Antibody Purification

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Summary The method purifies antibodies or antibody fragments that are active at both Fab sites from a source of antibodies or antibody fragments using a non-chromatographic method that includes the formation and isolation of discrete cyclic aggregates of antibodies. As the technology consists of a non-chromatographic method the invention potentially offers a way to significantly reduce the cost of purification. Tests conducted at Harvard (using IgG antibody) also verifies a high degree of purification. In fact, the technology is the only method available that guarantees the purification of bivalently active antibodies. Advantages: • Chromatographic separation is not needed which increases scalability, the ease of use and at the same time significantly reduces the purification cost. • The method guarantee the purification of bivalent (two fully active Fab binding sites) antibodies because both sites are required to form the cyclic aggregates. Applications Monoclonal antibodies have become increasingly important for biomedical research and clinical therapeutics. The antibodies are used extensively in basic biomedical research, diagnostics and treatment of various illnesses such as infections and cancer. The present methods of purifying antibodies all require chromatography, which is labor intensive, requires expensive materials and is also operationally demanding at large scales. This has led the industry to constantly look for innovative ways to reduce the manufacturing and purification costs of antibodies. Another high priority has been to increase the purity because higher doses require lower contaminant levels. The invention describes a method for purifying bivalent antibodies made at large scale. The commercial application of the technology is primarily to significantly reduce the cost of purifying and generating bivalent antibodies of very high concentration. The market for therapeutic monoclonal antibodies has experienced significant growth in recent years. The global market is projected to increase to US $16.7 billion with a compound annual growth rate of about 20 % from 2002 (Nature reviews V. 3 May 2004). High concentrations of bivalent antibodies do not only facilitate further research on antibodies as such but might also, as a result of the increased affinity, be important in treatment of various illnesses like cancer.