvances in Immunology, 2006
- Phase III Study of Second-Line Chemotherapy for Advanced Non–Small-Cell Lung Cancer With Weekly Compared With 3-Weekly DocetaxelJournal of Clinical Oncology, 2005
- B7x: A widely expressed B7 family member that inhibits T cell activationProceedings of the National Academy of Sciences of the United States of America, 2003
- Determination of the immunoreactive function of radiolabeled monoclonal antibodies by linear extrapolation to binding at infinite antigen excessJournal of Immunological Methods, 1984
- An iterative technique for the rectification of observed distributionsThe Astronomical Journal, 1974
- Bayesian-Based Iterative Method of Image Restoration*Journal of the Optical Society of America, 1972