Optimizing Radiolabeled Engineered Anti-p185HER2 Antibody Fragments for<i>In vivo</i>Imaging

Olafsen, Tove; Kenanova, Vania; Sundaresan, Gobalakrishnan; Anderson, Aaron S.; Crow, Desiree; Yazaki, Paul J.; Li, Lin; Press, Michael F.; Gambhir, Sanjiv S.; Williams, Lawrence E.; Wong, Jeffrey Y.C.; Raubitschek, Andrew; Shively, John E.; Wu, Anna M.

doi:10.1158/0008-5472.can-04-4472

Cited by 151 publications

(109 citation statements)

References 39 publications

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“…We have shown that SarAr conjugation to both murine and chimerized mAb can be accomplished under nearly physiological conditions with no adverse affect on immunoreactivity. Incubation of the immunoconjugate with 64 Cu 2ϩ for 10-30 min results in nearly quantitative uptake of 64 Cu 2ϩ without the need for additional HPLC purification, yielding specific activities of Ϸ10 Ci/ g (Ϸ37 MBq/100 g), 2-3 times greater than previously published results using other chelating agents (9,25,26). Furthermore, these high specific activities were achieved without the need for postlabeling purification, as is required with other chelators.…”

Section: Discussionmentioning

confidence: 77%

Positron emission tomography (PET) imaging of neuroblastoma and melanoma with ⁶⁴ Cu-SarAr immunoconjugates

Voss¹,

Smith

DiBartolo

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

135

123

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The advancement of positron emission tomography (PET) depends on the development of new radiotracers that will complement 18 F-FDG. Copper-64 ( 64 Cu) is a promising PET radionuclide, particularly for antibody-targeted imaging, but the high in vivo lability of conventional chelates has limited its clinical application. The objective of this work was to evaluate the novel chelating agent SarAr (1-N-(4-aminobenzyl)-3, 6,10,13,16,19-hexaazabicyclo[6.6.6]-eicosane-1,8-diamine) for use in developing a new class of tumorspecific 64 Cu radiopharmaceuticals for imaging neuroblastoma and melanoma. The anti-GD2 monoclonal antibody (mAb) 14.G2a, and its chimeric derivative, ch14.18, target disialogangliosides that are overexpressed on neuroblastoma and melanoma. Both mAbs were conjugated to SarAr using carbodiimide coupling. Radiolabeling with 64 Cu resulted in >95% of the 64 Cu being chelated by the immunoconjugate. Specific activities of at least 10 Ci/ g (1 Ci ‫؍‬ 37 GBq) were routinely achieved, and no additional purification was required after 64 Cu labeling. Solid-phase radioimmunoassays and intact cell-binding assays confirmed retention of bioactivity. Biodistribution studies in athymic nude mice bearing s.c. neuroblastoma (IMR-6, NMB-7) and melanoma (M21) xenografts showed that 15-20% of the injected dose per gram accumulated in the tumor at 24 hours after injection, and only 5-10% of the injected dose accumulated in the liver, a lower value than typically seen with other chelators. Uptake by a GD2-negative tumor xenograft was significantly lower (<5% injected dose per gram). MicroPET imaging confirmed significant uptake of the tracer in GD-2-positive tumors, with minimal uptake in GD-2-negative tumors and nontarget tissues such as liver. The 64 Cu-SarAr-mAb system described here is potentially applicable to 64 Cu-PET imaging with a broad range of antibody or peptide-based imaging agents.

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Section: Discussionmentioning

confidence: 77%

Positron emission tomography (PET) imaging of neuroblastoma and melanoma with ⁶⁴ Cu-SarAr immunoconjugates

Voss¹,

Smith

DiBartolo

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

135

123

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“…Improved tumor localization has also been reported for other multimeric antibody formats (22,23,27,29,30,36,73) compared with their monomeric counterparts, although the use of different labeling methods, antigens and tumor types essentially precludes the direct and quantitative comparison of the data. However, what is fairly comparable to our finding is the biodistribution study of the 4D5 barnase-barstar miniantibodies (33), which only varies from our studies in the oligomerization modules used.…”

Section: Constructmentioning

confidence: 98%

“…On the other hand, large molecules, such as whole IgGs, show poor extravasation and slower tissue diffusion (20,21). At the same time, they can exhibit prolonged serum half-lives of up to several weeks (19), because they avoid renal excretion and are instead removed by the more delayed hepatic clearance (22). The resulting high serum concentration favors accumulation in the tumor, but also unspecific localization in non-target tissues.…”

mentioning

confidence: 99%

PEGylation and Multimerization of the Anti-p185HER-2 Single Chain Fv Fragment 4D5

