A January 2007 CMC Strategy Forum on the roles of bioactivity assays in lot release and stability testing was held in Washington, DC (1). Its purpose was to promote an understanding of the design and utility of bioassays throughout product development and to delineate the conditions under which surrogate assays could be used to determine product potency. Topics of discussion included appropriate assay selection at each stage of product development, the potential use of binding assays for potency testing, and…
Analytical
Quantitative Risk Assessment of Bioaccumulation Attributable to Extractables and Leachables in Cellular Immunotherapy Biomanufacturing
Precious patient samples, contamination concerns, and limited product purification options have compelled manufacturers of cellular immunotherapies (iTx) such as chimeric antigen receptor T cells (CAR-T) and T-cell receptor (TCR) technologies toward the disposables industry. Such companies are implementing single-use technologies (SUTs) almost exclusively (1). But despite the dominance of disposable bioprocess platforms and their extraordinary growth in the iTx marketplace, researchers have made limited efforts to understand the perennial and critical bioprocessing risks of leachables and extractables. Here we outline…
Experiences with a Benchtop-Scale Glass Bioreactor: Engineering Data and Cultivation Results
Animal cell lines (the dominant expression systems in biopharmaceutical production processes) are mostly cultivated in stirred bioreactors (1). Although such bioreactors are widely accepted and applicable over a wide range of scales, engineering data for these systems are still lacking. Nevertheless, studies have shown that the correct choice of key parameters (e.g., power input, tip speed, mixing time, and oxygen mass transfer) can influence the growth of animal cell cultures (2). Therefore, detailed characterization is essential. It enables reliable scaling…
Special Report: Turning Discoveries into Products — Developability Assessments and Highly Efficient Process Design
High costs and long timelines for biopharmaceutical development are cause for reflecting on how best to allocate resources from the earliest discovery stage through critical go–no-go junctures. With inputs ranging from science, engineering, and economics, the coined term developability becomes the synthesis of answers to such questions as How well does the target represent a disease state? Does manipulating that state bring about improvement? Does the molecule behave as expected in living systems? What can be done about the emergence of independent safety, toxicology, and/or immunogenicity warning signs? Can the molecule…
The Secret Life of Protein A
Affinity chromatography with protein A has become the foundation for purification of nearly every therapeutic IgG in commercial production. One of the features most responsible for its success has been its compelling simplicity. IgG binds. Contaminants do not. Load, wash, and elute pure IgG. In the real world, however, protein A does not elute pure IgG. It typically contains several hundred to a few thousand parts per million (ppm) contamination by host-cell proteins (HCPs) and other contaminants. Numerous studies demonstrate…
Identification and Quantification of Heat-Shock Protein 70: A Major Host-Cell Protein Contaminant from HEK Host Cells
Recombinant therapeutic proteins are commonly produced by cell lines such as Chinese hamster ovary (CHO), human embryonic kidney (HEK) 293, murine myeloma (NS0), and Escherichia coli bacterial cells. Host-cell proteins (HCPs) are indigenous proteins produced by those expression hosts and considered to be process-related impurities generated from the cell culture process (1). HCPs are potentially harmful and immunogenic to patients, and they can compromise the stability of protein drugs (2–4). For those reasons, HCPs must be consistently removed or reduced…
Comparison of Concentration Measurement Technologies in Bioprocess Solutions
Biopharmaceutical manufacturing involves complex process steps. Exacting production conditions are typically required to maximize the yield, purity, and quality of biological products. In recent years, process analytical technology (PAT) has been increasingly used to monitor key process and performance parameters in real time. That has enabled better control of production conditions. An important parameter required to achieve consistent results in many bioprocessing steps is solute concentration in process fluids. The Critical Need for Concentration Measurement Many biopharmaceutical manufacturing process steps require measuring…
Compatibility Assessment of a Model Monoclonal Antibody Formulation in Glass and Blow–Fill–Seal Plastic Vials
Blow–fill–seal (BFS) technology has been recognized by the industry as an advanced aseptic solution (1–3). Catalent Pharma Solutions has been commercially supplying sterile BFS products to the pharmaceutical industry for decades, primarily in the respiratory and topical ophthalmic markets. Such product formulations range from simple solutions to emulsions with drug substances from classical small molecules to large complex proteins such as biologics. The company also has optimized BFS processes and its Advasept plastic container system for the manufacture of sterile…
Cost-Effective Process Development for Plasmid DNA Manufacture: Evaluation of Single-Use Technologies to Support Escherichia coli Culture
DNA-based gene therapy products have been in clinical development since the 1990s. But over the past 24 months, the overall demand and therapeutic applications for plasmid DNA (pDNA) have rapidly grown and expanded. Currently, pDNA can be used directly as a therapeutic agent (e.g., in gene therapy or generation of vaccine antigens) and indirectly for a range of applications. Those include its use as a critical starting material for transient transfection to produce both viral-vector constructs (e.g., lentivirus or adenoassociated…
Mapping Success for Commercial Cell Therapy Manufacturing
Commercializing cell therapies can be much more challenging than commercializing traditional pharmaceuticals and biologics. Cell-based drug products are significantly more complex than protein or small-molecule drug products. Their mechanisms of action and product attributes are also more complex. Cell therapy product attributes rely heavily on the associated manufacturing processes. Process changes can influence products in ways that may not be discernible until their effects on efficacy effects become evident. Product characterization is critical, but cell therapy products are living organisms…