November 22, 2013

Evolution of the Monoclonal Antibody Purification Platform

The authors discuss the evolution of the purification platform for manufacturing of mAb therapeutics.

Monoclonal antibodies (mAb) increasingly form the majority share of the product pipeline, as well as revenue, of major biopharmaceutical companies (1). What is unique about mAbs from a processing perspective is the applicability of developing a common process and analytical platform (2, 3). Some process development related attributes with respect to production of mAbs include:
• Significant increase in titer levels over the past decade (from 0.5 mg/mL to 5-10 mg/mL)
• High product requirement (as much as tons) due to higher doses of typical mAb products
• Larger manufacturing facilities (from 1-5KL to 10-20KL)

The efficiency of the platform process, as it enables process development (e.g., time taken, resources required), analytical development, and manufacturing, is quite significant, such as:
• Process development timelines can be significantly reduced
• Analytical development timelines can also be significantly reduced (use of standardized assays and platforms)
• Ease of scale-up and technology transfer due to similarity in the processes
• Reduced capital expense when bringing in a new product to the manufacturing facility.

It has been more than a decade since the industry started establishing the process platform. This 31st article in the “Elements of Biopharmaceutical Production” series focuses on evolution of the purification platform for manufacturing of mAb therapeutics.

Traditional Monoclonal Antibody Platform
Figure 1 illustrates the traditional mAb platform that is commonly used (2,3). Typical steps include:
• Protein A chromatography for capture of the product and removal of host cell-related impurities (host cell proteins and DNA). Though extremely efficient and effective, the step primarily suffers from the significantly high cost of Protein A resins in comparison to other popular modes of chromatography (such as ion exchange). The low pH elution is another potential issue as it has been linked to product aggregation.
• Low pH viral inactivation as an orthogonal step for clearance of retroviruses. This step also suffers from the possibility of product aggregation at low pH.
• Cation exchange (CEX) chromatography is also quite commonly used. The primary objective of this step is to remove host-cell proteins, DNA, charged variants, and aggregates. Bind and elute mode is used to facilitate removal of product-related impurities.
• A second chromatography step is often used (either prior to the CEX step or following it) with the purpose of further removal of host-cell related impurities (e.g., host-cell proteins and DNA) or product-related impurities. Anion exchange (AEX) chromatography in a flow-through mode is the method of choice for removal of host-cell impurities. Hydrophobic-interaction chromatography (HIC) in bind and elute mode has been used to achieve further clearance of product-related impurities.
• Virus filtration step is the method of choice as another orthogonal step for virus removal.


Tags: multimodal, Capto, Mabselect sure, Protein A, polishing, purification, monoclonal antibody, Mab