A NON-FUCOSYLATED FULLY HUMAN MONOCLONAL ANTIBODY AGAINST IL-3RΑ, KHK2823, SHOWS PROMISING PHARMACOLOGICAL CHARACTERISTICS IN NONCLINICAL STUDIES.
(Abstract release date: 05/19/16)
EHA Library. Tawara T. 06/09/16; 132450; E901
Disclosure(s): Employment of Kyowa Hakko Kirin Co., Ltd.
Dr. Tomonori Tawara
Contributions
Contributions
Abstract
Abstract: E901
Type: Eposter Presentation
Background
Human interleukin-3 receptor alpha (IL-3Rα, CD123) is highly expressed in myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), and is considered to be an attractive target molecule for antibody targeting. We generated KHK2823, a non-fucosylated fully human IgG1 monoclonal antibody against human IL-3Rα, which is armed with ADCC-enhancing POTELLIGENT® technology.
Aims
KHK2823 is currently in Phase 1 study in the United Kingdom to investigate safety and efficacy on AML and MDS patients (NCT02181699). Here, we describe nonclinical profiles and binding characteristics of KHK2823 as a potential therapeutics against AML and other myeloid malignancies.
Methods
Binding profiles of KHK2823 were analyzed by primary cells derived from patients in AML, MDS and B-ALL, and cell lines by using flow cytometry. Epitopes were analyzed by overexpressing IL-3Rα-GM-CSF-R chimeric proteins on 293F cells. Antibody-dependent cellular cytotoxicity was measured by 51Chromium release assay using AML cells as target and peripheral blood mononuclear cells as effector Effects of IL-3 signal were assessed by using IL-3-dependent TF-1 cell line. Nude rats subcutaneously transplanted with MOLM-13 cells and cynomolgus monkeys were used for evaluating pharmacological activities in vivo.
Results
KHK2823 bound to various hematological malignant cells and leukemic stem cells, including AML, MDS and B-ALL. ADCC assay showed high antibody-dependent cellular cytotoxic activity in patients’ malignant cells. A IL-3Rα antibody 7G3 but not KHK2823 inhibited the growth of TF-1, a IL-3-dependent cell line, in the presence of human IL-3 in vitro, suggesting that KHK2823 does not interfere IL-3R to bind IL-3. For further characterization of KHK2823, we screened epitopes of IL-3Rα antibodies. Three dimensional structure of IL-3Rα protein was predicted from the homology modeling of IL-4Rα protein (PDB: 3BPNC). Three structural domains of the extracellular region of IL-3Rα, designated as A-, B- and C- domains from the N-terminal, were predicted and replaced by GM-CSFRα. For further precise epitope analyses, six regions with 7-amino acid in IL-3Rα were substituted to the equivalent regions of GM-CSFRα protein. The analyses showed that KHK2823 recognizes the epitope distant from the critical region for IL-3 signals. The data coincided with that KHK2823, in contrast to 7G3 antibody, did not interfere with the binding of IL-3 to IL-3R. The epitope analysis also unraveled that KHK2823 but not 7G3 could recognize a isoform of IL-3Rα without A-domain predicted in public database. Several in vivo studies were conducted to evaluate the nonclinical profile of KHK2823. The nude rat xenograft model showed pharmacological effects. The pharmacodynamics and the toxicology profiles of KHK2823 were assessed in cynomolgus monkeys administered by i.v. infusion, once weekly for 4 weeks. KHK2823 was found to be well tolerated in the monkey study at a maximum dose of 100 mg/kg. IL-3Rα-positive cells in the peripheral blood were depleted in all the KHK2823-administered monkeys tested.
Conclusion
The anti-IL-3Rα antibody KHK2823 possesses promising pharmacological and toxicological profiles analyzed on the animal studies and in vitro studies, and recognizes the distinctive epitope, which does not interfere with the IL-3 signals and also does not lose recognition to the isoform. These data suggest that KHK2823 might possess safer and more efficacious characteristics to show promising profiles in the future.
Session topic: E-poster
Keyword(s): ADCC, AML, Antibody targeting
Type: Eposter Presentation
Background
Human interleukin-3 receptor alpha (IL-3Rα, CD123) is highly expressed in myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), and is considered to be an attractive target molecule for antibody targeting. We generated KHK2823, a non-fucosylated fully human IgG1 monoclonal antibody against human IL-3Rα, which is armed with ADCC-enhancing POTELLIGENT® technology.
Aims
KHK2823 is currently in Phase 1 study in the United Kingdom to investigate safety and efficacy on AML and MDS patients (NCT02181699). Here, we describe nonclinical profiles and binding characteristics of KHK2823 as a potential therapeutics against AML and other myeloid malignancies.
