title: Unconjugated payload quantification and DAR characterization of antibody-drug conjugates using high-resolution MS.
abstract: OBJECTIVE
  The application of high-resolution MS to antibody-drug conjugate (ADC) drug development may provide insight into their safety and efficacy. Quantification of unconjugated cytotoxic drug (payload) and characterization of drug-to-antibody ratio distribution were determined in plasma using orthogonal acceleration quadrupole-time-of-flight MS.
  
  
  RESULTS
  Unconjugated payload quantification determined by quadrupole-time-of-flight-based MRM(highresolution) and triple quadrupole-based multiple reaction monitoring were comparable and achieved detection limits of 0.030 and 0.015 ng/ml, respectively. As determined by immunocapture and TOF-MS, drug-to-antibody ratio remained unchanged up to 3-weeks postdose for an ADC containing engineered glutamine linkers, but declined from four to three over 2 weeks in an ADC containing engineered cysteine linkers.
  
  
  CONCLUSIONS
  The use of high-resolution MS in ADC drug discovery confirms its utility within the bioanalytical discipline.
authors.affiliation: Pharmacokinetics, Dynamics & Metabolism, Pfizer Inc., Worldwide Research & Development, 445 Eastern Point Road, Groton, CT 06340, USA.
authors.forename: Leanne
authors.initials: L
authors.lastname: Grafmuller
authors.affiliation: Pharmacokinetics, Dynamics & Metabolism, Pfizer Inc., Worldwide Research & Development, 445 Eastern Point Road, Groton, CT 06340, USA.
authors.forename: Cong
authors.initials: C
authors.lastname: Wei
authors.affiliation: Pharmacokinetics, Dynamics & Metabolism, Pfizer Inc., Worldwide Research & Development, 445 Eastern Point Road, Groton, CT 06340, USA.
authors.forename: Ragu
authors.initials: R
authors.lastname: Ramanathan
authors.affiliation: Pharmacokinetics, Dynamics & Metabolism, Pfizer Inc., Worldwide Research & Development, 445 Eastern Point Road, Groton, CT 06340, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Barletta
authors.affiliation: Pharmacokinetics, Dynamics & Metabolism, Pfizer Inc., Worldwide Research & Development, 445 Eastern Point Road, Groton, CT 06340, USA.
authors.forename: Rick
authors.initials: R
authors.lastname: Steenwyk
authors.affiliation: Pharmacokinetics, Dynamics & Metabolism, Pfizer Inc., Worldwide Research & Development, 445 Eastern Point Road, Groton, CT 06340, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Tweed
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D018796:Immunoconjugates / Q000032:analysis / Q000097:blood*; D057230:Limit of Detection; D008252:Macaca fascicularis; D013058:Mass Spectrometry / Q000379:methods*; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000097:blood*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D018796:Immunoconjugates; D004364:Pharmaceutical Preparations
keywords: MRM; MRMHR; drug-to-antibody ratio; high-resolution MS; immunocapture; mass resolving power; unconjugated payload quantification