Eef Dirksen, PhD, Group Lead, NBE Extended Characterization, Byondis
The safety and efficacy of complex biopharmaceuticals, such as antibodies and antibody-drug conjugates, not only depend on their purity, but also on their higher-order structure (HOS). Consequently, the characterization of molecular structures is of utmost importance throughout the pharmaceutical development trajectory. To investigate the thermal stability of an antibody and its corresponding drug conjugate, a series of orthogonal analytical techniques, both 'classical' spectroscopic, as well as mass spectrometry-based, was applied. In this way, not only the performance of the methods applied could be studied, but the data obtained also provided insight into degradation pathways of the molecules investigated. In addition to providing a feel for the sensitivity, accuracy, linearity, and precision of biophysical, i.e. spectroscopic, characterization methods, the addition of mass spectrometric data potentially reveals the actual regions of the molecules impacted, which is essential information in the process of assessing whether a change in structure is not only significant, but also scientifically relevant. The results will be presented that together paint a comprehensive picture of: a) the performance and orthogonality of the methods routinely used for HOS characterization in the pharmaceutical industry; and b) the HOS of both antibodies and antibody-drug conjugates, how it differs amongst them, and how it responds to heat.