Antibody – drug conjugate (ADC) ratio determination

Novel antibody-drug conjugates (ADCs) are developed a lot nowadays. It requires QTOF mass spectrometry to resolve the mass of this protein conjugate, and especially to see how many drugs are coupled per antibody.

We use the following formula to calculate the drug-antibody ratio (DAR):

DAR = 2 X (Σ weighted peak area of heavy chain + Σ weighted peak area of light chain) / 100

References:

  • Siler Panowski, Sunil Bhakta, Helga Raab, Paul Polakis and Jagath R Junutula, Site-specific antibody drug conjugates for cancer therapy. mAbs 2014, 6:1, 34–45
  • Measuring Drug-to-Antibody Ratio (DAR) for Antibody-Drug Conjugates (ADCs) with UHPLC/Q-TOF, Agilent Application Note 2016