Viral Clearance

Impact of Process Interruption on Virus Retention of Small-Virus Filters

Manufacturers of biopharmaceuticals using mammalian cell culture must have processes in place to minimize the likelihood of virus contamination of their products. Regulatory agencies provide guidelines for testing strategies and best practices to assure raw-material safety and control of the manufacturing process. Safety assurance relies on an interdependent matrix of managed risks, including characterization and control of raw materials, extensive testing of process intermediates, and demonstration of the virus removal capabilities of purification unit operations Figure 1:  () A dedicated…

Virus Risk Mitigation for Raw Materials

Recombinant protein–based medicinal products and modern cell-based vaccines have a very strong safety history with respect to viral and microbial contamination. However, virus contamination incidents do occur occasionally in manufacturing processes, and they can consume many resources and be expensive to rectify. The root cause of contamination incidents in recent years is most likely the use of contaminated raw materials. These include bovine serum contaminated with reovirus, epizootic hemorrhagic disease virus, Cache valley virus or vesivirus 2117; porcine trypsin contaminated…

Development Strategies for Novel Vaccines for Infectious Diseases

In a vaccine development program, the probability of success at each transition decreases, even though the actual probability of moving from one phase to another can be 50–80% (Figure 1). Many compounds and vaccine candidates are screened out even before they get into preclinical studies. Developers can implement different approaches to reduce product failure risk before a program gets expensive, including Establishing a product development plan (PDP) Identifying and mitigating risk with gap analysis Learning from the mistakes of others…

Industry Adoption of Membrane Adsorbers

Membrane adsorbers (MAs) are the fastest-growing segment in single-use bioprocessing. But their future is not entirely certain. According to BioPlan Associates’ latest survey of biopharmaceutical manufacturing, the MA market has been growing at ~20% annually since 2006 (1). Paradoxically, however, the segment may not be a true “rising star.” Our study also shows that MAs remain among the least-often adopted devices among biomanufacturers. So the question of how and whether MA technology can revolutionize bioprocessing remains open. Market for Membrane…

Simpler and More Efficient Viral Vaccine Manufacturing

Human and veterinary vaccines are divided into five main categories: conjugate, toxoid, subunit, inactivated (killed), and live (attenuated) vaccines (1). The vast majority of currently licensed human and veterinary vaccines are inactivated or live (2, 3). They are produced mostly using adherent cells: primary cells such as chicken embryo fibroblasts (CEF), human diploid cells such as MRC-5, or continuous cell lines such as Vero and MDCK (4). The pioneering legacy inherited by vaccine manufacturing development has led to strategies for…

Biosimilars, Oxidative Damage, and Unwanted Immunogenicity

Concerns about the economic viability of biosimilars center on their high development cost relative to small-molecule generics, along with (and partly because of) the difficulty in demonstrating bioequivalence for these complex molecules. Immunogenicity is a particular area of increasing vigilance at both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) (1, 2). Unwanted immunogenicity is an underlying cause of multiple deleterious effects for all protein-based therapeutics — including loss of efficacy, altered pharmacokinetics, and reduced…

“Transformation By Infection”

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…

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…

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…

Performance of a Salt-Tolerant Membrane Adsorber in Flow-Through Mode

Monoclonal antibodies (MAbs) have become the most prevalent therapeutics in the biopharmaceutical industry. Their downstream purification typically involves protein A chromatography as a capture step followed by one or two additional chromatographic polishing steps. Additional unit operations dedicated specifically for viral clearance (e.g., viral inactivation and filtration) are added to ensure product safety. According to a survey of Amgen processes, after processing through a protein A column, only trace amounts of impurities such as Chinese hamster ovary cell protein (CHOP)…