AIM: 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. CONCLUSION: The use of high-resolution MS in ADC drug discovery confirms its utility within the bioanalytical discipline.
AIM: 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. CONCLUSION: The use of high-resolution MS in ADC drug discovery confirms its utility within the bioanalytical discipline.