A bispecific antibody can bind two different antigens. Immunoglobulin G (IgG) type antibodies have two binding sites with different variable regions. An IgG variable region is made up of a variable light-chain sequence (VL) and a variable heavy-chain sequence (VH). The light chains (LCs) of common LC antibodies are identical for both variable regions, leaving the heavy chain (HC) for generating different specificities. Thus, recombinant host cells for production of common LC bispecific antibodies carry genes for both HCs, with…
Downstream Processing
Artifacts of Virus Filter Validation
Virus filters are used in biomanufacturing to ensure the safety of biopharmaceutical drug products. As part of filter implementation, manufacturers are required to validate that the filtration process can indeed remove virus. Validations are typically performed at contract testing organizations (CTOs) that are “equipped for virological work and performed by staff with virological expertise in conjunction with production personnel involved in designing and preparing a scaled-down version of the purification process” (1). Virus removal capability of a filtration process is…
“Transformation By Infectionâ€
Every bioprocess begins with an expression system, and every expression system begins with DNA transfection. Derived from transformation and infection, the word paradoxically has come to be applied mainly to nonviral methods of genetically engineering cells; viral-vector–mediated DNA transfer is often called transduction. There are chemical, particulate, physical/mechanical, and viral means of getting new genetic material into a cell, and that DNA may take a number of different forms. Even the cloning method (pictured right) using a microscopic needle to…
Broadening the Baseline
When the editors of BPI asked us at BPSA to put together a content-rich article for the single-use supplement, we were happy to do so. Our challenge was how to bring in multiple viewpoints about the growing business of single-use that would be a “quick read” for the BPI audience. The answer: an expert colloquy (a “conversational exchange or topical dialogue”). Represented here are several of the most qualified industry spokespersons in single-use — all are members of BPSA and…
Implementing Disposable Sampling Devices for Fully Autoclaved Equipment
Sampling is used extensively to monitor both behavior and quality throughout biopharmaceutical processesing (1, 2). Methods must deliver representative samples and — more important — not compromise the integrity of a given unit operation or the process of which it is part. When microorganisms, animal cells, viruses, or nonfilterable materials are involved, sampling methods must not introduce contamination (see the “Regulatory Requirements” box). For successful sampling, three methods have been used routinely over the years: steam-in-place (SIP) valves; aseptic tube…
Supporting Continuous Processing with Advanced Single-Use Technologies
It has been 10 years since the US Food and Drug Administration (FDA) articulated — in its guidance for process analytical technology (PAT) — the goal of “facilitating continuous processing to improve efficiency and manage variability” (1). Since that time, regulators and industry have worked toward applying continuous processing (CP) to all facets of pharmaceutical manufacturing, including bioproduction (2, 3). Last year, the European Medicines Agency (EMA) referred to CP in its draft Guideline on Process Validation, and the FDA…
Downstream Technology Landscape for Large-Scale Therapeutic Cell Processing
The cell therapy industry (CTI) is poised to grow rapidly over the next decade, treating millions of patients and generating annual revenues into the tens of billions of US dollars (1, 2). To meet that high-growth demand, large CTI system manufacturers (e.g., Corning, Nunc/Nalgene, and GE Healthcare) and leading contract manufacturing organizations (CMOs, such as Lonza) are developing and integrating new upstream technology platforms such as gas-permeable membranes and microcarrier-based bioreactors to significantly increase therapeutic cell culture productivity. As those…
Advocating an Evolution
In a 2006 report, the US Department of Health and Human Services hailed regenerative medicine as “the vanguard of 21st century healthcare” and “the first truly interdisciplinary field that utilizes and brings together nearly every field in science” (1). To fuel support for regulatory, legislative, and reimbursement initiatives in this new therapeutic class, a small group of scientists, life science business executives, patient advocates, and other experts formed the Alliance for Regenerative Medicine (ARM, http://alliancerm.org). Starting with 17 charter members,…
Stress-Induced Antibody Aggregates
Biomanufacturing of monoclonal antibodies (MAb) involves a number of unit operations, including cell culture in a bioreactor followed by chromatography and filtration. Purification is intended to remove impurities, such as protein aggregates, but some such operations may actually generate protein aggregation (1). Table 1 summarizes potential sources of aggregate formation during biomanufacturing processes. Aggregates are multimers of native, partially denatured, or fully denatured proteins. Their presence in biological formulations can trigger detrimental immunogenic responses upon administration (2). Moreover, aggregates can…
Single-Use Technologies in Cell Therapy
Single-use technologies (SUTs) are tools that can be used in producing cell therapies and personalized medicines. Such products must meet specific requirements because of the way they are used. To meet those criteria, the cell therapy industry simply has no alternatives to single-use systems. SUT applications are rapidly changing. Traditional uses for single-use systems in cell therapy include processing in clinical settings (e.g., blood bags, transfer sets) and research and development (e.g., T-flasks, pipettes). Although such applications continue, the commercialization…