Purification of monoclonal antibody using cation exchange z2 laterally-fed membrane chromatography – A potential alternative to protein A affinity chromatography

Protein A affinity chromatography, which is the standard method for purifying monoclonal antibodies (mAbs) is expensive and involves elution at acidic pH, which could degrade the mAb. Moreover, it cannot be used to fractionate charge variants or to remove mAb aggregates. In this study, we examine the purification of Trastuzumab by cation-exchange z2 laterally-fed membrane chromatography (or z2LFMC). It has been shown that z2LFMC is suitable for carrying out high-speed, high-resolution protein purification. The results discussed in this paper demonstrate that the purity of Trastuzumab obtained by the z2LFMC process was comparable to that obtained by protein A chromatography (i.e., >95% with both methods), while the recovery was significantly greater with z2LFMC (90.4% as opposed to 81.7%). Also, the z2LFMC process was faster, did not require acidic pH conditions for elution, and the mAb was eluted in 2.24 bed volumes as opposed to 2.74 bed volumes with protein A chromatography. The mAb productivity obtained with the z2LFMC process was more than 3 times higher than that with the column-based purification process. The z2LFMC device is significantly cheaper than its equivalent protein A affinity column, and earlier studies have shown it to be suitable for separating mAb charge variants and aggregates. Therefore, the z2LFMC process could be evaluated as a cheaper and more efficient alternative to protein A affinity chromatography.