Kubetzko

Balic

Waibel

et al. 2006

Journal of Biological Chemistry

112

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A major goal in antibody design for cancer therapy is to tailor the pharmacokinetic properties of the molecule according to specific treatment requirements. Key parameters determining the pharmacokinetics of therapeutic antibodies are target specificity, affinity, stability, and size. Using the p185 HER-2 (HER-2)-specific scFv 4D5 as model system, we analyzed how changes in molecular weight and valency independently affect antigen binding and tumor localization. By employing multimerization and PEGylation, four different antibody formats were generated and compared with the scFv 4D5. First, dimeric and tetrameric miniantibodies were constructed by fusion of self-associating, disulfide-linked peptides to the scFv 4D5. Second, we attached a 20-kDa PEG moiety to the monovalent scFv and to the divalent miniantibody at the respective C terminus. In all formats, serum stability and full binding reactivity of the scFv 4D5 were retained. Functional affinity, however, did change. An avidity increase was achieved by multimerization, whereas PEGylation resulted in a 5-fold decreased affinity. Nevertheless, the PEGylated monomer showed an 8.5-fold, and the PEGylated dimer even a 14.5-fold higher tumor accumulation than the corresponding scFv, 48 h post-injection, because of a significantly longer serum half-life. In comparison, the non-PEGylated bivalent and tetravalent miniantibodies showed only a moderate increase in tumor localization compared with the scFv, which correlated with the degree of multimerization. However, these non-PEGylated formats resulted in higher tumor-to-blood ratios. Both multimerization and PEGylation represent thus useful strategies to tailor the pharmacokinetic properties of therapeutic antibodies and their combined use can additively improve tumor targeting.

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“…We used benzyl-DTPA in a previous study because of the easy and quick labeling at room temperature. Some publications (27,28) suggest that the use of DOTA derivatives requires heating up to 100˚C for efficient indium labeling, and that labeling at lower temperatures is rather inefficient (29). On the other hand, the gallium-DTPA complex is not considered to be sufficiently stable in vivo (30), and the use of PET with 68 Ga-labeled Z HER2:342 for visualization of HER2 would require the use of a macrocyclic chelator.…”

Section: Introductionmentioning

confidence: 99%

Pre-clinical evaluation of [111In]-benzyl-DOTA-ZHER2:342, a potential agent for imaging of HER2 expression in malignant tumors

Orlova¹,

Tran²,

Widström³

et al. 2007

Int J Mol Med

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Abstract. Imaging of expression of human epidermal growth factor receptor type 2 (HER2) in breast carcinomas may help to select patients eligible for trastuzumab therapy. The Affibody molecule Z HER2:342 is a small (7-kDa) non-immunoglobulin affinity protein, which binds to HER2 with a picomolar affinity. Previously, a benzyl-DTPA conjugate of Z HER2:342 was labeled with 111 In and demonstrated good targeting in murine xenografts. We considered that the use of the macrocyclic chelator DOTA could increase the label stability and enhance a choice of nuclides, which could be used as a label for Z HER2:342 .

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Optimizing Radiolabeled Engineered Anti-p185HER2 Antibody Fragments forIn vivoImaging

Cited by 151 publications

References 39 publications

Positron emission tomography (PET) imaging of neuroblastoma and melanoma with ⁶⁴ Cu-SarAr immunoconjugates

Positron emission tomography (PET) imaging of neuroblastoma and melanoma with ⁶⁴ Cu-SarAr immunoconjugates

PEGylation and Multimerization of the Anti-p185HER-2 Single Chain Fv Fragment 4D5

Pre-clinical evaluation of [111In]-benzyl-DOTA-ZHER2:342, a potential agent for imaging of HER2 expression in malignant tumors

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Optimizing Radiolabeled Engineered Anti-p185HER2 Antibody Fragments forIn vivoImaging

Cited by 151 publications

References 39 publications

Positron emission tomography (PET) imaging of neuroblastoma and melanoma with 64 Cu-SarAr immunoconjugates

Positron emission tomography (PET) imaging of neuroblastoma and melanoma with 64 Cu-SarAr immunoconjugates

PEGylation and Multimerization of the Anti-p185HER-2 Single Chain Fv Fragment 4D5

Pre-clinical evaluation of [111In]-benzyl-DOTA-ZHER2:342, a potential agent for imaging of HER2 expression in malignant tumors

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Positron emission tomography (PET) imaging of neuroblastoma and melanoma with ⁶⁴ Cu-SarAr immunoconjugates

Positron emission tomography (PET) imaging of neuroblastoma and melanoma with ⁶⁴ Cu-SarAr immunoconjugates