Contributions
Abstract: EP840
Type: E-Poster Presentation
Session title: Iron metabolism, deficiency and overload
Background
Hepcidin is a key endocrine mediator of iron metabolism that regulates dietary iron uptake and iron levels in blood. Hepcidin is expressed in part in response to signaling through the ALK2 receptor, a type I TGF-β receptor activated by complexing with the ligand BMP6 and the co-receptor hemojuvelin. Hepcidin signals to peripheral tissues and binds to and activates the degradation of the iron exporter, ferroportin. Thus, when hepcidin is high, iron is sequestered within cells and functions to increase tissue iron levels and reduce serum iron availability. Elevated hepcidin is associated with states of iron deficiency anemia such as iron-refractory iron deficiency anemia (IRIDA) and anemia of inflammation. We have previously reported that inhibition of ALK2 with a novel specific monoclonal antibody (KTI-mAb2.0) can suppress hepcidin and increase serum iron in healthy mice and in mice with iron deficiency anemia. KTI-mAb2.0 and KTI-mAb2.1 are two fully human antibodies that have been observed to specifically bind to and neutralize ALK2.
Aims
To determine the pharmacokinetic and pharmacodynamic properties of KTI-mAb2.0 and KTI-mAb2.1 in cynomolgus monkeys, a preclinical model highly representative of human biology.
Methods
Ad libitum-fed, female cynomolgus monkeys ranging in age from 2-4 years old were randomly assigned to receive KTI-mAb2.0 or KTI-mAb2.1 administered as a single subcutaneous dose (3mg/kg). Serum was sampled intermittently over a 56-day period and assessed for drug exposure, hepcidin and iron content. At a subset of timepoints, blood was sampled and assessed for reticulocyte and red blood cell hemoglobin content (RET-Hgb and RBC-Hgb, respectively). Hematological data was combined across both therapeutic groups.
Results
KTI-mAb2.0 and KTI-mAb2.1 were rapidly absorbed and reached Cmax within 48 hr and had half-lives of 33.9 hr and 49.1 hr, respectively. Robust and profound effects on hepcidin and serum iron were observed with both antibodies. Within 6hr of administration, KTI-mAb2.0 or KTI-mAb2.1 reduced serum hepcidin by 55.6% and 50.3%, respectively. The peak effect was observed beginning after 48 hr with reductions of 77.2% in the KTI-mAb2.0 treated group, and 77.8% in the KTI-mAb2.1 group and continued through day 10 before returning to baseline by day 14. The reduction in hepcidin corresponded to increased circulating iron with maximal changes occurring within 24hr of antibody administration. A 63.3% and 54.2% increase in iron was achieved with KTI-mAb2.0 and KTI-mAb2.1, respectively. Similar to hepcidin, the response was sustained through 10 days, returning to baseline by day 14. RET-Hgb increased by 4.9% at 3 days post dose and remained elevated for 10 days. Increases in RBC-Hgb content were observed initially 35 days post dose and remained 4.2% higher at study termination at day 56.
Conclusion
Our data demonstrate that both KTI-mAb2.0 and KTI-mAb2.1 reduced serum hepcidin and increased circulating iron in non-human primates, a preclinical model highly representative of human biology. Furthermore, the mobilized iron resulted in increased RET-Hgb and RBC-Hgb. These results provide evidence that treatment with KTI-mAb2.0 and KTI-mAb2.1 may be a viable approach to treating anemias that arise from elevated hepcidin, such as IRIDA and anemia of inflammation.
Keyword(s): Hepcidin, Iron
Abstract: EP840
Type: E-Poster Presentation
Session title: Iron metabolism, deficiency and overload
Background
Hepcidin is a key endocrine mediator of iron metabolism that regulates dietary iron uptake and iron levels in blood. Hepcidin is expressed in part in response to signaling through the ALK2 receptor, a type I TGF-β receptor activated by complexing with the ligand BMP6 and the co-receptor hemojuvelin. Hepcidin signals to peripheral tissues and binds to and activates the degradation of the iron exporter, ferroportin. Thus, when hepcidin is high, iron is sequestered within cells and functions to increase tissue iron levels and reduce serum iron availability. Elevated hepcidin is associated with states of iron deficiency anemia such as iron-refractory iron deficiency anemia (IRIDA) and anemia of inflammation. We have previously reported that inhibition of ALK2 with a novel specific monoclonal antibody (KTI-mAb2.0) can suppress hepcidin and increase serum iron in healthy mice and in mice with iron deficiency anemia. KTI-mAb2.0 and KTI-mAb2.1 are two fully human antibodies that have been observed to specifically bind to and neutralize ALK2.
Aims
To determine the pharmacokinetic and pharmacodynamic properties of KTI-mAb2.0 and KTI-mAb2.1 in cynomolgus monkeys, a preclinical model highly representative of human biology.
Methods
Ad libitum-fed, female cynomolgus monkeys ranging in age from 2-4 years old were randomly assigned to receive KTI-mAb2.0 or KTI-mAb2.1 administered as a single subcutaneous dose (3mg/kg). Serum was sampled intermittently over a 56-day period and assessed for drug exposure, hepcidin and iron content. At a subset of timepoints, blood was sampled and assessed for reticulocyte and red blood cell hemoglobin content (RET-Hgb and RBC-Hgb, respectively). Hematological data was combined across both therapeutic groups.
Results
KTI-mAb2.0 and KTI-mAb2.1 were rapidly absorbed and reached Cmax within 48 hr and had half-lives of 33.9 hr and 49.1 hr, respectively. Robust and profound effects on hepcidin and serum iron were observed with both antibodies. Within 6hr of administration, KTI-mAb2.0 or KTI-mAb2.1 reduced serum hepcidin by 55.6% and 50.3%, respectively. The peak effect was observed beginning after 48 hr with reductions of 77.2% in the KTI-mAb2.0 treated group, and 77.8% in the KTI-mAb2.1 group and continued through day 10 before returning to baseline by day 14. The reduction in hepcidin corresponded to increased circulating iron with maximal changes occurring within 24hr of antibody administration. A 63.3% and 54.2% increase in iron was achieved with KTI-mAb2.0 and KTI-mAb2.1, respectively. Similar to hepcidin, the response was sustained through 10 days, returning to baseline by day 14. RET-Hgb increased by 4.9% at 3 days post dose and remained elevated for 10 days. Increases in RBC-Hgb content were observed initially 35 days post dose and remained 4.2% higher at study termination at day 56.
Conclusion
Our data demonstrate that both KTI-mAb2.0 and KTI-mAb2.1 reduced serum hepcidin and increased circulating iron in non-human primates, a preclinical model highly representative of human biology. Furthermore, the mobilized iron resulted in increased RET-Hgb and RBC-Hgb. These results provide evidence that treatment with KTI-mAb2.0 and KTI-mAb2.1 may be a viable approach to treating anemias that arise from elevated hepcidin, such as IRIDA and anemia of inflammation.
Keyword(s): Hepcidin, Iron