title: The potency of erythropoietin-mimic antibodies correlates inversely with affinity.
abstract: Preclinical animal studies have shown that Ab12.6, an agonistic human Ab targeting the erythropoietin receptor (EPOR), exhibits several potential dosing and safety features that make it an attractive clinical candidate for the treatment of anemia. Ab12.6 was derived by yeast display affinity maturation of parental Ab12, a strategy initially intended to improve off-rate and affinity for EPOR, thereby enhancing erythropoietic activity. Analysis of full-length IgGs derived from yeast clones identified sequences within Ab12 CDRH2 that independently influenced both affinity and potency. The Ab12.6 derivative displayed improved in vitro potency and in vivo efficacy, although its binding affinity to the EPOR was lower than that of the parent Ab12. Additional Ab12 derivatives also exhibited an inverse correlation between affinity and potency. These results suggest that for this class of agonistic Abs, faster off-rates may permit continuous receptor stimulation and more efficient erythropoiesis.
authors.affiliation: Global Pharmaceutical Research and Development, Abbott Bioresearch Center, Worcester, MA 01605, USA.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Lacy
authors.forename: Peter J
authors.initials: PJ
authors.lastname: DeVries
authors.forename: Nancy
authors.initials: N
authors.lastname: Xie
authors.forename: Emma
authors.initials: E
authors.lastname: Fung
authors.forename: Richard R
authors.initials: RR
authors.lastname: Lesniewski
authors.forename: Edward B
authors.initials: EB
authors.lastname: Reilly
mesh_terms: D000906:Antibodies / Q000276:immunology* / Q000378:metabolism; D000915:Antibody Affinity; D004920:Erythropoiesis; D004921:Erythropoietin / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D018716:Molecular Mimicry; D017467:Receptors, Erythropoietin / Q000819:agonists* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism
chemical_list: D000906:Antibodies; D017467:Receptors, Erythropoietin; D011993:Recombinant Fusion Proteins; D004921:Erythropoietin