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Radiolabeled Monoclonal Antibody Against Colony-Stimulating Factor 1 Receptor Specifically Distributes to the Spleen and Liver in Immunocompetent Mice.

ABSTRACT: Macrophages can promote tumor development. Preclinically, targeting macrophages by colony-stimulating factor 1 (CSF1)/CSF1 receptor (CSF1R) monoclonal antibodies (mAbs) enhances conventional therapeutics in combination treatments. The physiological distribution and tumor uptake of CSF1R mAbs are unknown. Therefore, we radiolabeled a murine CSF1R mAb and preclinically visualized its biodistribution by PET. CSF1R mAb was conjugated to N-succinyl-desferrioxamine (N-suc-DFO) and subsequently radiolabeled with zirconium-89 (⁸⁹Zr). Optimal protein antibody dose was first determined in non-tumor-bearing mice to assess physiological distribution. Next, biodistribution of optimal protein dose and ⁸⁹Zr-labeled isotype control was compared with PET and ex vivo biodistribution after 24 and 72 h in mammary tumor-bearing mice. Tissue autoradiography and immunohistochemistry determined radioactivity distribution and tissue macrophage presence, respectively. [⁸⁹Zr]Zr-DFO-N-suc-CSF1R-mAb optimal protein dose was 10 mg/kg, with blood pool levels of 10 ± 2% injected dose per gram tissue (ID/g) and spleen and liver uptake of 17 ± 4 and 11 ± 4%ID/g at 72 h. In contrast, 0.4 mg/kg of [⁸⁹Zr]Zr-DFO-N-suc-CSF1R mAb was eliminated from circulation within 24 h; spleen and liver uptake was 126 ± 44% and 34 ± 7%ID/g, respectively. Tumor-bearing mice showed higher uptake of [⁸⁹Zr]Zr-DFO-N-suc-CSF1R-mAb in the liver, lymphoid tissues, duodenum, and ileum, but not in the tumor than did ⁸⁹Zr-labeled control at 72 h. Immunohistochemistry and autoradiography showed that ⁸⁹Zr was localized to macrophages within lymphoid tissues. Following [⁸⁹Zr]Zr-DFO-N-suc-CSF1R-mAb administration, tumor macrophages were almost absent, whereas isotype-group tumors contained over 500 cells/mm². We hypothesize that intratumoral macrophage depletion by [⁸⁹Zr]Zr-DFO-N-suc-CSF1R-mAb precluded tumor uptake higher than ⁸⁹Zr-labeled control. Translation of molecular imaging of macrophage-targeting therapeutics to humans may support macrophage-directed therapeutic development.

SUBMITTER: Waaijer SJH

PROVIDER: S-EPMC8716378 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ObjectiveMavrilimumab, a human monoclonal antibody, targets granulocyte-macrophage colony-stimulating factor receptor α. We undertook to determine the long-term safety and efficacy of mavrilimumab in rheumatoid arthritis patients in 2 phase IIb studies (1071 and 1107) and in 1 open-label extension study (ClinicalTrials.gov identifier: NCT01712399).MethodsIn study 1071, patients with an inadequate response to disease-modifying antirheumatic drugs (DMARDs) received mavrilimumab (30, 100, or 150 mg) or placebo every other week plus methotrexate. In study 1107, patients with an inadequate response to anti-tumor necrosis factor agents and/or DMARDs received 100 mg mavrilimumab every other week or 50 mg golimumab every 4 weeks plus methotrexate. Patients entering the open-label extension study received 100 mg mavrilimumab every other week plus methotrexate. Long-term safety and efficacy of mavrilimumab were assessed.ResultsA total of 442 patients received mavrilimumab (14 of 245 patients from study 1071, 9 of 70 patients from study 1107, and 52 of 397 patients from the open-label extension study discontinued mavrilimumab treatment throughout the studies). The cumulative safety exposure was 899 patient-years; the median duration of mavrilimumab treatment was 2.5 years (range 0.1-3.3 years). The most common treatment-emergent adverse events (AEs) were nasopharyngitis (n = 69; 7.68 per 100 patient-years) and bronchitis (n = 51; 5.68 per 100 patient-years). At weeks 74 and 104, 3.5% and 6.2% of patients, respectively, demonstrated reduction in forced expiratory volume in 1 second, while 2.9% and 3.4% of patients, respectively, demonstrated reduction in forced vital capacity (>20% reduction from baseline to <80% predicted). Most pulmonary changes were transient and only infrequently associated with AEs. Mavrilimumab at 100 mg every other week demonstrated sustained efficacy; at week 122, 65.0% of patients achieved a Disease Activity Score in 28 joints using the C-reactive protein level (DAS28-CRP) of <3.2, and 40.6% of patients achieved a DAS28-CRP of <2.6.ConclusionLong-term treatment with mavrilimumab maintained response and was well-tolerated with no increased incidence of treatment-emergent AEs. Safety data were comparable with those from both phase IIb qualifying studies.

