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Preclinical evaluation of multistep targeting of diasialoganglioside GD2 using an IgG-scFv bispecific antibody with high affinity for GD2 and DOTA metal complex.

ABSTRACT: Bispecific antibodies (BsAb) have proven to be useful targeting vectors for pretargeted radioimmunotherapy (PRIT). We sought to overcome key PRIT limitations such as high renal radiation exposure and immunogenicity (e.g., of streptavidin-antibody fusions), to advance clinical translation of this PRIT strategy for diasialoganglioside GD2-positive [GD2(+)] tumors. For this purpose, an IgG-scFv BsAb was engineered using the sequences for the anti-GD2 humanized monoclonal antibody hu3F8 and C825, a murine scFv antibody with high affinity for the chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) complexed with ?-particle-emitting radiometals such as (177)Lu and (90)Y. A three-step regimen, including hu3F8-C825, a dextran-based clearing agent, and p-aminobenzyl-DOTA radiolabeled with (177)Lu (as (177)Lu-DOTA-Bn; t1/2 = 6.71 days), was optimized in immunocompromised mice carrying subcutaneous human GD2(+) neuroblastoma (NB) xenografts. Absorbed doses for tumor and normal tissues were approximately 85 cGy/MBq and ?3.7 cGy/MBq, respectively, with therapeutic indices (TI) of 142 for blood and 23 for kidney. A therapy study (n = 5/group; tumor volume, 240 ± 160 mm(3)) with three successive PRIT cycles (total (177)Lu: ?33 MBq; tumor dose ?3,400 cGy), revealed complete tumor response in 5 of 5 animals, with no recurrence up to 28 days after treatment. Tumor ablation was confirmed histologically in 4 of 5 mice, and normal organs showed minimal overall toxicities. All nontreated mice required sacrifice within 12 days (>1.0-cm(3) tumor volume). We conclude that this novel anti-GD2 PRIT approach has sufficient TI to successfully ablate subcutaneous GD2(+)-NB in mice while sparing kidney and bone marrow.

SUBMITTER: Cheal SM

PROVIDER: S-EPMC4221074 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Preclinical evaluation of multistep targeting of diasialoganglioside GD2 using an IgG-scFv bispecific antibody with high affinity for GD2 and DOTA metal complex.

Cheal Sarah M SM Xu Hong H Guo Hong-fen HF Zanzonico Pat B PB Larson Steven M SM Cheung Nai-Kong NK

Molecular cancer therapeutics 20140618 7

Bispecific antibodies (BsAb) have proven to be useful targeting vectors for pretargeted radioimmunotherapy (PRIT). We sought to overcome key PRIT limitations such as high renal radiation exposure and immunogenicity (e.g., of streptavidin-antibody fusions), to advance clinical translation of this PRIT strategy for diasialoganglioside GD2-positive [GD2(+)] tumors. For this purpose, an IgG-scFv BsAb was engineered using the sequences for the anti-GD2 humanized monoclonal antibody hu3F8 and C825, a ...[more]

PMID: 24944121

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Project description:BackgroundSince treatment of neuroblastoma (NB) with anti-GD2 monoclonal antibodies provides a survival benefit in children with minimal residual disease and our preclinical study shows that anti-CD3 x anti-GD2 bispecific antibody (GD2Bi) armed T cells (GD2BATs) were highly cytotoxic to GD2+ cell lines, we conducted a phase I/II study in recurrent/refractory patients to establish safety and explore the clinical benefit of GD2BATs.MethodsThe 3+3 dose escalation study (NCT02173093) phase I involved 9 evaluable patients with NB (n=5), osteosarcoma (OST) (n=3), and desmoplastic small round cell tumors (DSRCT) (n=1) with twice weekly infusions of GD2BATs at 40, 80, or 160 x 106 GD2BATs/kg/infusion with daily interleukin 2 (300,000 IU/m2) and twice weekly granulocyte-macrophage colony stimulating factor (250 μg/m2). Phase II portion of the trial was conducted in patients with NB at the dose 3 level of 160 x 106 GD2BATs/kg/infusion but failed to enroll the planned number of patients.ResultsNine of 12 patients in the phase I completed therapy. There were no dose limiting toxicities (DLTs). All patients developed mild and manageable cytokine release syndrome (CRS) with grade 2-3 fevers/chills, headaches, and occasional hypotension up to 72 hours after GD2BAT infusions. GD2-antibody associated pain was not significant in this study. The median OS for patients in the Phase I and limited Phase II was 18.0 and 31.2 months, respectively, whereas the combined OS was 21.1 months. There was a complete bone marrow response with overall stable disease in one of the phase I patients with NB. Ten of 12 phase II patients were evaluable for response: 1 had partial response. Three additional patients were deemed to have clinical benefit with prolonged stable disease. More than 50% of evaluable patients showed augmented immune responses to GD2+ targets after GD2BATs as measured by interferon-gamma (IFN-γ) EliSpots, Th1 cytokines, and/or chemokines.ConclusionsOur study demonstrated safety of up to 160 x 106 cells/kg/infusion of GD2BATs. Combined with evidence for the development of post treatment endogenous immune responses, this data supports further investigation of GD2 BATs in larger Phase II clinical trials.

Dataset Information

Preclinical evaluation of multistep targeting of diasialoganglioside GD2 using an IgG-scFv bispecific antibody with high affinity for GD2 and DOTA metal complex.

Publications

Preclinical evaluation of multistep targeting of diasialoganglioside GD2 using an IgG-scFv bispecific antibody with high affinity for GD2 and DOTA metal complex.

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