By Payal Khandelwal, PhD
Comprehensive Solutions for Aggregate Issues
The success of any biologic drug, for example, monoclonal antibodies (mAbs), recombinant proteins, or biosimilars, depends greatly on downstream purification. Among the challenges process scientists often face during this process is the formation and/or removal of aggregates of monomers. Although the aggregates are physically and chemically similar to monomers, their presence in the final purified product, especially a therapeutic mAb, is undesirable for many reasons. First, aggregates also often contain other impurities, like host cell proteins (HCPs) and DNA, leading to the formation of complex contaminants. This can increase the risk of anaphylaxis or immunogenic response in patients. Second, aggregates of therapeutic mAbs often demonstrate different bioactivity/ potency profiles, storage stability, and pharmacodynamic/pharmacokinetic properties than their monomeric counterparts (Lang et al. 2011). For these reasons, aggregate removal has become a major focus of downstream processing.