title: Pharmacokinetics, Biotransformation, and Excretion of [14C]Etelcalcetide (AMG 416) Following a Single Microtracer Intravenous Dose in Patients with Chronic Kidney Disease on Hemodialysis.
abstract: Etelcalcetide (AMG 416) is a novel synthetic peptide calcium-sensing receptor activator in clinical development as an intravenous calcimimetic for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease (CKD) on hemodialysis. Etelcalcetide is composed of seven D-aminoacids with an L-cysteine linked to a D-cysteine by a disulfide bond. A single intravenous dose of [14C]etelcalcetide (10 mg; 26.3 kBq; 710 nCi) was administered to patients with CKD on hemodialysis to elucidate the pharmacokinetics, biotransformation, and excretion of etelcalcetide in this setting. Blood, dialysate, urine, and feces were collected to characterize the pharmacokinetics, biotransformation product profiles, mass balance, and formation of anti-etelcalcetide antibodies. Accelerator mass spectrometry was necessary to measure the microtracer quantities of C-14 excreted in the large volumes of dialysate and other biomatrices. An estimated 67 % of the [14C]etelcalcetide dose was recovered in dialysate, urine, and feces 176 days after dose administration. Etelcalcetide was primarily cleared by hemodialysis, with approximately 60 % of the administered dose eliminated in dialysate. Minor excretion was observed in urine and feces. Biotransformation resulted from disulfide exchange with endogenous thiols, and preserved the etelcalcetide D-amino acid backbone. Drug-related radioactivity circulated primarily as serum albumin peptide conjugate (SAPC). Following removal of plasma etelcalcetide by hemodialysis, re-equilibration occurred between SAPC and L-cysteine present in blood to partially restore the etelcalcetide plasma concentrations between dialysis sessions. No unanticipated safety signals or anti-etelcalcetide or anti-SAPC antibodies were detected.
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA. raju.subramanian@gmail.com.|Gilead Sciences, Foster City, CA, USA. raju.subramanian@gmail.com.
authors: Raju
authors: R
authors: Subramanian
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: Xiaochun
authors: X
authors: Zhu
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: M Benjamin
authors: MB
authors: Hock
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: Bethlyn J
authors: BJ
authors: Sloey
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: Benjamin
authors: B
authors: Wu
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: Sarah F
authors: SF
authors: Wilson
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: Ogo
authors: O
authors: Egbuna
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: J Greg
authors: JG
authors: Slatter
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA.
authors: Jim
authors: J
authors: Xiao
authors: Amgen Inc., One Amgen Center Drive, Thousand Oaks, CA, 91320, USA. gskiles@amgen.com.
authors: Gary L
authors: GL
authors: Skiles
mesh_terms: D061605:Administration, Intravenous; D000328:Adult; D000368:Aged; D001711:Biotransformation / Q000187:drug effects / Q000502:physiology; D002250:Carbon Radioisotopes / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D015314:Dialysis Solutions / Q000378:metabolism*; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D011849:Radioactive Tracers; D006435:Renal Dialysis / Q000639:trends; D065667:Renal Elimination / Q000187:drug effects / Q000502:physiology*; D051436:Renal Insufficiency, Chronic / Q000378:metabolism* / Q000628:therapy
chemical_list: D002250:Carbon Radioisotopes; D015314:Dialysis Solutions; D010455:Peptides; D011849:Radioactive Tracers; C583569:etelcalcetide hydrochloride