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Pharmacokinetics and biodistribution of 177Lu-labeled multivalent single-chain Fv construct of the pancarcinoma monoclonal antibody CC49
- Source :
- European journal of nuclear medicine and molecular imaging. 32(3)
- Publication Year :
- 2004
-
Abstract
- Lutetium-177 (177Lu) is a radionuclide of interest for radioimmunoimaging (RII) and radioimmunotherapy (RIT) on account of its short half-life (161 h) and the ability to emit both beta and gamma radiation. Single-chain Fv (scFv) constructs have shown advancement in cancer diagnosis and therapy due to the pharmacokinetics advantage and seem to be intriguing tools in oncology. The objective of this study was to evaluate the pharmacokinetics and biodistribution characteristics of the 177Lu-labeled tetravalent scFv of CC49 MAb and intact CC49 IgG in vivo.Conjugation and labeling conditions of multivalent scFv with 177Lu were optimized without affecting integrity and immunoreactivity. For this purpose, multivalent scFv constructs {dimer, sc(Fv)2; tetramer, [sc(Fv)2]2} of the MAb CC49 were expressed as secretory proteins in Pichia pastoris. The purified scFv constructs and IgG form of CC49 were conjugated with a bifunctional chelating agent, ITCB-DTPA, and labeled with 177Lu. The comparative biodistribution, blood clearance, and tumor-targeting characteristics of 177Lu-labeled tetravalent [sc(Fv)2]2 construct of CC49 MAb and intact CC49 IgG were investigated in the athymic mice bearing LS-174T xenografts.Approximately, 90% of 177Lu incorporation was achieved using ITCB-DTPA chelator, and the labeled immunoconjugates maintained integrity and immunoreactivity. Blood clearance studies demonstrated an alpha half-life (t1/2alpha) of 177Lu-labeled [sc(Fv)2]2 and IgG of CC49 at 4.40 and 9.50 min and a beta half-life (t1/2beta) at 375 and 2,193 min, respectively. At 8 h post administration, the percent of the injected dose accumulated/gram (%ID/g) of the LS-174T tumor was 6.4+/-1.3 and 8.9+/-0.6 for 177Lu-labeled [sc(Fv)2]2 and IgG of CC49, respectively, in the absence of L-lysine. The corresponding values were 8.0+/-0.6 and 8.4+/-1.2 in the presence of L-lysine. Renal accumulation of [sc(Fv)2]2 was significantly (p0.005) reduced in the presence of L-lysine.The results of this study demonstrate that the ITCB-DTPA conjugation and 177Lu-labeling of scFvs are feasible without influencing the antibody characteristics. 177Lu-labeled [sc(Fv)2]2 showed faster clearance and equivalent tumor uptake at 8 h compared with its IgG form, with a markedly reduced renal uptake in the presence of L-lysine. Therefore, 177Lu-labeled [sc(Fv)2]2 may be a potential radiopharmaceutical for the treatment of cancer.
- Subjects :
- Biodistribution
medicine.drug_class
Antibodies, Neoplasm
Metabolic Clearance Rate
medicine.medical_treatment
Mice, Nude
chemical and pharmacologic phenomena
Lutetium
Monoclonal antibody
Mice
Monoclonal antibody CC49
Pharmacokinetics
In vivo
medicine
Animals
Radiology, Nuclear Medicine and imaging
Tissue Distribution
Radionuclide Imaging
Immunoglobulin Fragments
Radioisotopes
biology
Chemistry
Carcinoma
Antibodies, Monoclonal
General Medicine
respiratory system
Radioimmunotherapy
Virology
Organ Specificity
Cancer research
biology.protein
Female
Antibody
Radiopharmaceuticals
Single-Chain Antibodies
Subjects
Details
- ISSN :
- 16197070
- Volume :
- 32
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- European journal of nuclear medicine and molecular imaging
- Accession number :
- edsair.doi.dedup.....83f79667446356b21b19519112d37ab2