Table 3.

mAb quality attributes evaluated during developability assessment.

Attributes	Objectives and objectives
Primary structure and PTMs	Determine the primary structure and PTMs. The intended primary structure needs to be confirmed. PTMs may impact efficacy and safety
FcRn	Rank ordering mAb candidates based on their binding affinities. Higher binding affinity correlates with longer in vivo half-life
Thermal stability	Rank ordering mAb candidates based on their thermal stability. Higher thermal stability correlates with lower tendency of unfolding and aggregation
Solubility	Rank ordering mAb candidates based on their solubility. MAbs with lower solubility pose challenges for process development, especially for high concentration formulation
Viscosity	Rank ordering mAb candidates based on their solubility. MAbs with higher viscosity pose challenges for process development, especially for high concentration formulation
Hydrophobicity	Rank ordering mAb candidates based on their hydrophobicity. MAbs with lower hydrophobicity correlate with lower tendency to aggregation, lower viscosity and higher solubility
Aggregation propensity	Rank ordering mAb candidates based on their aggregation propensity. Aggregates are the common product-related impurity potentially causing immunogenicity
Charge variants	Compare the charge profiles of mAb candidates. If no difference in safety and efficacy, it is desirable to select mAb with lower level of heterogeneity
Free thiols	Avoid mAbs with abnormally high level of free thiols. A high level of free thiols correlates with lower thermal stability, increased tendency to form aggregates and potentially lower antigen biding affinity.
Protein-protein interactions	Rank ordering mAb candidates based on self- or unspecific interactions. Strong self-interaction correlates with higher aggregation propensity, lower solubility and higher viscosity. Strong non-specific interactions may cause shorter half-life.