Anti-repulsive guidance molecule C (RGMc) antibodies increases serum iron in rats and cynomolgus monkeys by hepcidin downregulation

• Verfasst von: Böser, Preethne [VerfasserIn]
• Verfasst von: Hafner, Mathias [VerfasserIn]
• Titel: Anti-repulsive guidance molecule C (RGMc) antibodies increases serum iron in rats and cynomolgus monkeys by hepcidin downregulation
• Verf.angabe: Preethne Böser, Dietmar Seemann, Michael J. Liguori, Leimin Fan, Lili Huang, Mathias Hafner, Andreas Popp, and Bernhard K. Mueller
• E-Jahr: 2015
• Jahr: 22 April 2015
• Umfang: 9 S.
• Fussnoten: Gesehen am 18.01.2018
• Titel Quelle: Enthalten in: American Association of Pharmaceutical ScientistsThe AAPS journal
• Ort Quelle: Arlington, Va. : Soc., 2004
• Jahr Quelle: 2015
• Band/Heft Quelle: 17(2015), 4, Seite 930-938
• ISSN Quelle: 1550-7416
• DOI: doi:10.1208/s12248-015-9770-4
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1567330754

Abstract

High levels of hepcidin, the main regulator of systemic iron metabolism, lead to various diseases. Targeting hepcidin and lowering its concentration is a possible form of intervention in order to treat these diseases. High turnover rate of hepcidin is a major drawback of therapies directly targeting this peptide. We developed two monoclonal antibodies ABT-207 and h5F9-AM8 which inhibit hemojuvelin/repulsive guidance molecule C (RGMc) and downregulate hepcidin. We conducted single-application and dose response studies to understand the antibodies’ mechanism and subchronic toxicology studies to exclude safety-related concerns. Investigation was carried out at different biological levels through qPCR, Affymetrix, liquid chromatography coupled with mass spectrometry (LC-MS/MS), histopathology, serum iron, unsaturated iron binding capacity (UIBC), and drug concentration measurements. After a single application of these antibodies, hepcidin expression in liver and its serum protein levels were reduced. Serum iron increased for several weeks. The RGMc antibodies show a pronounced dose response relationship in rats with h5F9-AM8 having an IC50 (UIBC) of approximately 80-fold higher than ABT-207. When hepcidin levels were downregulated, iron deposition in the liver was visible histologically 1 week post application. These antibody-mediated iron depositions were not associated with any adverse toxicologically relevant effect at the doses and time points evaluated. Iron depositions seen after 14 weekly treatments with ABT-207 were reversible in rats and in cynomolgus monkeys. Due to their long-lasting effects and excellent safety profile, both RGMc-blocking antibodies ABT-207 and h5F9-AM8 are favorable clinical candidates for diseases characterized by high serum hepcidin levels like anemia of chronic disease.