title: Nonclinical Pharmacokinetics, Disposition, and Drug-Drug Interaction Potential of a Novel d-Amino Acid Peptide Agonist of the Calcium-Sensing Receptor AMG 416 (Etelcalcetide).
abstract: AMG 416 (etelcalcetide) is a novel synthetic peptide agonist of the calcium-sensing receptor composed of a linear chain of seven d-amino acids (referred to as the d-amino acid backbone) with a d-cysteine linked to an l-cysteine via a disulfide bond. AMG 416 contains four basic d-arginine residues and is a +4 charged peptide at physiologic pH with a mol. wt. of 1048.3 Da. The pharmacokinetics (PK), disposition, and potential of AMG 416 to cause drug-drug interaction were investigated in nonclinical studies with two single (14)C-labels placed either at a potentially metabolically labile acetyl position or on the d-alanine next to d-cysteine in the interior of the d-amino acid backbone. After i.v. dosing, the PK and disposition of AMG 416 were similar in male and female rats. Radioactivity rapidly distributed to most tissues in rats with intact kidneys, and renal elimination was the predominant clearance pathway. No strain-dependent differences were observed. In bilaterally nephrectomized rats, minimal radioactivity (1.2%) was excreted via nonrenal pathways. Biotransformation occurred primarily via disulfide exchange with endogenous thiol-containing molecules in whole blood rather than metabolism by enzymes, such as proteases or cytochrome P450s; the d-amino acid backbone remained unaltered. A substantial proportion of the plasma radioactivity was covalently conjugated to albumin. AMG 416 presents a low risk for P450 or transporter-mediated drug-drug interactions because it showed no interactions in vitro. These studies demonstrated a (14)C label on either the acetyl or the d-alanine in the d-amino acid backbone would be appropriate for clinical studies.
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.) rajus@amgen.com.
authors.forename: Raju
authors.initials: R
authors.lastname: Subramanian
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Savannah J
authors.initials: SJ
authors.lastname: Kerr
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Joel D
authors.initials: JD
authors.lastname: Esmay
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Steven W
authors.initials: SW
authors.lastname: Louie
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Katheryne Z
authors.initials: KZ
authors.lastname: Edson
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Sarah
authors.initials: S
authors.lastname: Walter
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Michael
authors.initials: M
authors.lastname: Fitzsimmons
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Mylo
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Marcus
authors.initials: M
authors.lastname: Soto
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Roger
authors.initials: R
authors.lastname: Pham
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Sarah F
authors.initials: SF
authors.lastname: Wilson
authors.affiliation: Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California (R.S., X.Z, S.J.K., J.D.E., S.W.L., K.Z.E, S.W., M.W., M.S., R.P., S.F.W, G.L.S); and Covance Laboratories, Madison, Wisconsin (M.F.).
authors.forename: Gary L
authors.initials: GL
authors.lastname: Skiles
mesh_terms: D061605:Administration, Intravenous; D000818:Animals; D001711:Biotransformation; D057966:Calcimimetic Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000633:toxicity; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D015394:Molecular Structure; D010455:Peptides / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics* / Q000633:toxicity; D011485:Protein Binding; D011914:Rats, Inbred BN; D044169:Receptors, Calcium-Sensing / Q000819:agonists* / Q000737:chemistry / Q000378:metabolism; D065667:Renal Elimination; D018570:Risk Assessment; D012709:Serum Albumin / Q000378:metabolism; D013329:Structure-Activity Relationship; D014018:Tissue Distribution; D014162:Transfection
chemical_list: D057966:Calcimimetic Agents; D026901:Membrane Transport Proteins; D010455:Peptides; D044169:Receptors, Calcium-Sensing; D012709:Serum Albumin; C583569:etelcalcetide hydrochloride; D003577:Cytochrome P-450 Enzyme System