Methods
Binding profiles of KHK2823 were analyzed by primary cells derived from patients in AML, MDS and B-ALL, and cell lines by using flow cytometry. Epitopes were analyzed by overexpressing IL-3Rα-GM-CSF-R chimeric proteins on 293F cells. Antibody-dependent cellular cytotoxicity was measured by 51Chromium release assay using AML cells as target and peripheral blood mononuclear cells as effector Effects of IL-3 signal were assessed by using IL-3-dependent TF-1 cell line. Nude rats subcutaneously transplanted with MOLM-13 cells and cynomolgus monkeys were used for evaluating pharmacological activities in vivo.
Results
KHK2823 bound to various hematological malignant cells and leukemic stem cells, including AML, MDS and B-ALL. ADCC assay showed high antibody-dependent cellular cytotoxic activity in patients’ malignant cells. A IL-3Rα antibody 7G3 but not KHK2823 inhibited the growth of TF-1, a IL-3-dependent cell line, in the presence of human IL-3 in vitro, suggesting that KHK2823 does not interfere IL-3R to bind IL-3. For further characterization of KHK2823, we screened epitopes of IL-3Rα antibodies. Three dimensional structure of IL-3Rα protein was predicted from the homology modeling of IL-4Rα protein (PDB: 3BPNC). Three structural domains of the extracellular region of IL-3Rα, designated as A-, B- and C- domains from the N-terminal, were predicted and replaced by GM-CSFRα. For further precise epitope analyses, six regions with 7-amino acid in IL-3Rα were substituted to the equivalent regions of GM-CSFRα protein. The analyses showed that KHK2823 recognizes the epitope distant from the critical region for IL-3 signals. The data coincided with that KHK2823, in contrast to 7G3 antibody, did not interfere with the binding of IL-3 to IL-3R. The epitope analysis also unraveled that KHK2823 but not 7G3 could recognize a isoform of IL-3Rα without A-domain predicted in public database. Several in vivo studies were conducted to evaluate the nonclinical profile of KHK2823. The nude rat xenograft model showed pharmacological effects. The pharmacodynamics and the toxicology profiles of KHK2823 were assessed in cynomolgus monkeys administered by i.v. infusion, once weekly for 4 weeks. KHK2823 was found to be well tolerated in the monkey study at a maximum dose of 100 mg/kg. IL-3Rα-positive cells in the peripheral blood were depleted in all the KHK2823-administered monkeys tested.
Conclusion
The anti-IL-3Rα antibody KHK2823 possesses promising pharmacological and toxicological profiles analyzed on the animal studies and in vitro studies, and recognizes the distinctive epitope, which does not interfere with the IL-3 signals and also does not lose recognition to the isoform. These data suggest that KHK2823 might possess safer and more efficacious characteristics to show promising profiles in the future.
Session topic: E-poster
Keyword(s): ADCC, AML, Antibody targeting
Abstract: E901
Type: Eposter Presentation
Background
Human interleukin-3 receptor alpha (IL-3Rα, CD123) is highly expressed in myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), and is considered to be an attractive target molecule for antibody targeting. We generated KHK2823, a non-fucosylated fully human IgG1 monoclonal antibody against human IL-3Rα, which is armed with ADCC-enhancing POTELLIGENT® technology.
Aims
KHK2823 is currently in Phase 1 study in the United Kingdom to investigate safety and efficacy on AML and MDS patients (NCT02181699). Here, we describe nonclinical profiles and binding characteristics of KHK2823 as a potential therapeutics against AML and other myeloid malignancies.
Methods
Binding profiles of KHK2823 were analyzed by primary cells derived from patients in AML, MDS and B-ALL, and cell lines by using flow cytometry. Epitopes were analyzed by overexpressing IL-3Rα-GM-CSF-R chimeric proteins on 293F cells. Antibody-dependent cellular cytotoxicity was measured by 51Chromium release assay using AML cells as target and peripheral blood mononuclear cells as effector Effects of IL-3 signal were assessed by using IL-3-dependent TF-1 cell line. Nude rats subcutaneously transplanted with MOLM-13 cells and cynomolgus monkeys were used for evaluating pharmacological activities in vivo.
Results
KHK2823 bound to various hematological malignant cells and leukemic stem cells, including AML, MDS and B-ALL. ADCC assay showed high antibody-dependent cellular cytotoxic activity in patients’ malignant cells. A IL-3Rα antibody 7G3 but not KHK2823 inhibited the growth of TF-1, a IL-3-dependent cell line, in the presence of human IL-3 in vitro, suggesting that KHK2823 does not interfere IL-3R to bind IL-3. For further characterization of KHK2823, we screened epitopes of IL-3Rα antibodies. Three dimensional structure of IL-3Rα protein was predicted from the homology modeling of IL-4Rα protein (PDB: 3BPNC). Three structural domains of the extracellular region of IL-3Rα, designated as A-, B- and C- domains from the N-terminal, were predicted and replaced by GM-CSFRα. For further precise epitope analyses, six regions with 7-amino acid in IL-3Rα were substituted to the equivalent regions of GM-CSFRα protein. The analyses showed that KHK2823 recognizes the epitope distant from the critical region for IL-3 signals. The data coincided with that KHK2823, in contrast to 7G3 antibody, did not interfere with the binding of IL-3 to IL-3R. The epitope analysis also unraveled that KHK2823 but not 7G3 could recognize a isoform of IL-3Rα without A-domain predicted in public database. Several in vivo studies were conducted to evaluate the nonclinical profile of KHK2823. The nude rat xenograft model showed pharmacological effects. The pharmacodynamics and the toxicology profiles of KHK2823 were assessed in cynomolgus monkeys administered by i.v. infusion, once weekly for 4 weeks. KHK2823 was found to be well tolerated in the monkey study at a maximum dose of 100 mg/kg. IL-3Rα-positive cells in the peripheral blood were depleted in all the KHK2823-administered monkeys tested.