Project description:ImportanceChimeric and murine anti-GD2 antibodies are active against neuroblastoma, but the development of neutralizing antibodies can compromise efficacy. To decrease immunogenicity, hu3F8, a humanized anti-GD2 antibody, was constructed.ObjectiveTo find the maximum-tolerated dose of hu3F8 with granulocyte-macrophage colony-stimulating factor.Design, setting, and participantsThis phase 1 clinical trial used a 3 + 3 dose-escalation design in a single referral center (Memorial Sloan Kettering Cancer Center, New York, New York). Participants were enrolled from December 24, 2012, through May 3, 2016, with follow-up and analyses through February 28, 2018. Eligibility criteria included older than 1 year and resistant or recurrent neuroblastoma regardless of the number or kinds of prior treatments. All 57 participants met the eligibility criteria, received treatment according to the protocol, and were included in all analyses.InterventionsTreatment cycles were monthly, if human antihuman antibody remained negative. Each cycle comprised hu3F8 infused intravenously for 30 minutes on Monday, Wednesday, and Friday as well as granulocyte-macrophage colony-stimulating factor administered subcutaneously daily from 5 days before infusion through the last day of infusion. After cycle 2, hu3F8 was increased to the highest dose level that had been confirmed as safe.Main outcomes and measuresToxicity, pharmacokinetics, immunogenicity, and disease response.ResultsOf the 57 participants, 34 (60%) were male and 23 (40%) were female (male-to-female ratio of 1.5), with a median (range) age of 6.8 (2.4-31.3) years at enrollment and a median (range) time of 3.1 (0.6-9.0) years since initial chemotherapy. Participants received a median (range) of 4 (1-15) cycles. Treatment was outpatient with reversible neuropathic pain and without unexpected toxic effects. No maximum-tolerated dose was identified. Dose escalation was associated with increased serum levels and proceeded through dosage of 9.6 mg/kg/cycle (approximately 288 mg/m2), which is more than 2.5 times higher than the standard dosage of 75 mg/m2/cycle or 100 mg/m2/cycle of dinutuximab and m3F8. Human antihuman antibody positivity developed in 5 of 57 patients (9%) after cycle 1, including in 1 of 10 patients (10%) not previously treated with anti-GD2 antibody and in 4 of 47 patients (9%) previously exposed to 1 or 2 anti-GD2 antibodies. Antineuroblastoma activity included major responses associated with higher dosing and prolonged progression-free survival despite a history of relapses.Conclusions and relevanceThis phase 1 clinical trial found hu3F8 to be associated with modest toxic effects, low immunogenicity, and substantial antineuroblastoma activity; phase 2 trials are in progress.Trial registrationClinicalTrials.gov identifier: NCT01757626.

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Radiolabeled Monoclonal Antibody Against Colony-Stimulating Factor 1 Receptor Specifically Distributes to the Spleen and Liver in Immunocompetent Mice.

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