Glycoengineering of CHO cells to express recombinant alpha-1 antitrypsin

ABSTRACTAlpha-1 antitrypsin (A1AT) is well-established as a biotherapeutic used for the treatment of alpha-1 antitrypsin deficiency, and shows promise for treating a variety of other diseases. However, A1AT augmentation therapy carries unnecessary risk since it relies upon the weekly transfusion of plasma-derived product, which presents supply chain and contaminant risks. This could be remedied with recombinant A1AT, if it adequately matches or improves upon the plasma-derived product, including its post-translational modifications and functional attributes. However, major hurdles to the development of recombinant A1AT exist, since post- translational modifications, such as glycosylation, impact drug activities and half-life, and it has remained challenging to match glycosylation of recombinant A1AT to the plasma derived isoforms. Here we developed a large panel of diverse GMP-ready glycoengineered CHO (geCHO) cell lines that allowed us to discover a host cell line, geCHO-L, that matches glycosylation of the plasma derived product. Here we will demonstrate our platform not only allows us to identify a CHO clone matches the glycosylation of the approved product, but that we can also match the function and half-life of the approved A1AT to enable the manufacturing of a recombinant A1AT to increase the safety and protect the supply of therapeutic A1AT. We further engineer the recombinant A1AT to obtain a product with improved activity and half-life as a candidate therapeutic for alpha-1 antitrypsin deficiency and other diseases.PROJECT NARRATIVEAlpha-1 antitrypsin (A1AT) deficiencies require replacement therapies derived from blood plasma, but recombinant expression systems have limited the ability to produce safer recombinant A1AT matching the approved drug. Using engineered CHO cells and further protein engineering, we develop effective production of recombinant A1AT matching and exceeding plasma-derived product in quality, efficacy, safety and half-life, yielding a safe and reliable drug source.