Conclusion
The anti-IL-3Rα antibody KHK2823 possesses promising pharmacological and toxicological profiles analyzed on the animal studies and in vitro studies, and recognizes the distinctive epitope, which does not interfere with the IL-3 signals and also does not lose recognition to the isoform. These data suggest that KHK2823 might possess safer and more efficacious characteristics to show promising profiles in the future.
Session topic: E-poster
Keyword(s): ADCC, AML, Antibody targeting
Type: Eposter Presentation
Background
Human interleukin-3 receptor alpha (IL-3Rα, CD123) is highly expressed in myeloid malignancies, including acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), and is considered to be an attractive target molecule for antibody targeting. We generated KHK2823, a non-fucosylated fully human IgG1 monoclonal antibody against human IL-3Rα, which is armed with ADCC-enhancing POTELLIGENT® technology.
Aims
KHK2823 is currently in Phase 1 study in the United Kingdom to investigate safety and efficacy on AML and MDS patients (NCT02181699). Here, we describe nonclinical profiles and binding characteristics of KHK2823 as a potential therapeutics against AML and other myeloid malignancies.
Methods
Binding profiles of KHK2823 were analyzed by primary cells derived from patients in AML, MDS and B-ALL, and cell lines by using flow cytometry. Epitopes were analyzed by overexpressing IL-3Rα-GM-CSF-R chimeric proteins on 293F cells. Antibody-dependent cellular cytotoxicity was measured by 51Chromium release assay using AML cells as target and peripheral blood mononuclear cells as effector Effects of IL-3 signal were assessed by using IL-3-dependent TF-1 cell line. Nude rats subcutaneously transplanted with MOLM-13 cells and cynomolgus monkeys were used for evaluating pharmacological activities in vivo.
Results
KHK2823 bound to various hematological malignant cells and leukemic stem cells, including AML, MDS and B-ALL. ADCC assay showed high antibody-dependent cellular cytotoxic activity in patients’ malignant cells. A IL-3Rα antibody 7G3 but not KHK2823 inhibited the growth of TF-1, a IL-3-dependent cell line, in the presence of human IL-3 in vitro, suggesting that KHK2823 does not interfere IL-3R to bind IL-3. For further characterization of KHK2823, we screened epitopes of IL-3Rα antibodies. Three dimensional structure of IL-3Rα protein was predicted from the homology modeling of IL-4Rα protein (PDB: 3BPNC). Three structural domains of the extracellular region of IL-3Rα, designated as A-, B- and C- domains from the N-terminal, were predicted and replaced by GM-CSFRα. For further precise epitope analyses, six regions with 7-amino acid in IL-3Rα were substituted to the equivalent regions of GM-CSFRα protein. The analyses showed that KHK2823 recognizes the epitope distant from the critical region for IL-3 signals. The data coincided with that KHK2823, in contrast to 7G3 antibody, did not interfere with the binding of IL-3 to IL-3R. The epitope analysis also unraveled that KHK2823 but not 7G3 could recognize a isoform of IL-3Rα without A-domain predicted in public database. Several in vivo studies were conducted to evaluate the nonclinical profile of KHK2823. The nude rat xenograft model showed pharmacological effects. The pharmacodynamics and the toxicology profiles of KHK2823 were assessed in cynomolgus monkeys administered by i.v. infusion, once weekly for 4 weeks. KHK2823 was found to be well tolerated in the monkey study at a maximum dose of 100 mg/kg. IL-3Rα-positive cells in the peripheral blood were depleted in all the KHK2823-administered monkeys tested.
Conclusion
The anti-IL-3Rα antibody KHK2823 possesses promising pharmacological and toxicological profiles analyzed on the animal studies and in vitro studies, and recognizes the distinctive epitope, which does not interfere with the IL-3 signals and also does not lose recognition to the isoform. These data suggest that KHK2823 might possess safer and more efficacious characteristics to show promising profiles in the future.
Session topic: E-poster
Keyword(s): ADCC, AML, Antibody targeting
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