Pfizer Applies Integrated Technology for Cell-Line Development of Proprietary Antibodies

The number of approved antibody therapies has been increasing over the last two decades as antibody production technology has advanced. Significant progress has been made in addressing problems associated with early murine-based antibodies, such as allergic reactions, the induction of anti-drug antibodies (ADAs), and poor antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Today, antibodies that are glycoproteins belonging to the immunoglobulin (Ig) superfamily that are secreted by B cells to identify and neutralize foreign organisms or antigens have been developed as therapies for the treatment of numerous diseases, including autoimmune, cardiovascular, and infectious diseases, various cancers, and inflammation.

One of the recent advances in host-cell line technology for the manufacture of recombinant antibodies has been achieved by combining the specially engineered glycosylation POTELLIGENT Technology from BioWa with the GS Gene Expression System from Lonza, which includes the CHOK1SV host-cell line. The result–the POTELLIGENT CHOK1SV cell line–retains the features of a high-producing cell line (robust, high-yielding, scalable) with the bioprocess platform for the CHOK1SV cell line. Antibodies produced by this cell line can exert potent cytotoxic effects even when their target antigen is low, according to Karen Fallen, vice-president of licensing with Lonza Biologics. In addition, they work in whole blood and retain all other desirable features of common antibodies.

Fallen, Shintaro Hasegawa, director of business development for BioWa and Tim Charlebois, vice-president of biotherapeutics technology and innovation strategy at Pfizer Inc., spoke with Cynthia Challener, editor of the Pharmaceutical Sciences, Manufacturing & Marketplace Report, about the GS Gene Expression System, the POTELLIGENT CHOK1SV cell line, and Pfizer’s interest in this system.

Cost-efficient productionPharmaceutical Sciences, Manufacturing and Marketplace Report: What does the GS Gene Expression System involve and how is it differentiated from other gene-expression systems?

Fallen (Lonza): Lonza's GS Gene Expression System is used for the production of therapeutic recombinant proteins and monoclonal antibodies. Glutamine synthetase (GS) is the enzyme responsible for the biosynthesis of glutamine from glutamate and ammonium. This enzymatic reaction is the pathway for glutamine formation in a mammalian cell.

In the absence of glutamine in the growth medium, the GS enzyme plays an essential role in the survival of mammalian cells in culture. Some mammalian cell lines, such as mouse myeloma lines, do not express sufficient GS to survive without added glutamine. With these cell lines, a transfected GS gene can function as a selectable marker by permitting growth in a glutamine-free medium. Other cell lines, such as Chinese hamster ovary (CHO) cell lines, express sufficient GS to survive without exogenous glutamine. In these cases, the GS inhibitor methionine sulfoximine can be used to inhibit endogenous GS activity such that only transfectants with additional GS activity can survive.

Lonza’s GS Expression System is characterized by its speed and ease of use and the fact that its higher yielding cell lines provide cost-efficient production of therapeutic proteins. More than 120 biotechnology and pharmaceutical companies and more than 85 academic laboratories worldwide are using the GS Gene Expression System. It is also used in 13 commercial products and has shown titers up to 10 g/L.

Substantially higher titersPharmaceutical Sciences, Manufacturing and Marketplace Report: What are the differentiating features of the CHOK1SV host cell line for the manufacture of recombinant antibodies?

Fallen (Lonza): Assuming the same antibody is used, substantially higher titers have been shown using the GS-CHO platform with the CHOK1SV host cell line as compared to other CHO platforms.  This improvement is due to increased production of biomass in the bioreactor and the ability of the cells to make more recombinant antibody per cell per time than other systems, which may be attributed to higher mitochondrial mass and a larger endoplasmic reticulum. When combined with Lonza’s GS Expression Vectors, high titers are achieved quickly because, unlike other systems, there is no need to do time-consuming rounds of gene amplification. The system is based on a cell line that works in a proven cGMP bioreactor process for the manufacture of recombinant antibodies, allowing for substantial time savings.

Enhanced ADCCPharmaceutical Sciences, Manufacturing and Marketplace Report:  What are the advantages offered by BioWa's POTELLIGENT Technology for engineered glycoslation? How does it work?

Hasegawa (BioWa): POTELLIGENT technology improves the potency and efficacy of antibody therapeutics by enhancing ADCC via reduction of the amount of fucose in the carbohydrate structure of an antibody using a proprietary fucosyltransferase-knockout CHO cell line as a production cell. The elimination of fucose from the sugar chains on an antibody has, in fact, forever changed the art and science of therapeutics. POTELLIGENT technology has the ability to create 100% fucose-free monoclonal antibodies

Creation of the new host-cell line that combines POTELLIGENT technology with Lonza’s CHOK1SV host-cell line is a significant advancement in gene-expression technology. An α-1, 6-fucosyltransferase (FUT8) double gene knockout variant of CHOK1SV has thus been developed for therapeutic protein expression, and this new host-cell line has been called the POTELLIGENT CHOK1SV Cell Line.

Significant opportunity to advance innovative technologiesPharmaceutical Sciences, Manufacturing and Marketplace Report: Why did Pfizer choose the Lonza/BioWa technology over other options?

Charlebois (Pfizer): Antibodies are an important area of focus for Pfizer's pipeline. Pfizer determined that the Lonza/BioWa technology provides a significant opportunity to continue to advance innovative technologies and design and develop the next-generation of antibody therapies.